Long-term tillage and nitrogen management for improving productivity and profitability of a rainfed maize-wheat system in north western Himalaya

Abstract

The study aimed to identify the optimum tillage and source of nitrogen for refining yields, yield sustainability and rainwater-use efficiency, and to develop predictive models explaining the relationships between crop yield and monthly rainfall with main goal of reduced cost of cultivation and increased profitability for long-term sustainability of maize-wheat system. A long-term field experiment of maize-wheat system was conducted from 2000 to 2012 at RRS Ballowal Saunkhri, PAU, Ludhiana in split-plot design with 3 replications. The treatments included 3 tillage practice, viz., conventional tillage (CT), reduced tillage (RT1), and RT + herbicide (RT2) in the main plots and 3 nitrogen (N) management practices, viz., 100% N from organic source (F1), 50% N from organic + 50% N from inorganic source (F2), and 100% N from inorganic source (F3) in the sub-plots. The parameters included maize and wheat yields, rainwater use efficiency, economics, sustainability yield index to develop predictive models. Prediction models expressing relation between yield and monthly rainfall showed beneficial effect of rainfall in June, July and September months of maize and January and February in wheat on crop productivity. RT2, gave highest maize grain yield (2264 kg/ha) with 13.8 and 1.8% yield superiority over RT1 and CT, respectively. However, in wheat CT recorded highest grain yield (2110 kg/ha) with 7.9 and 1.7% higher yield than RT1 and RT2, respectively. The RT2F3 gave highest net returns of US$ 222.60/ha with B:C ratio of 1.88, rainwater-se efficiency (RWUE) of 4.78 kg/ha/mm and sustainability yield index (SYI) of 60.7% in maize, whereas in wheat it provided net returns of US$ 315.45/ha with B:C ratio of 2.28, RWUE of 23.0 kg/ha/mm and SYI of 47.4%