Law And Mechanism Of Soil Wind Erosion On Different Land Use Types In Sandyland Of Yellow River Floodplain

Wind erosion, which is the essential part in the floodplain of the Yellow River wind-sandy land, influence directly the production, life, regional ecological security and agriculture economic sustainable development of the zone. The paper basing on different types of land use, combining methods that field investigation test, positioning monitoring and indoor analysis test and Spectral determination, studied temporal-spatial pattern and dynamic of wind erosion, wind erosion influence factors, spectral characteristics and its relationship with organic matter to reveal regional wind erosion rule. The main results are as follows:(1) The significant difference existed between different land types'soil erosion status. The wind erosion depth and amount of peanut sample plot in agricultural land was the largest, belonging to moderate erosion; the abandoned land and agroforesty systems belonged to mild erosion; the wheatland and corn stubble land was in wind-blown state. The wind erosion intensity of forestry land decreaced with the growth of afforestation years; one year'afforestation ground belonged to moderate wind erosion; three years and five years'afforestation grounds belonged to mild wind erosion, while eight years'afforestation ground was in wind-blown state.(2) The change rules and dynamic between months of soil erosion integrated varied from different land use types. Peanut sample plot, abandoned land and afforestation ground were in Wind erosion state between months, changing as the shape of "V", and the first and the second peaks appeared respectively in November and April; the corn stubble land and eight years'afforestation ground were mainly in wind-blown state between months; the soil erosion status changes of other land use types between months was complex, presenting roughly a single-peak trend.(3) The mechanical composition of soil in different land use types all major in powder sand, very fine and fine sand. It presents that the depth of wind erosion are in positive linear correlation with the sand content, in negative correlation with powder content where the correlation is not significant. The soil organic content correlate with the depth of erosion in a significant negative linear relation, whose variation follows as D =0.646-0.383×XO. Moreover, the soil compactness and the moisture content relate with the soil erosion presenting a negative relation to a certain degree, which is in no significant number relationship.(4) It changes obviously between the rows of trees with different afforestation age and the tiny terrain under the tree, which shows the discipline that the wind erosion of the depressions is less than that of the highland and that wind-blow is more than the highland, influenced by both the tiny terrain and the afforestation age. The content of the soil organic matter increase, the wind erosion decrease and the wind-blown increase with the afforestation age extension. The soil erosion increase caused by artificial landuse.(5) The agricultural land and the forestry land plays an important role on the weakness of the wind speed at the place of 0.2 meters except the earthnut land. The percentage of the decreased wind speeds are respectively 0.36%～40.07% and 28%～52.46%, with the increasing roughness of near land surface by 5.35～186.45 times and 1.31～52.79 times. The surface leaved stubbly, the crops and the afforestation can increase the surface roughness, decrease the wind speed near the land and slow down the wind erosion. Surface leave stubble, crop planting and silviculture measures such as surface roughness can increase, about the near-surface wind speed, slow down the occurrence of wind erosion.(6) Activities of different types of land in the near-surface of wind flow within 50cm, there is sediment transport rate with height follows y=ae-bx exponential decrease; and the weight of sediment load distribution with height power function relationship; Increasing altitude, wind flow silt and sand content decreased and clay content increased, erosion tapered diameter.(7) The spectral characteristics of the soil has big different in the different land use values, mainly in the 500～750nm, 1350～1500nm ,1750～2000nm and 1900～2200nm Department, and the spectral characteristics of soil organic matter was between the value of the multiple linear correlation, but the fitting Equations involved in the characteristic bands are not the same.