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Surveillance plays a crucial role in controlling the spread of AMR . Identifying resistance patterns and mechanisms helps create timely and efficient AMR control strategies. The problem of AMR spread can be addressed by implementing and promoting the One Health approach . WHO’s first global report on AMR surveillance showed that monitoring the AMR is very helpful for orienting treatment choices, understanding the evolving patterns of AMR, and determining priority areas for interventions. The need for more surveillance in many countries and areas undermines the possibility of therapeutic interventions . However, additional measures are necessary to address the AMR problem more effectively. Since stakeholders, industries, and consumers are involved in the farm to fork process, all these sides should work hand in hand with each other to solve AMR problems. Therefore, public awareness and education is very important measure to help tackle the issue. Another measure is stewardship of farm workers. Therefore, training and education of farm workers is a very important measure that should continue to be implemented across the livestock industry. Developing new antimicrobials and using existing antimicrobials in full capacity are other strategies to combat antimicrobial resistance that prevent infections and improve diagnostics . Lastly, strengthening industrial and academic research on AMR and occupational exposure to AMR is very crucial. The research is necessary for several reasons.First, cannabis growing equipment research on AMR is the bedrock for the formulation of new drugs and improvement of existing drugs.

For example, understanding mechanisms of resistance and how they develop is crucial for designing a new drug. Second, robust research is fundamental in improving surveillance systems and diagnostics because advanced surveillance methods and accurate diagnostics help to provide appropriate treatments and infection control actions. Third, collaborative actions of industrial and academic researchers can bring the knowledge and resources together to fight AMR, as academic researchers might have expertise and novel ideas that can be implemented by industrial partners who have resources for drug development. Finally, research on AMR is essential in raising public awareness and can cause governments to improve their policies on fighting AMR . In conclusion, controlling, reducing, and optimizing antimicrobial usage are the main methods to fight AMR. Controlling and reducing the spread of AMR and optimizing antimicrobial consumption require collective, coordinated actions at local, regional, and international levels. Also, strengthening research is crucial in order to develop new drugs or improve existing drugs, improve surveillance systems and diagnostics, raise public awareness, and affect government policies.The literature review examined the existing literature on ways of transmission of antimicrobial resistance bacteria in the food chain. The literature review revealed that occupational exposure of farm workers to antimicrobial resistance has been neglected due to a variety of factors and need for more research to improve the awareness of stakeholders, farm owners and farm workers. With the growing concern of dissemination of AMR globally, occupational exposure needs serious attention to assist in combat with AMR. Additionally, the literature review critically assessed the existing body of literature on antimicrobial resistance patterns of Salmonella inretail meat as this type of pathogen becomes very dangerous if acquired multi-resistance to antimicrobials.

Despite being the most populous state in the U.S. and the leading agricultural producer in agriculture, antimicrobial resistance patterns in retail meat in California have yet to be adequately characterized. With the advent of the development of WGS, an opportunity has arisen to confirm phenotypic resistance detected by AST genotypically using WGS. This literature review also discussed the pros and cons of using WGS for tracking and monitoring AMR. In the end, AMR mitigation strategies and surveillance’s vital role were discussed.Antimicrobial resistance occurs when microorganisms survive by developing resistant mechanisms after exposure to antibiotics or without exposure to antibiotics by evolution . Continuous use of antimicrobial drugs for therapeutic purposes in food animal production and human medicine selects for antimicrobial-resistant bacteria . As a result, infections caused by ARB are increasing, which are difficult and expensive to treat . Moreover, some infections due to AMR cannot be treated with existing drugs, leading to increased morbidity and mortality . Therefore, antimicrobial resistance is a serious public health issue . Approximately 2.8 million clinical cases of individuals infected by ARB result in 35,000 deaths annually in the U.S. . In addition, the estimated economic burden of AMR is $21,832 per case, which results in total costs of $20 billion to the U.S. healthcare system . The poultry industry is a substantial portion of food animal production where antibiotics have historically been widely used to treat sick birds and prevent disease . However, intensive poultry production in confinement in large-scale operations with flocks can increase the spread of ARB among the animal population and their surroundings, potentially posing health risks to workers . A significant portion of zoonotic diseases and infectious disease outbreaks that make humans sick are caused by pathogens . Antimicrobial-resistant genes can be transferred through mobile genetic elements between zoonotic pathogens and commensal bacteria .

Commensal Escherichia coli is common in chickens, and Salmonella is a major pathogen in chickens . Commensal E. Coli has shown resistance to a wide range of essential antimicrobials, and multidrug resistance of E. coli results in treatment failure . Antimicrobial-resistant Salmonella has been shown to cause elevated morbidity and mortality among infected patients, with 212 500 infectious diseases and 70 deaths each year in the U.S. . Multidrug resistance in Salmonella causes more severe and prolonged illnesses in humans and animals that are harder and sometimes impossible to treat . It has been reported by many studies that animal farm workers can be exposed to ARB via direct contact with animals, through a contaminated environment, or due to poor hygiene . However, occupational exposure of farmworkers to ARB has been largely neglected compared to other aspects of ARB research due to a lack of awareness of the farmworker’s lack of resources and regulations . A few studies have examined the occupational exposure of poultry farmworkers to ARB; most of these studies were conducted in Europe and in other countries . In the U.S., very few studies have assessed poultry farm workers’ risk for colonization with antimicrobial-resistant E. coli. The results of one of the found studies showed that gentamicin-resistant E. coli from worker’s stool samples were 32 times higher compared with stool samples from community references . Despite the substantial research in establishing pathways for the spread of ARB, the transmission routes of ARB from the poultry production environment to workers are still unclear . Besides, with the increasing prevalence of small-scale poultry farms  in the U.S. in recent years, cannabis drying trays and studies are needed to identify ARB transmission routes in these farms . Some studies have shown that workers in small farms do not follow bio-security rules such as wearing personal protective equipment, washing hands with soup, and avoiding stepping into boot baths . Moreover, no studies examined occupational exposure and AMR patterns at university-owned small-scale poultry facilities in the U.S. Here, students and interns who are employed and their safety is a priority. Therefore, the objective of this study was to conduct a pilot study in a university-owned small-scale poultry production facility to characterize ARB phenotypes and identify potential transmission routes of ARB from the working environment to employees in the facility.The samples for this study were collected weekly for ten consecutive weeks from the Hopkins Avian facility of the University of California, Davis between June 2022 and September 2022. The facility had two houses: layer house , where adult layers hens were kept, and floor house , where young chickens were kept after hatching until their age reached ten weeks. In the LH, the birds were kept in cages as a group hovered above the floor with manure under the cage’s concrete slab. The FH was divided into pens with pine shavings as litter. A total of 70 samples were collected from the environment and employees , who were responsible for the following animal care in both houses: feeding, checking water, collecting eggs, nail trimming, and cleaning the houses. All samples were collected at the end of the workday, with employees exposed to the working environment for 5-6 hours before sample collection. The same employee worked in both houses on each duty period. Therefore the samples were collected only for one employee in each sampling week. Three types of environmental samples were collected from the LH: a mix of feces and litter from the floor, cage swabs, and fresh eggs. Two types of environmental samples were collected from the FH: a mix of feces and litter from the floor front door swabs of the pens.

Two types of samples were collected from employees at the end of the workday: outwear and boots swab. In order to collect fecal samples from LH, two rows of cages were chosen randomly each time, and ten pellets mix of feces and litter were collected by hand; then pellets were placed into a non-filtered Whirl Pak bag and mixed by hand to homogenize the pooled sample. For FH, five pens were chosen randomly, and five pellets of a mix of feces and litter from each pen were collected by hand and placed into a non-filtered Whirl Pak bag at each sampling point. The bag’s contents were mixed by hand to homogenize the pooled sample. Five pens were chosen randomly, and the handles of each front door were swabbed using EZ-Reach™ sponge samplers . After swabbing, the sponges were placed into their original bags sealed, and the bags were placed on ice in coolers. Workers’ swab samples were collected by swabbing the entire surface of workers’ outwear and boots using EZ-Reach™ sponge samplers . Additionally, at each sample collection time, a tray with 30 eggs was chosen, and the surface of eggs was swabbed using one EZ-Reach™ sponge samplers .After sample collection, all the collected samples in plastic bags were transported on ice to the laboratory for further processing, including bacteria isolation and enumeration within 2 hours. Ten grams of the fecal and litter mix samples were put in a sterile filter bag , with 90 ml of Tryptic Soy Broth . Afterwards, the bags were homogenized by hand for 3 minutes and incubated at 35°C for 24 hours. For swab samples, 10 ml of phosphate-buffered saline  was added to each sponge bag. Then, the bags were homogenized for 40 seconds by hand. Homogenized mixtures were serially diluted into buffered peptone water tubes. For the enumeration of aerobic bacteria and E. coli, 1 mL of contents from the bags with feces and sponges were serially diluted into the tubes, and appropriate dilutions were then plated onto E. coli and APC petrifilms . Escherichia coli petrifilms were incubated at 35°C for 24 hours and APC petrifilms were incubated at 35°C for 48 hours. After the incubation period, E. coli and aerobic bacteria were counted from the E. coli and APC petrifilms, respectively. Three colonies from the E. coli petrifilms per sample type were randomly selected and were streaked one more time onto MacConkey Difco™ Sorbitol agar . Colonies were inoculated into TSB culture and incubated at 37°C for 20-24 hours. Then, 667 µL of the overnight culture added to 333 µL of 50% glycerol in a 2 mL screw top tube and gently mixed by vortexing. The glycerol stock tubes were put into an 80°C freezer until further characterization for antimicrobial susceptibility test . The results of the present study showed that farm workers can be exposed to ARB in their working environment, and wearing personal protective equipment such as boots and outwear is a crucial measure to protect workers from exposure to ARB. The outcomes of the present study will help lay the foundation for a large-scale study to mitigate the risks of occupational exposure to ARB. Salmonella was not recovered from any collected samples in the present study. In previous studies, the Salmonella recovery rate was very diverse from collected poultry environmental samples . Such variability of prevalence in Salmonella in these studies might be caused by factors such as geographic location, season, farm environment, feed and water quality, farm size and type, antibiotic usage, sample collection methods, and farm bio-security practices. Therefore, comparing prevalence results from different studies should be cautiously assessed, considering all the factors that might affect the outcome. For example, a study found that fecal samples in an organic poultry farm have lower Salmonella prevalence than a conventional poultry farm, 5.6% and 38.8%, respectively .

We choose FPE because it privileges gender as an axis of difference, it uncovers complexities of presumed social orders such as family and community, and it takes into account larger geopolitical processes that shape individual experiences. FPE privileges gender as the critical variable in the shifting landscape of family life because gender interacts with “class, caste, race, culture, and ethnicity to shape processes of ecological change, the struggle of men and women to sustain ecological viable livelihoods, and the prospects of any community for “sustainable development” . FPE seeks to challenge conventional understandings of household as “a presumed unit of homogeneous conditions and shared interests, the household” , as well as similar assumptions of local or community identity. FPE also takes into account national, regional, and global processes of socioeconomic change as they impact individuals and households. The chapter proceeds in the following fashion. The first part of this chapter describes migration trends, the competing identities of modern families, and spaces in which they compete. It outlines the major trifurcation of traditional, Socialist, ebb and flow flood table and modern Vietnamese gender identities; the dominant other identities described by men and women of this study; and the spaces and places in which these identities are negotiated as part of migration. The second part describes the methods and approach taken in conducting interviews and analyzing the data. The third section discusses the results of this spatial study for the city and village, work place, public meetings, and rural and urban homes.

