香椿人工林土壤抗蚀性研究

Erosion Resistance of Soils in Toona Sinensis Plantations

选择贵州省镇宁县香椿人工林为研究对象,按Ⅰ龄级(8～13龄),Ⅱ龄级(15～25龄),Ⅲ龄级(>25龄)3个林龄级分别进行研究。通过土壤有机质含量、机械组成、>0.25mm干筛团聚体含量、水稳性团聚体含量、结构破坏率等指标,研究了香椿人工林土壤的抗蚀性能。结果表明,Ⅰ龄级、Ⅱ龄级和Ⅲ龄级有机质含量分别为4.56%,5.02%,5.35%;>0.25mm干筛团聚体含量分别为92.19%,96.72%,98.07%;水稳性团聚体含量分别为65.83%,70.72%,75.29%。对抗蚀指标间相关性进行了分析,结果表明有机质、水稳性团聚体及结构破坏率是评价土壤抗蚀性强弱的较好指标。林龄对土壤抗蚀性具有影响,经方差分析发现,林龄间差异显著,随着林龄的增大其土壤抗蚀性增强。有林地土壤抗蚀性比无林地强。

The Toona sinensis plantation in Zhenning County of Guizhou Province were classified according to the age as class I（8~13 a）,class Ⅱ（15~25 a） and class Ⅲ（25 a）.Indicators such as the content of soil organic matter,particle size composition,content of dry soil aggregates（0.25 mm）,content of water-stable aggregates,and soil structure destruction rate were determined for erosion resistance evaluation of the soils under the plantations.The results show that,the average contents of soil organic matter were 4.56%,5.02% and 5.35%,the contents of dry soil aggregates（0.25 mm） were 92.19%,96.72% and 98.07%,and the contents of water-stable aggregates were 65.83%,70.72% and 75.29% in class I,class Ⅱ,and class Ⅲ,respectively.Correlation analysis showed that the contents of soil organic matter and water-stable aggregate,and structure destruction rate were the best indicators for evaluating soil resistance to erosion.The erosion resistance of soil was influenced by forest age significantly according to variance analysis;soils from older forests showed stronger resistance to erosion.As expected,soil erosion resistance in Toona sinensis plantation was stronger than that in non-forest lands.