| 李海涛,谢春梅,刘成前,李祖然,李元,湛方栋,何永美.UV-B增强后秸秆还田分解对土壤氮转化微生物及酶活性的影响[J].农业环境科学学报,2024,43(1):111-121. |
| UV-B增强后秸秆还田分解对土壤氮转化微生物及酶活性的影响 |
| Effects of UV-B-enhanced straw decomposition on soil nitrogen transformation microorganisms and enzyme activities |
| 投稿时间：2023-02-22 |
| DOI：10.11654/jaes.2023-0123 |
| 中文关键词: UV-B辐射 秸秆还田 氮转化 微生物 酶 氮含量 N2O |
| 英文关键词: UV-B radiation straw return nitrogen transformation microorganism enzyme nitrogen content N2O |
| 基金项目:国家自然科学基金项目（32060287）；云南省教育厅科研基金项目（2021J0122） |
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| 中文摘要: |
| 为明确UV-B辐射增强对水稻秸秆化学成分的影响，阐释UV-B辐射增强后秸秆还田分解特征及其对稻田土壤氮素转化的间接效应，本研究在元阳梯田（海拔 1 600 m）开展大田试验，以当地水稻品种白脚老粳为研究对象，研究 UV-B辐射增强（5.00kJ·m-2）对水稻秸秆化学成分及其还田后秸秆降解、土壤氮素转化的影响。结果表明：UV-B辐射增强显著降低水稻秸秆纤维素含量，增加木质素含量，提高秸秆木质素/氮；并导致秸秆纤维素、木质素、总氮的降解速率总体降低，最大降幅分别达38.7%、18.1%、25.8%。与自然光照秸秆相比，UV-B辐射后的秸秆还田显著降低土壤固氮细菌、氨化细菌、硝化细菌和反硝化细菌数量，增加土壤蛋白酶、氨单加氧酶、硝酸还原酶活性，提高土壤硝化和反硝化速率。相关性分析表明，秸秆木质素/氮与秸秆降解速率呈极显著负相关；秸秆纤维素、木质素、总氮降解速率与硝酸还原酶活性呈显著正相关，后者又与N2O排放通量呈显著正相关；硝化细菌数量与NO3--N含量呈负相关。研究表明，UV-B辐射增强通过提高秸秆木质素/氮，抑制秸秆纤维素、木质素、总氮降解，减少土壤氨化细菌数量，增加氨单加氧酶和硝酸还原酶活性，从而促进土壤NH4+-N向NO3--N转化，导致N2O排放通量增加。 |
| 英文摘要: |
| To clarify the effect of enhanced UV-B radiation on the chemical composition of rice straw, the characteristics of straw decomposition after enhanced UV-B radiation and its indirect effect on nitrogen transformation in paddy soil were explored. In this study, a field experiment was performed in terraced fields in Yuanyang（1 600 m above sea level）, taking the local rice variety Baijiao Laojing as the research object. The effects of enhanced UV-B radiation（5.00 kJ·m-2）on the chemical composition of rice straw, straw degradation, and soil nitrogen transformation were studied. The results showed that：Enhanced UV-B radiation significantly decreased the cellulose content of rice straw, increased the lignin content, and increased straw lignin/nitrogen. The degradation rates of cellulose, lignin, and total nitrogen decreased by 38.7%, 18.1%, and 25.8%, respectively. Compared with straw under natural light, the straw applied after UV-B radiation significantly decreased the number of soil nitrogen-fixing bacteria, ammonifying bacteria, nitrifying bacteria, and denitrifying bacteria, increase the activities of soil protease, ammonia monooxygenase, and nitrate reductase, and increased the soil nitrification and denitrification rates. The correlation analysis showed that the straw lignin/nitrogen was significantly negatively correlated with the straw degradation rate. The degradation rates of straw cellulose, lignin, and total nitrogen were significantly positively correlated with the nitrate reductase activity, and the latter was significantly, positively correlated with the N2O emission flux. The number of nitrifying bacteria was negatively correlated with the content of NO3--N. This study showed that enhanced UV-B radiation inhibited the degradation of straw cellulose, lignin, and total nitrogen by increasing the straw lignin/nitrogen, decreased the number of soil ammonifying bacteria, increased the activities of ammonia monooxygenase and nitrate reductase, promoted the transformation of soil NH4+-N to NO3--N, and increased the N2O emission flux. |
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