<p><UnorderedList Mark="Bullet"> <ItemContent> <p>P addition increased rates of net N mineralization and ammonification but not nitrification.</p> </ItemContent> <ItemContent> <p>P addition increased soil bacterial biomass, but did not change fungi biomass.</p> </ItemContent> <ItemContent> <p>Soil enzymatic stoichiometry and microbial P limitation were responsible for N mineralization.</p> </ItemContent> </UnorderedList></p><p>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.</p>

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Linking microbial nutrient limitation and community composition to nitrogen mineralization in bamboo forest soil with phosphorus addition

  • Tong-Tao Hu,
  • Dong Bu,
  • Yang Zhang,
  • Fang-Chao Wang,
  • Jian-Jun Li,
  • Kui-Ling Zu,
  • Ming-Hui Meng,
  • Chao Liang,
  • Xiang-Min Fang

摘要

P addition increased rates of net N mineralization and ammonification but not nitrification.

P addition increased soil bacterial biomass, but did not change fungi biomass.

Soil enzymatic stoichiometry and microbial P limitation were responsible for N mineralization.

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.