| As the second largest type of sloping land in sichuan province,which is prone to serious soil and water loss and seriously restricts the sustainable development of regional agriculture and ecological environment construction.Maize is one of the main crops in sloping farmland of yellow soil.Therefore,this study focuses on the subject of sichuan PenZhou mountain yellow soil slope,using field runoff plots positioning monitoring and indoor analysis,the method of combining in different slope and cultivation measures in corn season changes under the condition of the surface roughness and the influence of the runoff and sediment yield,in order to mountain yellow soil zone of agricultural sustainable development and provide a theoretical basis for ecological protective screen construction along the Yangtze river upstream.The main research results are as follows:(1)The average rainfall during the whole growth period of maize was 1106.37 mm,and the erosive rainfall was concentrated in the tastigation stage and maturity stage of maize,accounting for 24.35% and 43.81% of the cumulative erosive rainfall respectively.Different slope under the condition of natural rainfall process moderate rain before the surface roughness in 15 ° slope,the largest more before the surface roughness and surface roughness amplitude in corn tasseling stage and mature period is minimal.The surface roughness of horizontal ridge and vertical ridge before rain was much higher than that of horizontal ridge and vertical ridge before rain.The maximum was in the tasseling stage under the ridge planting.The surface roughness and surface roughness amplitude before rain were smaller in tasseling stage and mature stage of maize,and fluctuated greatly with the growth period of maize before rain.(2)Surface runoff,0-20 cm soil runoff and 20-40 cm soil runoff on 15 degree slope are much larger than those on 10 degree slope,and fluctuate obviously with the advance of rainfall field.The erosion surface runoff was the highest(50-90 L)on the slope along ridge,the lowest(45-70 L)on the cross ridge,and the highest in the 0-20 cm and 20-40 cm soils under the Cross Ridge and the lowest in the ridge along the slope.With the advancement of maize growth period,soil erosion and sediment yield fluctuated upward,and reached the maximum at Maize heading stage and maturity stage,which were 20 g and 30 g,respectively.The erosion sediment yield of 15 degree slope is much greater than that of 10 degree slope,and the erosion sediment yield of cross slope ridge cultivation is the smallest,and that of along slope ridge cultivation is the largest.With the prolongation of maize growth period,the soil erosion and sediment yield on the slopes were the largest in maize heading stage and maturity stage,and the fluctuation was the most obvious.(3)Rainfall intensity and leaf area index are significantly or extremely significantly correlated with surface runoff,soil runoff and sediment yield,and the variation of surface roughness is significantly correlated with sediment yield.The fitting effect of erosion runoff and sediment yield on slope surface of 15 degree is better than that of surface roughness,rainfall intensity and leaf area index,while that of slope surface of 10 degree is better than that of surface runoff and sediment yield.Under flat cropping conditions,the runoff and sediment yield of slope erosion are greatly affected by rainfall intensity and vegetation coverage,and the soil middle flow is significantly correlated with the initial surface roughness,and the variation of surface roughness is significantly correlated with sediment yield;Soil middle flow is significantly correlated with the initial surface roughness;under along-slope ridge cultivation,rainfall intensity is significantly correlated with slope surface invasion.The effects of erosion,runoff and sediment yield are obvious,and the fitting effect of surface roughness,rainfall intensity and leaf area index with slope erosion,runoff and sediment yield under different tillage measures is better.With the prolongation of maize growth period,the correlation between leaf area index and surface runoff was weakened,and the influence on soil runoff was enhanced.Rainfall intensity was significantly or extremely significantly correlated with sediment yield at seedling stage,jointing stage and heading stage,and the impact of rainfall intensity on erosion and runoff was increased at maturity stage.Surface roughness was significantly or extremely significantly correlated with soil runoff,while the correlation between surface roughness and soil runoff was weakened at maturity stage.Except for surface roughness,rainfall intensity and leaf area index,the fitting effect under other conditions is significant or extremely significant. |
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