To explore the potential for voluntary mitigation of agricultural emissions in Yolo County, local officials held a series of stakeholder meetings in 2010 and 2011 where members of the agricultural community provided input on proposed mitigation strategies and policies outlined in the county’s climate action plan. Table 7 and the paragraphs below highlight many of the trade offs and co‐benefits identified by local stakeholders. Since N2O emissions originating from the use of N fertilizers were the largest source of agricultural emissions, strategies to further optimize N management are a high priority . Local field and modeling studies suggest that reducing N applications, organic production, and cover cropping all have potential to reduce N2O emissions with minimal affects on crop yield . An examination of local archived cost and return studies indicates that recommended N rates have already decreased somewhat for corn, wheat, hay, and grapes over the past 20 years, but have increased slightly for tomatoes, melons, rice, and almonds . Thus, while some growers have already improved N management, further reductions in N inputs are possible for some crops . County records indicate that organic production has expanded from approximately 250 to 2500 ha over the study period, but is still less than 2 percent of the total irrigated cropland. Cover cropping has become more common in recent years , but is less viable in rotations that require early planting dates. Local outreach programs conducted in partnership with agricultural organizations and local UCCE cooperative extension are underway to share information on practices, technologies,blueberry package and incentives that will help growers optimize N rates while maintaining yields, cover cropping, and other organic‐based practices.
Policy makers should seek opportunities to align future mitigation initiatives with these nascent efforts. Local strategies to minimize emissions from mobile farm equipment and diesel irrigation pumps were also considered . As a first step, local officials have proposed a series of workshops and information bulletins that would focus on possible fuel savings achieved through routine engine and pump bowl assembly maintenance or more efficient field operations . These workshops could also be used to encourage participation in California’s Carl Moyer Off‐Road Equipment Replacement Program, which provides financial assistance for new equipment or engine upgrades that meet or exceed state air quality standards . The benefits and trade offs of policies to reduce CH4 emissions from livestock were also explored. For livestock raised primarily on pasture, practical options to reduce CH4 emissions from enteric fermentation and manure management are limited. This is because livestock managers cannot intensively manage the diet and manure of animals raised in an extensive rangeland setting. Furthermore, manure deposited in pasture undergoes aerobic decomposition and thus has a lower rate of CH4 emissions than manure stored in the anaerobic lagoons used by confined livestock operations . For the small number of animals in confined facilities, policies to help livestock managers fund biogas control systems could reduce countywide CH4 emissions from livestock by as much as 10 percent. In addition to the expense of installation, strict air quality standards can sometimes pose a disincentive for adoption since they require engines that burn methane to emit less than 50 parts per million of nitrogen oxides . A reevaluation of state and local air quality regulations in light of the possible climate change benefits associated with biogas control technologies could help strike a balance between air quality and climate change objectives.
Emissions of CH4 from rice cultivation in Yolo County provide another example of how differing air quality and climate change priorities can sometimes lead to policies that run contrary to one another. Prior to 1991, virtually all rice straw in California was burned in the field after harvest; a practice that led to protracted public debate about local air pollution and culminated with the passing of the Rice Straw Burning Act . As an alternative to burning, most rice farmers shifted their post‐harvest practices to a combination of residue incorporation and winter flooding, which has led to lower yields and higher production costs . These policy‐driven changes in residue and water management have improved air quality in the Sacramento Valley and enhanced winter habitat for migratory waterfowl. However, field studies testing the effects of residue incorporation and winter flooding now estimate that this policy has led to a two‐ to three‐fold increase in the amount of CH4 emitted from California rice fields . The increase in countywide CH4 emissions arising from this regulatory measure, as estimated in this study using the DNDC model, is consistent with these findings. Management options that can help reduce CH4 emissions include baling straw for off‐ farm uses , mid‐season drainage, and reduced winter flooding. However, before promoting such practices policy makers should carefully consider how they might affect grower livelihoods and the other ecosystem services provided by local rice fields. Estimates presented in this study indicate that emissions from burning crop residues and the application of lime and urea are a very small fraction of agricultural emissions in Yolo County, and have already been declining over the past two decades. This suggests that additional policies targeting residue burning, lime, and urea will have little impact on overall emissions. By contrast, recent landscape studies conducted in Yolo County suggest that programs to sequester carbon in agricultural soils and plant biomass through various reforestation projects have considerable potential to offset the county’s GHG emissions .
