晋西黄土区果农间作系统根系生态位特征

Niche of Roots in the Economic Tree and Crop Intercropping System in the Western Shanxi Province of Loess Plateau

为了进一步分析农林复合系统的土壤水肥效应,指导农林复合系统的物种选择和行间配置及其水肥管理等农艺措施,以晋西黄土区核桃—大豆间作系统为研究对象,采用分层挖掘根系法,研究核桃和大豆的根系生态位分布特征及地下种间竞争关系。结果表明,在1.0~3.0m各区域,核桃根系生态位宽度均大于大豆根系生态位宽度,而在3.0~3.5m区域,则反之;在垂直方向上,除1.5~2.0m区域的大豆外,大豆和核桃的根系生态位均随土壤深度的增加而下降;距树行1.0~3.0m各区域,核桃对大豆的生态位重叠指数均大于大豆对核桃的生态位重叠指数,而在距树行3.0~3.5m区域,则反之。距树行1.0~2.5m区域的核桃和大豆根系生态位相似性和地下种间竞争指数均较大,为种间土壤水肥竞争的主要区域。

In order to further study the soil water and fertilizer effect of agroforestry system and guide species selection, spacing form, tillage and fertilize. A walnut-soybean intercropping system in the western Shanxi Province of Loess Plateau was used as material. Distribution of niche and underground competition characteristics of roots in a walnut-soybean intercropping system were examined by stratified digging method. The results showed that niche breadths of walnut roots were higher than that of soybean in plots 1.5-3.0 m from the tree row but it was the opposite situation in plot 3.0-3.5 m, niche breadth of roots for both walnut and soybean were decreased with the depth except for that of soybean in plot 1.5-2.0 m, niche overlap of soybean roots were lower than that of walnut in plots 1.5-3.0 m from the tree row beside the plot 3.0-3.5 m. Both niche similarity of roots and underground species competitive index between walnut and soybean were greater in the 1.0-2.5 m from the tree row, where is the main area competing for soil moisture and nutrients.