The fourth section outlines implications of the Portable Family for the social fabric of Vietnamese society. We conclude with some potential future research directions in the area of mobile families.There are a number of motivating factors for rural-to-urban, internal, female migrants. Motivators are primarily financial, and include the anticipated increase in pay rate, the unemployment rate between provinces moving costs, public service disparities between provinces, demographic composition between provinces . Pay and unemployment rates are perhaps the most important motivators, regardless of actual availability of jobs in the city. Unemployment is 10 percent or under in urban areas, while it hovers around 25 percent in rural places . This pushes migrants to city centers for promises of higher wages with more regular employment. Public services are also a huge draw. The Tiebout hypothesis, that people “vote with their feet” and shop around for a province that provides a high quality of public service, is a proven motivator for migration . These services include education, health care, and phone services. Often times the decision to move can be highly influenced by a perceived loss of good public services in the destination location. Migrants face pitfalls and windfalls in their new lives in the city. The primary benefit of migration is to improve economic prospects, especially by sending remittances back home. Remittances make up between 60 and 70 percent of rural household income . They can be used for paying debt, sending children to school; costs incurred by ill family members, and can reduce the need to sell paddy rice for income, increasing a family’s food security.

Older women tend to participate in the informal economy, hired by families or selling prepared food on the street; while younger women tend to participate in the formal economy, working in physically-demanding factory jobs that prefer to hire younger female employees . Migrants unfortunately also face psychological, physiological, cultural, and practical challenges. City cost of living is higher, leaving the migrant family member with a meager allowance once remittances are sent . Cultural norms and expectations are very different than village life, with increased noise, population density, foreign influence, and a distinct lack of social support. These environmental factors take a toll on the satellite family member.Dominant ideologies in Vietnamese spaces underwent distinct shifts during the same time periods in which migration patterns shifted, as described above. In Southern Vietnam prior to 1975, Confucian philosophy was still the dominant ideological tradition. In this Confucian philosophy, there are three foundational concepts of community: household , country , and people . The home, or household, has a particularly important history in Vietnam, invoking “a moral economy characterized by unity and solidarity” . Regions include not only Vietnam as a whole, but also the three major geographic regions of the nation, North, Central, and South. Within each region, the village is a distinct and important geographic unit, where collective regional identity is enacted and reproduced through daily activities. These daily activities produce and reproduce personal identities, such as the “four virtues” traditional women must maintain: labor , appearance , speech , and behavior . Men must be the “pillar of the household,” a role model for the children, and the breadwinner . Following the end of the war in 1975, these identities and relations in space shifted.

Reunification brought a tumultuous time period for many people in Ho Chi Minh City and Southern Vietnam. Confucian philosophies were subsumed by Socialist party ideals. The People’s Committee in each village and city district became the embodiment of an organized community institution, holding public meetings at which households sent a representative, usually male. Individual identities gave way to the Socialist concept of citizen, and the home morphed into the household as a registered entity of the state, a focus of reunification efforts . In this new conception of society, women and men were meant to be equal in the home, as well as the public sphere where women were granted the right to study and seek employment . The phrase for citizen, công dân, conveyed both an abstract version of a person without social ties, but also a contributor to the revolution . After 1975 in Southern Vietnam, citizens were assigned to a household at birth through the registration system , and allocated government resources such as education and health care. In urban areas such as Ho Chi Minh City, these resources are doled out on a tiered basis, first to urban residents and selectively to migrant populations. Because many citizens of Southern Vietnam were regarded with suspicion after the war, the household became the target of many reformist policies that punished previous capitalist endeavors or anti-Socialist activities. It was not simply the individual judged by their own actions, but the citizen connected to the historic actions of all household members. Following Doi Moi implementation, the government shifted productive functions from society as a whole to household economies . This campaign was an effort to remove some of the capitalist undertones of shifting Vietnam to a market economy . In other words, integrating family economies with the larger economy still connoted positive socialist behavior, but encouraged individual entrepreneurship. Because of relaxed restrictions on household registration guidelines, the Doi Moi era has seen a decrease in deep regional divides, with more cross-pollination between North, Central, and South Vietnamese populations. Urban economies were revitalized by FDI, lessening the need for government subsidies and relieving the limitations on urban migrants subject to the household registration system . Families increasingly focus on providing high quality education for their children, hydroponic drain table attending school meetings, and migrating to urban centers to increase income for their household. Today, as Vietnamese migrants move through a variety of spaces, several important situations and identities remain. Important locations include the city and village; the work place, whether formal or informal; public meetings and celebrations; and the rural and city home. In each space, the recent history of Vietnam demands differing social pretense and decorum. In each space, family members enact varying identities to contest or comply with tradition.

There are limitless identities in a given person, but the dominant aspects of personal history that influence behaviors in migrant families include the traditions of the three primary regions of Vietnam, age, gender , level of physical ability, parenthood, and fealty to traditional values. Throughout recent history, the concept of family remains strong in Vietnamese society, although it has shifted in practice for the Portable Family. Absence of family members forces each person to consciously construct their household because daily practices are missing due to migration. Family is less about daily interactions in the rural home, and “…family materializes as an imagined community of emotional ties and reciprocal obligations” . In this way, some believe family has been “relativized,” and that women must “do family” through actions that take place at a distance and in person, periodically. The following case study explores this imagined community, and how men and women of the Vietnamese Mekong Delta do family.The research team conducted interviews of spousal couples to understand how female migration impacts performance of “social reproductive work” in rural communities and in the city. As in similar studies in Vietnam, a convenience sample was used, as research was conducted out of the University of Social Sciences and Humanities in Ho Chi Minh City . We identified local women whom had migrated to Ho Chi Minh City for work, either seasonally or permanently. Respondents self-identified as “migrants.” No minimum amount of migration tenure is required to be considered a “mobile family.” Nineteen total interviews were conducted in-person between January and May of 2017, 11 of which were women and eight of which were men. Interviews were then translated into English for analysis . This research used spatial intersectionality analysis, employing grounded theory to understand how identities manifest in different spaces. We used a grounded theory approach to determine a concepts, themes, and processes that pertain to thePortable Family. Grounded theory principles3 were used in developing codes and themes, with literature review co-occurring with interview coding in a flexible approach . As the individuals give answers for each question, I will code initial transcripts to establish categories, then selectively code transcripts as I move farther into the interviews . In this way, the research elicits a “thick description” of how constructed gender roles are being reformed in the new rural Vietnam, as well as a systematic approach to this theoretical description. As codes were established, we continued detailed memo writing to capture themes, phases, and processes . The salience and centrality of each theme was tested using Dedoose software to check for connectivity and frequency between cases. In other words, salience was measured by consistency with which the code appeared throughout all transcripts , while centrality was measured by the number of occurrences across cases .The city and village encapsulate modernity and tradition, respectively, in Portable Family minds. This is especially true if the dominant values of the destination city contrast with the regional identity of the home village. In the city, the identity that dominates decisions among migrant populations is regional identity. For women, this identity influences how often to return home for visits, whether or not to take children with them to migrate, and how much help they receive from home village connections in getting a job or housing. For men, regional identity influences their decision to stay back home because men are traditionally responsible for caring for elderly parents and practicing the family’s worshipping ceremonies. Finally, regional identity can be shifted when men and women migrate between the city and the village, having a profound impact on perceived and practiced gender roles for both men and women.Much of the western San Joaquin Valley is plagued by high water tables, which require drainage for sustained agricultural production. The land in this area was formed from materials that in geologic time originated under the ocean, and thus contains high concentrations of chemicals associated with ocean waters. Water percolates through the crop root zone, where some is drawn into the plant via transpiration. The water that remains is more concentrated than that which was applied. It moves vertically through the unsaturated area below the root zone to the saturated zone, where soil pores are all filled with water. The water table forms the interface between these unsaturated and saturated zones. The water in the saturated zone is highly concentrated with salts, including selenium, which has ecotoxic effects to wildlife, especially birds. In order to effectively drain this huge subsurface “pool” of highly concentrated water, growers in the western San Joaquin Valley have developed subsurface drainage systems.

These women and men negotiate a Portable Family identity, based onactions rather than interactions, and oscillating between the urban-productive home and the rural-reproductive home.Alternate Wetting and Drying is an irrigation technique in which water is applied to the field a number of days after the disappearance of ponded water. This is in contrast to the conventional irrigation practice of continuous flooding in which farmers never let ponded water disappear. AWD allows intermittent drying during certain stages of rice growth because roots of the rice plant are still adequately supplied with water due to the initial flooding. The number of days in which the field is allowed to be “non-flooded” before irrigation is applied can vary from one day to more than 10 days. Under the effects of climate change, water scarcity will be a main concern for Asian rice producers in the dry season. Regionally, applying AWD could conserve fresh water resources and either extend the growing cycle during the dry season or expand rice production areas. Unfortunately, estimating adoption of AWD is quite difficult. Determining the extent and degree of AWD adoption has proven difficult. The Irrigated Rice Research Consortium introduced AWD to paddy fields in the Mekong River Delta beginning in 1997 through the various projects in coastal provinces, such as Bac Lieu, as well as inland provinces, such as An Giang . There have been a number of evaluations of barriers to adoption , plant grow table and one widely accepted estimate of 40,000 farmers adopting the practice by 2011 .

However, these studies are based on small sample sizes, expert interviews, and household surveys. These methods can be time consuming, expensive, and prone to subjectivity. Thus, the core objective of the project is to determine if remotely sensed data can be used to determine the geographic extent and the degree of adoption in MRD Provinces in Vietnam. Radar remote sensing is an effective data for mapping soil moisture regardless of cloud cover or atmospheric interference . Synthetic Aperture Radar detects a back scatter digital number using microwave bursts from satellites that orbit earth. Radar data has fewer limitations than pure reflectance data due to the lack of cloud cover interference . Sentinel-1 in particular shows promise for change-detection approaches to understanding surface wetness . There are three transformations possible with Sentinel-1 data: alpha , beta , and nought . We do not discuss ϒ° transformation possibilities in this paper. Further, σ° poses a great deal of trouble in creating a reliable wetness index. Vegetative interference must be carefully calculated and accounted for as a function of σ° . Surface roughness is also a confounding factor in σ° transformation and use . However, SAR σ° data has been used to understand different characteristics of the rice paddy and plant, including the contribution of leaf area index, and plant growth stage and type . Ithas also been used successfully to understand the extent of the triple rice crop . Most recently, a number of authors have used the β° transformation of the SAR data in a change detection analysis. Experts have used change detection to create wetness indices that avoid the pitfalls of cloud cover interference inherent in reflectance data .

The change detection approach also reduces complications of surface roughness and vegetative interference that arise from the alpha transformation. For these reasons, the GIS team adopted the β° transformation and change detection approach for the purposes of this project, referred to as a “multi-temporal SAR for SWC change detection” that uses multiple passes from the same incidence angle and polarization . The chapter proceeds in the following fashion. The first part of the chapter discusses the environmental setting of the Mekong River delta. It then outlines the need for developing low-cost methods for determining adoption of AWD and a promising remote sensing approach using change detection of a wetness index. The third part of the chapter outlines the results of the work flow we explored. We conclude with the implications of these results, the limitations of the study, and some promising avenues for further validation of this method.Sustainable water management is a regionally urgent issue in Vietnamese agriculture. Vietnam has a complex system of barrages, weirs, and dikes to mitigate flood and salt water intrusion . The canal system expanded from two canals in 1824, 40 canals in 1934, to hundreds in the 1980s . Today, the channel network is over 50,000 kilometers long. Community groups in the delta often govern sluice gates and this control over hydrology allows for a double- or triple-cropping system. However, since the canal system was built, Vietnam has experienced subsequent water quality issues, salt-water intrusion, and canal bank erosion.

