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Economic evaluation of agronomic production practices is required to determine the feasibility of inputs used in cropping systems with two or more crops. The objectives of this study were to determine the effect of preplant tillage and seedbed type on subsequent monocrop wheat (Triticum aestivum L.) seed yield and net returns, and compare the results with those from a wheat-soybean [Glycine max (L.) Merr.] doublecrop system (TRT 6). Net returns were calculated using data from plantings made for 4 yr on a Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic Vertic Haplaquept) near Stoneville, MS. Within the monocropped wheat treatments, preplant management inputs were : TRT 1-wheat planted flat following summer fallow ; TRT 2-wheat planted flat following a summer legume crop [Hemp sesbania, Sesbania exaltata (Raf.) Rydb. ex A.W. Hill] ; TRT 3-wheat planted flat following summer fallow and subsoiling ; TRT 4-wheat planted on 80-in.-wide beds following summer fallow ; TRT 5-wheat planted on 80-in.-wide beds following summer fallow and subsoiling ; and TRT 6-wheat-soybean doublecrop, where soybean was planted no-till in burned wheat straw and wheat was planted in harrowed (disk and/or spring-tooth) soybean stubble. Wheat yields from TRT 3 were among the highest each year, but net returns resulting from this treatment were among the highest in only 2 of the 4 yr. Combined net returns from TRT 6 were among the highest in all years, but they were positive in only 2 of the 4 yr and soybean yields averaged only 14.8 to 25.2 bu/acre. Net returns (losses in all 4 yr) resulting from TRT 2 were among the lowest each year because of the expense associated with establishing and incorporating the legume residue. These results indicate that monocropping of wheat, regardless of preplant management, is not a feasible replacement for winter wheat-soybean doublecropping in a nonirrigated environ on clay soil, even though wheat yields were higher in the monocrop treatments in most years Expenses associated with summer fallow maintenance for monocropped winter wheat were not offset by sufficiently higher yields. |
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