STUDY ON SOIL IMPROVEMENT FOR RECLAIMED SUBSIDED LAND WITH FLY ASH AND ORGANIC FERTILIZER

摘要

Reclaimed land usually has some problems such as poor soil structure and nutrients shortage. The man-made improvement treatments could accelerate soil development of reclaimed soil and increase soil productivity. This study was conducted to determine the effectiveness of soil improvement with fly ash and organic fertilizer for reclaimed subsided land. A 0.23 ha of experimental site was chosen in Jiawang coal mining area, Jiangsu province, and 6 treatments were used in the design with 3 types of materials such as 1 percent fly ash, 5 percent fly ash and poultry litter. The results showed that the application of fly ash could improve the reclaimed soil, but the amount of the fly ash should be more than 1 percent. The treatment of 1 percent fly ash had the lowest yield of soybeans, even lower that of the reference plot. As fly ash has fewer nutrients, some organic fertilizers are needed for higher yield. The treatment with 5 percent fly ash with poultry litter had the highest yield of soybeans. All the treatments of soil amendments were lower or equal to the concentrations of metal elements found for the control plot. The addition of organic fertilizer (D, E, F treatments) resulted significant decreases in the concentrations of Zn and Cu in the soybeans while the addition of 5 percent fly ash had only a slight decrease of the concentration of Zn and Cu in the beans. The pH and available nutrient contents of soils after harvest of the soybean were not affected by the application of fly ash.