In maximum flooding conditions, these flow obstructions can worsen flood impacts, preventing saline waters from escaping croplands. Dredging canals, upgrading roads, and other waterway improvements to protect crops can cause between five and 10 additional days of flooding, or between 0.2 and 0.3 additional meters of water depth during peak flood conditions . Additionally, planned dam construction upstream in Laos could also have a synergistically negative effect with projected climate change impacts . Sediment deposits would accumulate behind the dam, causing a deficit of sediment and nutrient deposition downstream in the latter half of the century when projected impacts of climate change will be worse than the first half of the century. This may, in turn, have impacts on rice and other crop production. Flooding is a strength and weakness of the Mekong River Delta agricultural setting. The area is considered a monsoon system, with the rainy season lasting between May and October and averaging between 1400 and 2400 millimeters annually, and the length of the growing season is between 270 and 300 days A large proportion of the Malay Peninsula is seasonally inundated, which includes much of the Mekong River Delta in Vietnam. The floodwaters are filled with nutrient-rich sediment, which replenishes agricultural land and reduces the need for agricultural inputs . However, climate change is expected to increase the average and maximum water levels and flood duration in the Mekong River Delta between 2010 and 2049 . This will negative consequences for annual crops, infrastructure integrity, floodplain vegetation, and most likely decrease the amount of fertile land. The changes in flooding may increase ecosystem productivity and produce dry season water availability, which could allow extended cropping. Drought is one of the most formidable vulnerabilities in rice cropping systems of Vietnam, in spite of the vast irrigation network. Because rice yield is linearly related to the number of days it is grown in saturated soil, water shortages can have a severe impact on rice production . Lack of water reduces biomass, grain set, and forestalls emergence. It also disrupts crop management techniques such as weeding, fertilization, and transplanting. It is especially damaging during flowering and can incur a large weed problem if drought occurs during emergence periods. In locations without a clay hardpan, acidic water can infiltrate from deeper soil during the dry season or drought years . However, some authors have taken a nutrient management approach to the drought issue,arguing that drought is less important than how loss of soil-water saturation impacts uptake of nitrogen, phosphorus, and iron, as well as impacting toxic levels of aluminum . Additionally, small undulations in rice fields and between bunded fields, known as toposequences, can produce equally important hydrologic shifts as precipitation patterns. Climate change precipitation changes may cause yield fluctuations in already irrigated lands due to anticipated lack of irrigation water. This presents a hurdle for increasing yields in the light of increased water insecurity. Vietnam has a double- or triple-cropping system in the project area, hydroponic table which is sometimes subject to salt-water intrusion from the South China Sea and Gulf of Thailand. HISTORY OF AWD AWD was developed through the research efforts of the International Rice Research Institute , one of the major research centers under the CGIAR.

In particular, the Water-Savings Workgroup under the Irrigated Rice Research Consortium was instrumental in the development and dissemination of this technology in the major rice-growing countries of Asia. The IRRC was established in 1997 with the aim of providing a platform to facilitate the identification, development, dissemination, and adoption of natural resource management technologies suitable for irrigated rice-based ecosystems in several Asian countries, including Vietnam. With funding support mainly from the Swiss Agency for Development and Cooperation through four project phases , the IRRC has provided a mechanism that has expedited partnerships between national agricultural research and extension system partners and scientists from IRRI. In Vietnam, AWD has been introduced to paddy fields in the MRD through the various projects of IRRI, CGIAR, the Climate Change Agriculture and Food Security project, and Climate and Clean Air Coalition . There are projects in coastal provinces, such as Bac Lieu, as well as inland provinces, such as An Giang. With respect to specific IRRI/IRRC dissemination efforts for AWD, there has been an integrated approach to promoting AWD. This integrated approach has been built on the long established relationship between IRRI/IRRC and the Plant Protection Department of the Ministry of Agriculture and Rural Development . Through the IRRI-PPD partnership, AWD was first evaluated in An Giang Province in 2005-2006 for three successive rice-growing seasons. In 2006, AWD was incorporated into a large-scale existing program called “Three Reductions, Three Gains” that aimed to reduce inputs of fertilizers, pesticides, and seeds. In 2009, technologies that reduce irrigation water use and post-harvest losses were included and the program was transformed into the “One Must Do, Five Reductions” program. The successful evaluation and dissemination of AWD in Vietnam through the 3R3G program and subsequently the 1M5R program were facilitated by the widespread media campaigns and training on AWD through these integrated programs. The collaboration of IRRC with the PPD was instrumental in this endeavor. Moreover, 1M5R is now a national policy that aims to make rice production more sustainable. All the components of the IM5R program are being promoted and wide-scale implementation is being done throughout An Giang and in nearby provinces in the Mekong Delta. Promotion of this program is also underway for the northern part of Vietnam, particularly in the Red River Delta. The AWD technique starkly contrasts to traditional rice cultivation. Rice fields are not kept continuously submerged, but are allowed to dry intermittently during the rice growing stage. The number of days in which the field is allowed to be “non-flooded” before irrigation is applied can vary from 1 day to more than 10 days . The underlying premise behind this irrigation technique is that the roots of the rice plant are still adequately supplied with water for some period even if there is currently no observable ponded water in the field. To assist farmers in the practical implementation of AWD, a simple tool was introduced. The field water tube can be made of plastic pipe or bamboo or any cheap material, and is embedded in the paddy field to a depth of 15 cm, with the soil removed from inside the tube, to reveal the perched water-table level. During AWD implementation, the field is irrigated to a depth of around 5 cm whenever the ponded water level has dropped to about 15 cm below the surface.The best source of data for this project currently includes the European Space Agency’s Sentinel-1 satellite. The Vietnamese Mekong River Delta is approximately 40,000 square kilometers, with the majority of the area covered by a single tile of ascending and descending passes by Sentinel 1-a and 1-b. SAR data is downloadable in raster format, with thousands of individual cells representing a setarea in space, or tile. Each cell within the tile of Sentinel-1 data represents 10 by 10 meters for which a back scatter number, or digital number , is given for that area of space. Each cell contains two bands of data collected from the satellite platform at different sending and retrieving angles: vertically sent and vertically retrieved , and vertically sent and horizontally retrieved . The VV band was used in this analysis because it has a higher accuracy in other similar wetness index studies . Table 1 outlines acquisition dates for which VV and VH data was available for our study location.

This alternative outcome here suggests that while this soil chemical property shows sensitivity to differences perceived by farmers in their selected fields, this commonly used indicator does not adequately capture the direction of farmer knowledge of soil fertility between their selected fields. On the one hand, it is not surprising that total soil nitrogen was the only soil indicator able to detect differences between farmer-selected “most challenging” and “least challenging” fields, especially given that after nearly a century of research total soil nitrogen remains one of the most predictive measures of soil fertility status . However, the contradictory direction of our results for total soil nitrogen between farmer-selected “most challenging” and “least challenging” fields emphasizes that current scientific application of this soil indicator does not readily transfer for use on-farm. One potential reason for this inconsistency may be because as a soil indicator, total soil nitrogen reflects both the amount of chemically stable organic matter and more active organic matter fractions, and therefore gives a rough indication of nitrogen supplying power in the soil. However, in practice it is possible that fields deemed by farmers as “least challenging” have depleted their nitrogen supplying power due to more frequent crop plantings, for example— compared to fields that are “most challenging” and therefore may be less frequently planted with crops throughout the year. This finding underscores the current lack of interpretation of soil test results in community with both agricultural researchers and farmers present together; the current gap in interpretation of soil testing results was repeatedly emphasized by farmers during interviews, and suggests that— moving forward, seedling grow rack contextualizing and interpreting soil test results in local farming contexts is key to disentangling potential mismatches between farmer knowledge systems and agricultural researcher knowledge systems.

To move toward this outcome requires deep listening and relationship building on the part of agricultural researchers not currently widely applied .Whereas another similar study found that active carbon was the singular most sensitive, repeatable, and consistent soil health indicator able to differentiate between fields in their study on organic farms in Canada , we highlight that one potential reason for this difference in our results might be as a result of differences in management in each study. While our study consisted of farms along a gradient of organic management , the prior study focused on three organic farms with similar management. This divergence in results highlights the importance of accounting for a gradient in management when evaluating the efficacy of soil health indicators on working farms. Much remains to be learned about how inherent soil properties and dynamic soil processes interact with complex management systems on working farms . Limited prior research that has looked at the effects of multiple soil management practices indicates that metrics for soil health are a product of both inherent soil properties and dynamic soil properties . Whether available soil indicators could translate these soil properties and processes when management systems are complex remains unclear. As an added layer of complexity, field variability is hard to distinguish from management-induced changes in soil properties . To address this challenge, prior studies have suggested increasing samples, the number of sites, and sampling strategies that account for spatial and temporal variability ; however, as farmers themselves expressed in this study, such an approach requires additional time and resources, and may not increase their utility—at least to farmers—in the end.

In this sense, farmer knowledge may serve as an important mechanism for ground-truthing soil health assessments, particularly when management is synergistic and does not rely heavily on organic fertilizers. As emphasized by our results above, farmer involvement in soil health assessment studies is imperative to better converge soil indicators with farmer knowledge of their soil. Lastly, our results also highlight the utility of incorporating information about nitrogen-based fertilizer application on sampled field sites, particularly when assessing soil indicators on working farms with a large variation in the quantity of N-based fertilizers applied . Farms on the low end of additional organic fertilizer application showed minimal differences between farmer selected fields for soil fertility, particularly in terms of soil inorganic nitrogen —which suggests that differences in soil fertility in fields with more circular nutrient use may be less detectable using commonly available soil indicators. This cursory finding here corroborated farmer observations touched on in the previous section above, and requires further investigation to see if similar trends extend to other organic systems.In this dissertation, I have shared a small slice of farmer knowledge of soil from a region of northern California that represents a central node of the organic movement in the United States. I have also attempted to intersect this knowledge system with agricultural researcher knowledge systems of soil. Not surprisingly, I found that the frame of reference used among farmers in this dissertation mapped out quite differently from the frame of reference used among agricultural researchers that collaborated on this work. Of course, this broader conclusion is not to say that farmer knowledge bases of soil and agricultural researcher knowledge bases of soil did not overlap at all; indeed, the two ways of knowing had much in common, as outlined in Chapter 3. However, stepping back—as a person who was not born in the US and for whom English is not their first language—I see part of the divergence in knowledge systems among the two groups as partially stemming from a lack of a shared language .

While I am not in any way suggesting that both knowledge bases be “watered down” to a universal language that strips away the richness of each knowledge base, I am suggesting that careful translation between the two knowledge bases is needed to work toward a common language. Through my informal conversations with the local cooperative extension advisor in this region of northern California , this need for a shared language among diverse agricultural stakeholders is also surfacing among her communities and networks as well. Exactly what this shift looks like in academic research practice and within the academic research process is still unfolding and in emergence as I write these words. It is clear, however, that this shift should not be delegated to science communicators and/or extension advisors as their responsibility alone; and moreover, such a shift requires fundamental change in current research frames. In this dissertation, I have provided an offering to the collective murmurations of this critical need in agricultural research that is slowly resurging. So, in addition to widening our frame of reference as academic researchers in agriculture, there is also a need to work toward a shared language with other non-academic researchers—most imminently, farmers. Engaging in such a process can only further widen our frames as academic researchers in agriculture; ideally, greenhouse growing racks the hope is that we might widen our frames and enlarge our capacity for richer language and mutual understanding so much that we are collectively rewired to allow other ways of knowing into the academic lexicon of agricultural research. I have learned so much from these farmers with whom I had the honor and privilege to interact with through this dissertation work. But, if I had to elevate one nugget of wisdom that nearly every farmer always seemed to circle back towards—that was the power of listening, of observing, of being tactile, of tasting, of smelling, and of being in reciprocity to their particular milieu. Through such embedded, sensorial exchange, we can invite a multiplicity of perspectives and reanimate what is considered academic research in agriculture, and more importantly, how academic research in agriculture is carried out. In weaving together distinct perspectives and different voices, we can enlarge the whole and rewire the largely monochromatic traditions of agricultural research. In this process of rewiring, it is my modest hope that agricultural researchers can move towards creating a more textured and more complicated understanding of agricultural systems. I look forward, backward, inward, and outward to the unfurling of this hope.With its Mediterranean climate of moist, mild winters and dry moderate summers, a broad range of fruit and vegetable crops can be grown year round on the central coast of California. Monterey and Santa Cruz counties combined produced $912 million gross value of strawberries and over $2.7 billion worth of vegetables in 2011 . As the interest in organic farming and the demand for organic produce has increased during the last decade, organic farming on the central coast has also greatly increased. There were over 9,300 certified organic hectares in Monterey and Santa Cruz Counties in 2011, five times the number recorded in 1998 . The total farm gate revenue from organic farming in these counties was over $197 million in 2011, representing a dramatic 12-fold increase in 13 years . This trend is also true for organic strawberry production. In 2000, 77 ha of organic strawberries were grown in central coastal California, but by 2012 this had increased to 509 ha, representing 8.3% of the total strawberry production in the area .

