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模拟降雨条件下工程边坡土壤磷素流失特征
杨兴1,2, 庞鑫3, 曹卓冰1, 彭培好1,3, 谢成晟1, 李伟2
1.成都理工大学 地球科学学院, 四川 成都 610059;2.中国科学院 水利部 成都山地灾害与环境研究所山地表生过程与生态调控重点实验室, 四川 成都 610041;3.成都理工大学 生态资源与景观研究所, 四川 成都 610059
摘要:
[目的] 探究西南高山-亚高山地区工程边坡土壤磷素流失机理,为同类型工程边坡生态环境恢复研究提供理论依据。[方法] 采用室内人工模拟降雨试验及原状土搬迁等方法,研究在2种坡度(30°,50°)和4种雨强(25,45,65,85 mm/h)条件下工程边坡全磷(TP),泥沙全磷(STP),溶解态磷(DP)迁移变化特征及其与土壤侵蚀状况的关系。[结果] ①工程边坡径流平均DP浓度整体较低且受雨强影响较小,STP浓度在降雨初期较高,随之降低或趋于稳定。②不同雨强下工程边坡DP流失率、STP流失率变化曲线具有明显差异性,当雨强为25 mm/h和45 mm/h时,工程边坡STP流失率、DP流失率较低且较为稳定;当雨强为65 mm/h和85 mm/h时,工程边坡STP流失率、DP流失率迅速上升后趋于稳定;当雨强由45 mm/h增至65 mm/h时,工程边坡STP流失率、DP流失率迅速增大。③土壤侵蚀率与DP流失率、DP平均浓度、STP流失率和浓度、TP流失率有极显著正相关关系;径流率与DP流失率、STP流失率、TP流失率、DP平均浓度有极显著正相关关系,与STP浓度无显著相关关系。工程边坡TP流失率随径流率、土壤侵蚀率皆以幂函数形式逐渐增加。[结论] 雨强和坡度对工程边坡磷素流失动态变化特征具有显著的影响且整体呈现出先增后减的趋势。
关键词:  降雨强度  坡度  磷流失  工程边坡  土壤侵蚀
DOI:10.13961/j.cnki.stbctb.2020.01.004
分类号:S157.1
基金项目:国家重点研发计划项目"西南高山亚高山区工程创面人工土壤重建技术"(2017YFC0504903);中国科学院关键技术人才项目(CAS201665)。
Characteristics of Soil Phosphorus Loss from Engineered Slopes Under Simulated Rainfall
Yang Xing1,2, Pang Xin3, Cao Zhuobing1, Peng Peihao1,3, Xie Chengsheng1, Li Wei2
1.College of Earth Sciences, Chengdu University of Technology, Chengdu, Sichuan 610059, China;2.Key Laboratory of Mountain Surface Process and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Ministry of Water Resources, Chengdu, Sichuan 610041, China;3.Institute of Ecological Resources and Landscape, Chengdu University of Technology, Chengdu, Sichuan 610059, China
Abstract:
[Objective] The mechanism of soil phosphorus loss from engineered slopes in a southwest alpine-subalpine region was studied to provide a theoretical basis for the restoration of the ecological environment on the same type of slopes.[Methods] The characteristics of total phosphorus (TP), sediment total phosphorus (STP), dissolved phosphorus (DP) migration, and their relationships with soil erosion, were studied under two slope gradients (30°, 50°) and four rainfall intensities (25, 45, 65, and 85 mm/h) using indoor simulated rainfall experiments and undisturbed soil removal.[Results] ① The average DP concentration of runoff from the engineering slopes was generally low and was less affected by rainfall intensity. The STP concentration was higher at the beginning of the rainfall and then decreased, or tended to be stable. ② The curves of the DP loss rate and STP loss rate from the engineered slopes had obvious differences under different rain intensities. When the rain intensities were 25 and 45 mm/h, the STP loss rate and DP loss rate from the engineered slopes were lower and more stable. When the rainfall intensity was 65 and 85 mm/h, the loss rate of STP and DP of the engineering slopes increased rapidly in a parabolic trend and tended to be stable. When the rainfall intensity increased from 45 to 65 mm/h, the loss rate of STP and DP increased rapidly. ③ The soil erosion rate was positively correlated with the DP loss rate, mean DP concentration, STP loss rate and concentration, and TP loss rate. The runoff rate was positively correlated with the DP loss rate, STP loss rate, TP loss rate, and mean DP concentration, but not with the STP concentration. The rate of TP loss from the engineered slopes increased gradually with the runoff rate and soil erosion rate in the form of a power function.[Conclusion] Rainfall intensity and slope gradient have significant influence on change of the dynamics of phosphorus loss from engineered slopes, and the trend of phosphorus loss first increases, and then decreases.
Key words:  rainfall intensity  slopes  phosphorus loss  engineering slope  soil erosion