C/N值对嵌草铺装系统N迁移转化的影响

Effect of C/N Ratio on Nitrogen Migration and Transformation in Grassed Paving System

以模拟嵌草铺装系统为研究对象,运用^(15)N同位素示踪技术研究不同进水C/N值条件下土壤吸附、植物吸收、微生物固定、硝化、反硝化和硝酸盐异化还原为铵(DNRA)作用对氮的去除效果,量化分析氮的迁移转化规律。结果表明,嵌草铺装系统可有效去除雨水径流中的COD、TN、NH_4^+-N和NO_3^--N,去除率分别可达到77.5%、85.8%、85%、96.3%;0~5 d时以土壤无机颗粒吸附、植物吸收、微生物同化和硝化反应为主,5~12 d时以反硝化反应为主,12~20 d时以硝化和反硝化反应为主;低C/N值条件下,DNRA和反硝化作用较弱,硝化反应较强;随着进水C/N值的增加,硝化反应削弱,DNRA作用和反硝化作用增强。进水C/N值对土壤无机颗粒吸附、植物吸收和微生物同化作用无显著影响。

The effects of soil adsorption, plant uptake, microbial fixation, nitrification, denitrifi- cation and dissimilatory nitrate reduction to ammonium （DNRA） process on nitrogen removal under dif- ferent influent C/N ratio by using 15 N isotope tracing technique in a simulated grassed paving system were studied, and the migration and transformation of nitrogen were quantitatively analyzed. The results showed that NH4 - N, NO3- - N, TN and COD in rainwater could be effectively removed by the grassed paving system, and the removal rates were 85% , 96.3% , 85.8% and 77.5% , respectively. The ad- sorption of soil inorganic particles, plant uptake, microbial assimilation and nitrification were the main factors during 0 -5 days; however, the denitrification reaction was predominant during 5 -12 days, and then the nitrification and denitrification reactions were significant during 12 -20 days. Under low C/N ratio, the DNRA effect and denitrification were weak, but the nitrification was strong. With the increase of C/N ratio, the nitrification reaction was inhibited, but the DNRA effect and denitrification were en-hanced. C/N ratio had no significant effect on the adsorption of soil inorganic particles, planl uptake and microbial assimilation.