摘要
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。
Different patterns of soil erosion cause differences in soil aggregate breakdown and its loss processes. Previous studies concentrated mainly on the variation in soil aggregates under various land uses and breakdown mechanisms. This paper used simulated rainfall experiments to investigate how sheet and gully erosion affected soil aggregate losses. The tested soil is black soil collected from Yushu city in Jilin Province and the experiment was conducted in the simulated rainfall hall of the Institute of Soil and Water Conservation. The lateral spraying nozzles, whose height was 16 m above the ground, were used in this study. The size of the test soil pan was 8 m long, 3 m wide and 0.6 m deep. The experimental design covered two rainfall intensities of 50 and 100 mm/h, one slope of 10°, and two erosion patterns of sheet and gully, and each treatment had two replications. During the rainfall process, runoff samples were collected and lost aggregates were collected through a set of sieves with different apertures of 5, 2, 1, 0.5 and 0.25 mm in every five minutes. The dry sediment was used to calculate erosion rate and different sizes of dry lost aggregates in the sediments were used to compute aggregate loss. The results showed that under rainfall intensities of 50 and 100 mm/h, the gully erosion rate was almost 1.42 and 3.51 times greater than that of sheet erosion, respectively. When the rainfall intensity increased from 50 to 100 mm/h, the 〈 0.25 mm micro-aggregates in the sediments from sheet erosion treatment increased from 45% to 74%; while for the gully erosion dominated treatment, the aggregate in the sediments was mainly comprised of ≥0.25 mm of macro-aggregates, which occupied 65.5% of total aggregate loss. Under the rainfall intensity of 50 mm/h, 〉 5 and 2-5 mm aggregates in the sediments from the sheet erosion treatment were lower than those from the gully erosion dominated treatment; while the other sizes of aggregates in the sediments from the sheet erosion treatment were greater than those from
出处
《生态学报》
CAS
CSCD
北大核心
2013年第24期7774-7781,共8页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(41271299
40871137)
关键词
片蚀
沟蚀
团聚体流失
黑土区
模拟降雨
sheet erosion
gully erosion
aggregate loss
black soil region
simulated rainfall
