长江流域资源与环境 >> 2013, Vol. 22 >> Issue (06): 779-.

• 生态环境 • 上一篇    下一篇

降雨过程中红壤团聚体粒径变化对溅蚀的影响

马仁明|王军光|李朝霞|蔡崇法|王 硕   

  1. (华中农业大学水土保持研究中心|湖北 武汉 430070)
  • 出版日期:2013-06-20

EFFECTS OF DYNAMIC DISTRIBUTION OF AGGREGATE SIZE ON SPLASH EROSION UNDER RAINFALL IN RED SOILS 

MA Renming|WANG Junguang|LI Zhaoxia|CAI Chongfa|WANG Shuo   

  1. (Research Center of Water and Soil Conservation, Huazhong Agricultural University, Wuhan 430070, China
  • Online:2013-06-20

摘要:

为揭示团聚体粒径动态变化对溅蚀的影响,通过室内人工模拟降雨试验,以第四纪粘土、泥质页岩发育红壤为研究对象,研究了酒精预湿润后的2~5 mm团聚体在降雨过程中粒径动态变化及溅蚀率的变化。试验结果表明:在60 mm/h雨强下,团聚体受雨滴机械打击破碎主要发生在降雨的最初阶段,团聚体>0.25 mm百分含量(P>0.25)及平均重量直径(M)均随降雨时间(T)增加呈幂函数减小,溅蚀率(Dr)随降雨时间(T)增加呈幂函数增加,而溅蚀率(Dr)随团聚体平均重量直径(M)减小呈幂函数增大。为揭示不同土样在降雨溅蚀过程中溅蚀率的变化规律,利用团聚体稳定性特征参数—机械破碎指数(R)及降雨时间(T),建立了不同团聚体稳定性土样溅蚀率随降雨时间变化的经验方程,且方程可决系数较高(R2=0.82),揭示出团聚体稳定性越好,其破碎过程越缓慢,溅蚀率越小。研究结果为红壤区土壤侵蚀的防治及侵蚀机理研究提供了新思路

Abstract:

Rainfall splash erosion is a critical element in hillslope water erosion.Raindrops splash is a precursor to the start of interrill erosion and surface seal formation.It is the direct results of raindrop strike on top soil,and causes detachment and transportation.And it is usually the first step in soil loss and sediment transport.Soil detachment and transportation occur when erosive forces of raindrops are greater than the inherent strength and particle distribution.The aggregate size distribution is a recognized factor influencing crust characteristics and transport during rainfall erosion events.The red soil hilly regin is located in the tropical and subtropical zones of central China.Because of the plentiful light,heat and efficient rainfall,the area is favourable to erosion.The soil erosion in red soil hilly regin becomes severe.Therefore,it is very disadvantageous to ecoenviromental and agricultural protection.The objects of this study were to improve the understanding of the relationship between aggregate stability and size distribution and rainfall splash erodibility under simulated rainfall.In this study,four red soils derived from quaternary clay and shale were studied.2-5 mm aggregates which were prewetted in alcohol of each soil were exposed to simulated rainfall with an intensity of 60 mm/h.Bissonnais’s method was applied to simulate the aggregate breakdown mechanisms.And the relative mechanical breakdown index (R) was used as the aggregate stability index.The results showed that soil splash rate was significantly related to aggregate stability,but the relationship varied with the aggregate stability index (R).The dynamic change of aggregate sizes had great effect on rainfall splash rate.Percentage of >025 mm size aggregate (P>025) and mean weight diameter (M) both decreased at a power function with rainfall time(T),while rainfall splash rate(Dr) increased at a power function with time.The bigger the aggregate mean weight diameter (M) was,the less the rainfall splash rate(Dr) got.The relative mechanical breakdown index (R) was used to quantitatively describe the relationship between different soils M and their rainfall splash rate(Dr) with time(T),and their equation was established with a good correlation coefficient (R2=082).The equation revealed that the breakdown process of aggregates was alleviated by increasing aggregate stability,thus the splash rate was decreased,and showed a good prediction performance.This study provides a new approach to reveal the rainfall splash erosion mechanism of red soil,which has great significant for perfection of the physical progress model of rainfall erosion

No related articles found!
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed   
[1] 李 娜,许有鹏, 陈 爽. 苏州城市化进程对降雨特征影响分析[J]. 长江流域资源与环境, 2006, 15(3): 335 -339 .
[2] 孙维侠, 赵永存, 黄 标, 廖菁菁, 王志刚, 王洪杰. 长三角典型地区土壤环境中Se的空间变异特征及其与人类健康的关系[J]. 长江流域资源与环境, 2008, 17(1): 113 .
[3] 时连强,李九发,应 铭,左书华,徐海根. 长江口没冒沙演变过程及其对水库工程的响应[J]. 长江流域资源与环境, 2006, 15(4): 458 -464 .
[4] 张代钧,许丹宇,任宏洋,曹海彬,郑 敏,刘惠强. 长江三峡水库水污染控制若干问题[J]. 长江流域资源与环境, 2005, 14(5): 605 -610 .
[5] 王肇磊, 贺新枝. 晚清时期湖北自然灾害的治理及其经验教训[J]. 长江流域资源与环境, 2009, 18(11): 1080 .
[6] 韦 杰, 贺秀斌. 人类活动对嘉陵江流域泥沙负荷的影响[J]. 长江流域资源与环境, 2010, 19(2): 196 .
[7] 彭 峰. 国际法与比较法视野中的水权研究[J]. 长江流域资源与环境, 2010, 19(03): 287 .
[8] 郑建蕊| 蒋卫国, 周廷刚, 侯鹏, 李雪. 洞庭湖区湿地景观指数选取与格局分析[J]. 长江流域资源与环境, 2010, 19(03): 305 .
[9] 黄, 薇, 陈 进, 王 波. 梯级开发对河流径流过程和水温过程均化作用的研究[J]. 长江流域资源与环境, 2010, 19(03): 335 .
[10] 罗秉征. 河口及近海的生态特点与渔业资源[J]. 长江流域资源与环境, 1992, 1(1): 4 .