Mustard (Brassica juncea): agood option for diversification of rice-wheat system under irrigated ecosystem of north eastern plain zone of India

摘要

Rice-wheat is the predominant cropping system in entire south- west Asia, more particularly the Indo Gangetic Alluvial belt.However, the prolonged cultivation of the same nature of crops has resulted in yield plateauing or even decline in high productive zone of northern India. Therefore, a long-term experiment was initiated under All India coordinated Research Project on Cropping Systems in 2001-02 to study the crop diversification options in rice-wheat system. The treatment consisting of ten cropping sequences: rice-wheat, rice-chickpea, rice-wheat-green gram, rice-wheat-Sesbania (green manure), rice-mustard-green gram,rice-lentil-cowpea (fodder), rice-pea (grain), rice-lentil + mustard (3:1)-cowpea (fodder), rice-maize (green cob) + vegetable pea (1:1)-cowpea (fodder) and rice-potato-green gram were arranged in randomized block design with four replications in the plot size of 7 m × 6 m with one meter plot border. Individual plots were thoroughly prepared by using power tiller. For comparison of different crop sequences, the yield data for different seasons and years (2001-02 and 2002-03) were pooled and converted into rice equivalent yield (REY). The results indicated that rice-potato-greengram sequence was most productive in terms of REY. It recorded significantly higher net return, output-input ratio and engaged maximum number of man-days. The next best sequence in terms of productivity, profitability and employment generation was rice-mustard green gram. However, the rice-chickpea sequence proved to be the most inefficient. Mustard and potato provided better option than wheat for intensification of the sequence by taking green gram during summer. System net energy return and energy use efficiency was significantly higher in recorded significantly higher system net return than remaining sequences. Nevertheless, the lowest system net energy return as well as energy use efficiency were associated with rice-chickpea sequence. Among the two most remunerative sequences viz.rice-potato- green gram and rice-mustard-green gram, the latter has better scope to be followed by farmers in the area because of the perishable nature of the potato and limited cold storage facility in the area besides limited scope for its export.