2010 Annual Report
1a.Objectives (from AD-416)
Develop ecologically-based soil and pest management strategies that enhance soil quality, nutrient cycling, and profitability, and reduce off-farm inputs in high-value, organic vegetable production systems.
Sub-objective 1.A. Evaluate the effects of cover cropping frequency and compost application on soil quality, vegetable yield and quality, and system profitability.
Sub-objective 1.B. Evaluate the effects of a legume-rye mix versus non-legume cover crops on vegetable yield.
Sub-objective 1.C. Evaluate the effects cover crop seeding rates on weed density and weed management costs in subsequent vegetable crops grown in rotation sequences.
Evaluate the energy efficiency, costs, and effectiveness of standard and alternative technologies and strategies for managing cover crop residue in high-value organic vegetable production.
Sub-objective 2.A. Compare fuel use, labor costs, and agronomic effectiveness of cover crop residue incorporation with standard primary tillage implements (disc-and-chisel) versus with an alternative implement (spader).
Sub-objective 2.B. Evaluate the roller-crimper implement for killing cover crops on beds for no-tillage organic vegetable production.
1b.Approach (from AD-416)
Organic production is increasing in the U.S., a response in part to public concerns about agricultural sustainability, food safety, & environmental quality. While farmers may consider moving to an organic system, continuity of economic viability during the transition from conventional to organic farming systems is a serious challenge. There is little scientific, organic-based information for farmers as they choose among the options available for the build-up of soil organic matter, maintenance of soil fertility, crops and cultivars, and disease and insect pest management practices. Improved understanding of the processes that occur during the transition to mature organic production systems is necessary to ensure the economic success of organic farming systems.
Replacing 5305-21620-011-00D (9.08).
Research in organic systems is severely lacking despite the recent growth of the organic market. The research in this project occurs on certified organic land at the ARS and on collaborating farms and includes short-term component research and long-term systems research. The long-term systems research during the past year focused on crop rotations, soil fertility management, weed management, and cover cropping in high-value organic vegetable systems. The short-term component research during the past year included (1) evaluating an implement called a roller/crimper for mechanically killing cover crops on beds used for vegetable production, and (2) intercropping studies with organic vegetable crops and beneficial insect habitat crops. This research is applicable to small, medium and large-scale organic farms, and to conventional farms that are shifting to more sustainable soil management practices. This research involved collaboration on multidisciplinary projects with scientific and extension personnel from other agencies.
The seventh year of the long-term, multidisciplinary experiment with eight different organic systems for high-value organic vegetable production was completed in FY 2010. This ongoing study is the major focus of this project and is the longest running systems study in California on high-value organic vegetable production systems. Data were collected on cover crop yield, weed biomass and densities, vegetable production, soil quality, soil microbes, and profitability. These data demonstrated the critical importance of using higher seeding rates for a legume-rye cover crop to maximize weed suppression in subsequent vegetables. The data also revealed that frequent cover cropping is much more important than compost application for maintaining vegetable yields and improving soil quality.