| This profile is part of "Sustainable Agriculture... Continuing to Grow", a publication developed to present some of the excellent sustainable agriculture research and education work done by universities, nonprofit organizations and other institutions in the Western Region over the past twelve years. Additional profiles and abstracts will be posted weekly, with links provided in the Table of Contents. |
Pioneering
Conservation Tillage Row Crop Production
Systems in California
Jeff P. Mitchell
Co-authors: W.T. Lanini, E.M. Miyao, S.R. Temple, M.D. Cahn, P.N. Brostrom, K.J. Hembree, D.S. Munk, T.S. Prather, C. Summers, J. Stapleton, B. Fouche and R.J. Mullen
Despite a 300% increase in conservation tillage (CT) production in the Midwest during the past decade, less than 0.3% of the acreage in California’s Central San Joaquin Valley is currently farmed using CT practices.
Preplant tillage operations typically account for 18-24% of overall production costs for annual crops grown in the West Side region of the San Joaquin Valley. An average of 9-11 tillage-related passes are routinely done during the fall-spring period to prepare the soil for summer cropping. These passes represent not only considerable energy, equipment and labor costs, but recent research indicated that tillage reduced soil organic matter (SOM) and emits considerable respirable dust as well. Because SOM is widely regarded as an important attribute of good soil quality and long-term productivity, interest has been growing over the last several years, in developing alternative production systems that reduce costs while at the same time improve the soil resource through greater carbon sequestration. Primary incentives for row crop producers in California’s Central Valley that have led to this interest include reducing production costs, conserving and improving the soil resource base, and for organic producers, the potential of using surface residues as an adjunct weed management strategy.
Over the last five years, we have conducted numerous evaluations and demonstrations of CT practices in a variety of row crop contexts throughout California. These studies have demonstrated that for a number of crops including processing and fresh market tomatoes and melons, that planting and harvesting in surface residues is possible, productivity is maintained with certain mulches, weed control by mulches alone is generally not adequate and additional in-season cultivation or intervention may be needed, changes in a variety of soil properties may result, air temperatures over mulches tend to be lower, and that there may be allelopathic interactions between certain mulches and these crops.
Jeff P. Mitchell
Kearney Agricultural Center
University of California
9240 S. Riverbend Ave.
Parlier, CA 93648
Tel: (559) 646-6565
The work to create this publication was sponsored by the Western Sustainable Agriculture Research and Education (Western SARE) program. Western SARE is an effort of the U.S. Department of Agriculture. Since 1988 through federal fiscal 2000, the U.S. Congress has allocated more than $114.6 million to the federal SARE effort; Western SARE has received $26 million. The Western region includes Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming and the Island Protectorates of American Samoa, Guam, Micronesia and the Northern Mariana Islands.