Soybean Residue Management and Tillage Effects on Corn Yields and Response to Applied Nitrogen
- Kevin A. Schoessowa,
- Kenneth C. Kilianb and
- Larry G. Bundy *c
- a Univ. of Wisconsin-Extension, W6646 Hwy 70, Spooner, WI 54801
b School of Agriculture, Univ. of Wisconsin, Platteville, WI 53818
c Dep. Soil Sci., 1525 Observatory Dr., Univ. of Wisconsin, Madison, WI 53706. Research supported by the Univ. of Wisconsin Consortium for Extension and Research in Agriculture and Natural Resources, the Wisconsin Soybean Marketing Board, Inc., and the College of Agricultural and Life Sciences, Univ. of Wisconsin-Madison through project 3879
Variability in N fertilizer requirements for corn (Zea mays L.) following soybean [Glycine max (L.) Merr.] across sites and years emphasizes the need to understand management practice effects on apparent soybean N contributions. This study was conducted to determine the effects of three soybean harvest management systems (HMS) and tillage on subsequent corn grain yields, and apparent soybean N contributions. Field experiments to evaluate the effects of returning or removing soybean residue, soybean forage harvest at the R6 growth stage, and applied N (0–180 kg N ha−1) on corn grain yields were conducted for 3 yr at four locations. The soybean residue returned treatment significantly decreased yields by 1.1 and 2.5 Mg ha−1 for 2 of 12 site years. The soybean residue returned treatment also required 134, 41, and 87 kg ha−1 more fertilizer N to maximize yields for 3 of 12 site years, but not at the remaining sites. Greater early season soil NO3–N in the forage harvested or residue removed treatments before planting and when corn plants were 30 cm tall (presidedress) is probably a result of warmer soil temperatures and increased soil N mineralization where residue was removed. Economic optimum N rates for corn following soybean varied substantially across sites and years and ranged from 0 to 180 kg N ha−1 but were not greatly affected by soybean HMS or tillage at most sites. This work emphasizes the need for a field-specific approach to better predict the apparent soybean N contribution to a subsequent corn crop.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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