Effect of different tillage and residue management practices on crop and water productivity and economics in maize (Zea mays) based rotations

In recent years, increasing water and labor scarcity & production cost, decreasing farm profitability and climatechange- induced variability are major challenges faced by the farmers of Indo-Gangetic Plains (IGP) in South Asia. Conservation agriculture (CA) based best-bet crop management practices may increase crop productivity, profitability and conserve the natural resources. In a 2-year (2012-2014) study, we assessed the effects of six combinations of tillage and crop establishment (TCE) and residue management options on crop & water productivity, profitability and soil thermal and moisture regimes in maize (Zea mays)-wheat (Triticum aestivum L.) (MW) and maize-chickpea (Cicer arietinum L.) (MC) rotations in Western IGP of India. The treatments consisted of both crops sown on permanent raised beds with residue (PB+R) and without residue (PB-R); zero tilled flat with residue (ZT+R) and without residue (ZT-R) and conventional tilled flat with residue (CT+R) and without residue (CT-R). Overall, 2-year mean maize, wheat and chickpea grain/seed yield was found to be 17.0-23.2, 20.8-24.8 and 22-31.7% higher under CA-based PB+R/ZT+R than CT-R, but it was 5.3-10.9, 4.9-8.4 and 13.8-22.8% higher than CT+R, respectively. The yield of maize, wheat and chickpea was significantly (P<0.05) higher in CA-based PB+R and ZT+R systems compared to CT-R right from first year onwards. The MW and MC, 2-year mean system productivity (based on maize equivalent yield- MEY) was higher by 21.1-21.9 and 18.7-27.5% in CA-based systems (PB+R & ZT+R) than in the CT-R, respectively. CA-based PB+R and ZT+R practices reduced the total system water use in MW and MC rotations by 75-112 mm and 55-90 mm and resulted enhanced system water productivity (WP) compared to CT-R system. Irrespective of crop rotations and TCE practices residue management treatments enhances the soil moisture (in the range of 14.5 to 30.4% during winter and monsoon seasons) and also moderates the soil temperatures. Economic profit for MW and MC rotations was always significantly (P