Field water budget of crops as influenced by soil texture, climate change and management interventions

Information on water balance from cropped soils is crucial for enhancing water productivity and computing spatial and temporal irrigation water and evapo-transpiration (ET) demand. The available literature on water balance components in the major crops reveals that percent utilization of the total water input (irrigation+ precipitation) ranges 34–97% to ET and 9–63% to drainage (D). In the upper range, utilization to ET is >90% in cotton, winter maize and mustard; to evaporation (E) >30% in maize and soybean; to transpiration (T)>60% in wheat, cotton, winter maize; to drainage (D)>60%in rice. Amongst different factors and management interventions, generally the percent utilization is more to ET in hot and arid zones, higher evaporative demand, low irrigation regimes, longer duration varieties, finer-textured soils and permanent bed system; to (D) in coarser-textured soils, conventional methods of irrigation, high irrigation regime, longer duration varieties, semi-arid zones with more precipitation and conventional tillage system. Such understanding of water budgeting helps in improving irrigation strategies for conserving irrigation water and reducing ET; and provides a foundation for Efficient water resource planning and management.