Continued growth of organic strawberry production in this area, however, faces the challenge of managing soil-borne diseases without the use of synthetic fumigants and fungicides. Verticillium wilt is a soil-borne disease caused by Verticillium dahliae that can damage a wide range of important crops in California. Host crops include lettuce, tomatoes, potatoes, apples, cotton, artichokes, and strawberries . Due to its resilient overwintering structure , this pathogen can survive many years in soil even without host plants . In the premethyl bromide era, Verticillium wilt was a major limiting factor to strawberry production in California . Today, Verticillium wilt is one of several key soil-borne diseases facing California strawberry production and poses a long-term threat for organic strawberry production in the state.To avoid Verticillium wilt and other soil-borne diseases, as well as meet the requirements of the USDA National Organic Program , organic strawberry growers must implement crop rotation. Due to its high sensitivity to the disease, several years between strawberry plantings are necessary . For specialized strawberry growers in California, establishing a crop rotation system implies a major change in the design and management of the farming system. Due to the high costs of production and the high leasing fees of crop lands , specialized organic strawberry growers need to minimize the break time between strawberry crops as much as possible to stay in business. The following biological and cultural approaches to soil-borne disease management in strawberries have been tested: host resistance ; small cell transplants ; organic amendments such as compost ; high nitrogen organic fertilizers ; broccoli residues ; mustard residues , Sudan grass , and other cover crops ; microbial amendments including vesicular arbuscular mycorrhizal fungi ; plant growth promoting rhizobacteria ; crop rotations with broccoli, lettuce or Brussels sprouts ; mustard seed meal ; soil-less trough production ; and anaerobic soil disinfestation . Further, a minimum of a three-year rotation is recommended for strawberries that do not use chemical fumigants in Europe , the Northeast and Midwest United States, and in eastern Canada . However, no research has yet integrated multiple biological and cultural practices for different rotation periods of organic strawberries in California. The objective of this project was to demonstrate the effects of strawberry planting frequency in organic strawberry/vegetable rotations and combined biological and cultural practices on fruit yield and disease level. We hypothesized that the use of non-host rotation crops for Verticillium wilt plus bio-fumigation with broccoli, mustard cover crop residues, relatively resistant strawberry cultivars, and compost application would suppress disease sufficiently to grow strawberries in rotation every two or three years. To test the above hypothesis, in 2001, we initiated a fiveyear organic strawberry/vegetable rotation experiment in a commercial California field.The on-farm research site for this project was the Elkhorn Ranch in Moss Landing, Monterey County, CA, USA . The ranch is adjacent to the Elkhorn Slough National Estuarine Research Reserve, one of the state’s largest and the last remaining coastal wetlands and a habitat for hundreds of plant and animal species, including more than 135 aquatic bird species . The last conventional strawberry was grown in the 1997–1998 season and the last methyl bromide/chloropicrin fumigation was applied in the fall of 1997. Divided into three 8-ha parcels, in 1998 the land was placed into the mandatory three-year organic transition period, alternating winter cover crops with summer fallow.

However, farmers possess wide and deep place-based knowledge of their soils that has the potential to advance work on soil health beyond its currently limited scope . Inclusion of farmer knowledge is integral if one outcome of ongoing research on soil health is to address both social and ecological resilience. Farmers are uniquely positioned to share their on the-ground social realities and their local ecological knowledge of their soils and farming systems . To be clear, inclusion of farmers in this research arena is essential if only to contribute farmer knowledge and farmer voices to the existing body of work—which to date has been lacking . This call for inclusion of farmer knowledge represents: 1) a departure from the majority of prior research in the US that tends to emphasize the advancement of research and policy agendas aimed at behavioral change ; and 2) simultaneously, a shift towards explicit inclusion of farmer knowledge in the knowledge-making of emergent soil health research. While farmer knowledge is certainly important and underutilized, grow rack consideration for quantitative assessments of soil health remains a critical component of advancing soil health. Available indicators to quantify soil health already exist and are widely applied both on farms and in scientific studies.

These soil indicators prioritize so-called “principles of soil health” to assess health through evaluating soil function, usually emphasizing metrics for organic matter quality, nitrogen availability, soil biological activity, and water cycling . Currently, our understanding of how local farmer knowledge of soil health and management might interact with available soil health metrics is limited. Farmer inclusive research evaluating soil metrics is generally sparse—with only a handful of studies on mostly non-organic farms in the midwestern US . Yet, if a central goal of soil health research is to further develop the concept of soil health, and also to better understand the key management practices associated with this concept, then examining the ways in which local farmer knowledge can interact with quantitative soil metrics evaluated in the field may offer a complementary approach to prior work . In this study, we focus on a functional expression of on-farm soil health related to crop production—soil fertility. Soil fertility is generally defined as the capacity of a soil to supply the nutrients needed for crop growth, and is therefore linked to crop nutrient availability . More broadly, soil fertility underpins the productivity of agricultural systems, and has social and environmental implications related to fertilizer application and nutrient management . Ongoing efforts to measure soil fertility have placed particular emphasis on how farmers consider key nutrients, such as nitrogen, as part of their farm management .

Although metrics for quantifying aspects of soil fertility have existed for several decades now, it is less understood how—if at all—these commonly available metrics for soil fertility actually inform farmers and their fertility programs . Moreover, there currently is a gap in the literature in mapping how these knowledge spheres—farmer knowledge of soil fertility and soil indicators for soil fertility—interact to co-produce new insights to evolve this component of soil health research.To investigate these questions, we applied a case study approach, engaging in on-farm research of 13 organic farms and their respective farm owners in Yolo County, California, USA—a region where this type of farmer inclusive soil health research has been limited to date. We used qualitative, in-depth field interviews in combination with quantitative field sampling and subsequent laboratory analysis. This research focused on Yolo County in particular, because of its unique role as a hub for innovative, high-value organic vegetable production . These thirteen organic farmers specifically—because of their historical relationship to their land and their intimacy with the physical place they farm—collectively represented a salient case study through which to understand soil health and fertility from a grounded perspective. More broadly, we led this work with a Farmer First approach in order to give voice to organic farmers of this region, and to provide a model for future inclusivity of farmer knowledge in the growing body of work on soil health.We conducted our experiment on 13 farms in Yolo County, California, on unceded Patwin speaking Wintun Nation tribal lands—located along the western side of the Sacramento Valley between late March 2019 and December 2020. The region is characterized by Mediterranean type climate with cool, wet winters and hot, dry summers.

Precipitation in the 2019 water year 2019 was 807 mm—the fifth wettest winter on record. The mean maximum and minimum temperatures were 33.9oC and 15.5oC, respectively for July 2019. Mean annual maximum and minimum temperatures for 2019 were 24oC and 9.8oC, respectively. All farm sites were on similar parent material . Most farms were situated on either loam, clay loam, or silty clay loam. All 13 farms selected for this soil health study were located in Yolo County . The organic farms represent a majority of the farms in the region with a diversified array of vegetable and fruit crops that sell to a variety of consumer markets, including farmers’ markets, wholesale markets, and restaurants. The 13 farmers interviewed represent 13 individuals who oversee management and operations on their farms. These individuals were most often the primary owner and operator of the farm, and made key management decisions on their farm. To identify potential participants for this study, we first consulted the USDA Organic Integrity database and assembled a comprehensive list of all organic farms in the county . Next, with input from the local University of California Cooperative Extension Small and Organic Farms Advisor for Yolo County, we narrowed the list of potential farms by applying several criteria for this study: 1) organic operation on the same ground for a minimum of 5 years; 2) a minimum of 10 years of experience in organic farming; and 3) a focus on growing diversified fruit and vegetable crops. These requirements significantly reduced the pool of potential participants. In total, 16 farms were identified to fit the criteria of this study . These 16 farmers were contacted with a letter containing information about the study and its scope. To establish initial trust with farmers identified, we worked directly with the local UCCE advisor. Thirteen farmers responded and agreed to participate in the entirety of the study .Because this research is informed by a Farmer First approach—which emphasizes multiple ways of knowing and challenges the standard “information transfer” pipeline model that is often applied in research and extension contexts—farmers were viewed as experts and crucial partners in this research . As a result, farmers were considered integral to field site selection, and were not asked to change their management or planting plans. In addition to the Farmer First approach, greenhouse grow tables we intentionally used a two-tiered interview process, in which we scheduled an initial field visit and then returned for an in-depth, semi-structured interview at a later date—after summer field sampling was complete. The overall purpose of the preliminary field visit was to help establish rapport and increase the amount and depth of knowledge farmers shared during the semi-structured interviews. The initial field visit typically lasted one hour and was completed with all 13 participants. Farmers were asked to walk through their farm and talk generally about their fields, their fertility programs, and their management approaches. The field interview also provided an opportunity for open dialogue with farmers regarding specific management practices and local knowledge . Because local knowledge is often tacit, the field component was beneficial to connect knowledge shared by each farmer to specific fields and specific practices. During the initial field visit, field sites were selected in direct collaboration with farmers. First, each farmer was individually asked to describe their understanding of soil health and soil fertility. Based on their response, farmers were then asked to select two field sites within their farm: 1) a field that the farmer considered to be exemplary in terms of their efforts towards building soil fertility ; and 2) a field the farmer considered to be a challenge in terms of their efforts towards maintaining soil fertility .

Essentially, farmers were asked, “Can you think of a field that you would consider ‘least challenging’ in terms of building soil fertility on your farm?” and “Can you also think of a field that you would consider ‘most challenging’ in terms of building soil fertility on your farm?” . Farmers would often select several fields, and through back-and-forth dialogue with the field researcher, together would arrive at a final field selected for each category . Only fields with all summer vegetable row crops were selected for sampling. For each site, farmers delineated specific management practices, including information about crop history and crop rotations, bed prepping if applicable, the number of tillage passes and depth of tillage, rate of additional N-based fertilizer inputs, and type of irrigation applied. Following field site selection, soil sampling was designed to capture indicators of soil fertility in the bulk soil at a single time point. Fields were sampled mid-season at peak vegetative growth when crop nitrogen demand was the highest. This sampling approach was intended to provide a snapshot of on-farm soil health and fertility. Because the farms involved generally grow a wide range of vegetable crops, we designed the study to have greater inference space than a single crop, even at the expense of adding variability. As such, we collected bulk soil samples that we did not expect to be strongly influenced by the particular crop present. To sample each site, a random 10m by 20m transect area was placed on the field across three rows of the same crop. Within the transect area, three composite samples each based on five sub-samples were collected approximately 30cm from a plant at a depth of 20cm using an auger . Subsamples were composited on site and mixed thoroughly by hand for 5 minutes before being placed on ice and immediately transported back to the laboratory. Laboratory Processing Soil samples were preserved on ice until processed within several hours of field extraction. Each sample was sieved to 4mm and then either air dried, extracted with 0.5M K2SO4, or utilized to measure net mineralization and nitrification . A batch of air-dried samples were measured for gravimetric water content , which was determined by drying fresh soils samples at 105oC for 48 hours. Moist soils were immediately extracted and analyzed colorimetrically for NH4 + and NO3 – concentrations using modified methods from Miranda et al. and Forster . Additional volume of extracted samples were subsequently frozen for future laboratory analyses. To determine soil textural class, another batch of air-dried samples were further sieved to 2mm and subsequently prepared for analysis using the “micropipette” method . Water holding capacity was determined using the funnel method, adapted from Geisseler et al. , where a jumbo cotton ball thoroughly wetted with deionized water was placed inside the base of a funnel with 100 g soil on top. Deionized water was added and allowed to imbibe into the soil until no water dripped from the funnel. The soil was allowed to drain overnight . A subsample of this soil was then weighed and dried for 48 hours at 105oC. The difference following draining and oven drying of a subsample was defined as 100% WHC. Additional air-dried samples were sieved to 2mm, ground and then analyzed for total organic carbon , total soil nitrogen , soil protein, and pH at the Ohio State Soil Fertility Lab . The former two analyses were conducted using an elemental analyzer . Soil protein was determined using the autoclaved citrate extractable soil protein method outlined by Hurisso et al. . Remaining air-dried samples were sieved to 2mm, ground, and then analyzed for POXC using the active carbon method described by Weil et al. , but with modifications as described by Culman et al. . In brief, 2.5g of air-dried soil was placed in a 50mL centrifuge tube with 20mL of 0.02 mol/L KMnO4 solution, shaken on a reciprocal shaker for exactly 2 minutes, and then allowed to settle for 10 minutes. A 0.5mL aliquot of supernatant was added to a second centrifuge tube containing 49.5mL of water for a 1:100 dilution and analyzed at 550 nm. Theamount of POXC was determined by the loss of permanganate due to C oxidation .After the initial field visit and following summer field sampling, all 13 farmers were contacted to participate in a follow up visit to their farm, which consisted of a semi-structured interview followed by a brief survey.

