Behera Soumya Sucharita, Ojha C S P, Prasad K S Hari, Dash Sonam Sandeep
Department of Civil Engineering, Indian Institute of Technology, Roorkee-247667, Roorkee, Uttarakhand, India.
School of Civil Engineering, University College, Dublin, Ireland.
Environ Monit Assess. 2023 Apr 5;195(5):544. doi: 10.1007/s10661-023-11117-9.
Water and carbon footprint assessment can be a good indicator of sustainable agricultural production. The present research quantifies the potential impact of near-future (2026-2050) climate change on water footprint (WF) and carbon footprint (CF) of farm-level kharif rice production of three locally grown varieties (Khandagiri, Lalat, and Swarna) in Odisha, India, under the two RCP scenarios of 4.5 and 8.5. The crop yield, water resources utilization, and greenhouse gas (GHG) emissions were estimated using the calibrated and validated DSSAT crop simulation model. The precipitation and temperature estimates from three regional climate models (RCM), namely HadGEM3-RA, RegCM4, and YSU-RSM were downscaled using the quantile mapping method. The results revealed a considerably high increase in the total WF of the Khandagiri, Lalat, and Swarna rice varieties elevating up to 101.9%, 80.7%, and 71.8% respectively during the mid-century for RCP 4.5 scenario, and 67.3%, 66.6%, and 67.2% respectively for RCP 8.5 scenario relative to the baseline WF. Moreover, compared to the green WF, the blue WF was projected to increase significantly (~ 250-450%) in the future time scales. This could be attributed to increasing minimum temperature (~ 1.7 °C) and maximum temperature (~ 1.5 °C) and reduced precipitation during the rice-growing periods. Rice yield was projected to continually decline in the future period (2050) with respect to the baseline (1980-2015) by 18.8% and 20% under RCP 4.5 and 8.5 scenarios respectively. The maximum CF of Swarna, Lalat, and Khandagiri rice were estimated to be 3.2, 2.8, and 1.3 t COeq/t respectively under RCP 4.5 and 2.7, 2.4, and 1.3 t COeq/t respectively under RCP 8.5 scenario. Fertilizer application (40%) followed by irrigation-energy use (30%) and farmyard manure incorporation (26%) were the three major contributors to the CF of rice production. Subsequently, management of N-fertilizer dose was identified as the major mitigation hotspot, simultaneously reducing carbon footprint and grey water footprint in the crop production process.
水足迹和碳足迹评估可以成为可持续农业生产的良好指标。本研究量化了近期（2026 - 2050年）气候变化在印度奥里萨邦两种代表性浓度路径（RCP）情景（4.5和8.5）下，对当地种植的三个品种（坎达吉里、拉勒特和斯瓦纳）的季风雨季水稻农场层面水足迹（WF）和碳足迹（CF）的潜在影响。利用校准和验证后的DSSAT作物模拟模型估算作物产量、水资源利用和温室气体（GHG）排放。使用分位数映射方法对来自三个区域气候模型（RCM），即哈德利全球环境模型3 - 区域大气（HadGEM3 - RA）、区域气候模型4（RegCM4）和YSU区域气候系统模式（YSU - RSM）的降水和温度估算值进行降尺度处理。结果显示，在RCP 4.5情景下，坎达吉里、拉勒特和斯瓦纳水稻品种的总水足迹在本世纪中叶分别大幅增加高达101.9%、80.7%和71.8%，在RCP 8.5情景下相对于基准水足迹分别增加67.3%、66.6%和67.2%。此外，与绿水足迹相比，预计未来时间尺度上蓝水足迹将显著增加（约250 - 450%）。这可能归因于水稻生长期间最低温度（约1.7℃）和最高温度（约1.5℃）的升高以及降水量的减少。预计到未来时期（2050年），相对于基准期（1980 - 2015年），水稻产量在RCP 4.5和8.5情景下将分别持续下降18.8%和20%。在RCP 4.5情景下，斯瓦纳、拉勒特和坎达吉里水稻的最大碳足迹分别估计为3.2、2.8和1.3吨二氧化碳当量/吨，在RCP 8.5情景下分别为2.7吨、2.4吨和1.3吨二氧化碳当量/吨。肥料施用（40%）、其次是灌溉能源使用（30%）和农家肥施入（26%）是水稻生产碳足迹的三大主要贡献因素。随后，氮肥施用量的管理被确定为主要的减排热点，同时在作物生产过程中减少碳足迹和灰水足迹。
