| Sub-humid Yellow River Alluvial Area in Eastern of Henan occurs easily soil wind erosion,because it is low vegetation cover and synchronous drought and high winds, soil wind erosion directly affects the people's production and living environment and agricultural ecological and limited economic benefits. Based on Lankao County Soil wind Erosion observation points in Henan Province, using a combination of field observation and indoor analysis method, to research on soil wind erosion and its impact factors, to explore soil wind erosion model of the region to provide a scientific basis, to provide technical support for the comprehensive improvement of the Huaihe River and the region of soil wind erosion in the sub-humid Yel ow River al uvial area. The main conclusions are as follows:(1)On the whole, the sediment discharges of the 4 plots were large in spring than in winter. The sediment discharge of the control plot(bare land) was the largest, followed by the single crop plot. The sediment discharge of the natural recovery plot was the least. And the sediment discharge of the control plot(bare land) and the singe crop plot were significantly larger than that of the double of the sediment discharge of 4 plots was first increased and the decreased, and largest in March or April. The total sediment discharge in the month when soil wind erosion was serious was the sum of that of the remaining months for each plot. From October to December in 2014 the total thickness of soil wind erosion was about 0.226 mm.(2) To identified the critical condition of the critical wind speed of about 4.0m/s. In the season of soil wind erosion, the north wind of cumulative time of wind velocity of threshold sand is the most, accounted for about 40%, the second is the south wind; there is a slight difference in each month in the dominant wind direction. Spring's cumulative time of wind velocity of threshold sand is more than that of winter, and the mostly month is March, which January, and May, November and December are the same basically.Monthly mean wind speed is between the 1.22~2.02m/s in the wind season, and there is a slight difference in each month, spring was higher than that of the winter; the monthly maximum wind speed occurs in February; rainfall concentrated in April and May, precipitation in spring is more than winter.Four areas of vegetation coverage and height difference, closely related to the growth of crops and vegetation coverage / height changes, micro topography changes with time farming time, sowing and seedling growth period, the most rapid changes in crop growth and harvest. Aerodynamic roughness in natural restoration area, followed by two crops a year, the control area of bare minimum.In terms of mechanical composition of soil, soil particle size is within 0 ~250?m, mainly in 50?m<D?100?m, secondly, mainly in 20?m<D?50?m; including 65%sand, 33% silt and 2% clay; Soil wind erosion sediment particle size and soil mechanical composition was similar, mainly in 50?m<D?100?m, secondly, mainly in 20?m<D?50?m; All the surface soil particles are erodible particles, and the sand is most easily erodible particles, followed by silt; the most of the wind erosion sediment is suspension in the region, With the increase of the weight of wind erosion sediment; <2?m, 2-20?m, 50-100?m, 250-500?m particles are not changed with the weight of the wind erosion sediment, however, 20-50?m and 100-250?m present that ?as one falls,another rises?;The largest of the average surface soil moisture content is a two- year in the four observation plots, the second is a one – year; The least of that is control areas; From October of that year to January of the next year could be described as the phases of stabilization, From February to May could be described as the phases of accumulation.(3) The direct effect of cumulative time of wind speed is the largest in the 4 plots, and the relationship between the cumulative time of wind speed and the amount of sediment transport can be a true response to the relationship between the two.With the increase of cumulative time of wind speed, the sediment discharge of 4 plots increased significantly, and there was a significant power correlation between them. When cumulative time of wind speed was small, the sediment discharges were obviously dispersed of 4 plots. The cumulative time of 5-6 m/s wind speed had the strongest relation with the sediment discharge.With the increase of vegetation coverage, the cumulative time of wind velocity of threshold sand decreases subsequently, that is extremely significant negative exponential relationship; With the increase of vegetation coverage, aerodyna mic roughness length also increase, the correlation of that is strong. Based on the above,that's more reasonable to explore the relationship between the vegetation coverage or surface roughness and soil wind erosion sediment. |
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