LAUSR

Residue management and cover crops are important cropping system components. Maize (Zea mays L.) residue removal and cover crop effects on soybean [Glycine max (L.) Merr.] seed moisture at harvest, grain yield, and seed mineral concentrations were examined. Maize residue removal treatments [low-residue removal (LRR) (grain harvest only), medium-residue removal (MRR) (stalks chopped and baled after grain harvest), and high-residue removal (HRR) (stalks cut and removed as silage)] under no-till maize/soybean rotations were established near Brookings, SD, in 2000. Subplot treatments, begun in 2005, were the absence or presence of the cover crops fall-planted slender wheatgrass [Elymus trachycaulus (Link) Gould ex Shinners] in maize and hairy vetch [Vicia villosa (Roth)] plus oats (Avena sativa L.) in soybean. Soybean data from 2009 through 2012 were evaluated. Across years and cover crops, LRR maintained 3587 ± 280 kg ha⁻¹ preseason maize residue, MRR had 2269 ± 227 kg ha⁻¹, and HRR had 1414 ± 172 kg ha⁻¹. Grain moisture was greater (P = 0.03) in LRR (119.6 ± 1.8 g kg⁻¹) than MRR (114.0 ± 1.4 g kg⁻¹) or HRR (114.7 ± 1.5 g kg⁻¹). Grain N was less (P = 0.04) under LRR (62.4 ± 0.5 g kg⁻¹) than MRR (63.4 ± 0.6 g kg⁻¹) or HRR (63.8 ± 0.5 g kg⁻¹). Only during 2012, which had a warm and very dry summer, did MRR (3294 ± 88 kg ha⁻¹) or HRR (3363 ± 141 kg ha⁻¹) have less grain yield than LRR (3766 ± 145 kg ha⁻¹). Cover crops reduced yield in 2012 (3233 ± 78 kg ha⁻¹ with cover crops; 3716 ± 102 kg ha⁻¹ without). Maize residue removal or cover crop cultivation reduced yield only during a growing season with a warm and very dry summer.