The food-energy-water-carbon nexus of the rice-wheat production system in the western Indo-Gangetic Plain of India: An impact of irrigation system, conservational tillage and residue management.

The conventional rice-wheat system in the western Indo-Gangetic plain of India is energy and water intensive with high carbon footprint. The transition towards resource-efficient eco-friendly production technologies with lower footprint is required for inclusive ecological sustenance. A five-year (2016-17 to 2020-21) field experiment was conducted in RWS with hypothesis that pressurized irrigation systems [drip (DRIP) and mini-sprinkler (MSIS)] in conservation tillage [reduced (RT)/zero (ZT)] and crop residue management [incorporation (RI)/mulch (RM)] might result in higher resource use efficiency with lesser carbon footprint compared to conventional system. Experiment consisted five treatments namely (1) puddled transplanted rice followed by conventionally tilled wheat (PTR/CTW), (2) DRIP irrigated reduced till direct seeded rice (RTDSR) followed by zero-till wheat with 100 % rice residue mulching (ZTW + RM) (DRIP-RTDSR/ZTW + RM), (3) surface irrigated RTDSR followed by ZTW + RM (SIS-RTDSR/ZTW + RM), (4) MSIS irrigated RTDSR followed by ZTW + RM (MSIS-RTDSR/ZTW + RM), and (5) MSIS irrigated RTDSR with 1/3rd wheat residue incorporation followed by ZTW + RM (MSIS-RTDSR + RI/ZTW + RM). The pressurized irrigation system in RWS established under conservational tillage and residue management (DRIP-RTDSR/ZTW + RM and MSIS-DSR + RI/ZTW + RM) produced at par system productivity compared to PTR/CTW. Substantial nitrogen (79-114 ka ha) and irrigation water (536-680 mm) savings under pressurized irrigation systems resulted in 41-64 % higher partial factor productivity of nitrogen with 48-61 % lower water footprint. These systems had lower energy consumption attaining 15-21 % higher net energy, 44-61 % higher energy use efficiency, and 31-38 % lower specific energy. Efficient utilization of farm inputs caused lower greenhouse gas emission (39-44 %) and enhanced carbon sequestration (35-62 %) resulting 63-76 % lower carbon footprint over PTR/CTW. The information generated here might useful in developing policies for resource and climate-smart food production system aiming livelihood security and ecological sustainability in the region. Further, trials are needed for wider adaptability under different climate, soil and agronomic practices to develop site-specific climate smart practices.