Dynamics of well irrigation systems and CO2 emissions in different agroecosystems of South Central India

Abstract

Water application systems under wells extracting groundwater are one of the major factors influencing climate change in the agricultural sector. In the context of growing demand for adaption of pressurized irrigation with electric pumps in South Central India, the present study was undertaken to assess the carbon dioxide emission (CO2 e) for different irrigation systems. The crop water requirements and pumpsets prevailing in the area were considered for estimation of CO2 e. The estimation includes operational energy consumption, well digging, installation and manufacturing of the irrigation system as well as the pumpsets. The irrigation systems used in major crops under wells include surface (rice, maize, groundnut, vegetables and sugarcane), raingun (maize, groundnut, vegetables and sugarcane), sprinkler (maize, groundnut and vegetables) and drip (vegetable and sugarcane). The analysis indicated that the energy used in pumping irrigation water made the highest contribution to total CO2 e footprint, which ranged from 2.52 to 15.72 t/ha depending on the irrigation system. Sugarcane crop showed maximum energy requirement (17.27 MWh/ha) under surface irrigation system, contributing 15.72 t/ha CO2 e. Maximum reduction in energy requirement and CO2 e was recorded in the case of drip (11.52 MWh/ha; 10.48 t/ha) system followed by sprinkler (12.58 MWh/ha; 11.52 t/ha) and raingun (14.81 MWh/ha; 13.47 t/ha) under tube wells. It was observed that among all the irrigation systems, the drip system gave the lowest CO2 e indicating the maximum climate change mitigation potential in the irrigation sector of selected region under wells.