长武塬区苹果园和农田相互转换的深层土壤水环境效应

研究长武塬区苹果园和农田相互转换后0~1 000 cm土壤含水量特征,分析了苹果园土壤干燥化和苹果园转换为农田后土壤水分的恢复效应。结果表明：2、7、17、23、29 a苹果园200~1 000 cm的平均土壤含水量分别为22.8%、21.4%、16.8%、15.4%、14.9%。500~1 000 cm土层中,29 a苹果园平均土壤含水量（14.5%）高于23 a的果园（13.3%）;17~29 a的苹果园均表现为轻度干燥化;基于苹果园和农田转换后土壤水分变化情况估算,苹果园最大种植年限为21 a。苹果园转换为农田1、5、10 a后,农田200~1 000 cm土层土壤含水量分别为：15.3%、15.7%和16.2%,恢复到土壤稳定湿度以上的土层厚度分别为140 cm（1 a）、220 cm（5 a）和400 cm（10 a）。

Deep soil water environmental effects after the mutual conversion between apple orchard and farmland in Changwu tableland region

By quantifying the soil moisture characteristics of 0~1 000 cm layer after the mutual conversions between apple orchard and farmland in Changwu tableland region, soil water environment effects resulted from the mutual conversions between apple orchard and farmland were analyzed. The results showed that, the average soil moistures of 200~1 000 cm in the apple orchards of 2 a, 7 a, 17 a, 23 a, and 29 a were 22.8%, 21.4%, 16.8%, 15.4%, and 14.9%, respectively. In the 500~1000 cm soil layer, the average soil moisture (14.5%) of the 29 a apple orchard was higher than that of the 23 a apple orchard (13.3%), and the orchards of 17~29 a showed slight drying. Based on the change of soil moisture in apple orchards and farmlands after the conversions, the maximum planting years for apple orchard was 21 a. As the farmlands converted from apple orchards were cultivated for 1 a, 5 a, and 10 a, the soil moisture of their 200~1 000 cm layers were 15.3%, 15.7%, and 16.2%, respectively. The thicknesses of dried soil layers that could restore to the stable soil moisture were 140 cm (1 a), 220 cm (5 a), and 400 cm (10 a), respectively.