PRODUCTION POTENTIAL OF CROP SEQUENCES IN PLATEAU REGION OF BIHAR

A field experiment was conducted during 1983-90 at Ranchi, to study th e stability in production potential of 4 crop sequences. The cropping systems were maize (Zea mays L.)-wheat (Triticum aestivum L. emend Fio ri and Paol.), rice (Oryza sativa L.)-wheat, soybean [Glycine max (L.) Merr.]-wheat and groundnut (Arachis hypogaea L.)-wheat. Among the rai ny-season crops the production of legumes was more stable in different years than of cereals. Wheat grown after groundnut or soybean recorde d higher (15.6%) and stable yield than after maize or rice. Total prod uction of soybean-wheat (4 409 +/- 598 kg/ha), groundnut-wheat (4 294 +/- 678 kg/ha) and rice-wheat (3 962 +/- 681 kg/ha) was more stable th an of maize-wheat (5 402 +/- 1 129 kg/ha). Groundnut-wheat system was more efficient in terms of wheat-equivalent yield (6 373 kgma), net re turn (Rs 16 410/ha), benefit : cost ratio (1.87) and monetary producti vity (Rs 68.38/ha/day), whereas soybean-wheat was more efficient in te rms of calories (19.59 millions/ha) and protein (943 kg/ha) yield. The legume-based cropping system also improved soil-available P (191%) an d available K (54%) with minimum depletion in organic C (41%), indicat ing the significance of legume in crop sequence for sustainable produc tion.