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土壤侵蚀方式的差异必然会导致土壤团聚体破碎程度及流失过程的不同。基于室内模拟降雨试验,对比研究了黑土坡耕地片蚀和沟蚀对土壤团聚体流失的影响。结果表明,在50和100 mm/h降雨强度下,沟蚀试验处理的侵蚀量分别是片蚀试验处理的1.42倍和3.51倍左右。在片蚀试验处理下,当降雨强度由50 mm/h增加至100 mm/h时,侵蚀泥沙中微团聚体(<0.25 mm)含量由45.7%增加至74.2%;而在沟蚀试验处理下,侵蚀泥沙中以大团聚体(≥0.25 mm)为主,其占团聚体流失量为65.5%。片蚀试验处理下,50 mm/h降雨强度时,侵蚀泥沙中>5和2—5 mm粒级的团聚体含量均小于沟蚀处理,而其它粒级的团聚体含量均大于沟蚀处理;在100 mm/h降雨强度下,侵蚀泥沙中团聚体各粒级的含量均小于沟蚀处理。与试验土壤相比,表征团聚体流失的两个特征指标平均重量直径(MWD)和几何平均直径(GMD)均明显减少;在两种降雨强度下,片蚀试验处理的MWD和GMD均明显小于沟蚀处理。研究还发现MWD和GMD两种团聚体指标均能反映黑土农耕地坡面片蚀和沟蚀方式下的团聚体流失特征,且MWD能够更好的反映出雨强变化时两种侵蚀方式下土壤团聚体的流失特征。
Differences in soil erosion will inevitably lead to different levels of soil aggregates crushing and loss process. Based on the simulated indoor rainfall experiment, the effects of soil erosion and gully erosion on the loss of soil aggregate were compared. The results show that erosion rates of gully erosion test are 1.42 times and 3.51 times higher than those of erosion test respectively under the rainfall intensities of 50 and 100 mm / h. Under the erosion test, when the rainfall intensity increased from 50 mm / h to 100 mm / h, the content of microaggregates (<0.25 mm) in erosion sediment increased from 45.7% to 74.2% In the erosion of sediment, large aggregates (≥0.25 mm) dominated, accounting for 65.5% of the total aggregates loss. At the 50 mm / h rainfall intensity, the content of aggregates> 5 and 2-5 mm in the erosion sediment is less than that of the gully erosion, while the content of other fractions is larger than that of the gully erosion At the rainfall intensity of 100 mm / h, the content of aggregates in the erosion sediment was smaller than that of the erosion treatment. Compared with the test soil, the MWD and GMD of the two characteristic indexes, which indicate the loss of aggregates, were significantly decreased. Under both rainfall intensities, the MWD and GMD of the plate erosion test were significantly less than Gutter treatment. The study also found that both MWD and GMD aggregates can reflect the characteristics of aggregate loss under slope erosion and gully erosion on arable land in black soil. MWD can better reflect the change of soil moisture Agglomeration loss characteristics.