CAJ | 학술논문

为研究耕作对浅沟径流产沙及形态发育特征的影响，在野外调查的基础上，设计坡度（15°、20°、25°）、雨强（1.0、1.5、2.0 mm/min）及放水流量（7.53～23.45 L/min）3个处理，采用室内模拟降雨和放水冲刷的方法，测定了不同处理下浅沟径流量、产沙量。结果表明：1）2种浅沟水流均为紊流，耕作使浅沟水流雷诺数和弗劳德数分别减小0.95%~30.77%、2.64%～39.14%，阻力系数和糙率系数分别增加4.01%～58.82%、0.88%～27.87%；2）试验条件下，耕作使浅沟土壤剥蚀率增大9.48%～37.87%，未耕作与耕作浅沟土壤剥蚀率分别与坡度—流量交互作用、雨强—坡度交互作用呈极显著线性关系，土壤剥蚀率与径流剪切力、径流功率及单位径流功率均呈显著的线性关系，未耕作浅沟发生剥蚀的临界剪切力、临界功率及临界单位径流功率分别为17.576 N/m2、5.036 W/(m2·s)、0.0381 m/s，耕作浅沟为10.585 N/m2、3.544 W/(m2·s)、0.0277 m/s；3）耕作使浅沟宽度增加1.98%～31.79%，浅沟面积增大0.84%～32.03%，下切深度降低2.82%～26.67%；4）耕作使浅沟土壤侵蚀量增加0.91%～22.80%，未耕作和耕作浅沟土壤侵蚀量分别占坡面土壤侵蚀总量的44.09%～74.16%和42.44%～56.44%，与雨强—流量交互作用均呈极显著的线性函数关系。结果可为该区浅沟侵蚀预测模型的建立及农业生态环境安全与保护提供科学依据。
위연구경작대천구경유산사급형태발육특정적영향，재야외조사적기출상，설계파도（15°、20°、25°）、우강（1.0、1.5、2.0 mm/min）급방수류량（7.53～23.45 L/min）3개처리，채용실내모의강우화방수충쇄적방법，측정료불동처리하천구경류량、산사량。결과표명：1）2충천구수류균위문류，경작사천구수류뢰낙수화불로덕수분별감소0.95%~30.77%、2.64%～39.14%，조력계수화조솔계수분별증가4.01%～58.82%、0.88%～27.87%；2）시험조건하，경작사천구토양박식솔증대9.48%～37.87%，미경작여경작천구토양박식솔분별여파도—류량교호작용、우강—파도교호작용정겁현저선성관계，토양박식솔여경류전절력、경류공솔급단위경류공솔균정현저적선성관계，미경작천구발생박식적림계전절력、림계공솔급림계단위경류공솔분별위17.576 N/m2、5.036 W/(m2·s)、0.0381 m/s，경작천구위10.585 N/m2、3.544 W/(m2·s)、0.0277 m/s；3）경작사천구관도증가1.98%～31.79%，천구면적증대0.84%～32.03%，하절심도강저2.82%～26.67%；4）경작사천구토양침식량증가0.91%～22.80%，미경작화경작천구토양침식량분별점파면토양침식총량적44.09%～74.16%화42.44%～56.44%，여우강—류량교호작용균정겁현저적선성함수관계。결과가위해구천구침식예측모형적건립급농업생태배경안전여보호제공과학의거。
In the hill-gully area of the Loess Plateau, serious man-made soil and water loss occurs in disturbed soils of sloping farmlands formed in the process of tillage operation. Frequent farming activities cause ephemeral gullies to develop continuously on sloping farmlands. Although an ephemeral gully may be refilled and rehabilitated, new ephemeral gully may develop in the original position in next rainy season. An indoor flow scouring experiment under artificially simulated rainfall was carried out in the State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, China in July 2014. The effects of tillage treatments on runoff and sediment yielding in ephemeral gully and its morphology were investigated at different rainfall intensities and slope degrees under the condition of upslope concentrated flow. Based on preliminary field investigations, 3 slope degrees of 15°, 20° and 25° were selected. Rainfall intensity was designed at 1.0, 1.5, and 2.0 mm/min. Flow discharges were 7.53 to 23.45 L/min. Plots of 8 m×1m were laid out for experiments and 3 flow sections were set up for runoff and sediment measurements. Before each test, rainfall intensity was calibrated repeatedly until the rainfall uniformity coefficient reached 85% or above. During each test, flow velocity was measured with dye tracing method and flow width and depth were measured with point gauge system. Runoff sample was taken once a minute within 3 minutes before runoff generation, and once 3 minutes after runoff generation. The results showed that: 1) Flow regimes for non-tilled and tilled ephemeral gullies were characterized by turbulent flow; Tillage could decrease Reynolds number and Froude number by 0.95%-30.77% and 3.41%-35.66%, and increase Darcy-Weisbachcoefficient and Manning roughness coefficient by 4.01%-58.82% and 0.88%-27.87%, respectively; and 2) Compared to non-tilled ephemeral gully, the soil detachment rate for tilled ephemeral gully increased by 9.48%-37.87% under the experimental condition; The soil detachment rates for non-tillage and tillage ephemeral gullies were in a very significantly linear relationship with the interaction of slope and flow discharge, and the interaction of rainfall intensity and slope; It was also significantly linearly correlated with flow shear stress, stream power and unit stream power; Critical shear stress, stream power and unit stream power was 17.576 N/m2, 5.036 W/(m2·s) and 0.0381 m/s, respectively for non-tillage ephemeral gully, and 10.585 N/m2, 3.544 W/(m2·s) and 0.0277 m/s, respectively for tillage ephemeral gully; 3) Compared to non-tillage ephemeral gully, the eroded width and area of tilled ephemeral gully increased by 1.98%-31.79% and 0.84%-32.03%, respectively, but the incised depth was reduced by 2.82%-26.67%; 4) The soil erosion mass for ephemeral gully increased from 0.91% to 22.80% due to tillage treatment; The ratios of soil erosion mass for tillage and non-tillage ephemeral gullies to the total soil erosion mass were 35.95%-57.72% and 42.68%-69.03%, respectively. The erosion masses for non-tillage and tillage ephemeral gullies were a significantly linear function of the interaction of rainfall intensity and flow discharge. This study may provide valuble information for the construction of an ephemeral gully erosion model and the security and protection of agricultural eco-environment.