Evaluation of soil water dynamics and crop yield under furrow irrigation with a two-dimensional flow and crop growth coupled model

Aiming at investigating an appropriate furrow irrigation management strategy for high melon yields and water productivity (WP), a new coupled model was developed based on the CHAIN_2D and the crop growth model of EPIC. In the coupled model, the root water uptake model of Vrugt was coupled with the root depth growth model in order to consider the interaction between root water uptake and crop growth. The coupled model was calibrated and validated with the observed values obtained from melon field experiment conducted in 2008 and 2009 in Gansu province, Northwest China. Simulation of total water use, leaf area index, melon yield and soil water dynamics fitted well with the field observations. The calibrated model was then used to predict the yield and water productivity (WP) of melon under different furrow irrigation scenarios. The relative yield and WP for different irrigation depth were considered as the criteria for investigating the appropriate irrigation management practices. Results showed that the relative yield and WP increased and decreased, respectively, as the relative irrigation increased through a quadratic function. The appropriate irrigation amounts for melon in the study area were 209 mm and 218 mm in 2008 and 2009, respectively.