Physical-chemical Properties And Tillage Suitability In Fly Ash Filling Reclamation Soil

Huainan city is an important thermal power base in East China. With thermal power projects continuously building, the discharge and accumulation quantities of fly ash are increasing yearly. It has good prospects that reclamation subsidence areas are filled with fly ash. That is able to solve subsidence areas by mining coal synthetically. That also can increase cultivated areas. But covering thickness is usually different in engineering practice, which affect soil physical and chemical properties and growing development of crops.In this research, we select Panyi colliery subsidence area as test site and select fly ash from Tianji power station as test materials. Three different covering thickness test fields are designed including 20cm, 30cm and 50cm. Due to the physical-chemical properties and fertility of soil, choose the index such as volumeweight, porosity, texture, water regime, pH, organic matter, total nitrogen, available phosphorus and rapidly-available potassium, then analyze the variation of soil physical-chemical properties in vertical and horizontal direction and the influence on crop growing development in different test fields.Test results show:The physical properties of fly ash (color, porosity, texture) can improve the capillary porosity and soil temperature of Sandy loam. The change of PH value in three kinds of covering thickness fields are not obvious; Ash layer have good water storage capacity and can improve water ratio of neighboring layers. Compared with "soil fertility index classification", the average level of organic matter in topsoils is between Gradeâ…¡andâ…¢, organic matter in ash layers come to Gradeâ… . The average level of total nitrogen in topsoils reachs Gradeâ…¢, and reachs Gradeâ… in ash layers. The average level of effective phosphorus in topsoils and ash layers are all Gradeâ…¢, but the content of available phosphorus in ash layers is less than half of the topsoils; The average level of rapidly-available potassium in the topsoils come to Gradeâ… , and come to Gradeâ…¡-â…¢in ash layers .Synthetically Considering the soil physical-chemical characteristics, the costs of covering earth and fertilizing, the mode of covering 20cm is a better choice. The evolution of soil physical-chemical properties and the influence on crops are complicated and long-term in different models, so a durative study is necessary.