晋西苹果与大豆间作系统土壤养分分布特征

为了研究晋西黄土区果农间作系统中土壤养分分布特征,选取研究区具有典型代表性的4,6和8年生苹果(Malus pumila)+大豆(Glycine max)间作系统为研究对象,对间作系统土壤养分(速效钾、速效磷、有机质、全氮)含量进行了定位、定量监测。结果表明:(1)在垂直方向上,不同树龄苹果+大豆间作系统速效钾、速效磷和有机质含量均随着土层深度增加而减少,而全氮含量表现为先增加再减少;(2)在水平方向上,随着距树行距离的增加,4年生间作系统与6年生间作系统土壤养分总体上呈现"W"型分布,而在8年生间作系统中呈现"M"型分布(全氮除外),极值分别出现在距树行1.5,2.5,3.5m处,且极大值点养分含量与极小值点含量有显著差异(p0.05);(3)随着树龄增长,果树与农作物的养分竞争关系逐渐发生变化,且在8年生间作系统中养分竞争最激烈。基于间作系统土壤养分特征,建议在田间施肥管理时,应以施氮肥为主,且随着树龄的增长应该适时增大复合界面的距离或停止复合经营。

Soil Nutrients Distribution in Intercropping System of Apple and Soybean on West Shanxi Loess Plateau

In order to investigate the spatial distribution characteristics of soil nutrients in fruit+crop intercropping system, Malus pumila+Glycine max intercropping pattern, typical and representative in the loess region of West Shanxi Province, was studied and soil nutrients in the intercropping system of different ages were monitored separately for comparison. Results showed that:(1) In vertical direction, with the increasing soil depth, available K, available P and organic matters decreased, while total N increased at first and then decreased.(2) In horizontal direction, with the increase in the distance from tree row, soil nutrient contents in 4-year-old intercropping system and 6-year-old intercropping system showed a "W" type distribution, while the 8-year-old intercropping system had a "M" type distribution(except total N). Coincidently, all the extreme values appeared in the distances of 1.5, 2.5 and 3.5 m from tree row, and soil nutrient contents at the maximum points were significantly different from those at the minimum points(p<0.05).(3) Nutrients competition relations between fruit trees and crops changed gradually with the growth of the trees, and the competition of soil nutrients in the 8-year-old intercropping system was fiercest. In accordance with the distribution characteristics of soil nutrients in intercropping systems, nitrogen fertilizer should be the main fertilization, the distance of fruit tree and crops should be increased or planting crops in 8-year-old apple orchard should be prohibited.