Location: Integrated Cropping Systems ResearchTitle: Assessment of soil attributes and crop productivity after diversification of the ubiquitous corn-soybean rotation in the northwestern U.S. Corn Belt
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/12/2017
Publication Date: 7/31/2017
Citation: Riedell, W.E., Osborne, S.L. 2017. Assessment of soil attributes and crop productivity after diversification of the ubiquitous corn-soybean rotation in the northwestern U.S. Corn Belt. p. 15. In: D. Presley (ed.) Abstracts of the Soil and Water Conservation Society Annual Conference. 30 July – 2 Aug 2017. Madison WI.
Technical Abstract: Highly specialized cash-grain production systems based upon corn-soybean rotations under tilled soil management are common in the northwestern U.S. Corn Belt. This study, initiated in 1997, was conducted to determine if diversification of this ubiquitous corn-soybean rotation would affect soil characteristics and crop productivity under no-till soil management. The effects of corn-soybean (C-S), corn-soybean-spring wheat (C-S-W), or corn-soybean-oat/pea hay-alfalfa-alfalfa (C-S-O/P-A-A) rotations on soil bulk density, organic C sequestration, and residual soil nitrate-N as well as on corn and soybean yield productivity and seed protein were investigated at Brookings SD on a Barnes loam soil. The C-S-O/P-A-A rotation reduced soil bulk density (1.37 g/cm3) compared to C-S (1.48 g/cm3) when measured prior to the corn phase. Soil C sequestration rates, extrapolated from soil C measurements made in 1999 and 2007 at 0-15 cm depth, were 142 kg C/ha/year for C-S, 33 for C-S-W, and 253 for C-S-O/P-A-A. Residual nitrate-N prior to corn was about 38 kg/ha for C-S-O/P-A-A and about 27 kg/ha for the other rotations. Prior to soybean, residual nitrate-N was about 129 kg/ha for C-S-O/P-A-A and about 65 kg/ha for the other rotations. For corn, when measured in 2008-2011, diversification of the C-S rotation with C-S-O/P-A-A increased grain yield (+9%) and increased seed protein (+6%). Diversification with wheat (C-S-W) increased corn yield (+10%) but had no effect on seed protein. For soybeans, when measured in 2009-2010, diversification of the C-S rotation with C-S-O/P-A-A increased yield (+9%) and seed protein (+3%). Diversification with wheat (C-S-W) also increased soybean yield (+3.5%) but had no effect on seed protein. Thus, diversification of the C-S rotation with C-S-O/P-A-A decreased bulk density, increased C sequestration, increased residual nitrate-N, increased corn and soybean grain yield and seed protein. In contrast, diversification with C-S-W only increased corn and soybean grain yield. These data elucidate the complex relationships between soil attributes, crop rotations, and crop yield that help provide a basis for improving the sustainability of agricultural systems to meet the demand for increased productivity while maintaining or improving the soil resource.