THE PROFIT POTENTIAL OF SOYBEAN PRODUCTION ROTATION SYSTEMS IN ARKANSAS

The objective of this study was to provide agronomic, nematode, and ec onomic analysis of alternative production rotation systems for soybean s (Glycine max L. Merr.) on a silt loam soil association in Arkansas. Monocropped soybeans and soybeans double-cropped with wheat (Triocum a estivum L.) was included as well as grain sorghum (Sorghum bicolor L. Moench) under dryland conditions in order to reduce soybean cyst nemat ode (SCN, Heterodera glycine Ichinohe) populations. A total of seven c rop rotations and eleven treatments that included alternative tillage conditions and wheat stubble management practices were analyzed using data from 1980-1984 experiments conducted at the Arkansas Cotton Branc h Experiment Station on a silt loam Loring-Calloway-Henry Association (Alfisols). Although crop rotation was effective for nematode suppress ion, yields for double-cropped soybeans were comparable to soybean yie lds under monocropped' continuous management practices. Economic resul ts indicated that average net returns of $338.50 per hectare (about $1 37 per acre) were highest for the continuous double-cropped wheat-soyb ean production management systems which combine the conventional tilla ge method with burning of wheat stubble. For the conditions analyzed a nd level of SCN present, this research provides evidence that control of the soybean cyst nematode: through rotation practices that utilize grain sorghum is not economically efficient where continuous double-cr opped wheat-soybeans systems can be incorporated.