Assessing the influence of cover crop on soil water dynamics using soil moisture measurements and hydrus-1D simulations

Winter cover crop (CC) has the potential for improving soil physical condition; however, both improvement and depletion of soil water storage because of CC were reported depending on the soil depth and the rainfall received in a growing season. The present study used sensors to measure the soil moisture content (cm(3) cm(-3)) and soil water potential (-cm) for a no-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] system managed with and without winter CC. The sensors were installed at three soil depths (15, 30, and 45 cm) and the measurements were continued for three cash crop growing seasons (corn, 2017; soybean, 2018; and corn, 2019). The observed soil water potential (-cm) was lower (high tension) for the no cover crop (NCC) system as compared to the CC for the 45-cm depth in 2017 and 2019, and 15- and 30-cm depth in 2018. The Hydrus-1D satisfactorily simulated the soil water potential and moisture content values for the CC and NCC systems with a coefficient of determination (R-2) ranging from .58 to .93 and .57 to .92, respectively. The CC stored 12, 17, and 7% less soil water in the Ap soil layer (0-18 cm) than NCC for the day of cash crop planting for the years 2017, 2018, and 2019, respectively. However, the water input from rainfall replenished the soil moisture after the establishment of the cash crop and resulted in increased soil water storage in the CC as compared to the NCC in the Ap soil layer for the years 2018 and 2019. The present study, therefore, concluded that the use of winter CC improved soil water status for the following cash crop as compared to a NCC system.