Effects of Autumn Tillage Systems on Corn and Soybean Harvest Residues in Illinois

Abstract

The early winter abundance of waste corn and soybeans was evaluated relative to common tillage practices in central Illinois. In 1981, waste corn averaged 430.5 kg/ha in untilled, 45.4 kg/ha in intermediately tilled, and 3.7 kg/ha in moldboard-plowed fields, whereas in 1982, waste corn averaged 273.7. kg/ ha in untilled and 65.0 kg/ha in intermediately tilled fields. Waste soybeans averaged 47.9 and 63.3 kg/ha in untilled and 12.3 and 11.5 kg/ha in intermediately tilled fields in 1981 and 1982, respectively. Waste grain abundance was not related (P > 0.05) to field size and location of plots within fields, except for intermediately tilled soybeans where less (P < 0.05) grain occurred along borders. Predictive modeling indicated that waste corn abundance may be sparse following common autumn tillage practices, particularly for multiple-pass operations. The amount of waste corn in untilled fields appears to have approximately doubled since the early 1940's. J. WILDL. MANAGE. 49(1):185-190 Corn and soybeans are the major agricultural commodities in the Midwest. In Illinois, 8.3 of the 9.6 million ha of cropland are devoted to these row crops (U.S. Dep. Agric. 1981). Waste corn and soybeans-grains remaining on the ground surface after harvest and tilling-are important energy sources for many wildlife species during late autumn, winter, and early spring (Baldassarre et al. 1983). Soil loss has become a serious problem with the expansive production of corn and soybeans and associated intensive autumn tillage in the Midwest. The reduction of autumn tillage practices-cropresidue management or conservation tillage-has become a primary means for conserving soil (Walker 1981). The objective of this study was to appraise the abundance of waste corn and soybeans in early winter relative to tillage practices applied following the preceding autumn harvest in central Illinois. In 1981, the abundance of waste grain was considered in relation to tillage systems, crop residues (plant litter excluding grain), field size, and location within fields. In 1982, waste grain abundance was considered according to tillage systems and compared with 1981 grain abundance. Using predictive models developed from 1981 and 1982 data, a generalized comparison was made of the winter food resource base available to wildlife for a variety of typical corn-tillage practices. J. H. Moak, D. A. Newhouse, and K. J. Woods, Ill. Dep. of Conserv., and H. K. Belcher, M. M. Georgi, G. A. Perkins, and R. J. Siemers, Ill. Nat. Hist. Surv., provided technical assistance. S. J. Brady, Soil Conserv. Serv., and J. R. Kendall, retired Agric. Stat. in Charge, Ill. Coop. Crop Rep. Serv., read a first draft of the manuscript. G. C. Sanderson, W. R. Edwards, S. L. Etter, and C. M. Nixon, Ill. Nat. Hist. Surv., rev ewed the manuscript. This work is a cont ibution, in part, of Fed. Aid in Wildl. Restoration Proj. W-66-R, the Ill. Dep. of Conserv., the U.S. Fish and Wildl. Serv., and the I11. Nat. Hist. Surv., cooperating. The Ill. Dep. of Conserv. and the U.S. Fish and Wildl. Serv. have n responsibility for the form and content of the data in this report or for the conclusions reached.