Factors controlling net soil nitrogen mineralization rates in Japanese forest ecosystems

Autor: Mayu SASAKI, Mana Mukai, Shin-ichiro Aiba, Kosuke Homma, Masaaki Takyu, Hiroko Kurokawa, Kanehiro Kitayama
Rok vydání: 2022
DOI: 10.21203/rs.3.rs-1572931/v1
Popis: Background and aimsNet soil nitrogen (N) mineralization rate represents bioavailable N supply rate. Exploring its controlling factors improves the knowledge of N cycling. Previous studies in Japanese forests revealed that high soil organic matter (SOM) content of volcanic soils enhanced net N mineralization rates. However, the effects of cations and phosphorus (P) added by volcanic ash are not fully understood. We investigated the influences of volcanic ash addition on net N mineralization via P and cation availabilities.MethodsNet soil N mineralization rates of surface soils (0-5 cm) collected from 20 sites across Japan were determined under the common laboratory condition (20 ℃, 10 days). The concentration of amorphous minerals (Alo+1/2Feo; a surrogate of volcanic ash) was included as an independent variable as a surrogate of volcanic ash in a structural equation modelling (SEM). In addition, conifer abundances and mean annual temperatures of the origins of soils were also included in the model.ResultsNet soil N mineralization rates differed among sites, suggesting that soil substrates were inherently determined by site conditions. Alo+1/2Feo positively affected net soil N mineralization rate via the concentrations of total P and labile P. Conifer abundance weakly affected net soil N mineralization rate. Temperature was not selected in the model.ConclusionsNet soil N mineralization rates in Japanese forest ecosystems are most strongly determined by the amount of added volcanic ash via P availability. These findings improve our understanding for the diversification of forest ecosystems under volcanic activities.
Databáze: OpenAIRE