International Commission of Agricultural and Biosystems Engineering
Abstract
This experiment aimed to determine the crop evapotranspiration (ETc), groundwater input in total water used by wheat crop, and to simulate the CROPWAT model to envisage the crop evapotranspiration rate. To estimate on-field ETc and groundwater contribution the combining lysimeter technique was used. The water levels below the soil surface were kept at 1.60, 2.20, and 2.80 m and each water table depth was replicated three times. The experiment was conducted under silt loam (SL) and silty-clay loam (SCL) soil conditions. The climatic parameters and water balance components were recorded accordingly. The on-field ETc was compared with the predicted ETc by CROPWAT model. Under SL soil, the observed ETc was 442, 427, and 401 mm at the water table depth of 1.60, 2.20, and 2.80 m, respectively. The recorded ETc under SCL soil was 419, 402, and 389 mm at the same water table depths, respectively. The ETc reduced with an increase in water level below the surface. The groundwater contribution at 1.60, 2.20 and 2.80 m depth of water level under SL and SCL soil was observed as 50, 41, and 30 % and 43, 34, and 24 %, respectively. The predicted ETc by CROPWAT model for SL and SCL soil conditions was 428.8 and 410.7 mm, respectively. The projected ETc is likely equal to the average ETc observed under lysimeter experiment. Thus, the use of CROPWAT model is recommended to overcome waterlogging and salinity problems and to conserve water resources
