摘要
新改土是刚经过农地整理工程改造工序且处于土体非稳定期的土体,其土壤结构松散,在降雨径流作用下易发生水土流失,研究新改土的产流产沙和水动力学参数特征具有重要意义。通过野外放水冲刷试验,研究了紫色土丘陵区新改土坡面(10°)在不同上方来水流量(5,15,30L/min)及不同坡长(5,10,20,30,40,50m)条件下的产流产沙和水动力学参数特征。结果表明:(1)坡面产流率随着放水冲刷过程的变化趋势为波动增长期—稳定发展期,产沙率变化趋势为波峰波谷变化—逐渐减小—稳定发展,均在30~50min后达到稳定;平均产流率变化范围为0.36~20.46L/min,平均产沙率变化范围为1.11~239.09g/min;累积产沙量与累积产流量呈极显著的线性正相关关系(p<0.01)。(2)径流稳定时呈层状缓流;径流剪切力和径流功率变化范围分别为8.36~28.36Pa和1.42~5.10N/(m·s),与上方来水流量分别呈二次曲线函数关系和线性方程函数关系;径流功率是描述新改土坡面侵蚀产沙的最佳水动力学参数,二者呈二次曲线函数关系。因此,上方来水流量和坡长均为紫色土丘陵区新改土坡面侵蚀的影响因素;产流产沙和水动力学参数与上方来水流量主要呈正相关性(R2为0.662~0.999),20,30m坡长是影响新改土10°坡面侵蚀的临界坡长。研究结果可为新改土坡耕地水土流失监测、预报和水土保持措施布置提供了理论依据。
New reconstruction soil is in an unstable state,and just is the reconstruction of farming plots.In this paper,a field scouring experiment,designed as three scouring inflow rates（5,15 and 30 L/min）and six different field widths（5,10,20,30,40,50 m）,was conducted in farming reconstruction soil in hilly-mountainous region of Chongqing,in order to explore the characteristics of runoff and sediment and hydrodynamic parameters.The results showed：（1）During the scouring process,the trend of runoff rate was the fluctuated increasing period-stable development period.The trend of sediment yield rate was the fluctuated perioddecrease-stable development period.（2）Hydrodynamic parameters,the mean rate values under the stable condition,and cumulative runoff and sediment yield increased with increasing scouring inflow rate.The effect of runoff and sediment yield and hydrodynamic parameters were different under different scouring inflow rates with different field width.The runoff and sediment yield fluctuated with the increase of field width.Under the scouring inflow rates of 30 and 15 L/min,the fluctuation was relatively large,and under the small scouring inflow rate（5 L/min）,which was relatively slow.（3）The cumulative sediment yield increased with the increasing cumulative runoff yield,and there was a significant linear relationship between them（p〈0.01）.The sediment yield was affected by all hydrodynamic parameters,of which runoff power was the most important.The scouring inflow rate was positively related to the runoff and sediment yield and hydrodynamic parameters.The influence of field width was more complex,and the field width range of 20 and 30 mis the critical of new reconstructed soil erosion at slope 10°.In conclusion,the scouring inflow rate and slope width are both the driving forces of the new reconstructed soil erosion under farming plots reconstruction in hilly-mountainous region.
作者
左烽林
钟守琴
冉卓灵
魏朝富
ZUO Fenglin, ZHONG Shouqin, RAN Zhuoling, WEI Chaofu(College of Resources and Environment, South~2est University, Chongqing 40071)
出处
《水土保持学报》
CSCD
北大核心
2018年第1期59-66,共8页
Journal of Soil and Water Conservation
基金
国家重点研发计划项目"构建源头削减-生物隔离-湿地消纳相结合的高效生态拦截技术体系"(2017YFD0800505)
关键词
产流产沙
水动力学参数
新改土
丘陵区
紫色土
runoff and sediment
hydrodynamic parameters
new reconstructed soil
hill area
purple soil
