Breeding Base of State Key Laboratory of Humid Subtropical Mountain Ecology, School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China.
Ying Yong Sheng Tai Xue Bao. 2023 Jan;34(1):18-24. doi: 10.13287/j.1001-9332.202301.002.
The variations in soil nitrification and denitrification processes, together with the abundances of functional microbes were investigated in plantations with different stand ages of 5, 8, 21, 27, and 40 years old. The results showed that the net nitrification rate fluctuated with increasing forest ages, with that of 8-year- and 27-year-old plantations being significantly lower than other stand ages. The abundance of ammonia-oxidizing archaea (AOA) in the 27-year-old plantation was significantly lower than that of the 40-year-old plantation, while there was no significant difference among the other stand ages. There was no significant difference in the abundance of AOB gene, denitrifying functional genes or soil denitrification potential among different stand ages. The results of stepwise regression analysis showed that the abundance of AOA gene was not significantly affected by soil physical and chemical properties. In addition, the abundance of AOB was positively associated with soil total carbon content and soil pH. The abundance of denitrifying functional genes including , and increased with increasing soil pH. The abundance of and was influenced by soil total carbon. Stand age influenced soil net nitrification rate through the AOA abundance. Moreover, soil denitrification potential was directly affected by stand age, or indirectly affected by stand age through soil microbial biomass carbon, soil pH and denitrifying gene abundance of and . Compared with the denitrification process, soil nitrification and associated AOA gene abundance were more sensitive to the development of plantations. The rotation period sould be appropriately extended to reduce the risk of nitrogen losses resulting from soil nitrification.
本研究调查了不同林龄（5、8、21、27 和 40 年）人工林土壤硝化和反硝化过程的变化以及功能微生物的丰度。结果表明，净硝化率随林龄的增加而波动，8 年和 27 年生人工林的净硝化率显著低于其他林龄。27 年生人工林氨氧化古菌（AOA）的丰度明显低于 40 年生人工林，而其他林龄之间无显著差异。不同林龄土壤 AOB 基因、反硝化功能基因丰度和土壤反硝化潜力无显著差异。逐步回归分析结果表明，AOA 基因丰度不受土壤理化性质的显著影响。此外，AOB 的丰度与土壤全碳含量和土壤 pH 值呈正相关。、和基因丰度随土壤 pH 值的增加而增加。和基因的丰度受土壤全碳的影响。林龄通过 AOA 丰度影响土壤净硝化速率。此外，土壤净硝化潜力直接受林龄的影响，或通过土壤微生物生物量碳、土壤 pH 值和、基因丰度间接受林龄的影响。与反硝化过程相比，土壤硝化作用及相关 AOA 基因丰度对人工林的发展更为敏感。应适当延长轮伐期，以降低因土壤硝化作用导致的氮素损失风险。
