不同改造方式对大兴安岭低质林土壤理化性质及重金属影响

Impact of Different Transformation Measures on Soil Physical and Chemical Properties and Heavy Metal Content in Low-Quality Forest Stands in Great Xing'an Mountains

对大兴安岭低质林进行带状和块状改造,分析不同方式改造后土壤理化性质及重金属的变化。结果表明:改造样地的土壤密度低于对照样地,而土壤含水率高于对照样地,土壤孔隙度也有所提高,林地土壤的物理性质得到了改善。各改造样地土壤pH值升高,土壤有机质质量分数在带宽较宽及面积较大的改造样地中更高;带状改造样地和中等采伐面积样地(225～400 m2)土壤全N质量分数高于对照样地;改造样地的土壤全P、全K以及水解N质量分数并没有得到改善;带状改造样地土壤有效P质量分数升高,块状改造样地土壤有效P质量分数下降;改造样地土壤速效K质量分数高于对照样地。样地S1、G4、G5土壤Cd质量分数高于对照样地,且与对照样地差异显著(P<0.05);各样地土壤Cu质量分数与对照样地差异不显著(P>0.05);各带状改造样地之间土壤Pb质量分数差异显著(P<0.05),样地S3土壤Pb质量分数最高。土壤Cd与Pb质量分数之间呈极显著正相关,土壤3种重金属质量分数与土壤总孔隙度正相关,与土壤有机质及水解N质量分数负相关。

A study was conducted to analyze the change in soil physical and chemical properties and heavy metal content in low-quality forest stands in Great Xing＇an Mountains after strip transformation and patch reconstruction.Compared with the check plot,the soil density of transformation plots decreased,while soil moisture content and soil porosity increased,indicating that the soil physical properties were improved.The soil pH increased,and soil organic matter content was higher in those plots with wide bandwidth and large size.Soil total nitrogen contents were higher both in the plots after strip transformation and in the medium size thinned plots（225-400 m^2）.However,the contents of soil total phosphorus,total potassium and hydrolyzed nitrogen in the transformation plots were not improved.Soil available phosphorus content increased in the plots after strip transformation,and decreased in the plots after patch reconstruction.Soil available potassium content in the transformation plots was higher than that in the check plot.The Cd content in plots S1,G4,G5 were significantly higher than that in the check plot（P〈0.05）;while there was no significant difference in soil Cu content between the transformation plots and the check plot（P〈0.05）.A significant difference in soil Pb content was observed between the plots after patch reconstruction（P〈0.05）,and the soil Pb content in the plot S3 was highest.Soil Cd content was significantly positively correlated with Pb content,and the contents of three kinds of heavy metals were positively correlated with soil total porosity and negatively correlated with contents of soil organic matter and hydrolyzed nitrogen.