Inspectors and auditors thus shape the ways in which growers put rules and standards into practice, yet it is very difficult to gauge their consistency and level of influence. Second, produce buyers may impose additional, case-specific production specifications on their suppliers through purchasing contracts or even verbal communication.Little scholarship has examined how these varied and dynamic pressures have played out on California farms since 2009 or assessed whether and to what extent pressures and practices vary by crop type and farm size. Several developments in the past 7 years lend urgency to the need for updated and expanded data in these areas. First, in response to the reported tension between managing for food safety and managing for environmental quality , UC Cooperative Extension in collaboration with USDA’s Natural Resource Conservation Service and others has developed guidance for and sought to raise awareness of co-management, an adaptive strategy that seeks to reduce food safety risks without impairing environmental goals . Second, the aforementioned Produce Safety Rule now requires growers to meet national standards for agricultural water, soil amendments and preventive programs to mitigate contamination risk from wildlife and livestock. Third, the ongoing drought in California and heightened water quality control regulations for agriculture — such as the Central Coast Water Quality Control Board’s Conditional Waiver of Waste Discharge Requirements under California’s 1969 Porter-Cologne Act, vertical racking system the first order that does not allow waivers for agricultural contamination to waterways — may give new impetus for growers to preserve riparian and wetland vegetation that helps reduce nutrient contamination and implement other water conservation practices.
Lastly, public health officials and media continue to draw attention to the persistent risk of foodborne illness associated with fresh produce . As these ongoing developments intensify scrutiny of field-level production, there is a pressing need to assess the current state of on-farm practices and grower perspectives for food safety and conservation. To help address the need for such data, we collaborated with the California Farm Bureau Federation in 2014 to survey growers across the state.Little scholarship has examined how these varied and dynamic pressures have played out on California farms since 2009 or assessed whether and to what extent pressures and practices vary by crop type and farm size. Several developments in the past 7 years lend urgency to the need for updated and expanded data in these areas. First, in response to the reported tension between managing for food safety and managing for environmental quality , UC Cooperative Extension in collaboration with USDA’s Natural Resource Conservation Service and others has developed guidance for and sought to raise awareness of co-management, an adaptive strategy that seeks to reduce food safety risks without impairing environmental goals . Second, the aforementioned Produce Safety Rule now requires growers to meet national standards for agricultural water, soil amendments and preventive programs to mitigate contamination risk from wildlife and livestock. Third, the ongoing drought in California and heightened water quality control regulations for agriculture — such as the Central Coast Water Quality Control Board’s Conditional Waiver of Waste Discharge Requirements under California’s 1969 Porter-Cologne Act, the first order that does not allow waivers for agricultural contamination to waterways — may give new impetus for growers to preserve riparian and wetland vegetation that helps reduce nutrient contamination and implement other water conservation practices.
Lastly, public health officials and media continue to draw attention to the persistent risk of foodborne illness associated with fresh produce . As these ongoing developments intensify scrutiny of field-level production, there is a pressing need to assess the current state of on-farm practices and grower perspectives for food safety and conservation. To help address the need for such data, we collaborated with the California Farm Bureau Federation in 2014 to survey growers across the state.The survey yielded responses from 588 produce growers who reported more than $25,000 annual sales for their operation. Of these respondents, 536 reported growing fruits and nuts and 118 reported growing vegetables and melons . About one-fifth of respondents reported growing at least some certified organic produce, with 7% reporting growing exclusively certified organic produce. To estimate our survey response rate, we compared our respondents to the subpopulation of CFBF members growing fruits and nuts or vegetables and melons, who have operations with annual sales above $25,000. When the survey was sent in 2014, CFBF had 29,519 agricultural members, 10,905 of whom were on the organization’s email listerv. Fruit and nut growers represented 41% of CFBF members on the listserv, while vegetable and melon growers represented 15%. We therefore estimate the survey instrument was emailed to 4,471 fruit and nut growers and 1,636 vegetable and melon growers. CFBF does not track its members’ annual sales. Additionally, the survey did not indicate the percentage of sales by commodity for each respondent. However, we estimate response rates by assuming that the distribution of operations by annual sales is similar between CFBF members and the full population of California growers as reported in the 2012 census of agriculture . This would mean the survey was distributed to approximately 2,618 fruit and nut growers and 684 vegetable and melon growers with annual sales above $25,000, yielding estimated response rates of 20% for fruit and nut growers and 17% for vegetable and melon growers.
