外加生物质炭对不同利用方式紫色土反硝化过程的影响

在有机碳添加下,研究同一区域不同利用方式紫色土反硝化过程差异,可为紫色土氮素管理及N2O减排提供科学依据。本研究以成土环境一致,土地利用方式分别为茶园、果园、林地、耕地的4种紫色土为研究对象,采用厌氧培养-15N标记法,研究了生物质炭添加下4种土壤的气态产物N2O、N2的排放速率和反硝化速率特征及其与土壤pH、有机质含量的关系。结果表明,N2O、N2排放速率和反硝化速率均为茶园＞耕地>果园＞林地；相关性分析发现N2O、N2排放速率和反硝化速率均随土壤pH的增加而减少(P < 0.01),而和土壤有机质含量显著正相关(P < 0.05),添加生物炭后,土壤N2排放速率和反硝化速率有所提高,但不显著；N2O排放速率的改变因土地利用方式不同而有所差异,其中,茶园N2O排放速率变化不显著,而果园和耕地显著降低(P < 0.05),林地显著增加(P < 0.05)。上述研究结果揭示了不同利用方式紫色土反硝化过程与土壤pH和有机质含量显著相关且受生物炭添加的影响。

Effects of Biochar on Denitrification of Purple Soils Under Different Land Use Types

In order to provide a theoretical basis for nitrogen management and N2O emission reduction of purple soil, the study focused on the denitrification process of purple soil with varied land-use types in the same area. In the study, with the addition of biochar, the emission rates of N2O and N2and denitrification rates of four purple soils (Tea garden soil, orchard soil, woodland soil, and cropland soil), as well as their relationships with soil pH and organic matter content, were examined by using the anaerobic culture-15N labeling method. Results showed that the emission rates of N2O and N2 and denitrification rates were tea garden soil > cropland soil > orchard soil > woodland soil. According to correlation analysis, the emission rate of N2O and N2 and denitrification reduced as soil pH increased (P < 0.01) and was strongly positively linked with soil organic matter content (P < 0.05). The emission rate of N2 and denitrification were both somewhat elevated after the addition of biochar. Different land-use types can affect the N2O emission rate by adding biochar, which showed that the N2O emission rate of tea garden soil did not change significantly, while that of orchard and cropland soil was significantly decreased (P < 0.05), and that of woodland soil was significantly increased (P < 0.05). The results revealed that the denitrification process of purple soil with different land-use types was significantly correlated with soil pH and organic matters and can be regulated by the addition of biochar.