不同干扰对黄土区典型草原土壤理化性质的影响

Effects of Different Disturbances on Soil Physical and Chemical Properties in the Typical Grassland of Loess Region

以黄土区云雾山典型草原为研究对象,分析4种干扰方式(封育、封育+施肥、封育+火烧和放牧)对土壤理化性质的影响。结果表明:(1)在0-50cm土层,封育、封育+施肥、封育+火烧地的土壤容重随土层深度的增加而增加,放牧地的土壤容重随土层深度的增加而减少。其中,在0-20cm土层,放牧显著高于其他3种干扰方式,封育+施肥显著低于其他3种干扰方式;(2)在0-50cm土层,4种干扰方式的土壤含水量随土层深度的增加而增加,依次为封育+火烧>封育+施肥>封育>放牧;(3)在0-50cm土层,4种干扰方式的土壤有机质、全氮和速效钾含量随土层深度的增加而减少;火烧地的全磷含量随土层深度增加而减少,其他3种干扰方式的全磷含量呈现先增加后减少的趋势。在0-30cm土层,4种干扰方式土壤养分(有机质、全氮、全磷和速效钾)含量为封育+施肥>封育+火烧>封育>放牧,且放牧会导致0-10cm所有养分含量显著降低(P<0.01)。(4)4种干扰方式,有机质与全氮、全磷和速效钾呈极显著的正相关关系(P<0.01)。

Effects of four types of disturbances（enclosure,fertilization,enclosure＋burning and grazing） to the soil physical and chemical properties were analyzed.Results were as follows：（1）In the 0-50 cm soil layer,the soil bulk density increased with soil depth in enclosure（E）,enclosure＋fertilization（EF） and enclosure＋burning（EB） grassland,while it was decreased in grazing（G） grassland.In the 0-20 cm soil layer,it was significantly higher of G than the other three types while EF was the lowest.（2）In the 0-50 cm soil layer,the soil water content increased with soil depth in the four types of disturbances and tended to be in the order of EB EF E G.（3）In the 0-50 cm soil layer,soil organic carbon,total nitrogen and available potassium all decreased with soil depth,and total phosphorus decreased with soil depth of EB while it was increased at first and then decline in the other three types.In the 0-30 cm soil layer,the order of soil nutrient content tended to be EF EB E G.The nutrient content of G in 0-10 cm soil layer was significantly lower than the other three types of disturbances（P0.01）.（4）Soil organic carbon content was positively related（P0.01） to total nitrogen,total phosphorus and available potassium in all the four types of disturbances.