Climate-smart technologies for reducing water footprints in different cropland ecosystems: a meso analysis

Abstract

Water footprints (WFs) in crop production are an ecological measurement of water utilization that represents the cumulative groundwater quantum consumed within a region (district/state or country) to produce the crops. WFs in crop production have great significance for ecosystem’s sustainability, as high WFs are posing a serious challenge for the scientists and presents researchable issues for reducing WFs for increased crop water productivity. Crop need based approaches and improved climate smart technologies (CSTs) instead of conventional approaches help in reducing the irrigation water use without compromising crop yields. In view of global warming, need to reduce the water intake in agricultural production has been thought as an urgently sustainable issue. Amongst various crops of South Asia, rice–wheat cropping system extensively cultivated on ~ 12.5 million ha (Mha), has large WFs. A large scale field experimentation suggested several permissible techniques having overwhelming significance for reducing WFs in crop production. Amongst the several CSTs, laser levelers for precision leveling, cultivars with short duration rice varieties, delayed transplanting of rice seedlings, soil matric potential (or tensiometer) based irrigation scheduling, direct drilling of rice seeds, crop establishment on permanent beds, mechanical rice seedling transplanting, and crop diversification through oilseed/pulses has considerable significance in water saving and decreased WFs. Nonetheless, all technologies are not universally efficient in reducing WFs, and depend up on several factors of which soil texture and climatic conditions are the major determinants. For feeding the burgeoning population and to sustain and/or increased food production, technological focus should be on widespread adoption of technologies which aims at reduced WFs either by decreasing water loss from the leaf and/or soil. The present review deals with WFs in crop production, and the technologies to enhance irrigation water productivity and ecosystems’ sustainability of predominant cropping system of South Asia, particularly in water-harassed regions.