Simulated Effects of a Novel Operational Strategy for Sustainable Water Management in Drained Croplands

In humid coastal areas of the US, water table management (WTM) in response to rainfall variability is crucial to reduce water loss and duration of drought and excess crop water stresses on artificially drained soils. However, such an active management cannot be applied manually. As an alternative, a real-time water table management (Rt-WTM) system has recently been developed by Bagheri et al. (2018) to automatically manage drainage and subirrigation in an agricultural land based on real-time monitoring of soil water content, rainfall, and crop growth stage. The objective of this study is to 1- simulate the long-term effect of the Rt-WTM strategy on hydrology and relative crop yield, 2- evaluate the effectiveness of this strategy compared to conventional WTM practices. DRAINMOD model will be used to perform 50-year simulations for a research site located in eastern North Carolina. Manual operation of drainage and subirrigation (if possible) are common WTM practices in this area. Accordingly, five scenarios will be simulated and model predictions for these scenarios will be compared. Two scenarios include an optimized conventional and a real-time management when subirrigation is applicable. Two other scenarios represent an optimized conventional and a real-time drainage management (a combination of free drainage and controlled drainage during growing season) without subirrigation. The last scenario represents free drainage all year without subirrigation. DRAINMOD code will be modified for the sake of simulating the real-time strategies. The results of relative crop yield, water loss, evapotranspiration, runoff, and subirrigation will be analyzed for the simulation period. Furthermore, the effectiveness of the Rt-WTM during dry and wet years will be quantified. The preliminary results show that the Rt-WTM with subirrigation slightly improved relative corn yield while decreased the volume of subirrigation and water loss by over 24% and 11%, respectively. The comparison of the results from the proposed strategies will illustrate how agricultural water productivity and cropland resiliency in humid areas can be further improved.