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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #269306
Title: Utilizing cover crop mulches to reduce tillage in organic systems in the southeastern USA

Author
item REBERG-HORTON, S - North Carolina State University
item GROSSMAN, JULIE - North Carolina State University
item Kornecki, Ted
item MEIJER, ALAN - North Carolina State University
item Price, Andrew
item PLACE, GEORGE - North Carolina State University
item Webster, Theodore

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2011
Publication Date: 3/1/2012
Citation: Reberg-Horton, S.C., Grossman, J., Kornecki, T.S., Meijer, A.D., Price, A.J., Place, G.T., Webster, T.M. 2012. Utilizing cover crop mulches to reduce tillage in organic systems in the southeastern USA. Renewable Agriculture and Food System. 27(1):41-48.

Interpretive Summary: Organic systems in the southeast offer unique challenges and solutions due to regional soil and climate characterized by highly weather soil types, high precipitation, and the capacity to grow cover crops in the winter. Recently high-residue cover crops and conservation tillage systems have increased in interest by producers and researchers. Long-term data is needed to predict when farmers should add supplementary weed control. More work is also needed on how much additional N is required for the cash crops and how best to deliver that N in a high residue environment using organic sources.

Technical Abstract: Organic sytems in the southeast offer unique challenges and solutions due to regional soil and climate characterized by highly weather soil types, high precipitation, and the capacity to grow cover crops in the winter. Recently high-residue cover crops and conservation tillage systems have increased in interest by producers and researchers. Various designs of the roller-crimper to manage cover crops have been invented and demonstrated to growers in the southeastern region of the U.S. over the past 17 years. The impacts of high-residue cover crop mulches on the agronomic systems are diverse. Legume cover crops assist with meeting N demand from cash crops though they decompose rapidly and are seldom sufficient for N demanding crops such as corn. Cereal cover crop mulches can have the opposite effect by immobilizing N; thus, they have a longer impact on soil moisture and weed dynamics. While undesirable for many crops, N immobilization is one possible mechanism for weed suppression in legume cash crops planted into cereal residues. Other cover crop weed suppression mechanisms include physical impedance, light availability, allelopathy and microclimate effects. Regardless of the cause, successful weed control by mulches is highly dependent on having substantial biomass. The southeastern region is capable of producing cover crop biomass in excess of 9,000 kg ha-1, which is sufficient for weed control in many cash crops, but supplementary weed control is sometimes necessary. Long-term data is needed to predict when farmers should add supplementary weed control. More work is also needed on how much additional N is required for the cash crops and how best to deliver that N in a high residue environment using organic sources.