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United States Department of Agriculture

Agricultural Research Service

Research Project: Strategies to Improve Soil and Pest Management in Organic Vegetable and Strawberry Production Systems

Location: Crop Improvement and Protection Research

Project Number: 5305-21620-013-00
Project Type: Appropriated

Start Date: Nov 08, 2013
End Date: Nov 07, 2018

Objective:
Organic farmers on the Central Coast of California produce a large proportion of the high-value, cool-season vegetables and strawberries for the U.S. Most farmers here lease their land and must produce several crops on each field annually to remain profitable. This limits the opportunity to include cover crops in rotations. The primary focus of this project is to produce information, management tools, and technologies to help farmers integrate cover crops and compost into intensive vegetable and strawberry production systems, maximize the benefits from cover cropping, and reduce production costs. The main objective of this project is to develop ecologically-based soil management strategies that enhance soil quality, nutrient cycling, pest and disease management, and profitability, and reduce off-farm inputs, organic vegetable and strawberry production systems. The subobjectives are as follows: 1. Evaluate the effects of cover cropping frequency and compost on soil quality, vegetable and strawberry yields, soil borne disease, and system profitability. 2. Evaluate the effects of a legume-rye mixture versus non-legume cover crops on vegetable and strawberry yields. 3. Evaluate the effects of cover crop seeding rates on weed density and weed management costs in subsequent vegetable and strawberry crops grown in rotational sequences. 4. Identify pathogens causing emerging bacterial diseases of organic vegetables and small fruit.

Approach:
The first three sub objectives will be addressed using unpublished data collected during the first 10 years of the Salinas Organic Cropping Systems (SOCS) experiment, and with additional laboratory analyses on archived soil samples using standard proceedures. During the next 5 years, experiment will continue with a less intense management phase to provide the team with the time to analyze and understand the existing data before deciding if the experiment should be terminated or continued. Furthermore, a complete analysis of unpublished data from the first 10 years is essential to provide insights into potential modifications to the existing treatments, and to formulate meaningful questions to be addressed if a new long-term study is initiated. The following hypotheses will be tested for the first three subobjectives outlined above. - Soil quality will be higher in systems where cover crops are used annually than in systems where they are used only quadrennially. - Soil quality will be higher in systems that receive compost annually than systems that only receive cover crops. - Vegetable and strawberry yields will be higher in systems where cover crops are used annually than in systems where they are used only quadrennially. - Vegetable and strawberry yields will be higher in systems that receive compost annually than systems that only receive cover crops. - Profits will be higher in systems where cover crops are used annually than in systems where they are used only quadrennially. - Profits will be higher in systems that receive compost annually than systems that only receive cover crops. - Verticillium microsclerotia counts will be higher in systems that receive legume-rye cover crops than systems with non-legume cover crops. - Vegetable and strawberry yields will be higher following legume versus non-legume cover crops. - Weed density will be lower in vegetable and strawberry systems where cover crops were planted at relatively high seeding rates over several years, than when using lower seeding rates. - Weed management cost during vegetable and strawberry production will be lower in rotations where cover crops were planted at relatively high seeding rates over several years, than when using lower seeding rates. The results from this SOCS experiment will be communicated to stakeholders by publications and presentations. The results from the first 10 years may indicate that there would be value in collecting additional field data or conducting additional analyses of archived soil samples. If this occurs we will modify our plan to collect this additional data with our existing collaborators or seek additional collaborations as needed. The fourth sub objective will be achieved by soliciting samples of new diseases from organic fields. Samples will be analyzed with standard methods to identify the bacterial pathogens. The results will be reported to the growers through publications and presentations. If samples are not submitted, work will be conducted to resolve the etiology of diseases from organic systems for which isolates have been obtained but research has not proceeded.

Last Modified: 9/21/2014
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