2011 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.
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 novel methods for preparing cover crop seed for planting with a cone seeder, (2) a preliminary evaluation of cover crop mixtures of faba bean mixed with rye versus oats and (3) 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 eighth year of the long-term, multidisciplinary experiment with eight different organic systems for high-value, organic vegetable production was completed in FY 2011. 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.
A time-efficient method for preparing seed for cone planter. Cone planters uniformly distribute seed over plots and are widely used for agronomic and cover crop trials. The standard method for preparing seed for such trials involves weighing individual seed packets and is extremely time consuming. An ARS researcher in Salinas, CA, developed and compared a novel scooping method with the standard method and found that the novel method required half as much time but was equally as accurate for a wide variety of seed types and seed mixtures. This novel method significantly reduced the time required for preparing seed agronomic and cover crop trials, and thus will reduce the labor costs of such research.
Brennan, E.B. 2011. A time-efficient scooping method to prepare cover crop seed for cone planters. Agronomy Journal. 103(3):906-913.
Brennan, E.B., Boyd, N.S., Smith, R., Foster, P. 2011. Comparison of rye and legume-rye cover crop mixtures for vegetable production in California. Agronomy Journal. 103(2):449-463.