Abstract

A field experiment was conducted on diversification and intensification of cropping system under irrigated production system over existing rice-wheat and rice-chickpea cropping systems during the year 2009–10 in clay loam soils of Jabalpur (M. P.). In kharif, different rice varieties were grown under various crop sequences and the lowest weed biomass was recorded in rice-p.otato-maize cob+fodder (3.98 q/ha) cropped sequences and highest weed biomass was recorded in rice-potato-groundnut (5.60 q/ha) under among different crop sequences grown. During rabi season, the weed intensity was minimum (94.4 to 95.4/m2) in onion and garlic crop grown under two different crop sequences, hence, the lowest weed biomass (1.24 to 2.07 q/ha) was recorded in onion and garlic fields. Both gobhi sarson crops faced almost similar kind of weed infestation, which were higher as compared to potato, hence, these resulted in production of higher weed biomass (4.84 to 5.29 q/ha). During summer season, the weed intensity was maximum (118.0 weeds/m2) in greengram field, which resulted in the highest weed biomass production (3.89 q/ha). The weed biomass was minimum (3.22 q/ha) in sesame associated fields due to the lowest weed density (97.8 weeds/m2). Other summer season crops viz., groundnut, maize, okra and greengram produced the weed biomass. In kharif, different rice varieties were grown under various crop sequences and the highest weed control efficiency was recorded in rice-potato-maize cob+fodder (29.9%) cropped sequences. During rabi season, the weed control efficiency was highest (50.0 to 70.6%) in onion, garlic and at potato crop grown under three different crop sequences, hence, the lowest weed control efficiency was recorded in gabhi sarson and chickpea 2.36 and 6.14%, respectively. In summer season, the weed control efficiency was lowest (1.02%) in maize field which resulted in the highest weed biomass production (3.85 q/ha). The weed biomass was lowest (3.22 q/ha) in sesame fields due to the highest weed control efficiency (17.2%).