纸坊沟流域撂荒地环境因子对植被变化的典范对应分析

Canonical Correspondence Analysis between Environmental Factors and Vegetation Variations on Abandoned Croplands in the Zhifanggou Watershed

为了解侵蚀环境下植被恢复对环境因子的响应规律,选取典型侵蚀环境黄土丘陵区纸坊沟流域生态恢复0、1、5、7、10、15、20、25、30、40和50年撂荒地长期定位试验点为研究对象,采用典范对应分析(Canonical correspon-dence analysis:CCA)从单因子和显著因子2个方面分析土壤养分、地形因素、恢复年限、土壤微生物和土壤酶活性对植被恢复的影响。结果表明:多酚氧化酶、纤维素酶和物种多样性指数是恢复过程中的关键因子;随着恢复年限的增加,物种多样性增大,土壤性质得到改良;土壤酶活性对植被演替反应迅速,呈现出较高的相关性(P<0.05)。由于土壤酶对土壤系统代谢需求和可利用营养物的直接表达,有助于更加深入地理解微生物群落和养分循环的关键过程,可作为土壤微生物和养分的指示物,同时用以评价土地格局改变对土壤性质的影响。

In order to better understanding relations between vegetation restoration and environmental factors,long-term located farmland with an abandoned age sequence of 0,1,5,7,10,15,20,25,30,40,and 50 year s in Zhifanggou watershed（8.27 km2）,Shanxi province were studied.Areas were selected for their typical erosion environment in loess hilly region.Additionally,effects of soil nutrient,landform,restoration age,soil microbial biomass and soil enzyme activity on vegetation restorations were evaluated by both single factor and significant factors using the Canonical correspondence analysis.Results indicate that key environmental factors affecting variation of species on loess hilly region are polyphenol oxidase,cellulose and Shannon-Wiener diversity index.Both species diversity increased and subsequent improved soil quality with restoration age increasing.Moreover,there was a sensitive response of soil enzyme activities to vegetation variation,while a significant correlation with vegetation variation（P0.05）.The direct expression of the soil community to metabolic requirements and available nutrients provided a more comprehensive understanding of those key processes linking microbial populations and nutrient dynamics.Data suggested that soil enzyme activity can be used as an indicator of soil fertility and microbial activity and to evaluate the influence of land use for soil properties.