洛川苹果园土壤水分变化特征

全面掌握洛川果园的土壤水分环境特征，不仅可为苹果的园址选择、砧穗组合和改进土壤水分管理措施提供理论依据，而且对我国苹果产区果园提质增效具有借鉴价值.采用定点土壤水分连续监测法，对洛川苹果园的总体土壤水分环境以及不同生长年限、不同立地类型和乔、矮化果园的土壤水分分异特征进行分析.结果表明： 苹果树根际区 (0～200 cm)土壤水分普遍亏欠，且0～60 cm土层的水分亏欠小于60～200 cm土层；生长季0～60 cm土层贮水量与降水量的变化一致，土壤相对含水量大多<60%，季节性旱象严重；果园剖面土壤含水量变异系数随土壤深度加深而递减；随果园生长年限的增大，土壤剖面贮水量下降；在栽培密度一致的条件下，矮化果园5 m土层土壤含水量均高于乔化果园，而栽培密度大的矮化果园的土壤贮水量低于栽培密度小的乔化果园；塬地成龄果园的土壤水分含量最高，川地次之,台地相对较低.密度对果园土壤水分含量有很大影响，在栽培密度一致的条件下，采用矮化栽培能减少土壤水分消耗，显著提高果园土壤含水量；挖株降低栽培密度是维持苹果园土壤水分平衡、实现可持续发展的有效途径.

Variation characteristics of soil moisture in apple orchards of Luochuan County, Shaanxi Province of Northwest China

To have an overall understanding on the soil moisture characteristics in the apple orchards of Luochuan County can not only provide theoretical basis for selecting apple orchard sites, choosing the best root-stock combination, and improving the soil water management, but also has reference importance in increasing the productive efficiency of our apple orchards. In this study, a fixed-point continuous monitoring was conducted on the overall soil moisture environment and the variation characteristics of soil moisture in the County apple orchards differed in age class, stand type, and tree type (standard or dwarfed). For the apple orchards in the County, the rhizosphere (0-200 cm) soils of most apple trees were water-deficient, and the deficit in 0-60 cm soil layer was less than that in 60-200 cm layer. During growth season, the water storage in 0-60 cm soil layer had the same variation trend as the rainfall pattern. The relative soil moisture content in most orchards was less than 60% , and seasonal drought was quite severe. The coefficient of variation of soil moisture content decreased with soil depth. With the increasing age of the orchards, soil water storage decreased. At the same planting density, the orchards with dwarfed trees had more water storage in 0-5 m soil layer than the orchards with standard trees. However, when the orchards were planted with dwarfed trees at a higher density, the soil water storage in the orchards with dwarfed trees was lesser than that in the standard orchards. The mature orchards on highland had the highest soil moisture content, followed by the mature orchards on flat land, and on terraced land. Tree density had great effects on the soil moisture content. When the tree density was the same, planting dwarfed trees could decrease the water consumption, and increase the soil moisture content significantly. To decrease the planting density through the removal of trees would be an effective way to maintain the soil water balance of apple orchards, and achieve the sustainable development of the orchards.