In the Loess Plateau, apple (Malus pumila Mill.) orchards converted from cropland are expanding because of the economic value of apples. Understanding the effects of the conversion of cropland to apple orchards on soil water and nitrogen distributions, as well as the potential soil nitrate accumulation, is important and necessary. In this study, apple orchards (Red Fuji) of different growing ages (5, 15, and 28 year old), an abandoned apple orchard, a wheat field, and a maize field in Changwu County of the Loess Plateau were selected to evaluate the soil water content (SWC), nitrate-nitrogen (NO₃⁻-N), and other soil parameters within the 0–5 m soil depth. Results showed that SWC of maize field (21.22%) was the highest, followed by that of the 5-years-old apple orchard (20.24%) and wheat field (18.83%). The SWC of the 28-years-old apple orchard (16.09%) was the lowest of the six treatments. Soil NO₃⁻-N storage within the 0–5 m soil profile under 5-, 15-, and 28-years-old, abandoned apple orchards, wheat fields, and maize fields reached approximately 613.2, 1929.4, 4277.9, 1282.4, 95.2, 275.9 kg ha⁻¹, respectively. The SWC deficits were found severe, and high nitrate accumulation was found in 15- and 28-years-old apple orchards. Soil water deficits and nitrate accumulation in abandoned apple orchards can persist for ten years. The soil NO₃⁻-N content was significantly (P < 0.01) negatively correlated with SWC. After converting croplands to apple orchards, soil water deficit and nitrate accumulation were the main soil environmental problems, which worsened with age. A reasonable amount of fertilizer should be applied in orchards to reduce contaminants in the soil environment. Coupling enhancement of the utilization efficiency of fertilizers and limited soil water resources could be important for establishing the soil environment in arid and semi-arid areas.

在黄土高原，由于苹果的经济价值，由农田改建的苹果（ Malus pumila Mill. ）果园正在扩大。了解农田转变为苹果园对土壤水和氮分布的影响，以及潜在的土壤硝酸盐积累，是重要和必要的。本研究选取黄土高原昌武县不同生育年龄（5、15、28 岁）的苹果园（红富士）、废弃苹果园、麦田和玉米田进行评价。土壤含水量 (SWC)、硝酸盐-氮 (NO ₃ ⁻-N)，以及 0-5 m 土层深度内的其他土壤参数。结果表明，玉米田SWC（21.22%）最高，其次是5年生苹果园（20.24%）和麦田（18.83%）。28年生苹果园的SWC（16.09%）是6个处理中最低的。5、15、28 年、废弃苹果园、麦田、玉米田在 0-5 m 土壤剖面内土壤 NO ₃ ^- -N 储存量约为 613.2、1929.4、4277.9、1282.4、95.2 ，275.9 kg ha ^-1，分别。发现 SWC 缺陷很严重，并且在 15 和 28 岁的苹果园中发现了高硝酸盐积累。废弃苹果园的土壤水分不足和硝酸盐积累可持续十年。土壤 NO ₃ ^--N含量与SWC呈显着( P  <0.01)负相关。将农田改成苹果园后，土壤水分亏缺和硝酸盐积累是主要的土壤环境问题，随着年龄的增长而恶化。果园应适量施肥，以减少土壤环境中的污染物。提高肥料利用率和有限的土壤水资源对干旱和半干旱地区土壤环境的建立具有重要意义。