摘要
坡耕地溅蚀特征研究可揭示和反映溅蚀的发生和发展机理,而以往研究大多在无垄作坡面进行,较少涉及顺坡垄体。为此,该研究基于野外人工模拟降雨试验,设计3个降雨强度(30、60和90 mm/h)和2个坡度(3°、5°),研究降雨强度和坡度对典型黑土(Mollisol)农田顺坡垄体溅蚀量、溅蚀过程和溅蚀分选特征的影响。研究结果表明:当降雨强度由30 mm/h增加到90 mm/h时,总溅蚀量增加2.5~17.9倍。当坡度由3°增大到5°时,总溅蚀量增加30.52%~74.08%。当降雨强度为30和60 mm/h时,总溅蚀率随降雨历时呈迅速减小-缓慢减小-波动稳定的趋势。当降雨强度为90 mm/h时,总溅蚀率随降雨历时呈迅速增加-迅速减小-波动稳定的趋势。整体而言,总溅蚀量随降雨强度和坡度的增加呈幂函数关系。各试验处理下,溅蚀分选水稳性团聚体中均以<1 mm粒级的团聚体为主,平均占总量的79.01%,以0.5~1 mm粒级最多,2~5 mm粒级最少,分别占总量的32.94%和3.36%。30和60 mm/h降雨强度下,分别为<0.25和<2 mm的各粒级团聚体在降雨后期达到波动稳定,其中<0.25 mm的团聚体均呈迅速降低-缓慢降低-波动稳定的变化趋势。90 mm/h降雨强度下,1~5和<0.25 mm各粒级团聚体均呈线性平稳变化,其中<0.25 mm的团聚体呈线性减少趋势。研究可为东北黑土区水蚀防治提供科学依据。
Splash erosion is the initial stage of soil erosion by water,particularly an important process of hillslope erosion.The main cause of splash erosion can be resulted from the destructive force of rain drops,when acting on soil surface aggregates.As such,the splash erosion strongly depends on the rainfall intensity and slope gradient.Most previous studies focused on the characteristics of splash erosion,and dominated affecting factors,in order to reveal the specific mechanism of splash erosion.Moreover,most current studies on splash erosion were usually conducted on non-ridge slope in the farmland.However,little information is available on the up-down ridged slope,especially for the distribution of soil water stable aggregates during splash erosion process in the typical black soil region of Northeast China.Therefore,in this study,an in-situ field simulated rainfall experiment was conducted to investigate the effects of rainfall intensity and slope gradient on the characteristics of splash erosion,and the distribution of soil water stable aggregates in the process of splash erosion.Three rainfall intensities(30,60,90 mm/h)of representative erosive rainfall,and two slope gradients(5°and 10°)were set,where all treatments were replicated three times.The soil in this experiment was a Mollisol(USDA System of Soil Taxonomy),with 31.6%sand(>50μm),30.8%silt(50 to 2μm),and 37.6%clay(<2μm).The filed study was conducted in the Hailun Monitoring and Research Station of Soil and Water Conservation,Chinese Academy of Sciences(47°21′16.95″N,126°49′56.43″E),located at the Hailun city,Heilongjiang Province,the center of the typical Mollisols zone in Northeast China.An up-down ridge system was used,where the ridged interval on the farmland was 70 cm,and the vertical height difference between ridge and furrow was 20 cm.In addition,the splash board was applied to measure splash erosion.The results showed that the total splash erosion increased by 2.5 to 17.9 times,as the rainfall intensity increased from 30 mm/h to 90 mm/h,whereas,the total splash erosion significantly increased by 30.65%to 64.34%(P<0.05),as the slope gradient increased from 3°to 5°.The relationship between splash erosion with rainfall intensity and slope gradient can be expressed as a power function.Besides,at the rainfall intensities of 30 mm/h and 60mm/h,the splash erosion rate first rapidly decreased,then gradually decreased,and finally reached a steady state.At the rainfall intensity of 90 mm/h,the splash erosion rate first rapidly increased to the maximum,then rapidly decreased,and finally reached a steady state.Furthermore,the<1mm soil aggregate was the main fraction of aggregate size that detached by raindrop splash,accounting for 79.01%of total splash erosion.Specifically,the proportion of 0.5-1 mm soil aggregate was the most,accounting for 32.94%of total splash erosion,while,the proportion of 2-5 mm soil aggregate was the least,accounting for 3.36%of total splash erosion.In addition,at the rainfall intensities of 30 mm/h and 60mm/h,the<0.25 mm and<2 mm soil aggregates reached the steady state at the end of rainfall,respectively.The proportion of micro aggregates first rapidly increased,then slowly increased,and finally reached a relatively stable stage.At the rainfall intensity of 90 mm/h,the 1-5 mm and<0.25 mm soil aggregates showed a linear trend,whereas,the proportion of micro aggregates showed a decrease trend.This study can provide a sound scientific basis to control water erosion in the typical black soil region of Northeast China.
作者
张兴义
乔宝玲
李健宇
祁志
严月
甄怀才
胡伟
Zhang Xingyi;Qiao Baoling;Li Jianyu;Qi Zhi;Yan Yue;Zhen Huaicai;Hu Wei(College of Resources and Environmental Sciences,Northeast Agricultural University,Harbin 150030,China;Key Laboratory of Mollisols Agroecology,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Harbin 150081,China;College of Resources and Environmental Sciences,Jilin Agricultural University,Changchun 130118,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2020年第16期110-117,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(41701313)
国家重点研发计划项目(2017YFC0504200)。
关键词
土壤
团聚体
侵蚀
垄体
溅蚀过程
溅蚀分选特征
东北黑土区
soils
aggregates
erosion
ridge body
splash erosion processes
splash selective characteristics
black soil region of Northeast China