The Soil Water Condition of a Typical Agroforestry System under the Policy of Northwest China

Abstract

The number of mixed cropland—apple orchard system has gradually increased in the Changwu Tableland region of the Loess Plateau, China. However, the soil water content (SWC) is not sufficient to maintain the sustainable development of apple trees in this agroforestry system. It is unclear whether the growing fruit trees would compete with crops for soil water. To systematically analyze the temporal and spatial distribution of soil moisture and to understand the effect of orchard hydrology in that cropland, the SWC was measured at different depths at different locations on cropland and in an apple orchard. The results show that: (1) The SWC of each soil layer in the cropland (0–20, 20–60, 60–100, 100–200, 200–300 cm) is higher than that of the orchard. The soil moisture changes dramatically in the 0–200 cm soil layer. (2) As the soil moisture monitoring distance from the apple orchard increases, the SWC gradually increases, the loss of soil water storage gradually decreases, and the drying effect gradually disappears. This is related to the different distribution ranges of the roots of apple trees and crops. Therefore, the government should control the proportion of the orchard and cropland, and then adjust the planting period of the orchard in the appropriate range to keep the green use of water in the region.