Tillage and nutrient-management practices for improving productivity and soil physico-chemical properties in maize (Zea mays)–wheat (Triticum aestivum) cropping system under rainfed conditions in Kandi region of Punjab

A field experiment was conducted during the rainy (kharif) and winter (rabi) seasons from 2012–13 to 2014–15 at Ballowal Saunkhri, Punjab, to study the effect of tillage and sources of nitrogen (N) on crop productivity and soil health in maize (Zea mays L.) – wheat (Triticum aestivum L.) cropping system. The experiment was conducted under rainfed conditions in a split-plot design with 3 replications. In the main plots 2 tillage practices, viz. rotavator and conventional tillage, were assigned and in the subplots 6 nutrient-management practices, viz. control, 40 kg N/ha through urea, 80 kg N/ha through urea, 20 kg N/ha through compost + 20 kg N/ha through urea, 40 kg N/ha through urea + 40 kg N/ha through compost and 20 kg N/ha through compost + 20 kg N/ha through Leucaena leaves, were alloted. Conventional tillage resulted in 15.5 and 0.44 % higher grain yield of maize and wheat (3.10 and 2.26 t/ha respectively) over rotavator (2.62 and 2.25 t/ha respectively). Consequently, system productivity of conventional tillage (5.58 t/ha) in terms of wheat-equivalent yield was 9.7% higher than that with rotavator (5.04 t/ ha). Application of 80 kg N/ha through urea increased the maize yield by 45% and wheat yield by 43% over the control. System productivity was significantly higher when N was applied either through urea (5.65 to 6.51 t/ha) or through urea and organic sources (4.89 to 6.19 t/ha) than the control (3.61 t/ha). The input-energy requirement in conventional tillage was 6.3 and 4.4% higher in maize and wheat than rotavator. In maize, output energy, energy balance, energy-use efficiency and energy productivity were significantly higher in conventional tillage than rotavator. While in wheat energy values were higher in rotavator, these were at par with conventional tillage. Bulk density (1.44 Mg/m3) and soil organic carbon (0.59%) with rotavator improved significantly. Application of 40 kg/ ha N from urea + 40 kg N/ha from compost recorded the highest bulk density (1.41 Mg/m3 ), organic carbon (0.60%), available N (199 kg/ha) and P (29.6 kg/ha). Benefit: cost ratio of the system was significantly higher with rotavator (1.70) and application of 80 kg N/ha (2.07) from urea.