Alternative crop production strategies for rice-wheat cropping systems in the Indo-Gangetic plains of India

Abstract

Field experiments were carried out in the Indo-Gangetic plains of India during 1997–98, 1998–99 and 1999–2000 with the objective to identify alternative crop sequences that are more productive as well as remunerative than the rice–wheat cropping system. The results indicated that the highest mean sunflower seed yield was obtained in the soybean–sunflower rotation followed by the rice–sunflower rotation and the lowest in the maize–mustard–sunflower crop rotation. Similarly, the sesbania–toria–sunflower rotation had the highest biological yield followed by the soybean–sunflower and urd–toria–sunflower rotations. The mean highest harvest index was found in the cowpea–toria–sunflower rotation (35.1%) followed by the urd–toria–sunflower (33.2%) and rice–sunflower (32.7%) rotations. A significantly high oil content in sunflower seeds was observed in both the soybean–sunflower and sesbania–toria–sunflower rotations that was similar to that in the urd–toria–sunflower and cowpea–toria–sunflower rotations. The maize–potato–sunflower, maize–mustard–sunflower, cowpea–toria– sunflower and rice–sunflower rotations had significantly higher sunflower seed yield equivalents (201, 17, 15 and 4% higher, respectively) than the rice–wheat rotation. Similarly, the maize–potato–sunflower rotation produced the highest net income followed by cowpea–toria–sunflower, rice–sunflower and maize–mustard–sunflower, that was 351, 37, 14 and 4%, respectively, higher than the net income of the rice–wheat rotation. The benefit : cost ratio was also observed to be significantly highest in the maize–potato–sunflower rotation (1.60). After 3 years of field experimentation, soil organic carbon, available nitrogen, phosphorus and potassium were observed to be highest in the urd–toria–sunflower, soybean–sunflower, cowpea–toria–sunflower and soybean–sunflower rotations, respectively. The mean value of total available nutrients was greater in soybean–sunflower than rice–wheat rotation.

It can be concluded that the cowpea–toria–sunflower, soybean–sunflower and rice–sunflower crop rotations may be preferred for greater sustainability over the rice–wheat system not only in the Indo-Gangetic plains of India but also in the whole of Asia, and these findings may be a very useful reference for future research on Australian crop diversification.