外加生物质炭对不同利用方式紫色土反硝化过程的影响

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

以成土环境一致不同土地利用方式茶园、果园、林地、耕地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种土地利用方式土壤的气态产物N_(2)O、N_(2)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:4种土地利用方式下紫色土N_(2)O、N_(2)排放速率和反硝化速率均为茶园>耕地>果园>林地;N_(2)O、N_(2)排放速率和反硝化速率均随土壤pH的增加而降低(P<0.01),而与土壤有机质含量显著正相关(P<0.05)。添加生物质炭后,土壤N_(2)排放速率和反硝化速率均有所提高;N_(2)O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N_(2)O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)。综上可见,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质炭添加的影响。

The emission rates of N_(2)O and N_(2) and denitrification rates of purple soils under four land use types(tea garden,orchard,woodland,and cropland),as well as their relations with soil pH and organic matter content were examined by using the anaerobic culture-15N labeling method.The results showed that the emission rates of N_(2)O and N_(2) and denitrification rates were tea garden>cropland>orchard>woodland.The emission rates of N_(2)O and N_(2) and denitrification rate were reduced as soil pH increased(P<0.01)and had the significant positive correlation with soil organic matter content(P<0.05).With the addition of biochar,the emission rate of N_(2) and denitrification rate were both increased,while the changes in N_(2)O emission rate were affected by land use type,which changed insignificantly in tea garden,significantly decreased in orchard and cropland(P<0.05),and significantly increased in woodland(P<0.05).In conclusion,the denitrification process of purple soil under different land use types is mainly influenced by soil pH and organic matter content,and can be regulated by the addition of biochar.