Changes in Soil Moisture Content and Characteristics of Water Movement in Citrus Orchards under Different Mulching Methods

[Objectives] The paper was to explore the effects of different mulching methods on soil moisture content and water movement in citrus orchards, and to provide the theoretical basis for improving water and weed management level in orchards. [Methods] Three ground mulching treatments including spraying herbicide (CK), grass-proof cloth cover (GPC) and natural grass mowing (NGM) were set up to analyze the soil moisture content and water flux characteristics of soil profile in the soil layers of 5, 20, 40 and 60 cm under different mulching methods. [Results] The GPC and NGM treatments significantly increased the soil moisture content in the soil layer of 0-60 cm at the young fruit stage and fruit expansion stage, which inhibited soil water evaporation and effectively improved soil water holding capacity, thus reducing irrigation water consumption and saving water resources. During the expansion stage of citrus fruits, the soil water flux in the soil layer of 0-60 cm in NGM and CK treatments was upward, and the upward soil water flux in NGM treatment was larger, which could mobilize more upward movement of deep soil moisture for uptake by citrus roots. However, the soil water flux in the soil layer of 0-60 cm in GPC treatment was downward, and the soil moisture conditions in the upper and middle layers were already sufficient for citrus growth. [Conclusions] Both GPC and NGM treatments can increase the overall soil moisture content. In the dry season, the soil moisture content in the upper layer treated by GPC is always relatively high, while more soil water in the lower layer move to the upper layer in NGM treatment, which has met the water requirements for citrus growth.