Carbon can also be sequestered in the biomass of perennial orchard crops, however at present offset protocols for these systems do not exist. At present, the lack of high‐resolution data on the diverse range of agricultural practices used here in Yolo and the shift in practices over the past 20 years makes it very difficult to estimate changes in soil and woody biomass carbon with any degree of accuracy. Future research could investigate how restoration efforts might be able to increase carbon sequestration in soil and wood using spatially explicit modeling, with special focus on management of marginal lands. The sale of carbon offset credits in California’s new carbon market is also a potential opportunity to raise funds for reforestation and farm scaping projects, assuming that future protocols to quantify and monitor local carbon storage can meet the criteria of being real, permanent, quantifiable, verifiable, enforceable, and additional .Given agriculture’s direct reliance on natural resources, people who make their living from agriculture are highly vulnerable to climate change . While climate change is a complex global phenomenon, localized impacts with significance to agriculture are already being observed in California. Noteworthy examples based on empirical records include; rising mean temperatures, declining snow pack in the Sierra Nevada, temporal changes in stream flows, and a reduction the in winter chill hours required for many fruit and nut crops . Since these climatic trends are expected to continue in the decades ahead,blueberry packaging strategies which integrate innovative agricultural practices with effective local outreach programs and policies are needed to support California’s agricultural stakeholders in their efforts to adapt to climate change and mitigate the emissions that contribute to it . To better inform climate change programs and policies, a sound understanding is needed about what influences farmers’ perception of climate change and their subsequent adaptation and mitigation responses. A number of studies have indicated that characteristics of the individual farmer and their farm can influence their perception of and response to climate change . Other studies have demonstrated that farmers’ views on the occurrence of climate change, as well as their response, is more often related to recent climate trends or weather events as opposed to long‐term changes in mean temperatures or precipitation . Levels of concern about the future impacts of climate change can also be a strong motivator to adapt or mitigate, though very few studies have explored this explicitly among farmers . Social networks and involvement in programs run by local institutions, agricultural organizations, and extension services have also been shown to play a key role in facilitating farmers’ ability to respond . Likewise, farmers’ views on government programs and environmental policies can also influence their perceptions of climate change and what adaptation and mitigation practices they are inclined to adopt .
Adaptation practices are meant to help farmers cope with potential future impacts, while mitigation practices are intended to minimized GHG emissions and/or sequester carbon in the agricultural landscape. Some agricultural practices may facilitate adaptation and mitigation simultaneously; however, most changes in practice require farmers to consider a mix of trade offs and co‐benefits . Whether or not a new practice is desirable to a farmer may also depend on the time frame of the benefit, and if the benefits of adopting are public or private . For example, adaptation and/or mitigation practices with direct short term benefits to the farmer are likely to be preferred over practices that yield only long‐term public benefits to society. As such, different factors can influence the practicality and profitability of certain adaptation and mitigation practices, and thus result in non‐uniform patterns of adoption. Against this brief conceptual backdrop, the goal of this study is to: examine farmers’ perceptions of climate change and its risks to agriculture; and develop a better understanding of how the various factors mentioned above influence farmers’ adoption of proposed adaptation and mitigation practices. To develop an ethnographic understanding of local farmers’ livelihoods, their perceptions of climate change, and their views regarding climate risks we conducted semi‐structured interviews with eleven farmers and two agricultural extension workers in the fall of 2010. A purposive sampling strategy was used to recruit respondents from a cross section of farm sizes, local cropping systems and market orientations . Interviewers followed a set of open‐ended questions to minimize prompting and interviewer bias, but allow respondents to share personal experiences from their career in agriculture and their perspectives on various economic, regulatory and climate‐related issues. Audio recordings of the interviews were transcribed and used to develop a quantitative survey which was mailed to farmers in Yolo County during February and March of 2011. Prior to mailing, the survey was further refined based on detailed comments provided by members of the Yolo County Farm Bureau. A copy of the final survey is available upon request. The survey sample was drawn from a mail and phone list of 572 individuals in Yolo County who have submitted pesticide use permits to the Yolo County Agriculture Commissioner’s office. The State of California requires all farms and businesses that apply conventional or certified organic pesticides to request a permit through the local agricultural commissioner, who then maintains this database as a part of the public record. The mail survey was conducted using the tailored design method . An alert postcard was mailed in mid‐February and followed a week later by a survey packet containing a cover letter, survey booklet, and return envelope. A second round of postcards and survey packets were mailed two weeks later. A final round of follow‐up postcards and phone calls were made to those on the mail list that did not respond. The follow‐up phone calls indicated that approximately 82 percent of unknown non‐ respondents were the owner or principle operator of a farm, and thus eligible for the study, while the remaining 18 percent were outside its intended scope . Of the 572 surveys mailed out, 162 were returned with sufficiently complete answers to be used in the study. This amounts to a raw response rate of 28.3 percent and a final response rate of 34.0 percent . An analysis of descriptive statistics and bivariate regressions was conducted using STATA 11 .Results of the survey indicated that 54.4 percent of farmers in Yolo County agreed to some extent with the statement “the global climate is changing” . A plurality also agreed that global temperatures were increasing and that human activities were an important cause of climate change . Those who were skeptical of the role of human activities, however, tended to disagree strongly. Most respondents agreed that climate change poses risks to agriculture globally , though many felt it also offered opportunities . As such, when asked if the overall impacts would be positive or negative, a larger fraction of farmers expressed uncertainty regarding the outcome .