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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #330431
Title: Crop yield and soil organic carbon in conventional and no-till organic systems on a claypan soil

Author
item CLARK, KERRY - University Of Missouri
item BOARDMAN, DARA - University Of Missouri
item STAPLES, JILL - University Of Missouri
item EASTERBY, STEVEN - University Of Missouri
item REINBOTT, TIMOTHY - University Of Missouri
item KREMER, ROBERT - University Of Missouri
item Kitchen, Newell
item Veum, Kristen

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2017
Publication Date: 3/9/2017
Citation: Clark, K., Boardman, D.L., Staples, J.S., Easterby, S., Reinbott, T.M., Kremer, R.J., Kitchen, N.R., Veum, K.S. 2017. Crop yield and soil organic carbon in conventional and no-till organic systems on a claypan soil. Agronomy Journal. 109(2):588-599. doi: 10.2134/agronj2016.06.0367.

Interpretive Summary: Organic crop production follows agricultural practices that limit the use of many conventional pesticides, fertilizers, or other amendments. Therefore, organic production systems often rely on tillage for weed control, despite the potential for losses of soil organic matter under conventional tillage (inversion tillage). Alternative management practices, such as reduced tillage with cover crops, have the potential to reduce soil disturbance and weeds while maintaining productivity. Reduced tillage practices are particularly important in regions with marginal and vulnerable soils, such as the claypan soils. Claypan soils cover 2.9 million km-2 globally, have a restrictive layer that impedes water infiltration, and are prone to runoff and degradation. This study evaluated crop yield and organic matter levels under three organic production systems and four poultry compost amendment rates on claypan soils in Boone County, MO from 2012-2014. Organic no-till with a cover crop was compared to a conventionally tilled organic system with and without cover crops in a wheat– corn–soybean rotation. Cover crops included cereal rye and hairy vetch. Under no-till, soil fertility declined, leading to insufficient cover crop biomass for weed suppression. In addition, corn yield declined 30% in 2013 under no-till due to insufficient N supply. In contrast, soybean grown under organic no-till was competitive with tilled treatments as long as soil moisture and weed control were adequate. Therefore, optimum timing of cover crop crimping (flattening with a roller to create mulch) appears to be a critical factor for successful no-till in organic production systems. Overall, the results of this study will benefit organic producers to help them improve environmental protection while maintaining productivity and profitability.

Technical Abstract: Organic crop production is dependent on tillage for weed control, but because tillage can lead to decreased levels of soil organic carbon (SOC), alternative management needs to be explored. This study was conducted in Boone County, MO in a Mexico silt loam soil (fine, smectitic, mesic Vertic Epiaqualfs) in 2012-2014 to determine the effects of three organic production systems and four poultry compost rates on crop yield and SOC on a claypan soil. Organic no-till was compared to a tilled organic system using a winter cover crop and to a system using tillage and no cover crop in a wheat (Triticum aestivum L.) – corn (Zea mays L.) –soybean (Glycine max L.) rotation. Cover crops included cereal rye (Secale cereale L) and hairy vetch (Vicia villosa L.). Achieving a cover crop biomass sufficient for weed suppression was a challenge when soil fertility declined during the study. Corn yield was reduced 30% in 2013 in no-till plots compared to tilled although plant populations were nearly equal, indicating the N immobilization may be significant in crimped cover crops. When there was adequate soil moisture and weed control from the cover crop, soybean grown under organic no-till was competitive with tilled treatments. Optimum timing of cover crop crimping for acceptable weed control was more successful in a soybean production system compared with corn. Organic no-till in this study was more successful in soybean and wheat than in corn, when the cover crop biomass was sufficient to suppress weeds.