While these farmers represent a case study for building a successful, organic farm within one generations, the results of this study beg the question: What advancements in farm management and soil management could be possible with multiple generations of farmer knowledge transfer on the same land? Rather than re-learning the ins and outs of farming every generation or two, as new farmers arrive on new land, farmers could have the opportunity to build on existing knowledge from a direct line of farmers before them, and in this way, potentially contribute to breakthroughs in alternative farming. In this sense, moving forward agriculture in the US has a lot to learn from agroecological farming approaches with a deep multi-generational history . To this end, in most interviews—particularly among older farmers—there was a deep concern over the future of their farm operation beyond their lifetime. Many farmers lamented that no one is slated to take over their farm operation and that all the knowledge they had accumulated would not pass on. There exists a need to fill this gap in knowledge transfer between shifting generations of farmers in order to safeguard farmer knowledge and promote adaptations in alternative agriculture into the future.Most studies often speak to the scalability of approach or generalizability of the information presented.

While aspects of this study are generalizable particularly to similar farming systems in California such as the Central Coast region, cannabis dry rack the farmer knowledge presented in this study is not generalizable and not scalable to other regions in the US. To access farmer knowledge, relationship building with individual farmers leading up to interviews as well as the in-depth interviews themselves require considerable time and energy. While surveys often provide a way to overcome time and budget constraints to learn about farmer knowledge, this study shows that to achieve specificity and depth in analysis of farmer knowledge requires an interactive approach that includes—at a minimum—relationship building, multiple field visits, and in-depth, multi-hour interviews. Accessing farmer knowledge necessitates locally interactive research; this knowledge may not be immediately generalizable or scalable without further locally interactive assessment in other farming regions.Local knowledge among farmers in US alternative agriculture has often been dismissed or overlooked by the scientific community, policymakers, and agricultural industry experts alike; however, this study makes the case for inclusion of farmer knowledge in these arenas. In-depth interviews established that farmers provide an important role in translating theoretical aspects of agricultural knowledge into practice. It is for this reason that farmer knowledge must be understood in the context of working farms and the local landscapes they inhabit.

As one of the first systematic assessments of farmer knowledge of soil management in the US, this research contributes key insights to design future studies on farmer knowledge and farmer knowledge of soil. Specifically, this study suggests that research embedded in local farming communities provides one of the most direct ways to learn about the substance of farmer knowledge; working with the local UCCE advisor in combination with community referrals provided avenues to build rapport and relationships with individual farmers—relationships that were essential to effective research of farmer knowledge. Farmer knowledge of soil management for maintaining healthy soils and productive, resilient agriculture represents an integral knowledge base in need of further scientific research. This study provides a place-based case study as a starting point for documenting this extensive body of knowledge among farmers. It is our hope that this research will inspire future studies on 26 farmer knowledge in other contexts so that research in alternative agriculture can widen its frame to encompass a more complete understanding of farming systems and management motivations—from theory to practice.A fundamental challenge in agriculture is to limit the environmental impacts of nitrogen losses while still supplying adequate nitrogen to crops and achieving a farm’s expected yields . To balance among such environmental, ecological, and agronomic demands, it is essential to establish actual availability of nitrogen to crops . A holistic, functional understanding of plant N availability is particularly imperative in organic agriculture, as in this farming context, synthetic fertilizers are not applied and instead, production of inorganic N—the dominant form of N available to crops—depends on internal soil processes . In organic agricultural systems, farmers may seasonally apply cover crops or integrate livestock as alternative sources of nitrogen to crops—in addition to or in place of using organic fertilizers. In applying these alternative sources of nitrogen to soil, organic farmers rely on the activity of soil microbes to transform organic N into inorganic forms of N that are more readily available for crop uptake .

Currently, the predominant way crop available N is measured in organic agricultural systems tends to examine pools of inorganic N in soil . Inorganic N, or more specifically ammonium and nitrate , represents the predominant forms of N taken up by crop species in ecosystems where N is relatively available, such as in non-organic agricultural systems that apply inorganic fertilizers . However, in organic systems, crop available N is largely controlled by complex soil processes not adequately captured by simply measuring pools of ammonium and nitrate. First, because nitrogen made available to crops is controlled by soil microbes—wherein crops only have access to inorganic forms of N after microbial N transformations occur to first meet microbial N demand—pinpointing the flow of N moving through inorganic N pools as a result of these microbial N transformations is necessary to accurately measure actual N availability to crops . Second, extensive recycling of N among components of the plant-soil-microbe system complicates relying solely on measurements of inorganic N pools, which do not reflect these dynamics . As an example, one previous study in organic vegetable systems showed examples where inorganic N pool sizes in the soil were measured to be low, yet there existed high production and consumption rates of inorganic N . This outcome highlighted that if the turnover of inorganic N is high—for instance, high rates of soil ammonium production exist in the soil with simultaneously high rates of immobilization by soil microbes and high rates of uptake by plants—measured pools of inorganic N may still be low . This study also showed that conversely, there may also exist situations when inorganic N pools are low and rates of ammonium and nitrate production are also low, in which case N availability would limit crop production. In organic systems especially, higher carbon availability as a result of organic management can increase these microbially mediated gross N flows, thereby increasing N cycling and turnover of inorganic N . Thus, trimming tray we hypothesize that measuring total production of ammonium from organic N, or gross N mineralization, and subsequent total production of nitrate from ammonium, or gross N nitrification, may provide a more complete characterization of crop available N in the context of organic systems . Though the application of such diverse management practices on organic farms is known to affect rates of N cycling in soil , measuring N flow rates as a proxy for crop available N is currently uncommon on working organic farms. The current historical emphasis on measuring inorganic pools of N in organic agriculture was originally imported from non-organic farming, wherein the Sprengel-Liebig Law of the Minimum was a widely accepted agronomic principle . In practice, this Law of the Minimum placed particular importance on using artificial fertilizers to overcome so-called “limiting” nutrients—namely, inorganic forms of N. Because inorganic N is relatively straightforward to measure, focus on quantifying pools of inorganic N has since become common practice among agronomists and agricultural researchers . However, the continued acceptance of the Law of the Minimum in organic agriculture underscores the gap in a functional understanding of organic agricultural systems, in particular the role of soil microbes in mediating N cycling. To understand crop available N more holistically, there is a need to measure actual flow rates of soil N—in addition to—static pools of inorganic N . Soil indicators that adequately capture N availability to crops are therefore necessary to move beyond the legacy of the Law of the Minimum in organic agriculture.

Unpacking the soil processes that mediate flows of N may ultimately provide a more accurate characterization of soil N cycling and in turn, N availability to crops. Unfortunately, gross N mineralization and nitrification rates are very difficult to measure in practice, particularly on working organic farms . While net N flows are easier to measure in comparison to gross N flows and can provide a useful measure of N cycling dynamics as a complement to measurements of inorganic N pools, net N flows still pose serious limitations— namely that net rates cannot detect plant-soil-microbe interactions and therefore are not adequate as metrics for determining crop available N . In particular, relying on net N flows as a measure of N availability does not account for the ability of plants to compete for inorganic N, and assumes plants take up inorganic N only after microbial N demands are satisfied . It is also possible that measuring soil organic matter pools could help indicate N availability because SOM supports microbial abundance and activity, and because SOM is also the source of substrates for N mineralization . Several studies have proposed measuring soil organic matter levels to complement measuring inorganic N pools, understand soil N cycling, and infer N availability . Assessing the total quantity of organic carbon and nitrogen within soil organic matter represents one established method for measuring levels of soil organic matter, and is morereadily measurable than gross N rates. Additional indicators for quantifying “labile” pools of organic matter, such as POXC and soil protein, have also become more widely studied in recent years, and applied on organic farms as well . When used in combination with more established soil indicators that measure organic C and N pools , this suite of indicators may potentially provide added insight to understanding crop available N . Importantly, applied together these four indicators for soil organic matter levels may also more readily and accurately serve as a proxy for soil quality—generally defined as a soil’s ability to perform essential ecological functions key to sustaining a farm operation . Despite the availability of these soil indicators, very few studies have systematically examined the way in which SOM levels on working farms compare to N cycling processes, and specifically how SOM levels compare to microbially mediated gross N rates. Further, it is still unclear to what degree the interactions between soil edaphic characteristics and soil management influence N cycling and N availability to crops . For instance, soil texture may play a mediating role in N cycling, where soils high in clay content may limit substrate availability as well as access to oxygen, which in turn, may restrict the efficiency of N cycling . In this sense, it is important to understand the role that soil edaphic characteristics play in order to identify the underlying baseline limits imposed by the soil itself. Compared to controlled experiments, soil management regimes on working farms can be more complex and nonlinear in nature due to multiple interacting practices applied over the span of several years, and even multiple decades. To date, a handful of studies conducted on working farms have examined tradeoffs among different management systems , though few such studies examine the cumulative effects of multiple management practices across a gradient of working organic farms. However, understanding the cumulative effects of management practices is key to link soil management to N cycling on working farms . Likewise, it is important to examine the ways in which local soil edaphic characteristics may limit farmers’ ability to improve soil quality through management practices. Though underutilized in this context, the development of farm typologies presents a useful approach to quantitatively integrate the heterogeneity in management on working organic farms . Broadly, typologies allow for the categorization of different types of organic agriculture and provide a way to synthesize the complexity of agricultural systems . Previous studies that make use of farm typologies found that differences in total soil N across farms are largely defined by levels of soil organic matter.To address these questions, we conducted field research at 27 farm field sites in Yolo County, California, USA, and used four commonly available indicators of soil organic matter to classify farm field sites into farm types via k-means cluster analysis.

The evidence in table 6 that mother’s bargaining power influences the amount of house-work that daughters take over when mothers get employed suggests that mothers have influence over daughters’ time. But should daughters themselves and fathers also be seen as decision makers participating in decisions about daughters’ time use? In table 7, I interact proxies for the mother’s, father’s and the oldest daughter’s preferences – answers to survey questions about each of the three family-members’ attitude towards girls’ schooling – with the treatment. In households in which the mother considers girls’ schooling more important, the negative effect of mother’s employment on daughters’ schooling is significantly smaller. The father’s attitude towards girls schooling appears to have less influence on time use substitution between mothers and daughters, and a daughter’s own preferences have no significant effect on the amount of house-work she is expected to take over when her mother gets employed. It thus appears that daughters in rural Ethiopia have little control over their own time use in times of need.Analysis of how households select into mother’s versus father’s employment is important in its own right but also represents a powerful auxiliary test of the main message of the framework above. If, as this paper has argued, a key determinant of rural Ethiopians’ time use is gender-specific, greenhouse benches intra-household labor substitution, greenhouse benches then household characteristics that influence the impact of mother’s and father’s employment on other family-members – such as the gender composition of a couple’s children – should also influence selection into mother’s versus father’s employment.

The sample analyzed consists of households in which either the mother or the father applied to a flower farm. To pool the two sub-samples and explore selection into the two groups, we must thus assume that, in for example a household in which the mother applied, the father would have applied had the mother not done so. While this assumption is ultimately untestable, it is arguably reasonable. As noted, there were only seven households in which both spouses applied – for most households the relevant choice options appear to have been for one or none of the two spouses to apply. There are few households in the sample in which the spouse of the applicant was already formally employed. In table 8 I investigate the comparability of the two sub-samples. Excluding the right-hand-side variables that the framework predicts should influence selection into the two groups , the only significant difference is that husbands are one year older in households in which the mother applied. I thus control for husband’s age in the analysis below. As we saw in table 6, perhaps the most important variable governing heterogeneity in the impact of mother’s employment on daughters’ time-use is the gender composition of the couple’s children because the presence of more daughters means that house-work can be shared between more hands. As such, we would expect the number of daughters to have an important influence on selection into mother’s versus father’s employment. But testing for a causal relationship is possible only if the number of daughters is exogenous conditional on the total number of children. If parents follow differential stopping rules – that is, if the probability of having another child depends on the gender composition of existing children – then the number of daughters is not exogenous even conditional on family size, as pointed out by Clark and discussed in detail in Washington .

