The soil nitrogen(N)supply plays a core role in nutrient cycling,whereas phosphorus(P)is generally considered the limiting element of ecological processes in subtropical forests.However,the specific characteristics an...The soil nitrogen(N)supply plays a core role in nutrient cycling,whereas phosphorus(P)is generally considered the limiting element of ecological processes in subtropical forests.However,the specific characteristics and regulatory mechanisms governing how P affects soil N mineralization remain incompletely understood.P fertilizer is often applied in bamboo forests,and we collected bulk soil and two types of rhizosphere soils(soils surrounding stump roots and rhizome roots,respectively)from a bamboo forest and conducted microcosm experiments with P addition(PA)to simulate the application of P fertilizer.The N mineralization and microbial and enzymatic parameters of the rhizosphere and bulk soils presented the same response to PA.PA increased the rate of net N mineralization and ammonification,suggesting that PA is beneficial to the N supply in the soil.PA increased the soil bacterial biomass but decreased the fungi:bacteria ratio.The soil enzyme C:N:P ratio indicated that the microbial community was subjected to P limitation.PA resulted in an increase in the enzyme C:P and N:P ratios and a decrease in the enzyme vector angle,suggesting alleviation of P limitation in the soil microbial community.Hierarchical partitioning and Pearson correlation analyses revealed that enzymatic stoichiometry and the vector angle were key regulators of soil N mineralization.These results indicate that PA can not only increase the concentration of soil P but also enhance the soil N supply in subtropical P-limited forests,primarily through changes in microbial nutrient limitation rather than in microbial biomass or community structure.展开更多
基金the National Natural Science Foundation of China(Grant No.32260379,32371852)the Jiangxi Provincial Natural Science Foundation(Grant No.20242BAB26101)the Jiangxi Provincial Postgraduate Innovation Special Fund Project(Grant No.YC2023-S352).
文摘The soil nitrogen(N)supply plays a core role in nutrient cycling,whereas phosphorus(P)is generally considered the limiting element of ecological processes in subtropical forests.However,the specific characteristics and regulatory mechanisms governing how P affects soil N mineralization remain incompletely understood.P fertilizer is often applied in bamboo forests,and we collected bulk soil and two types of rhizosphere soils(soils surrounding stump roots and rhizome roots,respectively)from a bamboo forest and conducted microcosm experiments with P addition(PA)to simulate the application of P fertilizer.The N mineralization and microbial and enzymatic parameters of the rhizosphere and bulk soils presented the same response to PA.PA increased the rate of net N mineralization and ammonification,suggesting that PA is beneficial to the N supply in the soil.PA increased the soil bacterial biomass but decreased the fungi:bacteria ratio.The soil enzyme C:N:P ratio indicated that the microbial community was subjected to P limitation.PA resulted in an increase in the enzyme C:P and N:P ratios and a decrease in the enzyme vector angle,suggesting alleviation of P limitation in the soil microbial community.Hierarchical partitioning and Pearson correlation analyses revealed that enzymatic stoichiometry and the vector angle were key regulators of soil N mineralization.These results indicate that PA can not only increase the concentration of soil P but also enhance the soil N supply in subtropical P-limited forests,primarily through changes in microbial nutrient limitation rather than in microbial biomass or community structure.
