Assessment of Wheat Crop Water Requirement for South Bihar by FAO CROPWAT 8.0

Background: Water is a precious resource that needs increase in its use efficiency for higher productivity of crops. The wheat crop responds more with irrigation and it is cultivated in large area after rice which requires understanding of wheat water requirements in the region for a practical guide for stakeholders involved in agricultural planning and water resource management. Methods: The present research aims to assess the irrigation water requirement of wheat crop in the specific agro-climatic conditions of South Bihar by using the FAO CROPWAT 8.0 model, a widely recognized tool for calculating crop water requirements. Result: Meteorological and crop-specific parameters of Patna were used in the model to estimate water requirement of wheat. The total crop water requirement for wheat crop in South Bihar was 267.2 mm with 70% irrigation efficiency. The gross and net irrigation requirement was 299.6 mm and 209.7 mm respectively scheduled in four irrigations. The actual irrigation requirement by the crop was 230.9 mm and the actual water use by the crop was 267.2 mm. The moisture deficit in the soil at the time of harvest was 93.25 mm.