Maize residue removal and cover crop effects on subsequent soybean crops

Authors: Riedell, Walter; Osborne, Shannon; DAGEL, KURT - Former ARS Employee

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2017
Publication Date: 11/7/2017
Citation: Riedell, W.E., Osborne, S.L., Dagel, K.J. 2017. Maize residue removal and cover crop effects on subsequent soybean crops. Agronomy Journal. 109:2762-2770. https://doi:10.2134/agronj2017.05.0245.
DOI: https://doi.org/10.2134/agronj2017.05.0245

Interpretive Summary: The current crop, soil, and residue management practices utilized in northwestern U.S. Corn Belt may not be environmentally sustainable because crop monoculture or short rotations depress grain yield and intense soil tillage enhances potential for topsoil loss to wind and water erosion. Additionally, residue harvest for silage or biofuel feedstocks may also have deleterious effects on soil quality. Given these constraints, farmers walk a fine line between agricultural degradation and sustainability when selecting crop, soil, and residue management practices. Because farmers are interested in how crop, soil, and residue management practices affect soil health and the sustainability of crop production, we designed a long-term experiment to study the effect of corn residue removal and cover crop treatments in a corn/soybean rotation under no-till soil management. The objectives of our study were to measure the effects of corn residue removal and cover crop treatments on the subsequent soybean crop in terms of grain yield, seed moisture at harvest, and essential mineral elements. In summary, we found that under drought conditions, when all crop residue was returned to the field after grain harvest, that these plots had greater soybean yield when compared to residue management practices where corn stalks were chopped and removed or if all residue and grain were removed as silage. Thus, the potential negative effect of corn residue removal on soybean grain yield was mitigated during years with moderate air temperature and adequate precipitation.

Technical Abstract: There is limited information on how maize residue removal and cover crops affect yield and seed composition in subsequent soybean crops. Objectives were to examine maize residue removal and cover crop effects on soybean grain yield, seed moisture at harvest, and seed mineral concentrations. Three maize residue removal treatments [LRR (low residue removal; grain harvest only), MRR (medium residue removal; stalks chopped after grain harvest, windrowed, and removed), and HRR (high residue removal; cutting stalks and removing fodder as silage)] were superimposed on a 2-yr maize-soybean rotation established near Brookings SD in 2000 under no-till soil management. Sub-plot treatments were the absence or presence of cover crops (fall planted slender wheat grass in corn and hairy vetch/oats in soybean). Data from the 2009 through 2012 were evaluated. Seed moisture was less while seed N concentration was greater under MRR or HRR than under LRR across all years. Warmer soil temperature under MRR and HRR likely increased plant development which reduced seed moisture at harvest and enhanced uptake of N. Only during the hot and dry 2012 season did the MRR and HRR treatments result in less grain yield than LRR while yield was also less under cover crops than in their absence. Thus, the potential negative effects of maize residue removal or cover crop cultivation on soybean grain yield were mitigated during growing seasons characterized by moderate temperature and adequate rainfall.