紫色土侵蚀区柑橘园套种印度豇豆对土壤水稳性团聚体的影响

Effects of interplanting Vigna sinensis on soil water stable aggregate of Citrus reticulata orchard in purplish soil erosion region

本研究针对紫色土侵蚀区山地果园开发易造成土壤结构破坏、肥力下降等问题,引进豆科牧草印度豇豆（Vigna sinensis）套种于柑橘（Citrus reticulata）园,测定土壤基本理化性状和水稳性团聚体百分含量,评价印度豇豆对柑橘园土壤肥力及水稳性团聚体的影响。结果表明,与清耕相比,印度豇豆套种有利于提高紫色土的土壤肥力,使土壤全氮、全磷、有机质和速效钾含量分别显著提高了63.64%、20.90%、93.43%和166.57%（P〈0.05）。与清耕相比,果园套种印度豇豆还有利于改善土壤结构,其中土壤团聚体以〉0.25 mm粒级为主（56.31%）,还能促进〉5和2-5 mm水稳性大团聚体的形成,显著提高水稳性团聚体稳定性,使水稳性团聚体比例（R（0.25））和平均重量直径分别显著提高了25.22%和35.90%（P〈0.05）,几何分形维数显著降低了5.17%（P〈0.05）。研究结果表明,紫色土侵蚀区柑橘园套种印度豇豆可增加土壤肥力,改善土壤团聚体结构,是一种可持续山地农业发展模式。

It is common issues that developing of orchard in mountain easily leads to the destruction of soil structure and fertility in purple soil area. In this study, we analyze the effect of interplanting Vigna sinen sis on the soil fertility and water stable aggregate of citrus orchard in purple soil region. The results indica ted that interplanting V. sinensis on citrus orchard was conductive to the improvement of soil fertility, sig nificantly （P〈0.05） increased by 63.64% of total nitrogen, 20.90% of total phosphours, 93.43% of organic matters and 166.57%0 of available K compared to clean tillage, respectively. Meanwhile, interplanting V. sinensis on citrus orchard was benefit to the improvement of soil structure and stability of water stable aggregates, significantly increasing proportion of 〉5 mm and 2-5 mm water stable aggregate. 53.61% of soil water stable aggregates of citrus orchard interpreted by V. sinensis were 〉0.25 mm of size compared to clean tillage. Ratio of water stable aggregate （R0.25） and mean weight diameter （MWD） of interplanting V. sinensis treatment was significant higher of 25.22% and 35.90% than clean tillage treatment, respectively, however fractal dimension was lower of 5.17 % than that. Finally, it was concluded that interplanting V. sinensis on citrus orchard increased soil fertility and soil structure in purple soil region, and it is a sustainable agricultural mode.