Trend analysis of tall crop reference evapotranspiration (ETr) for Bhilwara district

Evapotranspiration is simply a part of the energy budget for crop-surface activities. Environmental assessment includes awareness of evapotranspiration for successful water resource management and improved crop production. In water resource planning and management, evapotranspiration, which involves evaporation of water from the soil and water surface and continuous transpiration by vegetation, is primarily important. Considering this a study was undertaken to analyze the trend analysis of tall crop evapotranspiration for Bhilwara district. Under this study twenty years meteorological data for the duration 1991 to 2010 was collected and based on that the daily and annual ETr values was estimated. The results reflects that, the daily tall crop reference evapotranspiration (ETr) ranged from 3.75 mm/day to 5.89 mm/day and annual ETr ranged between 1367.52 mm to 2148.72 mm with a daily mean of 4.96 mm/day and annual mean of 1812.2 mm. The result also indicates a correlation between temperature, humidity, wind velocity and sunshine hours with the evapotranspiration. The linear regression analysis showed that the trend increased during annual (m = 0.0691), winter (m = 0.0678), pre-monsoon (m = 0.1485), post-monsoon (m = 0.0895), rabi (m = 0.0736), and zaid (m = 0.1461), respectively.