Abstract
The DRAINMOD model is a superior tool used to predict the changes in farmland water balance under different agricultural drainage layouts, fields, weather conditions, and management practices. In the present study, we assessed the sensitivity of the DRAINMOD predictions in farmland water balance to the time step (hourly or daily) in daily evapotranspiration (ET₀) computations for 12-hectares of farmland located at the lower reaches of the Yangtze River basin. The model was calibrated and validated and then was applied twice under two sets of daily ET₀ values, computed using the standardized ASCE Penman–Monteith model (one using the hourly time step (HTS) and the other using the daily time step (DTS)). Regarding daily computed ET₀ values, results show that abrupt diurnal changes in the weather always result in significant differences between daily ET₀ values when computed based on DTS and HTS. DRAINMOD simulations show that such differences between daily computed ET₀ values affected the model’s predictions of the “water fate” in the study area; e.g., adopting HTS rather than DTS resulted in a 4.8% increase, and a 3.1% and 1% decrease in the models’ cumulative predictions of runoff, drainage, and infiltration, respectively. Therefore, for a particular study area, it is critical to pay attention when deciding the best time step in ET₀ computations to ensure accurate DRAINMOD simulations, thereby ensuring better utilization of agricultural water alongside high agricultural productivity.
Highlights
Excess water on farmlands has always been a major threat as it causes severe crop yield losses and threatens the quality of adjacent water bodies [1,2,3]
Applied the DRAINMOD model to predict the water distribution pattern in the study area under two sets of daily ET0 values
The good statistics indicators assure that the model can satisfactorily predict the water balance in the study area and, can be applied to check the effect of any changes in input parameters on the hydrologic regime in the study area
Summary
Excess water on farmlands has always been a major threat as it causes severe crop yield losses and threatens the quality of adjacent water bodies (due to excess water runoff from such lands) [1,2,3]. Implementing artificial drainage projects in poorly drained farmlands is necessary to ensure better conditions for the agricultural process and the surrounding environment [4,5]. The best drainage layouts and practices require certain tools that could predict how current and future farmland water balances change under such layouts and practices, to achieve the desired agricultural and environmental conditions on the farmlands [6]. The DRAINMOD model is reported to be one of the best tools that enables decisionmakers to predict changes in farmland water balance under different drainage layouts and practice scenarios. Considering the importance of the model, it is necessary to assess its sensitivity to the inputs, thereby ensuring accurate outputs and better utilization of agricultural water and environmental resources alongside high crop yields
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
