2002-2004 Specialty Crops Research Program
University of California

Principal Investigators: Jeffrey P. Mitchell and Randal Southard

Project title: Does Conservation Tillage Reduce Dust Emissions in Central Valley Specialty Crop Rotations?

Adoption of conservation tillage (CT) practices may be a viable means for improving profitability and reducing energy use, dust, NOx, and CO2 emissions in California specialty row crop production systems. In their many and varied forms, CT systems aim at reducing primary tillage operations such as plowing, ripping, disking, and chiseling. Less than 0.5% of row crop acreage in California, however, is currently farmed using CT practices largely because producers lack information on the potential benefits of these alternatives. Participant feedback from UC Conservation Tillage Workgroup CT conferences indicates a genuine interest in CT technologies among California producers provided successful system benefits are demonstrated. A potentially significant benefit of reduced till systems might be reductions in PM10 and PM2.5 (particulate matter with an aerodynamic diameter less than 10 and 2.5 micrometers) emissions due to reduced tractor traffic across a field. The United Stated Environmental Protection Agency has designated the San Joaquin Valley a serious non-attainment area for PM10. This means the valley exceeds the National Ambient Air Quality Standards for PM10 to such a degree that extreme actions may be required to meet them. There currently is no data on the relative dust emissions associated with CT production systems. This proposed project will address the critical need for comparative information on field-scale dust emissions from standard and conservation tillage systems by collecting data at two 2-year farm test sites. Previously-developed, standard sampling techniques will be used to quantify field fugitive dust emissions under standard tillage, minimum (bed disking) tillage, and conservation tillage crop rotations. In conjunction with this sampling, we will also compile and analyze records of the operations, productivity and profitability of each production system under study. The project will be initiated in the fall of 2002 and will be conducted through two complete annual cropping cycles at two farms in the Central Valley. The interdisciplinary team that will carry out this proposed work consists of a University of California, Davis Cooperative Extension Vegetable Crops Specialist who is Chair of the University’s Division of Agriculture and Natural Resources Conservation Tillage Statewide Workgroup and a UC Davis soil scientist, with a UC Davis atmospheric scientist serving as a consultant to the project. The UC Division of Agriculture and Natural Resources Conservation Tillage Workgroup consisting of over 90 UC, USDA ARS and NRCS, private industry, public agency, and farmer members, will be the primary means through which the goals and findings of this study will be disseminated. This information will be included as part of the Workgroup’s Annual Conferences, website and public field meetings.