毛乌素沙地不同植被类型的土壤颗粒分形与土壤碳氮变化特征

摘要

为了探讨不同植被类型的土壤碳氮特征,测定了毛乌素沙地不同植被群落土壤0~10、10~20和20~60 cm土层土壤有机质 、全氮及土壤颗粒组成的动态变化,并分析了土壤颗粒组成中沙粒、极细沙和黏粉粒质量分数变化与土壤有机质和全氮质量分数间的关系.结果表明,固沙植被的建植显著提高土壤有机质和全氮质量分数,而不同植被类型对土壤有机质和全氮质量分数的影响差异主要发生在土壤表层(0~10 cm),深层差异不显著.而同一植被类型土壤有机质和全氮质量分数随土层加深呈下降趋势,表现出垂直方向的变异.其中樟子松样地对表层土壤有机质和全氮质量分数含量影响最大,具有明显表聚性,随土层加深土壤有机质和全氮质量分数含量下降最为显著,而沙柳+油蒿+杨柴样地和沙地柏+油蒿样地土壤有机质、全氮质量分数随土层加深无显著变化.固沙植被的建植显著提高土壤黏粉粒(Salix psammophila+Artemisia odr osica+Hedysaur m frutico-sum>Aret misia ordosica+Junpi erus Sabina, but contrary to the content of sand .However, the content of sand in the same vegetation type sample was increased with soil depth , while the contents of silt clay and fine sand were decreased with soil depth.The relationships between the particle size fraction and the content of soil organic matter and total nitrogen showed that the content of soil organic matter and total nitrogen had significantly positive correlation with the content of silt clay and fine sand, but significantly negative correlation with the content of sand (p<0.01).