DUAL CROPPING IN SEMIDRY RICE-A REVIEW

Semidry rice cultivation is growing rice under rainfed condition and later turning to lowland crop when rainwater is available from the tanks and/or from similar sources. The semidry rice cultivation is prevalent in twenty per cent of rice area of our country with low productivity of one t ha-1 which indicates an imminent need to raise the level of productivity to narrow down the wide disparity. Crop and weed seed germinate simultaneously in semidry rice and weed competition during critical period of crop growth is more severe. Loss in yield due to the absence of weed control measures in direct sown upland rice culture has been estimated to be upto 97 per cent. Cultural method such as growing intercrop also provides greater scope to control weeds. Dual cropping of Crotalaria juncea, Vigna sinensis, Glycine max, Sesbania in lowland rice combined with intercultivation, suppressed the weeds effectively. The scope of introducing legume crop as dual crop in rice is more, because of its efficiency to control weeds by way of smothering during the early period of weed emergence. It increases the fertility status of the soil by legume effect thereby increases crop yield. The literature revealed that green manure dual cropping resulted in reduced weed flora, higher weed smothering efficiency, lower nutrient removal by weeds, higher growth and yield of rice, nutrient uptake and improved soil fertility status.