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Economic evaluation of agronomic production practices is required to determine their feasibility in cropping systems with two or more crops. Net returns from continuous double-cropped wheat (Triticum aestivum L.) and irrigated soybean [Glycine max (L.) Merr.] were calculated using data from plantings made in 1988, 1989, and 1990 near Stoneville, MS, on a Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic, Vertic Haplaquept) in tilled and no-till seedbeds in both burned and standing wheat stubble. Yield of soybean was not affected by stubble management or seedbed preparation. Yield of wheat was reduced in plantings made following soybean that was planted in standing wheat stubble in the first 2 yr of the study. Seedbed preparation for wheat planting had an inconsistent effect on wheat yield. Wheat yields declined as the study progressed. Combined net returns were greater from the burned stubble treatment in 2 of the 3 yr, and this was attributed to the higher net returns from wheat in this treatment. Combined net returns from the tilled seedbed treatment were similar to those from the no-till treatment in 1988 and 1989; in 1990, net returns from the tilled seedbed treatment were higher. These results indicate that highest combined net returns from a continuous wheat-soybean doublecrop system will be obtained when soybean is planted in burned wheat stubble. Low and declining wheat yields in this short-term study (confounded with year effects) indicate that continuous wheat-soybean doublecropping using no-till planting of wheat is not a viable management option. This conclusion has to be verified with longer-term research, however. |
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