Estimation of Irrigation Return Flow in Sandy-Loam Soil using Water-balance Approach

In this study, irrigation return flow (deep percolation) has been estimated by using water balance approach. The experimental setup consisted of two lysimeters installed at the College of Agricultural Engineering & Technology field lab, SKUAST-Kashmir, Shalimar in which pea crop was grown, simulating the natural conditions available in the vicinity of lysimeter. Regular measurements of soil moisture were made at the depths 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm using gravimetric method. The evapotranspiration estimates were determined using FAO-Penman-Monteith equation. The deep percolation was calculated using the water-balance approach. The deep percolation losses calculated by water-balance approach are comparable to the observed values of deep percolation obtained by the lysimeters. The observed and the calculated values of deep percolation have 7.65% (using water balance method) difference. Results obtained showed that locally constructed lysimeters could effectively be utilized in water balance studies of a cropped area when used in combination with root zone soil moisture monitoring devices.