It turns out that parents in the sample do not follow such stopping rules: neither a variable equal to the total number of children, nor dummies for having a given number of children, predict the proportion of daughters, as seen in table 9. The explanation may be that desired family sizes in rural Ethiopia are so large that almost all couples have one or more sons through “natural” fertility behavior. Parents with son preference typically want “at least X number of sons” , where X is a positive but relatively low number.We can thus test if the gender composition of a couple’s children has a causal effect on the probability that a mother seeks employment. I do so in table 10, including interactions with the proxies for mother’s weight on daughters’ well-being and mother’s bargaining power to mirror the heterogeneity regressions in table 6. The selection analysis results are supportive of the idea that female time use substitution is key to household employment and schooling decisions in Ethiopia. For example, one additional daughter increases the probability that the mother applies by 8 percentage points, or 12 percent, controlling for the total number of children, in households with low weight on daughter well-being and low mother’s bargaining power. The results also indicate that the higher the weight on daughters’ well-being, the lower the influence of the number of daughters on the couple’s employment decision. The reason appears to be that highly valued daughters are expected to take over less household work when mothers get employed. Finally, mother’s bargaining power at baseline has a marginally significant positive effect on the influence of the number of daughters on the probability that the mother applies. The presence of daughters has a direct influence on the mother’s well-being under mother’s employment relative to father’s employment because a mother can likely decrease her time spent on house-work when employed more when more daughters are present. A father’s well-being under mother’s versus father’s employment may, in contrast, be less dependant on the gender composition of the couple’s children because “male” house-work is less time consuming.

It appears that greater bargaining power for the mother therefore increases the weight given to the gender composition of the couple’s children when the employment decision is made. The findings in table 10 thus suggest that parents take into account substitutability between a mother’s and daughters’ time use when making adult employment decisions. If daughters taking over house-work duties when mothers get employed is difficult to avoid, it may be that the best way to take daughters’ well-being into account is at the employment decision stage.Domestic violence represents a serious violation of women’s rights and imposes substantial costs on society. In parts of Ethiopia, 71 percent of ever-partnered women have been physically assaulted by a male partner . In the U.S., domestic violence assault is more common than all other forms of violence combined . But despite its prevalence throughout much of the world, the nature of physical abuse of women remains poorly understood. Little is therefore known about how to address the issue. In this paper, growers equipment we analyze the effect of female employment on domestic violence through a field experiment in rural Ethiopia that randomized job offers, the first of its kind. Conventional economic models of domestic violence are “optimistic” in the sense of predicting a decrease in abuse when women get employed; we find the opposite. We then begin to distinguish between “pessimistic” models. We find limited support for models in which violence is used as a tool to gain control over household resources, growers equipment and more support for models that allow men to see violence as a way to restore their dominance in the household. The sample consists of 329 households in which an adult woman applied to a flower farm job and was deemed acceptable for hiring by the farm. The treatment and control groups were re-surveyed 5 – 7 months after employment commenced. Our research design has important advantages. Because we directly vary job offers, we can attribute changes in violence to the causal effect of employment. There is to our knowledge no existing experimental evidence from poor countries on the effects of permanent female employment, by many thought to be the most effective way to reduce physical abuse. Policy and arguments are therefore made on the basis of assumptions on which clear-cut causal evidence is largely missing: the World Health Organization argues, for example, that “women’s access to. . . employment should. . . be strongly supported as part of overall anti-violence efforts” . In the absence of sufficient evidence, there is little consensus on which model of domestic violence best describes reality. In the main result of the paper, we find a 13 percent increase in the probability that a woman is experiencing physical domestic violence, when she gets employed. We also find a 34 percent increase in emotional abuse, and a 32 percent increase in the number of violent incidents per month. As discussed below, the effects are unlikely to represent a change in reporting behavior. Our results are hard to reconcile with conventional models, most of which are optimistic in the sense that employment and other forms of economic empowerment of women is predicted to decrease abuse. We thus explore the ability of more recent, pessimistic violence models to explain our findings. Authors of instrumental violence models argue that a husband may turn more violent when his wife’s income goes up in order to counteract a rise in her bargaining power, or to increase the husband’s slice of a bigger income pie. But there is no indication that violent husbands in our sample have greater control over household resources, neither before nor after female employment.

Alternatively, physical abuse may be seen as a way to restore a traditional order in the household; either used by husbands to influence wives’ behavior, or generating direct, expressive utility for husbands. We argue that a natural adjustment to existing expressive violence models would allow the marginal utility that a husband derives from violence to increase when he is “disempowered” by his wife’s employment. Consistent with this, the increase in the incidence of violence is greater in households in which the newly employed wife was likely to end up further ahead of her husband in income because her baseline income was comparatively high relative to her husband’s. This paper’s findings have significant implications for theory and policy. We document that the form of female empowerment most forcefully advocated in the effort to reduce abuse of women – employment – increases rather than decreases domestic violence in the context of rural Ethiopia, and that the reason appears to be that men act upon the emotional costs implied by deviations from traditional household roles. We do not attempt to survey the literature on domestic violence here, but briefly summarize some of the most relevant papers. There are two cross-cutting dichotomies of domestic violence models: optimistic versus pessimistic models, and instrumental models in which violence is used to gain control over household resources versus models in which violence is not used to gain control over resources. Examples of conventional optimistic models include Chwe and Aizer . In Chwe , a male principal can use financial disincentives to discourage low effort from a high income female agent but must instead use costly violence disincentives to motivate a low income female. In Aizer , improvements in a woman’s expected utility outside of marriage, for example due to employment, is expected to reduce the level of violence she is willing to “offer” a husband who derives utility from violence. Aizer finds that decreases in the male-female wage gap in the U.S. reduce violence against women. There are several potential reasons why Aizer’s findings differ from ours. One possibility is that, in more male-dominated cultures such as that of many developing countries, the marginal utility men derive from violence may increase as women’s standing improves. Though not all the findings of previous studies can necessarily be interpreted causally, our results add to increasing evidence that nominal empowerment of women in poor countries can increase domestic violence. Eswaran and Malhotra find that women in India who work outside of the home are subjected to more violence. Gonzalez-Bernes concludes that female labor force participation in Zambia, Rwanda and Tanzania is not associated with lower levels of violence. The evidence for middle income countries is mixed at best. Instrumental models typically argue that men use violence as a tool to gain control over household resources, rather than as an end in itself. Examples of pessimistic instrumental violence models include Bloch and Rao and Bobonis et al. . Alternatively, men may derive “expressive” utility directly from violence, in which case physical abuse can be triggered by events that have purely symbolic meaning . This paper’s findings are most supportive of the expressive “male backlash” theories emphasized by sociologists .

The estimates in table 7 provide a clear picture. In a sub-sample of teams consisting of workers from two different tribes categorized as belonging to the same tribal bloc, little if any discrimination against non-coethnic processors occurs. The output of vertically mixed teams is for example not significantly different from that of homogeneous teams in the Luo – Luhya sub-sample. But within two different sub-samples of teams consisting of workers of two specific tribes categorized as belonging to different tribal blocs here, discrimination is pervasive and of an extent similar to that seen in the full-sample analysis in table 4. There are only minor differences across the Kikuyu – Luo and the Kikuyu – Luhya sub-samples, analyzed in columns 1 – 2 and 3 – 4 of table 7 respectively. So far we have seen strong evidence indicating that team-level ethnic diversity lowers productivity in the context of factory production in Kenya. If diversity effects are driven by discriminatory preferences, then we would expect the negative effect of ethnic diversity on private sector output to vary with factors that influence taste for discrimination, such as the political climate and relations between groups. A shift in taste for discrimination should differentially lower the output of mixed teams. In the next sub-section, I analyze differences in output between homogeneous and mixed teams during the period of ethnically-based, political conflict in Kenya in early 2008.The two coalitions in Kenya’s December 27 2007 presidential election were ethnically based. In advance of the election, grow lights for cannabis opinion polls predicted that the coalition led by Luo challenger Raila Odinga would oust the sitting Kikuyu- led coalition represented by incumbent president Mwai Kibaki. But results were delayed and the Kibaki victory announced on December 29 disputed by the opposition and the international community.

Widespread violence against Kikuyu and Kikuyu- allied tribes erupted, and counter-attacks soon followed. More than 1,200 people were killed and 500,000 displaced in the months that followed . On February 28, a peace agreement was reached, though violence continued in many areas, and it was not until after April 3 when the two sides reached an agreement on the composition of a power-sharing government that the political crisis ebbed. The conflict period significantly disrupted life in parts of Kenya. However, plant supervisors reported that logistics and worker absence at the farm was largely unaffected and that production continued as usual. Because the workers live on the farm in a gated community it was safest to remain on the farm. If the plant’s ability to operate was nevertheless affected, a decrease in productivity, as measured by the econometrician, should be observed in all teams. The model predicts an increase in the gap between the average output of homogeneous and mixed teams if attitudes towards workers of the other ethnic group worsened when conflict began. I interpret a possible increase in taste for discrimination as a decrease in the weight attached to the well-being of non-coethnics. In table 8, the difference in output between mixed and homogeneous teams before and after conflict began is compared. Data from 2007 and the first six weeks of 2008 is used. There was no significant change in the output of homogeneous teams when conflict began. If suppliers have social preferences, the impact of conflict on the productivity of homogeneous teams will reflect a combination of two factors. First, farm-wide disruption effects may have negatively affected output in all teams. Second, it is possible that conflict led to an increase in workers’ weight on the utility of coethnics: the findings of Eifert, Miguel, and Posner suggest that Africans increasingly identify with coethnics during times of heightened political competition between groups. I cannot rule out general disruption effects or an increase in the utility workers derive from coethnics’ output and income. But the combination of supervisors’ reports and a conflict coefficient for homogeneous teams that is essentially precisely zero points to little farm-wide disruption effects and little effect on workers’ weight on coethnics’ utility.

The output gap between homogeneous and vertically mixed teams nearly doubled in early 2008. Output in vertically mixed teams decreased by seven percent when conflict began. The results in table 8 thus indicate that upstream workers undersupply non-coethnic downstream workers to a significantly greater extent during times of ethnic conflict, as predicted by the model if taste for discrimination increased. Output in horizontally mixed teams decreased by four percent when conflict began, but there was a small but significant increase in the output of coethnic processors in horizontally mixed teams. An increase in upstream discrimination against workers of other ethnic groups thus appears to increase the supply of flowers to those downstream workers who belong to the same ethnic group as suppliers, as predicted by the model. The relative benefits of flowers supplied to coethnic processors in horizontally mixed teams go up if conflict lowers the utility upstream workers derive from non-coethnics’ output, even if suppliers’ weight on coethnics’ utility is unaffected. In light of the model presented above, the results for the conflict period thus suggest that discriminatory attitudes towards co-workers of other ethnic groups worsened in Kenya in early 2008. It appears that the economic costs of ethnic diversity vary with the political environment. A back-of-the-envelope calculation suggests that the increase in supplier discrimination during conflict may have cost the farm as much as US$560,000 in profit per year, had it not responded. Firms may be forced to take measures to limit distortions that arise from internal, ethnic discrimination, especially in times of conflict. In the next sub- section, I analyze how the gap in output between homogeneous and mixed teams was affected when the plant six weeks into the conflict period changed the pay system for processors and thereby altered the incentives facted by biased upstream workers.On February 11 2008, the farm began paying processors w per rose finalized by the team, rather than 2w per rose finalized by the processor herself as before.

