Sustainable productivity and profitability of diversified rice-based cropping systems in an irrigated ecosystem

An experiment was conducted at ICAR Research Complex for Eastern Region, Research Farm, Sabajpura, Patna (longitude 85°13′N and 1atitude 25°37′E), Bihar, India for four consecutive years 2004–05 to 2007–08 to develop a diversified cropping system for an irrigated ecosystem in Bihar by introducing pulse/oilseed/vegetables as a second or third crop in 10 rice-based cropping systems. Four crop cycles have been completed for all the cropping systems. During all years of the experiment there were significant variations among the cropping systems. Maximum paddy yield equivalent was recorded in rice–tomato–bottle gourd (40.44 t ha^?1) followed by rice–potato–onion (28.47 t ha^?1), rice–coriander–lady's fingers (26.79 t ha^?1), rice–carrot–cowpea (24.59 t ha^?1) and rice–mustard–tomato (24.44 t ha^?1). A higher value for the diversification index (DI) represents a higher level of crop diversification. It is evident from the results, that DI varies from 0.299 on a medium-sized farm to 0.903 on a small farm, with an average DI value of 0.643 among all farm categories. A survey revealed that the average DI value for small-scale farmers was highest (0.741) compared with the medium- (0.591) and large-scale (0.626) categories, and the differences were negligible. This seems reinforce the view that the smaller the farm, the higher the level of crop diversification.