不同土地利用方式对陇东黄土高原土壤团聚体稳定性的影响

Effects of Different Land Use Patterns on the Stability of Soil Aggregates in the Loess Plateau of Eastern Gansu

以陇东黄土高原(庆阳市西峰区新桥村)4种土地利用方式(林地、园地、耕地、荒地)为研究对象,对0~10、10~20、20~40 cm土层的团聚体分布特征、稳定性和土壤抗侵蚀能力进行比较分析。结果表明:林地0~10 cm土层的机械稳定性团聚体和水稳性团聚体含量均显著低于耕地和荒地,但其有机碳含量显著高于园地、耕地和荒地;10~20 cm土层中机械稳定性团聚体含量排序为耕地>园地>荒地>林地,水稳性团聚体含量排序为耕地>荒地>园地>林地,且林地的有机碳含量显著高于园地、耕地和荒地;20~40 cm土层中机械稳定性团聚体含量排序为耕地>园地>荒地>林地,且园地的水稳性团聚体含量显著低于耕地,林地的有机碳含量显著高于园地、耕地和荒地;随着土层深度的增加,土壤机械稳定性团聚体含量随之增加。园地0~20 cm土层中机械稳定性土壤团聚体的平均重量直径(MWD)和平均几何直径(GMD)均高于其他3种土地利用方式,林地0~10、10~20、20~40 cm 3个土层水稳性土壤团聚体的MWD和GMD均高于其他3种土地利用方式;土壤抗侵蚀能力排序为林地>耕地>荒地>园地;土壤有机碳含量排序为林地>荒地>园地>耕地。总体来看,林地更有利于该区水土保持和土壤固碳。

Taking four land use patterns(woodland,garden land,cultivated land and wasteland)in Longdong Loess Plateau(Xinqiao Village,Xifeng District,Qingyang City)as research objects,the aggregate distribution characteristics,stability and soil anti-erosion ability of 0-10,10-20 and 20-40 cm soil layers were compared and analyzed.The results showed that the contents of mechanically stable aggregates and water stable aggregates in 0-10 cm soil layer of woodland were significantly lower than those of cultivated land and wasteland,but their organic carbon content was significantly higher than that of garden land,cultivated land and wasteland.The order of mechanical stable aggregates content in 10-20 cm soil layer was cultivated land>garden land>wasteland>woodland,the order of water stable aggregates content was cultivated land>wasteland>garden land>woodland,and the organic carbon content of woodland was significantly higher than that of garden land,cultivated land and wasteland.In 20-40 cm soil layer,the order of mechanical stable aggregates content was cultivated land>garden land>wasteland>woodland,and the content of water stable aggregates in garden land was significantly lower than that of cultivated land.The content of organic carbon in woodland was significantly higher than that in garden land,cultiva-ted land and wasteland.With the increase of depth,the composition content of soil mechanically stable aggregates increased.The average weight diameter(MWD)and average geometric diameter(GMD)of mechanically stable soil aggregates in 0-20 cm soil layer of garden land were higher than those of the other three land use patterns,and the MWD and GMD of water stable soil aggregates in forest land 0,10-20 and 20-40 cm were higher than those of the other three land use patterns,and the order of soil erosion resistance was forest land>cultivated land>wasteland>garden land.Generally speaking,woodland is more beneficial to soil and water conservation and soil carbon sequestration in this area.