东北黑土区片蚀和沟蚀对土壤团聚体流失的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 东北黑土区片蚀和沟蚀对土壤团聚体流失的影响 DOI: 10.5846/stxb201303230498 作者: 作者单位: 西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41271299，40871137） The impact of sheet and gully erosion on soil aggregate losses in the black soil region of Northeast China Author: Affiliation: College of Resources and Environment,Northwest A＆F University,College of Resources and Environment,Northwest A＆F University; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources,College of Resources and Environment,Northwest A＆F University,College of Resources and Environment,Northwest A＆F University,College of Resources and Environment,Northwest A＆F University,College of Resources and Environment,Northwest A＆F University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 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。 Abstract: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 the gully erosion dominated treatment. Under 100 mm/h of rainfall intensity, all sizes of aggregates in the sediments from the gully erosion dominated treatments were greater than those from the sheet erosion treatment. The results also demonstrated that, for the sheet erosion treatment, raindrop impact was the main driving force for aggregate breakdown, while for the gully erosion dominated treatment, concentrated flow detachment, transportation in gully channel and friction function of the different aggregates during transportation processes were the main driving forces for aggregate breakdown. Compared with the test soil, mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates in the sediments were lower for both treatments of sheet and gully erosion. Under the two rainfall intensities of 50 and 100 mm/h, MWD and GMD in sediments from the sheet erosion treatment were smaller than those from the gully erosion dominated treatment. This paper also proposed that under the experimental conditions, two indicators of MWD and GMD could reflect the lost aggregate characteristics, and MWD could better reflect aggregate variation with an increase in rainfall intensity. 参考文献 相似文献 引证文献