晋西苹果-大豆间作土壤水分的时空分布特征

选取晋西黄土区典型的苹果(Malus pumila)-大豆(Glycine max)间作系统为研究对象,在大豆的关键物候期对间作系统和对照单作的土壤水分、大豆生长状况和产量进行了定位监测。研究结果表明:(1)不同物候期,间作系统土壤平均含水量变化显著,苹果树和大豆对土壤水分竞争的空间区域和强度也有明显差异,土壤水分耗用最大的时期为大豆开花期;(2)水平方向上,各个物候期间作系统土壤含水量均随着与树行距离的增加而增加,最低值出现在距离果树行最近的区域;(3)垂直方向上,在大豆的苗期和结荚期间作系统土壤含水量随土壤深度的增加而递增,在开花期,土壤含水量随着土壤深度的增加出现先减小后增加的趋势;(4)当前树龄下,苹果-大豆间作系统的水分效应相对于大豆单作,整体表现为负效应,并对间作大豆的生物量和产量有着一定的负面影响。基于苹果-大豆间作系统土壤水分在不同物候期的分布特征,建议采取适当的管理措施以缓解种间水分竞争并提高大豆的产量。

Spatio-temporal Distribution of Soil Moisture in Apple-Soybean Intercropping System on Loess Plateau of West Shanxi Province

By taking apple-soybean intercropping system on the loess region of West Shanxi Province as the research object, the soil moisture content, biomass and yield of soybean were tested at different key phenophases. The results indicated that:(1) The soil moisture of apple-soybean intercropping system changed significantly in different phenophases, and the maximum consumption period for soil moisture was the flowering period of soybean. In different phenophases, the main competitive area and the degree of competition for soil moisture between apple trees and soybean were significantly different;(2) In horizontal direction, the soil moisture content increased with increase of the distance from the tree base, and the lowest soil moisture content was the area adjacent to the tree base;(3) In vertical direction, the soil moisture increased with the increase of soil depth in both of the intercropping system and soybean monoculture plots at soybean seedling stage and bearing pod stage. In the flowering stage of soybean, with the increase of soil depth, soil moisture decreased at first and then increased with the increase of depth;(4) Compared with monoculture plots, an overall negative soil moisture effect appeared in apple-soybean intercropping system and resulted in the loss of soybean production. Due to the soil water distribution in different phenological periods of apple-soybean system, the authors recommended that the appropriate regulation and management measures should be taken to alleviate interspecific competition for moisture and to improve soybean yields.