As in standard incentive models, the framework above predicts that processors will freeride on each others’ effort when paid in part based on the output of the other processor. Free riding should negatively affect output in all teams, but in horizontally mixed teams an offsetting positive effect is expected. Under team pay, suppliers are unable to influence the relative pay of the two processors through relative supply. If the higher output for processors of the supplier’s ethnic group observed under individual pay is driven by suppliers’ taste for discrimination, indoor cannabis grow system a decrease in the output gap between coethnic and non-coethnic processors in horizontally mixed teams is thus expected when team pay is introduced. To test these predictions, I consider the period after processors’ pay system was changed and through the remainder of 2008 as a single team pay period. Figure 8 displays team and individual output during the three sample periods: pre-conflict , conflict , and the team pay period . The decrease in output in mixed teams during conflict is apparent. Comparing the second and third periods, the figure also clearly indicates that the introduction of team pay had a positive effect on output in horizontally mixed teams.Corresponding regression results are in table 9. The results indicate that team pay leads to some degree of free riding among processors: output in homogeneous and vertically mixed teams is 1 percent lower under team pay. The modest magnitude of this effect is noteworthy and interesting in itself. Output in horizontally mixed teams is four percent higher under team pay, as seen in columns 3-4 and 7-8 in table 9. The difference in output between horizontally mixed and homogeneous teams thus decreased significantly when team pay was introduced. The introduction of team pay essentially canceled out the effect of conflict on output in horizontally mixed teams, returning the difference in output between homogeneous and horizontally mixed teams to pre-conflict levels. The increase in horizontally mixed teams’ output appears to be due to horizontal favoritism being eliminated when biased suppliers’ ability to increase the relative income of favored processors through relative supply was removed, as predicted by the model. There is no statistically significant difference in the output of the coethnic processor and the non-coethnic processor in horizontally mixed teams during the last ten and a half months of 2008. An output gap of 32 percent between processors of the supplier’s ethnicity and processors who are not of the supplier’s ethnicity in horizontally mixed teams was eliminated by the introduction of team pay. The positive impact on output in horizontally mixed teams, which make up half of all teams, led to an overall increase in output when team pay was introduced. However, output in horizontally mixed teams remains lower than in homogeneous teams under team pay, and output in vertically mixed teams still lower. Under team pay a biased supplier continues to derive greater benefit from flowers supplied the more downstream workers belong to her tribe. The ranking of output of teams of different ethnicity configurations observed under team pay is thus due to incentives for vertical discrimination remaining in place, it appears. The model presented above, in which the productivity effect of ethnic diversity in teams arises from a taste for discrimination on the part of upstream workers, thus predicts the output response to the introduction of team pay well. Approximately one fourth of the yearly expected profit loss due to the impact of conflict on misallocation of flowers was avoided through the change in suppliers’ contractual incentives. It is difficult to imagine a standard economic model of joint production that would predict an increase in output when team pay is introduced.In the previous sub-section we saw that the economic costs of ethnic diversity vary with the political environment. The results in this sub-section suggest that, in high-cost environments, firms adopt “second best” policies to limit the distortions caused by ethnic favoritism. Group-based pay leads to free riding and reduces output in homogeneous teams, but the new pay system introduced by the plant during the conflict period in Kenya in early 2008 was likely designed to remove the ability of biased upstream workers to increase one processor’s pay relative to the other’s through differential allocation of flowers. Distortionary discrimination fell and the net effect was positive. Interestingly, La Ferrara also finds that ethnically diverse cooperatives in Nairobi are more likely to adopt group-pay. It thus appears that ethnic diversity has an important influence on how firms organize production in the private sector.Note first that informational and technological diversity effects are unlikely to explain this paper’s results. Suppose that the higher output observed in homogeneous teams during the pre-conflict, individual pay period was due to inferior technology or information in diverse teams. In that case it is difficult to see why output in mixed teams would fall differentially during conflict, and why the output of the two processors in horizontally mixed teams would be equalized under team pay. Cooperational effects have proven difficult to distinguish from social preferences , in part because such theories typically have few testable implications. Some forms of cooperational diversity effects could explain the observed decrease in mixed teams’ output during conflict. If trust for example facilitates cooperation, an erosion of trust between workers of different ethnic groups during times of ethnic antagonism could lead to a decrease in mixed teams’ output. Other forms of cooperational diversity effects could explain the observed increase in the output of non-coethnic processors in horizontally mixed teams under team pay. Coethnic processors that can exert effective social pressure on the upstream worker may for example induce the supplier to supply more to non-coethnic processors in horizontally mixed teams under team pay because processors derive benefits from the output of the other processor under team pay. It is, however, difficult to think of cooperational or other forms of non-taste-based ethnic diversity effects that can simultaneously explain a decrease in mixed teams’ output during conflict, equalization of processors’ output in horizontally mixed teams when team pay is introduced, and the other results seen in this paper. Though I cannot rule out that other forms of ethnic diversity effects also play a role, I thus conclude that the leading explanation for the lower output observed in ethnically diverse teams at the plant is taste-based discrimination on the part of suppliers. 

The two most commonly used summer cover crops in our region are annual buckwheat and sudan grass. Buckwheat is the fastest-growing summer cover crop, and when planted at a high enough density and irrigated up, annual buckwheat will outgrow and “smother” most of the fast-growing summer annual weeds such as pig weed and lambs quarter. Once incorporated, buckwheat residue breaks down easily, allowing for seedbed preparation soon after incorporation. Growers always comment on the noticeable improvement in soil quality following buckwheat. Note that buckwheat is not very drought tolerant and therefore must be sprinkler irrigated at least every 7 to 10 days on the Central Coast. If planting buckwheat with a drill, a good seeding rate is around 60 lbs per acre. If broadcasting, increase this amount to 80 lbs per acre. The advantages of Sudan are that it can be mowed and incorporated 40 days after planting when the plants are in full bloom and it is a good weed competitor. Sudan grass grows best during very warm weather, so during cool foggy periods its growth may be less than optimal for good biomass production and weed suppression. At the UCSC Farm we have had good luck intercropping vetch and sudan grass as a summer cover crop. The advantage of the intercrop is that if the weather is unseasonably warm during the initial growth stage the sudan will dominate and, conversely, vertical grow system if the weather is unseasonably cool the vetch will dominate.

In either scenario the cover crop will provide good biomass and weed suppression. Typically, when intercropping two different species it is advisable to plant each at half the recommended seeding rate. If planting a sudan grass/vetch mix with a drill, a good seeding rate is around 20 lbs per acre of each seed type. If broadcasting, increase this amount to 30 lbs of each per acre. AGS104 rye or Merced rye will both germinate well and provide excellent weed suppression when grown as summer cover crops in our region, and can be mowed numerous times to keep biomass manageable and to knock off developing seed heads of escaped weeds. Cereals like rye and oats are typically drilled at around 80 lbs per acre and broadcast at between 100 and 120 lbs per acre. Residue breakdown and subsequent seedbed preparation will depend on the length of time the rye, sudan or vetch covers are allowed to grow prior to termination. Sudan grass can be drilled at 40 to 50 lbs per acre and broadcast at 60 lbs per acre. The higher the seeding rate the finer the stem will be and the easier the breakdown will be at time of incorporation.The best tool for planting cover crops is either a no-till or conventional grain drill. Depending on the scale of operation, either three point or wider pull-behind drills can be used. All grain drills have single or double disc seedline openers, which facilitate planting into high residue situations often encountered when cover crops are planted following high residue cash crops such as corn or broccoli. Some drills, such as the no-till drills, have press wheels that run behind the disc openers, which help to re-establish capillarity to aid in bringing deeper soil moisture up to the seed; this feature greatly facilitates planting to moisture. The press wheels, which can be adjusted with spring tensioners, also facilitate accurately setting the planting depth, which is a critical factor as well when planting to moisture.

Accurate seed depth is also easily set with a drill and information on how to set depth can be found in the operator’s manual. Drills typically put down seed lines spaced from 6 to 7.5 inches apart, providing a close enough spacing for good early cover crop canopy closure, which will greatly reduce weed competition during the critical early cover crop establishment phase. Drills typically have adjustable seed drop openers that allow for some level of accuracy in setting seeding rates. It is advisable to “calibrate” a drill to improve the accuracy of seeding, and thus avoid either over planting and running out of seed or under planting and having seed left over . Drills are fast and efficient at field planting cover crops once the proper seed delivery rate has been determined. The double disc openers seldom clog, but it is not uncommon for clogging to take place in the drop tubes especially when the drill is being used to plant large seeds at a high rate. The drill operator must continually monitor the output of the drops to ensure that no clogging is taking place. It is advisable to check drop output visually from the tractor seat at the end of each pass. Another common problem is for the disc openers to pick up field trash that can jam the openers. The drill operator must also be cautious about not allowing the drill to move backwards while soil engaged, as this will often clog the openers with soil. A clogged drop is easily detected in the field since seed from the clogged tube will start to overflow at the top of the drop tube near the hopper, and a mindful operator will notice this overflow while running the drill. When using the drill after it has been parked for extended periods it is critical to blow out each of the drop tubes with compressed air or high-pressure water to clear out spider webs and other debris that can cause clogging.

When going into a field with the drill it often takes several feet of ground wheel operation for the seed to make its way through the delivery mechanism, down the drop tubes, and into the soil in the slot opened up by the disc opener. For this reason it is always advisable to make a final perpendicular pass along both edges of the field, filling in the areas that were potentially skipped as the drill entered and exited the field.If a drill is not available the next best option is to broadcast the cover crop seed with a relatively inexpensive, three-point tractor mounted broadcaster. Small-scale growers planting out small areas can effectively broadcast cover crop seed using commonly available and inexpensive hand cranked broadcast seeders. Seeding rates are challenging to set with broadcast seeders. Depending on the area to be broadcast it is often advisable to set the seed opening smaller than anticipated and make numerous passes over a field to improve overall uniformity of seed application. Note that it is important to measure out your field sizes and estimate the acreage prior to broadcasting so that you know exactly how much seed needs to be broadcast on each block. Recommended seeding rates are typically increased by 30% when cover crops are broadcast and harrowed, compared to drilling, to compensate for the lack of seeding depth uniformity. Once the seed is broadcast at the desired rate the grower must go back over the field with some type of secondary tillage implement to improve soil/seed contact to ensure adequate germination and minimize seed exposed on the surface. Secondary tillage implements commonly used to cover broadcast seed include spring tooth and spike tooth harrows and three point rototillers. Implement choice will often depend on the amount of residue in the field, since spring tooth and spike tooth harrows tend to bring residue to the surface, vertical grow system which can negatively impact cover crop stand establishment. The drawback to rototillers is that they are best operated at much slower ground speeds than other types of harrows, so covering large areas can be time consuming. Discs can also be used to cover broadcast cover crop seed, but setting the correct depth is critical to avoid placing the seed too deep and/or over mixing the soil. Tandem discs are better than offset discs for covering broadcast cover crop seed since they tend to move less soil and are less aggressive. If available, it is advantageous to pull either a ring roller or drag bar behind the disc or spring tooth harrow when covering cover crop seed to leave a uniform soil surface. When broadcasting and harrowing cover crop seed, it is inevitable that some seed ends up getting buried too deep and some seed may be left on the surface where it is less likely to germinate due to either bird feeding pressure or inadequate moisture.

