Climate Change Mitigation and Adaptation through Conservation Agriculture and Precise Nutrient Management in Current and Future Cereal-based Cropping Systems of the Indo Gangetic Plains

Participatory trials in eight farmer fields in Haryana were conducted to assess the effect of nutrient and residue management on wheat yield, nutrient uptake and carbon sustainability index. Three residue management levels, viz., T1- full residue retention from the previous rice crop (FR), T2- partial residue (30 to 50%) retention from the previous rice crop (PR), and T3- complete residual removal (RR) were tested at all farmer’s fields. Under each residue management scenario, four nutrient management treatments were superimposed, S1: No N application (- N plot), S2: No P application (- P plot), S3: No K application (- K plot), and S4: ample NPK application (+NPK plot). The nutrients applied in the ample NPK treatment were 180 kg N, 80 kg P₂O₅ and 100 kg K₂O/ha. The C sustainability index was calculated based upon the total inputs and outputs under different scenarios at each farmer’s field. The inputs included tillage operations and implements, seed and seed rate, nutrient application both basal and splits, irrigation number and volume, biocide application and their residual effect, crop residue retained/removed and fuel consumed. The outputs included grain, straw and root biomass.

Wheat grain yield varied among different villages/sites due to variation in growing conditions. Highest wheat yields in the ample NPK treatment were recorded at Nakatpur, both under full residue retained (5.6 t/ha) and residue removed (5.4 t/ha). Average wheat yields improved by 2% under residue retention over residue removal. Averaged among the residue management practices, ample NPK application enhanced wheat yield by 224, 17 and 14% over –N, -P and –K treatments, respectively. Yield enhancement in the ample NPK treatment vis-a-vis the –N treatment was highest (600%) in Nakatpur and least in Taroari (79%). Nitrogen, P and K uptake changed significantly under different residue management as well as nutrient omission scenarios. The maximum nutrient uptake was recorded under no residue retained treatment, followed by full residue and least in partial residue. The study also showed that with ample NPK application, residue retention doubled the C sustainability index over residue removal, indicating lesser global warming potential and higher adaptation to climate change. Omission of nutrients reduced the C sustainability index under both residue management scenarios.