| China is the largest producer and consumer of coal and coal is our country's main source of energy. The One-time energy proportion of 74% is the consumption of coal.Approximately 96% of Chinese coal mining is work well, the remaining 4% is the Open mining. Underground goaf caused by work well result in the ground subsidence. Mining area ground subsidence bringed about more than 400 million hm2 destruction land, every year by 3.3 -4.7 million hm2 speed increases and the strip mine digged out 750,000 hm2 land, so the task of land reclamation is formidable.Our attention on land and the environment, land reclamation works have developed rapidly in recent years, and the reclamation rate has about 12%. State and mining enterprises spend more than 50 million yuan on the land reclamation every year. In order to reduce the risk of investment and ensure the subsiding land has higher productivity, we must pay attention to the quality of the acceptance and evaluation of land reclamation.In this paper, we take Houbulian stripe mine for example, which is located on Ejin Horo Banner on the Ordos Highlands in its province of Inner Mongolia. The land use change is anaied by using remote sensing. Master the characteristics of reclaimed soil physical properties by field sampling and establish a system of the indicators of reclaimed land quality to evaluate.Through research, I get conclusions as follows:1) The Vegetation area increased the area of 0.25 square kilometers between 1986 and 2006, the new bare area reduced 0.41 square kilometers.2) Because of the rolling machine by reclamation, reclaimed soil compaction degree is high, surface soil compaction degree is higher than undestroyed soil. With the reclamation of surface soil compaction degree increased gradually increased, but all reclaimed soil compaction degree is less than waste disposal site. Reclaimed soil compaction degree is in the soil profile distribution, the surface is lesser, most commonly at about 30cm.3) Reclaimed soil nutrient is lower than unbroken soil and the waste disposal site is the lowest. With the increase of reclamation to increase gradually, the soil nutrient level will come up with undestroyed soil after five years.It illiustrates that the surface protection is not enough in the process of reclamation. It wasn't completely according to the design requirements in the topsoil stripping and refilling, but blended with other soils. Because of this, the reclamation soil nutrient is relatively low. The reclamation soil nutrient is above normal in the vertical section 20cm depth. The main reasons are the underpart soil compaction degree is high and the plant roots is hard to penetrate the layer. It concentrate in 20cm depth. The plant litter and the root make the soil nutrient of the layer is high, especially the organic matter.4) After land reclamation, improvement effecial of the soil density vary from planting different vegetation. The herbage has the best effect,the woods is second, the land is the worst and coniferous tree is better than deciduous tree. Different vegetation make a big difference on reclaimed soil nutrient.Soil organic matter, the N, P and the K effective phosphorus of soil which plant grass have achieved or exceeded the level of undestroyed soil. The other nutrients are the lowest except the P, in the land soil.Tn the aspect of Improving soil nutrient status,coniferous tree is better than deciduous tree.5) Under the action of vegetation,the quality of the soil increased continuously with fixed reclamatio.Surface soil quality reach the level of without damaging soill after 5 years. Because of the litter and characters of vegetation,the quality of reclaimed surface soil is better than under layer. The soil quality variations is significant because of different vegetation conditions. The soil quality improvement effect of land and coniferous tree is poorer, the effect of grass and deciduous tree is better.
|
PDF Full Text Request