Growers have several effective tools for dealing with weeds in cover crops. Perhaps the best tool is selecting the optimum seeding density and having the ability to plant uniformly, in terms of both density and seeding depth, in mid to late October for fall planted cover crops, when soil temperatures are conducive to quick cover crop germination; this allows the cover crop to effectively out compete weed seeds. Timing in relation to soil temperature is critical for success since cooler soil temperatures later in the fall will favor the success of winter weeds over the cover crops. Soil temperatures are not an issue with summer planted cover crops. Other weed management tools include the use of cover crops known for their ability to outcompete weeds through allelopathy. Good examples of these include mustards and many of the cereals—most notably cereal rye—when planted as monocrops. Though effective at outcompeting weeds, growers must be mindful of the challenges of spring incorporation of cereal cover crops when planted as pure stands. Although often difficult to achieve, one of the most effective winter cover crop planting strategies for good weed management is to drill cover crop seed into ground that has had a flush of weeds from either a light overhead irrigation or early rainfall event in the fall. Light tillage with a spring tooth cultivator or under-cutter bar at time of weed seed emergence will knock out the newly emerged weeds. If done correctly the cover crop seed can then be planted into residual moisture and will germinate without additional rainfall or irrigation. This scenario will provide a strong and weed free legume/cereal mix cover crop stand. This technique is dependent on the use of a drill for planting . Soil moisture is critical as well since too much moisture will have a potentially negative impact on soil compaction. An effective way to deal with emerging weeds in a newly planted cover crop is to go over the field very quickly with either a rotary hoe or a tine weeder just as the cover crop is emerging. This technique is referred to as “blind” cultivation and can effectively clean up a weedy cover crop field. If the timing is right, the cultivation from the rotary hoe or tine weeder will not negatively impact the emerging cover crop seed but will effectively disrupt, kill, and/or desiccate the newly emerged weed seeds that are much smaller and closer to the surface than the drilled cover crop seed. This technique depends entirely on timing in terms of the stage of development of the cover crop and the stage of development of the weed seeds as well as soil moisture. Tine weeders work best when they can be run perpendicular to the drill lines—particularly on soils prone to crusting.On the Central Coast of California, incorporation of high residue cover crops can be extremely challenging. Because of our mild maritime-influenced winters and relatively high rainfall rates , a legume/cereal mix cover crop may produce 2 to 3 tons per acre of residue calculated as “dry weight.” The average weight per acre of a standing legume/cereal mix cover crop just prior to incorporation can be over 20 tons per acre . At time of incorporation this residue typically has a very high moisture level and, depending on the level of maturity, can be carbonaceous and lignified. Because of these conditions it is advisable to flail mow the residue prior to incorporation to break up the stems into manageable sizes to facilitate incorporation into the soil. Timing of incorporation is directly linked to soil moisture and the level of maturation of the cover crop. Every spring is different and cover crop incorporation timing often involves a lot of guessing about potential rainfall patterns and soil moisture and cover crop maturation dynamics. A standing cover crop can transpire a tremendous amount of water and soil moisture can vary at different depths, making incorporation decisions challenging.

Once the tube is filled, a small hand-held suction pump is used to remove air bubbles from the tube. The lid of the reservoir is then retightened, sealing the lower tube. It is important to follow all of the manufacturer’s recommendations for installation and maintenance, including the use of an additive to minimize algal contamination of the water in the tensiometer. When used properly, tensiometers will provide accurate “soil/water tension” readings on a range of crops. These readings provide the irrigation manager with critical information that can be used to establish irrigation schedules adequate to maintain soil moisture at levels conducive to good crop growth and productivity.In many ways electrical resistance sensing devices are similar to tensiometers—the main difference is the method used to measure soil moisture. ERSDs utilize two “electrodes” cast into a porous material . The two electrodes in the “block” are attached to wires that run from the ERSD to the surface. These wires are often protected within a ½-inch PVC tube that is attached to the ERSD. The ESRDs are buried in the soil at various depths and locations, similar to tensiometers, and like the tensiometer, a soil/water slurry is used when the ERSD is installed to establish good soil contact with the instrument. To get a reading from the ERSD the irrigator uses a small, inexpensive, growing cannabis indoors hand-held electrical resistance meter that is temporarily connected to the wire leads from the buried ERSD. The meter allows a very low electrical current to flow between the two electrodes in the ERSD and displays an electrical resistance reading.

This reading reflects the amount of moisture within the porous material, since the buried ERSD takes on the moisture properties of the surrounding soil. Due to the electrical conductivity potential of water, the higher the concentration of moisture within the porous block the lower the resistance and, conversely, the lower the concentration of moisture within the block the higher the resistance. At field capacity the block is wet; as the growing plants start to extract moisture from the soil, the moisture is also pulled from the ERSD and the conductivity reading will reflect this change in soil moisture. Note that high salt concentrations in the soil solution will affect the accuracy of the reading, since salts increase electrical conductivity. This potential salt impact needs to be taken into account when deciding which monitoring tool is best suited to your farm. Electrical resistance sensing devices are relatively inexpensive and easy to install and monitor. Like tensiometers, they are left in the field for the duration of the cropping cycle and provide critical irrigation scheduling information that enables the irrigation manager to make informed decisions about irrigation frequency and quantity based on site-specific data.Central California’s Mediterranean climate creates the conditions that make dry farming possible. In normal years Central Coast rainfall is generated by storms that develop in the Gulf of Alaska and sweep south and then east, moving from the Pacific Ocean across the region from November through February and into March. High pressure then dominates the region from April through September and often into October, pushing rainfall to the north during the Central Coast’s long “summer drought.” Thus the region rarely receives significant rainfall from May through September.

Rainfall amounts vary considerably across the Central Coast, influenced in large part by the location, height, and orientation of the area’s numerous mountain ranges. Steeper ranges parallel to the coast can cause significant orographic lifting of moisture-laden air, resulting in high rainfall amounts on the west side of these slopes. These ranges also create rain shadows on the east sides, reducing rainfall in these areas. From San Luis Obispo County in the south to San Mateo County in the north, rainfall amounts vary from approximately 8 inches up to approximately 35 inches per year depending on the effects of the mountain ranges and specific storm dynamics.Higher afternoon temperatures and ET rates in the range of .33 inches per day, typically encountered in the more inland valleys with less marine influence, are much less suited to dry farming, especially of tomatoes, since it can be difficult for the plants to access deeper moisture quickly enough to maintain turgidity during periods of high evapotranspiration. However, some crops can be successfully dry farmed in inland valleys: although not within the scope of this article, wine grapes, olives, and apricots are successfully dry farmed in California on small acreages in areas with little or no maritime influence.The best soils for dry farming have relatively high clay content. Sandy loam soils or loam soils that overlay deeper clay soils also work well for dry farming. Soils higher in sand content do not hold soil moisture as well as clay and clay loam soils and therefore are typically not used for dry farming. And because organic matter increases the soil’s porosity, it does not improve conditions for dry farming. A grower considering dry farming should bore numerous holes up to 4 feet deep throughout the production area using a 2-inch slide hammer and soil probe to obtain soil “plugs”: soils suitable for dry farming will exhibit continuity within the different horizons and a loam or sandy loam upper horizon going directly to clay.

Horizons with a larger particle size, e.g., containing sand or gravel, will impede water’s ability to be drawn upward to the plant’s root zone, thus making dry farming less feasible. Preparing and planting a small area of the field is the best way to determine whether the site and conditions are suited to dry farming.Soil preparation that conserves or “traps” winter rainfall is critical for successful dry farming. In the spring, prior to planting, residual rain moisture is typically lost from the root zone as water percolates down through the soil horizon with the help of gravity. High clay content in the soil, and to a lesser extent soil organic matter , greatly facilitates the soil’s ability to hold water in the root zone against the pull of gravity. As the weather warms, soil moisture is also lost through surface evaporation. Evaporation occurs as water is drawn upward via small channels between soil particles; these channels can be thought of as capillaries within the soil horizon. Polar bonds between water molecules and the forces of cohesion facilitate water’s upward movement through the soil: as water near the soil surface evaporates, growing indoor cannabis water lower in the soil is pulled nearer the surface, much like liquid being drawn through a straw. Thus in fields destined for dry farming it is critical to break up the capillaries near the surface to minimize the evaporative loss of residual rain moisture during late spring and summer. This breaking of capillaries is typically accomplished with relatively shallow mechanical soil tillage. Commonly used tillage tools include rototillers and disc harrows, often followed by secondary tillage implements such as spring tooth harrows. The resultant tilled zone is called a “dust mulch.” This dust mulch provides an effective barrier to the potential evaporative loss of residual rain moisture held within the root zone of the soon-to-be-planted dry-farmed crop. When creating the initial dust mulch, timing is critical: the grower must trap as much rain moisture in the soil as possible, yet avoid working the soil when it is too wet. Wet soils, especially “heavier” soils high in clay content, are subject to clod formation and compaction caused by tractor operations. It is also important to minimize tillage depth when preparing soil for planting annual dry-farmed crops, since deeper tillage could disrupt the lower soil capillaries that are critical for soil water movement below the tilled zone. The dust mulch needs to be maintained with fairly frequent and light tillage operations from the time of initial tilling until the crops are too large to cultivate effectively. Although dry farming relies on winter rainfall, several scenarios can necessitate irrigation prior to planting. During dry springs it is sometimes necessary to pre-irrigate the beds before planting using either overhead irrigation or drip lines in order to establish an optimal stand. When a mechanical spader is used to incorporate a high residue cover crop prior to dry farming it is often necessary, in the absence of post-tillage rain events, to pre-irrigate with overhead sprinklers to facilitate the cover crop’s breakdown. On a garden scale, you may need to hand water the newly planted plants to assist in rooting and uniform establishment.In any dry farming system, variety selection is absolutely critical. Varieties that do well as dry-farmed crops typically have an aggressive root system capable of reaching deep into the soil horizon to tap the stored rain moisture. It is interesting to note that growers in the Central Coast region have trialed literally hundreds of varieties of heirloom, open pollinated and hybrid tomatoes and, to date, none have compared to ‘Early Girl’ in their ability to set roots deep and consistently produce a high yield of high quality, flavorful, and marketable fruits with no irrigation. ‘New Girl’, a recently introduced variety, is closely related to ‘Early Girl’ and appears to have many of the same favorable characteristics.Dry-farmed crops with extensive root systems can effectively extract deep residual rain moisture from a fairly large area within their roots’ grasp.

Competition from other nearby crop plants or weeds can result in water-stressed plants that produce very little fruit and remain stunted. For this reason it is critical to plant out dry-farmed crops in a much wider spacing than is typically used for irrigated crops of the same type. Good weed management in a dry farm system is also critical, since most weeds have aggressive root systems capable of outcompeting most crop plants for both water and nutrients. As an example of plant spacing, irrigated tomatoes are commonly spaced 2 feet apart within the row with rows spaced 4 feet apart, a density of roughly 5,400 plants per acre. A typical spacing for dry-farmed tomatoes would be 6 feet between rows and 6 feet between plants, for a total plant population of 1210 plants per acre. As you can see from this example a significant yield reduction can be expected from most dry-farmed crops simply based on per acre plant populations. A higher price premium for dry-farmed tomatoes will often make up for the yield loss related to wider spacing.As a rotation within a diverse irrigated cropping system, dry farming has many advantages. The lack of irrigation in a dry-farmed production block can lead to improved soil tilth, since dry surface soil is not prone to compaction or clod formation from both foot traffic associated with harvest and tractor compaction from cultivation operations. Problem weeds are much easier to deal with when irrigation is eliminated for a season and weed seed development is easily minimized in a dry-farmed block. If water is a limited resource on a farm then dry farming makes perfect sense as a means of maintaining production while eliminating the need for irrigation. Forcing deep rooting of dry-farmed crops can also facilitate the extraction of nutrients that have leached below the root zone of most irrigated crops through excessive rainfall or irrigation. This is particularly true of tomatoes, which are highly sought after by savvy consumers and the Central Coast region’s chefs. As a result, the production and sale of dry-farmed tomatoes has become an important and economically viable niche market for small-scale organic specialty crop growers on the Central Coast. Finally, although dry farming may not be appropriate for every cropping system and region, understanding the basic principles of dry farming can lead to a greater knowledge of the complexities of water and soil dynamics, tillage, weed management, and fertility management. This knowledge can in turn lead to a greater understanding of your particular production system. In regions where conserving water is critical, applying dry farming principles to irrigated systems can result in improved water use efficiencies, better weed management, and improved soil tilth and productivity.While these statistics clearly illustrate the enormous quantity of water used in agriculture, they also suggest that irrigation has far-reaching consequences on water quality. In an effort to maximize crop yields, many farmers apply nitrogen-based synthetic fertilizers. More than half of the nitrogen applied may go unused by crops, ending up in surface water runoff or leaching into groundwater and causing severe water quality and other public health concerns for rural communities, many populated by poor, immigrant farm workers.3 4 As this supplement illustrates, how farmers use irrigation and apply fertilizers affects not only their crops, but also their neighbors.