The CFBF membership is not necessarily representative of all California growers, and as such our respondents should be conservatively interpreted as a convenience sample. To assess the potential selection bias resulting from this non-probabilistic sample, we compared the proportion of respondents by crop type and annual sales to the statewide proportions reported in the 2012 census of agriculture . Statewide, the ratio of fruit and nut operations to vegetable and melon operations with more than $25,000 in annual sales is approximately 9:1. The statewide ratio of produce operations with annual sales between $25,000 and $500,000 to those with annual sales greater than $500,000 is about 3:1. Among our respondents, the ratios are about 4:1 and 1:1, respectively, meaning that our sample over-represents both vegetable and melon growers and farm operations with more than $500,000 in annual sales.In our analysis, we compare respondents by the annual sales reported for their farms. Based on FDA’s definitions of farm size used in the Produce Safety Rule , we define “large” farms as respondents who reported annual sales of $500,000 or more per year and “small” farms as those who reported annual sales between $25,000 and $500,000 per year; we excluded respondents reporting sales under $25,000 per year. Different market channels represent different clusters of consumer demand, and thus may be associated with different types and intensities of food safety pressure. In our sample, respondents reporting annual sales of at least $500,000 per year also reported selling primarily to broker, wholesaler, packer/shipper and processor market channels, while respondents reporting annuals sales under $500,000 per year were more likely to report selling primarily to farmers market and community supported agriculture channels. In addition to annual sales, different crops are associated with different agronomic practices and present different food safety risk profiles. In recognition of these differences, indoor grow facility we analyze respondents who reported growing vegetable and melon crops separately from those who reported growing fruit and nut crops .The survey asked respondents to indicate when, if ever, they had used any of a list of 11 on-farm practices specifically because of a food safety concern. Respondents were also asked to indicate use of a list of 22 conservation practices on land they farm. We implemented generalized linear mixed models to assess whether and to what extent farm size and organic status affect the likelihood that a grower uses on-farm practices for food safety or conservation . Fruit and nut growers were analyzed separately from vegetable and melon growers. Predictor variables included whether growers operated a large versus small farm, and whether they grew organically versus conventionally. We first built separate models with binomial errors and logit links for each on-farm practice. We then used likelihood ratio tests to assess the significance of predictor variables, comparing nested models with and without each predictor variable .
Because each on-farm practice was modeled individually, we used false discovery rates to account for multiple tests.Most respondents reported using at least one of the 11 on-farm practices for food safety queried in the survey, with about half reporting using at least four such practices . Among fruit and nut growers , 53% reported using non-poison traps and 52% reported using poison bait because of a food safety concern. Rates were similar across organic/conventional status and farm size, although our models show that large farms growing fruits and nuts were more likely than small farms to use poison bait . A higher proportion of vegetable and melon growers reported using non-poison traps , but fewer overall reported using poison bait . However, among vegetable and melon growers , our models show that large farms were significantly more likely than small farms to report using non-poison traps and poison bait . Reported use of wildlife fences was relatively low among fruit and nut growers , but 48% of vegetable and melon growers reported using wildlife fences. No significant difference was detected across organic status or farm size for either group. Similarly, less than half of fruit and nut growers reported removing vegetation from ditches or farm ponds;large farms were slightly more likely to report removing vegetation than were small farms. The majority of vegetable and melon growers reported removing vegetation from ditches or farm ponds; no significant difference was detected across organic status or farm size. A total of 40% of fruit and nut growers and 45% of vegetable and melon growers reported clearing vegetation to create buffers; no significant differences were found across organic status or farm size. Very few respondents in either produce category reported stopping use of, draining, or filling ditches or farm ponds because of a food safety concern. One in four fruit and nut growers and 17% of vegetable and melon growers reported using copper sulfate due to a food safety concern; large fruit and nut farms were significantly more likely to report use of copper sulfate than were small farms .Most respondents reported using at least one of the 20 conservation practices queried in the survey and about half reported using at least 5 such practices . However, very few of the 20 conservation practices, when considered individually, were reported to be in widespread use . Less than a quarter of growers reported currently using constructed wetlands, vegetated water treatment systems, raw soil amendment , grassed waterways and roads, riparian restoration, bee nest boxes, or beetle banks. In addition, among just fruit and nut growers, less than a quarter reported currently using a fully composted soil amendment , heat treated soil amendments , or tail water recovery ponds. The most commonly reported conservation practice in both groups was integrated pest management , with 74% of fruit and nut growers and 80% of vegetable and melon growers reporting currently using IPM. Our models show that large farms in both groups were significantly more likely to use IPM than were small farms. Most vegetable and melon growers also reported using cover crops and crop rotation . Despite low overall use, significant differences in reported use between small and large farms were found for many conservation practices. Among fruit and nut growers , our models show that large farms were significantly more likely than small farms to use bio-control agents , sediment or stormwater basins , tail water recovery ponds , crop rotation , and physically heat-treated soil amendments . Among vegetable and melon growers, large farms were significantly more likely than small farms to use sediment or stormwater basins and tail water recovery ponds . However, among these growers , small farms were significantly more likely than large farms to use native bee nest boxes , vegetated strips for native pollinators , and fully composted soil amendments . Not surprisingly, organic growers in both categories were more likely than conventional growers to report using bio-control agents and vegetated strips for native pollinators and pest predators. Organic fruit and nut growers were also more likely than their conventional counterparts to use cover crops, crop rotation and physically heat-treated organic soil amendments.