典型石漠化区不同种植年限桃树下土壤微量元素变化特征

Variation of soil trace elements under peach trees with different planting ages in typical rocky desertification areas

为明确石漠化地区不同种植年限果树根系表层土壤微量元素的变化特征,选择桂林市恭城县大岭山村同一农户的不同种植年限桃树(2a、10a、20a)各5棵,以撂荒地(0a)作为对照,对土壤微量元素铁、铜、锰、锌、硼的全量及有效态变化规律进行研究,并探讨理化性质与微量元素有效态的相关性。结果表明:(1)研究区除全铁的变异系数小于10%,铜、锰、锌、硼的全量及有效态均为中等变异;(2)土壤铁、铜、锌、硼全量种植0~2a间均增加(P<0.05),种植2~10a则下降(P<0.05),种植10~20a间铁元素随年限增加而下降(P<0.05),其余研究元素全量均表现为增加趋势;(3)有效铁、锌、硼在种植0~10a先增加(P<0.05),种植10~20a均有明显下降趋势,有效锰在0~20a间趋势则与其他元素相反,并且与全量锰保持一致性,因此种植10a是果树土壤微量元素变化的转折点;(4)不同种植年限果树根系土壤性质的改变(pH值、有机质、全磷的变化)是微量元素有效态含量随时间变化的主要内在原因,而人为活动如施加有机肥是外在原因。在种植10a后,应重视微肥的施加。

In order to identify the variation of trace elements of peach orchard soil with different tree ages in typical rocky desertification areas, this work selected the peach trees with planting age of two years, ten years, and twenty years, five pieces each, as the study object. Compared with the abandoned agricultural land（zero year）, we analyzed the vibrations of the content of Fe, Cu, Mn, Zn, and B in the soils, and estab- lished the relationship between the content of available trace elements and their physicochemical properties. The results show that, （1） The total content of trace elements belong to a medium variation level except the total content of Fe. （2） The total contents of Fe, Cu, Zn and B increase when planting age reaches 2 a, but decrease between 2 a and 10 a（P〈0.05）. The total content of Fe decreases with growing ages （P〈0.05）, but the tendency of the rest trace elements is opposite between planting 10 year and 20 year （P〈0.05）. （3） The content of soil available Fe, Zn, and B increase between planting 0 year and 10 years（P〈0.05） ,but decrease in 20 years. The content of soil available Mn is opposite, which keeps consistency with the total con- tent of Mn. Thus, planting 10 year is a turning point. （4） Changes of the soil property for different planting ages of the fruit trees （the change of pH,organic matter, and total phosphorus） are the main internal reasons for that the available content of trace elements change with time and human activity, such as applying organic fertilizer, is the main external cause. So after planting 10 year, attention should be focused on the application of fertilizer of trace elements.