Simulation of water balance components in drip-irrigated sugarcane using SWAP model

Abstract

Imagine knowing exactly how much of every litre of irrigation water ends up as crop transpiration, deep drainage, or surface runoff—before the season even starts. This research calibrated the SWAP (Soil-Water-Atmosphere-Plant) model for drip-irrigated sugarcane at Bangladesh Agricultural University, Mymensingh, over two seasons (2021-2022 and 2022-2023). Simulated seasonal evapotranspiration (847 mm) matched observed values (812 mm) with NRMSE of 7.1%. Drainage was slightly underestimated (123 vs. 141 mm). The model indicated that drip irrigation saved 23.4% water compared with furrow while maintaining 94.6% of cane yield. Sensitivity analysis showed that saturated hydraulic conductivity and root depth were the two most influential soil parameters.