California Agriculture

Buffer zone requirements are by nature spatial and their effects are site-specific, with some fields — because of their location — more impacted than others. Using a set of strawberry fields in Ventura County that were preplant soil fumigated in 2013 as a baseline, we examined how much acreage eligible for chloropicrin fumigation would have been lost if either of two buffer zone distance regulations had been in effect: any one of the four sets of alternative distances proposed in May 2013 by the California Department of Pesticide Regulation (DPR) or the buffer zone distances DPR released in January 2015. Buffer zone distances are based on several factors including the anticipated protection of human health, referred to as the percentile of protection. We find that the effects are highly dependent on the percentile of protection. From 4% to 29% of the fumigated blocks analyzed would have had an increase in buffer zone acreage depending on the percentile of protection. In those blocks, the share of total acreage that would no longer have been eligible for fumigation with chloropicrin varied from 3% to 45%. We also identify strategies that growers employed to reduce required buffer zone distances under use requirements in effect in 2013. The most frequently used strategies were using a tarp type with the lowest buffer zone requirements (“60% tarp”), extending a buffer onto a neighboring property, road and/or farm path, and reducing application rates. The results have an important policy implication: spatially defined use regulations have very different effects for different fields; aggregated industry-level analyses will miss the range of impacts on growers.