| Purple soil is a soil with high fertility in the hilly area of southwest China,but it is seriously affected by hydraulic erosion(referred to as water erosion)and tillage erosion,and hydrological connectivity refers to the convenience of transmission of substances in the watershed with water as the medium in the spatial heterogeneous landscape or patch.Tillage is an important factor in its influence,but the mechanism of tillage erosion on slope hydrological connectivity and production convergence is not clear.In this study,under the treatment of three kinds of tillage intensity(CK,MT,IT),three kinds of rain intensity(60,90,120 mm/h),and five kinds of slopes(5°,10°,15°,20°,25°),based on indoor artificial simulated rainfall experiments,combined with close-up photography technology measurement to construct a digital elevation model(DEM),the change characteristics of slope fine furrows,slope hydrological connectivity and erosion-produced aborted sand under different tillage intensities of purple soil were carried out,and the relationship between the three was explored.Reveal the variability of sand production space on the downslope surface eroded by tillage.The main conclusions are as follows:(1)Tillage erosion can significantly affect the development of slope furrows.The average values of the width-to-depth ratio of fine furrows,the density of fine furrows and the degree of fine furrow cutting were the largest under strong tillage measures.Under different tillage measures,the slope width and depth of the fine furrow increased first and then decreased along the slope length,but the peak of the fine furrow width of the three tillage measures appeared in different locations,and the peak of the fine furrow depth was concentrated in the downslope.(2)Intense tillage increases slope hydrological connectivity.With the increase of tillage intensity,the confluence of the slope surface became significantly densified,and the generation location of the downslope tributary of the three measures was more random.The flow length(FL)of water flow path increased with the increase of slope and rain intensity,and the influence of rain intensity on FL was smaller than that of slope,and tillage would aggravate the influence of hydraulic erosion on slope.Under the tillage intensity,the maximum and average values of stream power index(SPI)increased with the increase of slope,and the average values were classified as IT > CK > MT.The maximum and average values of topographic wetness index(TWI)decreased with the increase of slope under the three tillage intensities,and the average values were sorted as IT > CK > MT.(3)Tillage erosion significantly alters slope furrow development and hydrological connectivity,resulting in changes in slope flow and sand yield.The initial yield flow time was sorted as CK > IT > MT,and the overall yield flow of cumulative yield was sorted as IT> MT >CK;and the slope runoff depth under the IT was significantly greater than that under CK and MT,and the law was more significant under the strong slope of heavy rain.The slope infiltration under the three kinds of tillage intensity showed a trend of first increasing and then decreasing with the increase of rain intensity,and the infiltration of light rain intensity was sorted as CK > MT > IT,while medium rain strength and heavy rain strong cultivation were the largest.The order of cumulative sand yield is IT > CK > MT.The relationship between the cumulative flow and the cumulative sand production is in line with the power function relationship.(4)Tillage erosion changes the morphology,hydrological connectivity parameters,and correlation of aborted sand.The increase of tillage intensity increased the correlation between FL,SPI and TWI,and significantly increased the correlation between sand yield,hydrological connectivity parameters and fine furrow morphological parameters.FL and TWI can be used to simulate sand yield,which can be simulated regardless of the impact of tillage erosion;The correlation coefficient of slope FL under tillage measures can be fitted by fine furrow splitting degree,and the correlation coefficient between yield and fine furrow depth is high,and the correlation coefficient reaches 0.776;when there is tillage intensity,the hydrological connectivity can be fitted by fine furrow width,and the simulation of yield flow and infiltration should consider the influence of tillage intensity,and the infiltration amount under strong tillage measures can be simulated by FL,and the correlation coefficient is 0.646. |
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