Ecological Characters And Improving Mechanism Of Gentle Hills In The Ecotone

The gentle slope hills of ecotone between agriculture and animal husbandry laid in the north of China The paper regards the areas on the Houshan region in Inner Mongolia as a target of study, because of its very serious natural condition, water and wind erosion, degradation and desertification is also serious. So the environment needs to be recovered. The condition of agricultural production is becoming bad with degradation of the environment, so it is urgently necessary to restore environment.Because most areas in the ecotone are gentle slope hills, the slope plowland accounts for a big proportion. Ploughing leads to soil erosion, so it's very important to manage eco-environment in the gentle slope hills. At the same time, we must also consider livelihood of the local farmers and develops the local agriculture. The seriously degenerated part of in the gentle slope hills should be recovered with their original vegetations (grasses, bushes or woods) , and the rest can be used for farming. In this way, we can reach our aim. In this paper, the obstacles and characters of environment in the gentle slope hills are studied, and the following results were found:(1) The obstacles of environment in the gentle slope hills of those areas include: wind erosion, water erosion, drought and shortage of water, leanness of soil, low temperature. On another hand, there is the conflict between land requirement due to population increase, economy development and harness of eco-environment. The effects of those obstacles are different in different years with various climatic background and different strategies of the state.(2) Eco-environmental factors are different at the different parts of the gentle slope hills: The total solar radiation on the top of the hills is higher in the day, the temperature and humidity is similar on the north and south slopes, but on the north it is a little higher due to longer sunshine and sandy soil. The soil temperature of Ocm on the top is lower than that on the north and south slopes in the early spring, but that's higher from May to July. The top and upper north slopes are the serious parts of wind erosion, and are more serious than the south. The quantity of wind erosion is becoming more and more small gradually from the top to the end of the gentle slope hills. The average percent content of soil water of 0~80cm on the south is higher than that on the north due to better soil, and that on the north is higher than that on the top. The production of agriculture is lower and lower gradually from the foot to the top, the natural grassland and the waste field are also the same.(3) According to the physiognomy characteristic of this areas, ecological engineering model should take the gentle slope hill as a cell, and the contents of the model are: "for a hill, there are grassland on the top, contour fields in the middle, ecological at the foot" or " for a hill, there are grassland on the top, crop fields in the middle, trees at the foot". In this paper, the ratio of fields stopping farming to recover vegetation is also stufied according to the characteristic of the eco-environment on the gentle slope hills, strategies of the state and the local conditions. In different parts of a hill, climatic productive potentiality of the southern part is larger than that of the northern part, and bottom is larger than that of the top part. This is highly agreed with the actual observed vegetation productions in different parts of the hill.