|TANAKA, DONALD - RETIRED ARS EMPLOYEE|
Submitted to: European Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2014
Publication Date: 8/25/2014
Citation: Liebig, M.A., Archer, D.W., Hendrickson, J.R., Schmer, M.R., Nichols, K.A., Tanaka, D.L. 2014. Agronomic responses to late-seeded cover crops in a semiarid region. European Society of Agronomy. P. 22. IN: European Society for Agronomy XIIIth Congress program book. 25-29 Aug 2014. Debrecen, Hungary.
Technical Abstract: Intensification of cropping systems in the Great Plains beyond annual cropping practices may be limited by inadequate precipitation, short growing seasons, and highly variable climatic conditions. Inclusion of cover crops in dryland cropping systems may serve as an effective intensification strategy, though there is a lack of science-based information to support their use in semiarid regions. We sought to quantify short-term agronomic, environmental, and economic outcomes associated with including late-seeded cover crops in dryland cropping systems in the Northern Great Plains. A strip-block experimental design was employed to evaluate effects of 20 cover crop treatments on a spectrum of relevant response variables. Strips of cover crop treatments (designated whole-block treatments) were planted following dry pea harvest in mid-August and allowed to grow through the remainder of the growing season. Cover crop treatments included a no-cover control, with and without a planting operation, and 18 combinations of one or more of seven cover crop species. In the following growing season, four ‘response crops’ (corn, spring wheat, dry pea, and soybean; designated split-block treatments) were seeded perpendicular to the cover crop strips, thereby creating a crop sequence/cover crop matrix. Aboveground biomass production of cover crops varied considerably across years and was strongly associated with late-season precipitation. Cover crop treatments including a mixture of warm- and cool-season crops were dominated by the latter, with spring triticale, turnip, and forage pea comprising the majority of aboveground biomass. Cover crop effects on subsequent crop production were neutral. Results from this study suggest inclusion of late-season cover crops in dryland cropping systems is highly risky and confers negligible agronomic benefits in the short-term.