Nutrient management may reduce global warming potential of rice cultivation in subtropical India
Kumar Abbhishek, Dillip Kumar Swain, Shiladitya Dey, Ajay Singh, J. Kuttippurath, Girish Chander, K. Ashok Kumar
Abstract
Agricultural practices contribute to greenhouse gas (GHG) emissions; therefore, it is essential to modify the production technologies. We analyzed decadal variation in CO2 and CH4 over a major rice cultivating area in subtropical India using GOSAT satellite data, which shows a sturdy increase. Furthermore, we carried out long-term field experiments with different nutrients management in the research farm to validate CERES–Rice (Crop Environment Resource Synthesis) and DNDC (De-nitrification and Decomposition model) models. The variations in Global warming potential per kg rice grain production over 90 years (2005–2095) are also projected. This study used a simulation technique to predict the rice yield using CERES–Rice and GWP using the DNDC model for three varied nutrient management treatments: chemical fertilizer (CF) at full (100%) recommended level (CF100), organic fertilizer using vermicompost at full recommendation (VC100), and integration of organic and chemical fertilizer (VC50 + CF50). The CF100 treatment showed the highest rate of increase in GWP as 0.014 and 0.021 kg CO2eq kg-grain season−1 in RCP 4.5 and 8.5 scenarios, respectively. Integrating organic fertilizers with chemical fertilizers may give a nearly similar yield in later decades of the century in both RCP 4.5 and 8.5 climate scenarios with substantial reductions (77% in RCP 4.5 and 66% in RCP 8.5) in the rate of change in GWP as compared to sole chemical fertilizer application. This study recommends integrated nutrient management using organic fertilizers as a feasible way to limit the GHG emission from rice fields and minimize global warming in future climate scenarios.