| Soil and water loss is one of the most serious natural disasters which affect agricultural production in China. The Loess Plateau is one of the most intensive areas of soil erosion.Soil erosion is the result of joint action which influenced with the surface soil and parent material in water, wind, gravity and other natural conditions and human condition.It can destroy the land productivity, cause soil erosion and water loss.Serious soil and water loss causes the decline of agricultural productivity, land desertification, ecological environment deterioration,all of these problems threaten the production and life of the people in the Loess Hilly region seriously.Loess hilly area of Ordos Basin is located in the arid and semi-arid climate transition zone, unique monsoon climate and quaternary the rapid increase in the formation of loess landform, under the combined action of wind and water erosion that becomes one of the most serious soil and water loss regions.This paper selects a wind erosion area and a water erosion area located in the crisscross region of Gezhenyan Village. Investigating the wind erosion?water erosion and complex erosion by sampling and experimental analysis of surface soil. The results have a certain guiding role in the application of the fertilization and the improvement of soil productivity on the loess slope.Research results show that:(1) The annual precipitation had great variation and had rainstorm. Soil water erosion occurs mainly in summer and autumn, the wind erosion is more intensive in winter and autumn, wind erosion and water erosion caused the losses of soil nutrients.(2) Soil erosion caused soil nutrient loss.Overall, the soil nutrient loss in water erosion is greater than the wind erosion of soil nutrient loss.Water erosion observation area in different parts of the nutrient erosion is not the same,different parts of soil nutrient loss is the bottom of the slope >slope crest.(3) There was no significant change of soil PH value in the loess hilly of the Ordos Basin.The PH value in wind erosion is lower than the average value of the water erosion. The content of organic matter in the soil surface was generally low in the study area. The arable soil organic matter in the study area is higher than that of the cultivated organic matter. The organic matter content decreased first and increased in water-eroded lands instability,The content of organic matter:Bottom of the slope>Middle part of slope>Top of slope.(4) With the sampling time of change,study area of total nitrogen and available nitrogen content is overall change and gradually decreased which content about 10%. With the spring and summer water erosion time, nitrogen content decreased gradually. With the change of slope position, slope crest<the bottom of slope < slope. Total nitrogen content of wind erosion>The total nitrogen content of the water,and the low value was effect by slope in water erosion. The content of total phosphorus in soil showed a significant change with the seasonal variation. The content of total phosphorus in spring, summer and autumn were more stable than that in autumn, but higher than second years in spring. From different observation sites:the slope crest slope <the bottom of slope <slope. From the time scale:spring > summer > autumn, the overall trend of decline. The content of total potassium in the study area is relatively low, and the change of total potassium content is small with the passage of the sampling time. The wind erosion > water erosion. The content of available potassium is generally low. From the time scale, spring > summer > autumn > second spring. Overall, the wind erosion loss > the water erosion loss. According to the observation and experiment, the wind erosion and water erosion in the sampling period can affect the soil nutrient change, which will result in the loss of soil nutrients. |
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