Abstract:

To understand the role of organic wastes from different sources in improving the soil organic carbon pool and biological activity of newly reclaimed coastal land, a pot experiment was carried out to observe the effects of eight kinds of organic wastes on soil organic carbon, easily oxidized organic carbon, stable organic carbon, water-soluble organic carbon, microbial biomass carbon and soil enzyme activity of a newly reclaimed coastal land, and to compare the improving effects of different types of organic wastes. The experiment included nine treatments, and they were pig manure, chicken manure, rice straw, vegetable harvest residue, kitchen waste compost, biogas residue, pig manure/rice straw compost, and domestic waste compost at equal application rate of organic carbon, and the control was without organic fertilizer. The experiment ran for 30 weeks. The results showed that the application of the organic wastes all had obvious effects on improving soil properties. The pig manure/rice straw compost, domestic waste compost, kitchen waste compost and biogas residue with biological fermentation were the best in improving soil organic carbon pool, biological activity and farmland carbon pool management index, followed by pig manure, chicken manure and rice straw. Vegetable harvest residue was mainly composed of fresh organic matter, which had poor stability and poor effect on improving soil organic carbon pool and biological activity. After the application of organic waste, the soil carbon pool, soil microbial biomass and other soil properties could change significantly with the incubation time. The study showed that the priority should be given to the application of pig manure/rice straw compost, domestic waste compost, kitchen waste compost and biogas residue for improving the soil organic carbon pool and biological activity in the newly reclaimed coastal land.

Key words: organic waste, newly reclaimed coastal land, soil, organic carbon pool, carbon pool management index