生物炭添加对太湖滨岸带土壤氮矿化和淋失特征的影响

滨岸带土壤的氮矿化改变了氮元素的迁移和利用效率,与水体富营养化控制息息相关,而土地利用导致的土壤性质差异使得氮的固持和运移能力不同.因此,以太湖西部沿岸3种土地利用类型的土壤(林地、草地和耕地)为研究对象,通过培养实验和土柱淋溶实验,探究不同生物炭添加(0%、 1%和5%)条件下滨岸带土壤氮矿化量的动态变化和淋失特征.结果表明,总体上生物炭添加抑制了林地和草地土壤的氮矿化,对耕地氮矿化的影响则为低浓度促进而高浓度抑制.淋溶实验研究发现,生物炭添加减少了土壤矿质氮的流失,对氨氮削减率为23.28%～39.79%, 3种土地利用类型之间的差异较小;硝氮降低了17.20%～44.49%,其中耕地的削减率较林地和草地小.综合来看,生物炭输入草地和耕地更能达到保持土壤肥力和减少滨岸带土壤氮素淋失的效果.

Effects of Biochar Addition on Soil Nitrogen Mineralization and Leaching Characteristics in Riparian Zone of Taihu Lake

Nitrogen mineralization in riparian soil changes the migration and utilization efficiency of nitrogen, which is closely related to the control of water eutrophication. The differences in soil properties caused by land use alter nitrogen retention and transport capacity. Therefore, the soil of three land use types (woodland, grassland, and cultivated land) in the western riparian zone of Taihu Lake were selected for research on the dynamic changes in nitrogen mineralization amount using an incubation experiment and a leaching characteristics by soil column leaching experiment, and their environmental effects were also studied under different biochar addition conditions (0%, 1%, and 5%). The results showed that, in general, the addition of biochar inhibited nitrogen mineralization in forest land and grassland soil, whereas the effect of biochar on nitrogen mineralization in cultivated land was promoted in low concentrations but inhibited in high concentrations. Leaching experiments showed that the biochar addition reduced the loss of soil mineral nitrogen, and the reduction rate in ammonia nitrogen was 23.28%-39.79%, whereas there was little difference between the three land use types. The nitrate decreased by 17.20%-44.49%, and the reduction rate of cultivated land was smaller than that of forest land and grassland. In conclusion, the input of biochar into grassland and cultivated land can better maintain soil fertility and reduce soil nitrogen loss in riparian soil.