冀西北坝上地区退化防护林的土壤性质

Soil Properties of Degraded Shelter Forests in Bashang Plateau of Northwestern Hebei Province

为了解冀西北坝上防护林退化与土壤性质的关系,以河北省张北坝上地区杨树防护林为研究对象,比较了不同退化程度杨树防护林的土壤养分和土壤硬度。研究结果表明:1随林分退化程度的增加,土壤硬度和出现钙积层的概率均有增加的趋势。2除速效钾表现出明显差异外,不同退化程度防护林土壤有机质、全磷、速效磷、全氮、碱解氮、全钾含量无明显差异。3张北坝上地区土壤养分含量总体处于较低水平。根据全国第2次土壤普查养分分级标准,其有机质为4级,磷素和氮素为6级,钾素为5级。4土壤有机质含量与全氮、碱解氮、全钾、速效钾、全磷和速效磷含量呈显著或极显著正相关关系,全氮与碱解氮、全钾与速效钾含量呈显著正相关关系,全磷与速效磷含量没有明显的相关关系。尽管张北坝上的地区土壤养分含量普遍较低,但防护林退化程度与多数土壤养分含量没有明显的相关关系,而与土壤硬度的高低及钙积层的有无具有一定的相关性。

To understand the relationship between degradation of shelter forests and soil properties in Bashang Plateau of northwestern Hebei province,the poplar forests in Zhangbei county of Hebei province was selected as research object to compare soil nutrients and soil hardness among poplar shelter forests at different degrees of degradation.The results showed that：（1）With the increase of the forest degradation degree,the soil hardness and the probability of calcic horizon occurrence in soil increased.（2）Except available potassium content,the contents of soil organic matter,total phosphorous,available phosphorous,total nitrogen,available nitrogen and total potassium in soil had no significant difference among poplar shelter forests at different degrees of degradation.（3）The soil nutrient content in Bashang Plateau of northwestern Hebei province was generally at a low level.According to the nutrient classification standard in the second national soil census,the content of soil organic matter was at level 4,while soil potassium content was at level 5,and the nitrogen and phosphorous contents were at level 6.（4）The soil organic matter content showed significant or extremely significant positive correlations with the contents of total and available nitrogen,total and available phosphorous,and total and available potassium.Positive correlations existed between total nitrogen content and available nitrogen content in soil,as well as between total potassium content and available potassium content,but no correlation was found between total phosphorous content and available phosphorous content.In conclusion,the soil nutrient content in Bashang Plateau of Zhangbei county was quite low.The degradation extent of shelter forests had no obvious relationship with soil nutrient content,but showed a certain correlation with soil hardness and the probability of calcic horizon occurrence.