AGRONOMIC AND ECONOMIC-PERFORMANCE OF CONVENTIONAL VS REDUCED INPUT BEAN CROPPING SYSTEMS

Few data exist concerning the agronomic and economic performance of re duced input management systems for dry bean (Phaseolus vulgaris L.) pr oduction. To help fill this void, a 3-yr field experiment was conducte d on a Buxton silt loam (fine, illitic, frigid Aquic Dystric Eutrochre pts) in central Maine with dry beans (cv. Maine Yelloweye) grown in re duced input vs. conventional management systems. Beans in the reduced input system were planted directly into a rye (Secale cereale L.) cove r crop, which was subsequently mowed; no fertilizers or herbicides wer e applied. The conventional system involved moldboard plowing and disk ing, and application of herbicides and NPK fertilizer. Marketable yiel ds of beans were 58% to 76% lower in the reduced input system than in the conventional system. Lower yields were attributed to greater weed competition, inadequate N nutrition, reduced seed quality, and reduced crop population density. Soil compaction, allelopathy, and other fact ors also may have decreased yields. Use of the reduced input system in place of the conventional system substantially decreased production c osts, but also greatly lowered revenues because of lower yields. As co mpared with the conventional system, the reduced input system resulted in decreased profits of $435/acre to $734/acre. Results of this study indicate that (i) more research attention should be directed toward m anagement of weeds and N fertility in reduced input systems; and (ii) acceptable economic performance of reduced input systems for high valu e crops, such as Maine Yelloweye beans, can be dependent on producing yields close to those obtained with conventional practices.