茂名小良土壤质量的灰色关联分析及评价

Grey relational analysis and evaluation of soil quality at Maoming xiaoliang

以茂名小良水保站林地和周边天然恢复林地为研究区域,对区域内9种不同植被类型下45个观测点土壤的物理性状、化学性状、微生物性状和酶活性共32个指标进行取土化验和灰色相关分析及综合评价,结果表明:(1)土壤肥力从高到低的顺序为天然恢复林>阔叶林>松桉混交林>U6.31>W5.31>W5.34>W5.41>W5.44>光板地。(2)用该方法把样地分为5个等级,各等级的土壤属性特征非常明显:1等最好,天然次生林植被茂盛,土壤肥力高;5等最差,保留的光板地,很少有草类生长,土壤肥力极低。(3)样地土壤肥力灰色相关分析综合评价的结果与样地实际植被生长情况看出的土壤肥力状况非常吻合,说明此方法科学可行。综合分析得出:桉树适合作为先锋林,用以恢复赤裸地,但不适合长期种植、连栽等,会导致肥力退化,不利于生态修复;如果必须栽植纯桉林,就要采取经常更换品种、轮种、混交、保护林下植被、保留枯枝落叶覆盖物等措施,对保护土壤肥力大有益处。

This paper studied soil samples in the region of Xiaoliang water conservation station in China, and the naturally restored forest around it. 32 indices on the mechanical, chemical, microbiological and enzyme activity properties were studied for soil from 9 different vegetation patterns at 45 observation points by laboratory soil testing, grey correlation analysis and comprehensive evaluation. The results showed that： （1）From the scores of the sample soil, the order of the soil fertility was： naturally restored forest〉broad leaf forest 〉eucalyptus pine mixed forest 〉U6.31〉WS.31〉WS.34〉W5.41〉WS.44〉bare land. （2） Through this method, the sample plots were categorized to 5 levels： Level 1 （the best）： the sample was naturally restored forest which provided higher soil fertility than planted forest; Level 5 （the worst）： the sample plot was bare land, where there was no vegetation cover and showed very poor soil fertility. （3） The comprehensive evaluation of the sample soil fertility by grey correlation analysis was in excellent agreement with the real situation, which proved this method was applicable and useful. Therefore, eucalyptus could be used as pioneer forest to recover the bare land, but it was not suitable for long-term planting and cropping, which would result in degradation of soil fertility that was unfavorable for ecological restoration. If planting eucalyptus was determined, the actions could be taken, such as changing the breed variety often, rotation of crops, mixing with broad-leaf forest, protecting undergrowth vegetation, detaining forest litter coverage, and so on, which would benefit the soil fertihty.