Effect Of Soil And Water Conservation Measures On Ephemeral Gully Erosion In Black Soil Farmland

In Ephemeral gully erosion,as the main erosion mode of slope farmland,not only determines the severity of soil erosion,but also is a direct factor of soil quality degradation.Therefore,it is urgent to control soil erosion in ephemeral gully.At present,there is still a lack of quantitative data to support the effect of soil and water conservation measures in ephemeral gully governance and how water conservation measures affect the occurrence of ephemeral gully erosion and deposition process remains to be further studied.In this study,coir geotextile,geocell and the combination of coir geotextile and geocell were taken as the research objects,and ephemeral gully erosion simulation scour tests were carried out at the confluence flow rates of 10L/min,30L/min,40L/min and 50L/min respectively.By analyzing the effects of different measures on sediment yield and sediment yield in ephemeral gully erosion,Combined with stereoscopic photogrammetry technology to obtain the erosion and deposition situation of ephemeral gully to further obtain the protection effect of different measures,The results are as follows :(1)the protection effect of coir geotextile on ephemeral gully erosion decreases gradually with the increase of confluence flow,and decreases rapidly at 50L/min confluence flow.The erosion pattern of ephemeral gully surface is a changing process from upper micro-erosion,lower micro-deposition to intermittent dropping,then intermittent rill and finally rill formation.With the increase of confluence flow,the proportion of ephemeral gully erosion gradually decreases,and the proportion of deposition gradually increases,and the erosion mode changes from planar erosion to linear erosion.(2)the effect of geocell on ephemeral gully erosion is more and more obvious with the increase of confluence flow.When the confluence flow increased from 10L/min to 50L/min,the erosion rate of ephemeral gully decreased by37.84%,26.09%,21.40% and 35.45%,respectively,but geocell measures had little effect on ephemeral gully erosion.The erosion pattern of ephemeral gully surface changes from continuous rill to intermittent rill and then to intermittent drop.With the increase of flow rate,the proportion of ephemeral gully erosion gradually increases and the proportion of deposition gradually decreases,and the erosion mode changes from rill erosion to plane erosion.(3)composite measures under different confluence flow,corrosion protective effect is better,ephemeral gully surface erosion form by the continuous rill depth of 10 mm to the rill width increases,the depth is constant,the central surface broken seriously,and increase to drop ephemeral gully rill depth and width are no longer increases the change process,ephemeral gully erosion and sedimentation of maintained at about 50%,The protection effect of ephemeral gully is stable,and can prevent the sediment transport from surface erosion to rill erosion.(4)four different flow under various measures of protection,when the catchment flow is less than 40L/min,the protective effect of coir geotextile,geocell and composite measures is in the order of composite measures > coir geotextile > geocell from large to small,while when the catchment flow is 50L/min,the protective effect of coir geotextile decreases,and the protective effect is in the order of composite measures >geocell > coir geotextile.