| 生物炭对华北农田土壤N2O通量及相关功能基因丰度的影响 |
| 摘要点击 2252 全文点击 867 投稿时间：2017-11-30 修订日期：2018-01-22 |
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| 中文关键词 生物炭 氧化亚氮 农田土壤 amoA nirS nirK nosZ |
| 英文关键词 biochar nitrous oxide agriculture soil amoA nirS nirK nosZ |
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| 中文摘要 |
| 为了探寻施用生物炭对农田土壤氧化亚氮（N2O）的减排效果和机制，于2015年3月27日至6月5日，利用盆栽实验研究了施用生物炭（CK，C1：5%，C2：10%，C3：15%，C4：30%）（质量分数）对华北农田土壤N2O通量、氨单加氧酶（amoA）、亚硝酸盐还原酶（nirS、nirK）以及氧化亚氮还原酶（nosZ）基因丰度的影响.结果表明：①施用低量生物炭（5%）能够促进N2O排放，施用中、高量生物炭可以起到抑制N2O排放的效果，且生物炭用量为15%时减排效果最佳.②实验初期，施用生物炭对土壤硝化反硝化基因丰度影响较大，AOA和nirS基因丰度与生物炭施用量呈极显著正相关关系，nirK基因丰度与生物炭施用量呈显著正相关关系，AOB和nosZ基因丰度与生物炭施用量呈显著负相关关系；实验末期，AOA丰度与生物炭施用量表现为显著负相关关系，AOB丰度与生物炭施用量表现为显著正相关关系.③实验初期，N2O排放通量与AOA、nirS基因呈现极显著的负相关关系，说明在土壤含水量较高的条件下，N2O的产生受AOA、nirS基因丰度控制调节；实验末期，N2O排放通量与nosZ基因呈现极显著正相关关系，说明在土壤含水量较低的条件下，N2O的产生受nosZ基因丰度控制调节.本研究结果表明施用生物炭能够增加硝化反硝化功能基因丰度，并降低N2O的排放，为华北农田合理施用生物炭提供了一定的理论依据. |
| 英文摘要 |
| To explore the effect and mechanism of biochar application in reducing nitrous oxide (N2O) content in agricultural soil, from March 27 to June 5 2015, pot experiments were conducted to study the effects of biochar application rates (CK, C1:5%, C2:10%, C3:15%, and C4:30%) (mass fraction) on soil N2O fluxes and the functional marker genes ammonia monooxygenase (amoA), nirK, nirS, and nosZ, which are responsible for nitrification and denitrification. The results revealed the following. ①The application of low doses of biochar (5%) promoted N2O emission. The application of middle and high doses of biochar reduced N2O emission. Furthermore, the application of biochar (15%) was found to be the best practice to reduce N2O emission. ② At the beginning of the experiment, biochar had a significant effect on the abundance of soil amoA and denitrification bacteria gene. Furthermore, the abundance of AOA and nirS had a significant positive correlation with the biochar rate, and the abundance of nirK gene and biochar rate were significant. There was a significant negative correlation between AOB and nosZ gene abundance and biochar rate. At the end of the experiment, AOA abundance correlated negatively with biochar rate, while there was a significantly positive relationship between AOB abundance and biochar rate. ③ At the beginning of the experiment, the N2O fluxes exhibited a significant negative correlation with AOA and nirS gene, indicating that N2O production was controlled by the abundance of AOA and nirS gene under high soil moisture content. At the end of the experiment, there was a significant positive correlation between N2O flux and nosZ gene, indicating that the production of N2O was regulated by the abundance of nosZ gene under low soil water content. The results of this study showed that the application of biochar altered the abundance of amoA and denitrification bacteria genes, and reduced N2O emission. These results provide a theoretical basis for a rational application of biochar in farmland. |
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