Assessing water productivity and energy use for irrigating rice in Pakistan

Abstract

Overirrigation of rice crops from groundwater negatively impacts water productivity, energy use and the environment in Pakistan. Therefore, four decades (1981–2020) of data on rice crop area and production were assessed for water productivity, and alternative options for irrigation application and energy use were explored. The results show a maximum average yield of 2.42 t ha‾¹ and water productivity of 0.16 kg m‾3 (6211 L kg‾¹) for the last decade (2011–2020), with an average decadal yield increase of 14%. The last year's rice crop during 2020 consumed 14.43 million acre‐feet (MAF) of groundwater, assuming a minimum irrigation application of 1500 mm per season. The maximum equivalent energy required for pumping is approximately 386 MW for electrical and 4966 MW for diesel‐driven tube wells. Diesel combustion for pumping caused 1.26 million t (467 kg ha‾¹) of CO2 emissions per season. The capital cost for converting all installed capacities of electrical (2311 MW, PKR 481 billion) and diesel (16 517 MW, PKR 1909 billion) tube wells to solar energy can be recovered in less than 4 years. Improved governance and optimized site‐specific solar system designs can avoid undergoing groundwater. Improving water productivity and using solar energy for irrigation indicates the prospects of improved sustainability of rice crops in Pakistan.

Maximization of Productivity and Water Saving through Alternate Wetting and Drying Irrigation (AWDI) in Rice under Tamil Nadu Irrigated Agriculture Modernization Project (TN IAMP) Aliyar Sub Basin Farmers of Tamil Nadu, India

“…"According the recent estimates it is predicted that there would be acute water shortage in the coming decade which urges need to develop an alternative system of rice cultivation to save the water and other inputs. AWD is a water conservation technique that can be utilized by farmers to minimize their rice field irrigation water usage while maintaining crop yield and it is an irrigation technique that reduces water inputs in rice without sacrificing rice yield by introducing unsaturated soil conditions during the growing season" [10,11]. "According to Tuong, it was recorded the successful usage of field water tube in AWDI management regime for water depth monitoring and capable to indicate the right time to irrigate crops and saved water, without incurring any yield penalty and using of field water tube in AWDI was very safe to restrict the water use to 25 per cent was reported by Suresh Kulkarni" [12,13].…”