Cover Crop Strategies to Build Soil Organic Matter, thereby Enhancing Soil Biology, Water Retention and Weed Control in Organic Cropping Systems of the Western Corn Belt

Principal Investigators:

Dr. Rhae A. Drijber
University of Nebraska-Lincoln
316 Keim Hall
Lincoln, NE 68583-0915
Fax: 402-472-7904
[email protected]

Dr. John L. Lindquist
University of Nebraska-Lincoln
279 Plant Science Hall
Lincoln, NE 68583-0817
Fax: 402-472-3654
[email protected]

Project Abstract

We request funding to expand research initiated in 2009 on organic weed management with support from the Ceres Trust. The experiment was modified in 2012 from a spring terminated cover crop diversity trial in a sunflower–soybean–corn certified organic crop rotation to a winter wheat-corn-soybean rotation with four new cover crop treatments designed to improve soil water and nutrient availability and soil health, and further suppress weed populations. This certified organic field and crop rotation established in 2009 has now become a long-term experiment on organic crop rotations, cover crop strategies, weed suppression, and soil health. The first three years showed that a diverse mixture of spring-sown mustard cover crop species can reduce weed pressure in a subsequent row crops when terminated using a sweep plow undercutter. Research over the last three years showed that some (e. g. sunn hemp) cover crop species successfully improved soil nutrient content and subsequent crop yield. Soil microbial communities responded uniquely to each cover crop treatment – main crop combination, with mycorrhizal fungi showing increased resilience to the drought in 2012 when planted to winter wheat and in the presence of some cover crops. Project results will build on the first 3-year crop cycle by providing data for second complete crop cycle during years 2015-2017 as the system moves towards greater ecosystem stability. Our goal is to provide innovative solutions for organic farmers seeking increased productivity, profitability, and system resilience by increasing biodiversity and reducing off-farm inputs, and these in combination will improve environmental quality.

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