晋西黄土丘陵区不同土地利用类型对土壤碳氮储量的影响

Effects of Different Land Use Types on Storage of Soil Organic Carbon and Total Nitrogen in Western shanxi Hilly Loess Plateau Region

通过对比晋西黄土区蔡家川流域人工刺槐林地、人工油松林地、退耕荒草地和农地土壤有机碳和总氮含量的差异性,探讨了土地利用变化对该流域土壤碳氮储量的影响。结果表明:(1)4种土地利用类型下,土壤有机碳和总氮均表现出表聚效应,且荒草地垂向降幅最大,各样地土壤有机碳和总氮均呈极显著线性正相关;(2)油松林地0—48cm土层有机碳含量高于其他样地,刺槐林地0—48cm土层总氮含量显著高于其他样地,而4种土地利用类型在48—96cm土层和96—160cm土层中有机碳和总氮含量差异不显著;(3)从蔡家川流域退耕土壤固碳和固氮效应整体而言,退耕林地具有显著的土壤碳氮固存效应,随着人工林地面积占比的增加,流域土壤总有机碳和总氮储量相应增加。

The difference of soil organic carbon and total nitrogen contents for cropland,abandoned land,Robinia pseudoacacia and Pinus tabulaeformis woodlands in hilly loess region were analyzed to explore the effects of land use types on the storage of soil organic carbon（SOC）and total nitrogen（TN）.The results showed that：（1）the contents of SOC and TN decreased with the increase of soil depth,the surface soils had higher contents of SOC and TN than the subsoils,especially for abandoned land.The highly significant correlation between SOC and TN centents was found in each land use type;（2）in the surface soil layer（0—48cm）,the SOC content in Pinus tabulaeformis stand is significant higher than others,and the TN content of Robinia pseudoacacia stand is significant higher than others,there are not significant different among them in superficial layer（48—96cm）and deep layer（96—160cm）;（3）the results also show that at the regional scale,abandoned land,Robinia pseudoacacia and Pinus tabulaeformis stands have remarkable SOC and TN sequestration compared with cropland,and the artificial forest is the best.The increase of forestland area will enhance the storage of SOC and TN in this region.