民勤不同林龄胡杨根区土壤理化性质及相关性分析

以民勤不同林龄胡杨根区土壤为对象，采集0~200 cm土壤样品，并对土壤的物理性质、养分含量及其相关性进行了分析。结果表明:1）随着胡杨林龄增加，土壤含水量增加，土壤中黏粒含量逐渐增加，粗砂粒含量减少，粉粒、细砂粒差异不明显。2）土壤有机质、全N、电导率变化均表现为成熟林＞中龄林＞幼龄林，且表层（0~20 cm）含量显著高于其他土层，表聚性明显。3个林龄胡杨根区土壤速效P含量、pH差异不显著（P＞0.05）。3）土壤理化性质之间关系密切，土壤含水量与黏粒、粉粒、有机质、全N、速效P、电导率均呈极显著（P<0.01）正相关，与粗砂粒呈极显著（P<0.01）负相关。黏粒、粉粒含量与含水量、有机质、全N、速效P均呈极显著（P<0.01）正相关。研究结果表明，林龄的增加改善了胡杨根区土壤理化性质，为干旱区胡杨的抚育与发展提供理论依据。

Physicochemical Properties and Correlations of the Soils in the Populus euphratica Forests with Different Ages in Minqin

Soils in the root areas of Populus euphratica forestswith different ages in Minqin were taken as the research objects,soil samples were collected from the depth of 0-200 cm,and the soil physical properties,nutrient content and the correlationships between them were analyzed.The results showed that 1) with the increase of forest age,the soil water content increased,the clay content increased gradually,the coarse sand content decreased,and the difference between silt particle and fine sand was not obvious.2) The changes of soil organic matter,total nitrogen and conductivity were all manifested as mature forest>medium age forest>young forest,and the content of organic matter in surface layer (0-20 cm) was significantly higher than that of other soil layers,with obvious surface cohesion.There was no significant difference in soil pH and available phosphorus in the root area of P.euphratica forest with three ages (P>0.05).3) There was a close relationship between soil physical and chemical properties.Soil moisture content was positively correlated with clay,powder,organic matter,total nitrogen,rapidly available phosphorus and electrical conductivity (P<0.01),and negatively correlated with coarse sand (P<0.01).The contents of clay and powder were positively correlated with water content,organic matter,total nitrogen and available phosphorus (P<0.01).The results showed that the increase of forest age improved the soil physical and chemical properties of P.euphratica root area,which would provide a theoretical basis for the cultivation and development of P.euphratica in arid area.