Wheat-Soybean Double-Crop Systems on Clay Soil in the Mississippi Valley Area

Abstract

Soybean [Glycine max. (L.) Merr‐.] double‐cropped with small grain accounted for 16% of the total U.S. soybean acreage in 1982. Projections indicate that double‐cropped acreage will increase in areas where adequate growing seasons and irrigation capabilities exist. Field experiments were conducted from 1982 to 1985 to determine the effect of continuous wheat (Triticum aestivum L.)‐soybean double‐cropping on yields, costs of production, and net returns for both irrigated and nonirrigated conditions. Treatments included monocrop soybean and three wheat‐soybean double‐crop systems planted either in standing stubble or burned residue with either conventional, minimum, or no‐till land preparation. Total returns for each irrigated production system in the stubble environment indicated monocrop soybean was more profitable than any of the double‐crop systems. However, for the nonirrigated production systems, total returns were higher from the double‐crop systems, mainly due to returns generated by wheat. In the burned stubble environment, the double‐crop production systems with minimum tillage provided maximum profits in both the irrigated and nonirrigated experiments. Returns from nonirrigated monocrop soybean were not sufficient to cover land rental charges.

Producing Soybean and Wheat Cropping Systems in Rainfed Environments

“…Yield of doublecrop soybean was significantly less than early‐season soybean in all years, and monocrop soybean in two of the three years. These results agree with previously published results where yield from double crop soybean following wheat was less than monocrop soybean (19,20,21,22). Wesley et al (20) reported yield of monocrop soybean exceeded yield from doublecrop soybean both in irrigated and nonirrigated environments, and attributed lower yields for doublecrop soybean to environmental factors, principally rainfall.…”

“…Early‐season soybean can be followed by planting winter wheat as a doublecrop (1,10). Alternatively, in winter wheat production regions with adequate frost‐free periods and rainfall, such as the southern USA, double cropping soybean following wheat is possible (8,9,17,19). Limited summer rainfall is not conducive to successful doublecropping, particularly with respect to soybean following wheat.…”

Cropping system influences on extractable water for mono- and double-cropped soybean

“…Double-cropping, especially winter wheat followed by soybean, is very common in the southeastern United States because of efficient land use and improved cash flow (Wesley and Cooke, 1988). In many non-irrigated double-cropping systems, the soil water available to the second crop (soybean) is critical.…”

“…Numerous authors (Sanford and Hairston, 1984;Crabtree et al, 1987;Daniels and Scott, 1991) have warned that high-yielding wheat could leave a water-depleted profile for the subsequent soybean crop, severely reducing yields (Roder et al, 1989). Also, water in the soil at the seeding depth must be sufficient at soybean planting to assure adequate germination and a stand (Crabtree and Rupp, 1980;Wesley and Cooke, 1988). Other actively transpiring plants, such as weeds, growing in areas planted with soybean will compete for water (Whisler et al, 1982;Banks et al, 1985 ).…”

“…Heatherly ( 1988) concluded that the alleviation of drought stress from soybean growing on a clay soil should be a management goal. Infrequent and variable rainfall throughout the lower Mississippi valley during soybean reproductive growth often limits soybean yield without irrigation (Wesley and Cooke, 1988). Efficient use of precipitation, especially in multiple cropping systems, is thus essential (Denton and Wagger, 1992).…”