INTEGRATED AND ECONOMICALLY VIABLE WEED MANAGEMENT IN SOYBEAN (GLYCINE-MAX) - WHEAT (TRITICUM-AESTIVUM) CROP SEQUENCE

A field experiment was conducted during 1987-88 and 1988-89 to study the weed-control efficiency, production potential and economic feasibility in soybean [Glycine max (L.) Merr.]-wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system at Jabalpur. The dominant weed flora were awnless barnyard grass [Echinochloa colona (L.) Link] (21.57%), umbrella grass (Cyperus iria L) (20.34%) and false daisy [Eclipta alba (L.) Hassk.] (9.15%) in soybean; and small canary grass (Phalaris minor Retz.) (38.96%), lambsquarters (Chenopodium album L.) (8.03%), toothed medick (Medicago hispida; syn M. denticulata Willd.) (6.83%) and scarlet pimpernel (Anagallis arvensis L.) (6.43%) in wheat. Though excessive tillage with tractor- or bullock-drawn implements improved the weed-control efficiency in both the crops (57 or 51% in soybean and 57 or 52% in wheat), it deteriorated the soil structure (bulk density) besides utilizing additional energy and the resultant higher cost of production. Among different tillage practices, seedbed preparation with rotovator (1 pass) proved more economical and safe for maintaining soil structure. Drilling of seeds in rows resulted in higher profitability (2.14) compared with broadcast sowing because of increased yield of 115 kg/ha soybean and 176 kg/ha wheat with the same investment of inputs. Hand-weeding and herbicidal control were equally effective in controlling the associated weeds, but the latter proved more economical.