Volcanic deposits increase soil organic carbon storage. However, little is known about the effect of volcanic deposits on forest soil nitrogen (N) dynamics and microbial communities. We explored gross and net N transformation rates and microbial community structure using a phospholipid fatty acid (PLFA) method across eight forests with soils derived from different parent material in Japan. Volcanic mineral soils had approximately three-fold greater total N and inorganic N contents and gross nitrification, ammonium immobilization, and nitrate immobilization rates that were one order of magnitude higher than in non-volcanic soils. Moreover, volcanic mineral soils had a 1.7-fold lower N turnover rate, which was estimated as net N mineralization rate per soil N. This was likely caused by a higher gross N immobilization rate, potentially due to the mineral traits of volcanic soils. Volcanic mineral soils had approximately four- and three-fold greater microbial biomass-N and bacterial PLFA contents, respectively, and the fungal:bacterial PLFA ratio was lower in volcanic mineral soils than in non-volcanic soils. Microbial community structure, analyzed using non-metric multidimensional scaling, was distinct between volcanic and non-volcanic soils, and was significantly affected by soil characteristics. This study demonstrates that aside from soil carbon storage, volcanic deposits are related to increases in soil N immobilization, N content, bacterial biomass, and N transformation rates in forest ecosystems.

火山沉积物增加了土壤有机碳的存储量。但是，关于火山沉积物对森林土壤氮（N）动态和微生物群落的影响知之甚少。我们使用磷脂脂肪酸（PLFA）方法探索了八种森林的土壤的总氮和净氮转化率以及微生物群落结构，这些森林的土壤来自日本的不同母本。火山矿物土壤的总氮和无机氮含量以及总硝化，固定铵和固定硝酸盐的速率比非火山土壤高大约三倍。此外，火山矿物土壤的氮素转化率降低了1.7倍，估计为每土壤N的净氮矿化率。这很可能是由于总固氮率提高所致，可能是由于火山土壤的矿物特性。火山矿物土壤中的微生物生物量氮和细菌PLFA含量分别高出大约四倍和三倍，而火山矿物土壤中的真菌：细菌PLFA比率要低于非火山土壤。使用非度量多维标度分析的微生物群落结构在火山土壤和非火山土壤之间是截然不同的，并且受到土壤特性的显着影响。这项研究表明，除了土壤碳存储外，火山沉积还与土壤氮素的固定化，氮含量，细菌生物量和森林生态系统中氮的转化率增加有关。火山矿物土壤中的真菌：细菌的PLFA比低火山土壤中的低。使用非度量多维标度分析的微生物群落结构在火山土壤和非火山土壤之间是截然不同的，并且受到土壤特性的显着影响。这项研究表明，除了土壤碳存储外，火山沉积还与土壤氮素的固定化，氮含量，细菌生物量和森林生态系统中氮的转化率增加有关。火山矿物土壤中的真菌：细菌的PLFA比低火山土壤中的低。使用非度量多维标度分析的微生物群落结构在火山土壤和非火山土壤之间是截然不同的，并且受到土壤特性的显着影响。这项研究表明，除了土壤碳存储外，火山沉积还与土壤氮素的固定化，氮含量，细菌生物量和森林生态系统中氮的转化率增加有关。