黄土高原地区水蚀风蚀交错带土壤质量综合评价

 为揭示黄土高原水蚀风蚀交错带土壤质量变化规律和总体水平,通过敏感性分析、主成分分析和相关分析,确定了研究区的土壤质量评价最小数据集,并利用综合指标和最小数据集定量评价了植被演替和不同植被恢复类型对土壤质量的影响。结果表明,研究区土壤质量评价指标最小数据集为有机质、速效磷、蔗糖酶和真菌。随着退耕年限的增加,土壤质量综合指数并非简单地线性增加,而是在演替的前15a呈现下降趋势,15a后开始呈现增加的趋势,即表现出非正U型的变化。就不同植被恢复类型而言,研究区土壤质量的排序为:刺槐林地>农地>退耕草地>油松林地>沙蒿地>柠条灌木地>杨树疏林地。所确定的土壤质量评价指标最小数据集能够反映综合评价指标的信息,评价结果具有较好的代表性。总体而言,研究区土壤肥力仍属于较低水平。因此,研究区生态建设的任务仍很艰巨,有关植被建设中如何缩短植被演替早期阶段的土壤质量退化是值得探讨的科学问题。

Integrated assessment on soil quality in the water-wind erosion region of the Loess Plateau area

In order to clarify the changes and level of soil quality in the water-wind erosion region of the Loess Plateau area,this paper established a Minimum Data Set（MDS） for soil quality assessment by the methods of sensitivity analysis,principal components analysis,and correlation analysis,quantitatively evaluated effects of vegetation succession stages and different vegetation restoration types on soil quality based on integrated indictors and MDS.The results showed that MDS included soil organic matter content,available phosphorus,invertase activity,and fungi.The trend of integrated fertility index（IFI） changes was partially U shape,namely,showing a decrease in 15 years following abandonment,but an increase after 15 years.Considering different vegetation types,the values of IFI ranked in the order： Robinia pseudoacacia forestland,cropland,abandoned farmland,Pinus tabulaeformis forestland,Artemisia desertorum land,Caragana korshinskii land,Populus simonii thining forestland.Established MDS could reflect the information of integrated indicators and results of assessment were of better representative.Conclusively,soil fertility level in the study area was low.Therefore,the task of eco-environmental rehabilitation is till very arduous,and how to shorten the evolution stage of soil quality in earlier vegetation succession should be addressed.