黄土丘陵沟壑区退耕地植物群落土壤抗蚀性研究

 国家退耕还林(草)科技示范点陕西省吴旗县的退耕地植物群落的抗蚀性试验研究结果表明:通过对衡量土壤抗蚀性的12项指标主成分分析,反映特征值大部分信息(88.671%)的主成分包括无机黏粒类、团聚类、无机胶粒类和水稳性团粒类4大类。对4个主成分进行聚类,将吴旗县内的植物群落分为3大类,其中以退耕时间长的人工林地和还草地为主的植物群落抗蚀性最好,其次是退耕时间长的蒿类群落为主,以新退耕还林(草)地和坡耕农用地为主的植物群落抗蚀性较差。从土壤抗蚀性这一重要指标来看,随着退耕时间的延伸,退耕地人工林地抗蚀性较坡耕农用地不断提高,逐渐接近于天然林地,而退耕时间较晚的还林(草)地和坡耕农用地相对较差。

Soil anti-erodibility of plant communities on the removal lands in hilly-gully region of the Loess Plateau

The study result on soil anti-erodibility in Wuqi County, Shaanxi Province, a national experiment site for conversion from cropland, into forest land and grassland showed that all the 12 anti-erodibility indexes can be divided into 4 categories, i.e. inorganic clay, aggregate, inorganic colloid and water-stable aggregate, capable of reflecting 88.671% of the information of the eigenvalues, by means of PCA. All the plant communities in Wuqi County can be clustered into three kinds based on the four categories with the Hierachical Cluster Method. The first kind with good anti-erodibility mainly includes forest land and grassland from cropland with a long removal time, and the second kind with medium anti-erodibility is composed of Artemisia, where as the third with poor anti-erodibility is made up of newly forest land and grassland removed from cropland and the cropland. The anti-erodibility of artificial forests is getting stronger and stronger as the forest ages, approaching that of natural forests.