Soil Water Distribution and Water Supply Characteristics of Farmland to Apple Orchard in Their Adjacent Areas on the Loess Tableland

Abstract

[Objective] To investigate the spatial distribution and cooperative utilization characteristics of soil water under the orchard-farmland mosaic pattern in the southern Loess Tableland. [Methods] The 10-year-old, 21-year-old, and 25-year-old apple orchards (AO10, AO21, and AO25) and their adjacent farmland were selected in Changwu tableland were selected to quantitatively calculate the contribution of soil water storage to water consumption of orchard. By measuring the soil water content at relevant sites in the orchard-farmland interface zone after the rainy season in 2021. [Results] The precipitation in 2021 is 756 mm, which was a typical wet year. The rainfall infiltration depth of farmland and AO21, AO25 orchards reached 8.4, 7.0, and 5.0 m at the end of November, respectively. AO10 orchard-farmland boundary zone is 4 m deep, the soil water content in the lower part is larger than that in the upper part, and the average soil water content was 25.5% in the 4—10 m soil layer. In AO21 orchard, the average soil water content of the 0—7 m soil layer was 22.1%, and that of the 7—10 m soil layer was 15.0%. the average soil water content of the 0—5 m soil layer of AO25 orchard was 20.9%, and that of 5—10 m was 13.6%. The soil dry layer of AO21 and AO25 orchard was below 7.0 and 5.0 m, respectively. In the horizontal direction, the distance of soil water used by AO21 and AO25 orchards from adjacent farmland reached 5 and 8 m, respectively, and the water supply from fields to orchards at the agro-fruit interface was 0.08 and 0.25 m3/m2 when the soil profile was divided by the upper boundary of the dry layer. Below is the actual water supply, which is 0.45 and 0.81 m3/m2, respectively. [Conclusion] The mosaic layout of apple orchards and farmland in the Loess tableland region is a reasonable utilization structure, and factors such as the age of apple trees and the width of adjacent farmland should be considered in land planning and management. The research results will contribute to promote the sustainable utilization and spatial optimization of regional soil water resources.

Keywords

• soil water content
• orchard-farmland interface zone
• vegetation pattern
• dry soil layer
• the loess plateau