CONSERVATION TILLAGE COTTON AND PROCESSING TOMATORESEARCH IN CALIFORNIA’S SAN JOAQUIN VALLEY

摘要

Less than 1% of row crop acreage in California is currently farmed using conservation tillage (CT) practices. Adoption ofCT systems in California has, however, recently been seen as a potential means for improving profitability and reducingenergy use and a number of research, demonstration and evaluation initiatives are currently underway to explore a variety ofcropping system options for reducing tillage. In the fall of 1999, we established a 3.2 hectare field experiment comparingconservation and standard tillage (ST) cotton and tomato production systems with and without winter cover crops at theUniversity of California West Side Research and Extension Center in Five Points, CA. To date, this study has demonstratedthat planting and harvesting crops with conservation tillage systems is possible given some equipment modifications and thatyields can be maintained relatively close to those of standard tillage in CT crop residue environments. Data from the secondyear of this study indicate that tomato yields in the CT + cover crop systems were similar to those in the standard till plots,with an elimination of six tillage operations following last year’s cotton crop in the CT plots relative to the standard tillsystems. 2001 cotton yields were reduced 11 and 18% in the CT – cover crop and CT + cover crop systems, respectively,relative to the standard tillage control system, however, there was an elimination of 8 or 9 tillage operations in the CTsystems relative to the ST approach following the 2000 tomato crop. Estimated resource use per acre (hours of labor andgallons of fuel) indicate the possibility of the CT systems to reduce these inputs relative to the standard till systems. Thisstudy is the first of its kind in California to systematically compare tillage system alternatives through a crop rotation.Longer-term implications of these reduced till regimes in terms of soil compaction, water use, profitability, soil carbonsequestration, insects and diseases are being evaluated as the study progresses through a four-year cycle.