Phosphorus Supply Increases Nitrogen Transformation Rates and Retention in Soil: A Global Meta‐Analysis. Issue 3 (14th March 2022) - Wang, Ruzhen
Abstract: Interactions between nitrogen (N) and phosphorus (P) are important for plant growth and ecosystem carbon (C) sequestration. While effects of N supply on P dynamics have been much studied, much less is known about the opposite (P‐effect on N). We conducted a meta‐analysis by compiling a total of 1, 734 individual experimental observations from 116 peer‐reviewed publications to assess P‐addition effects on soil N dynamics. Globally, P additions increased the soil total nitrogen (TN) pool, potentially as a result of enhanced plant and microbial immobilization and reduced N losses, with a stronger effect detected under longer duration of P addition (≥5 yr). A coupled increase in soil organic C with TN signifies the fundamental role of exogenous P supply in enhancing soil C sequestration. Phosphorus addition accelerated some of the soil N cycling processes including gross N mineralization, gross nitrification, and denitrification, with the effect sizes varying among ecosystem types and increasing with P addition rates. Our results indicate the fundamental role of P in affecting soil N pools and processes, and highlight the efficacy of P supply in sequestering soil C and mitigating global C emission. Plain Language Summary: Interactions between nitrogen (N) and phosphorus (P) are important for plant growth and carbon (C) sequestration. While effects of N supply on P dynamics have been much studied, much less is known about the opposite (P‐effect on N). We conducted a meta‐analysis by compiling a total of 1, 734 individual experimental observations from 116 peer‐reviewed publications to assess P‐addition effects on soil N dynamics. Globally, P additions increased soil total nitrogen (TN) pool, potentially as a result of enhanced plant and microbial immobilization and reduced N losses, with a stronger effect detected under longer duration of P addition ({greater than or equal to} 5 yr). A coupled increase in soil organic C with TN signifies the fundamental role of exogenous phosphorus supply in enhancing soil C sequestration. Phosphorus addition accelerated some of the soil N cycling processes including gross N mineralization, gross nitrification, and denitrification, with the effect sizes varying among ecosystem types and increasing with P addition rates. Our results indicate the fundamental role of P in affecting soil N pools and processes, and highlight the efficacy of P supply in sequestering soil C under global warming. This work is valuable for the discipline of Ecology in understanding N biogeochemistry under exogenous P supply. Key Points: We conducted a meta‐analysis by compiling 1, 734 individual experimental observations to assess phosphorus (P)‐addition effects on soil nitrogen (N) dynamics Soil total N increased with P addition, especially with longer duration of treatment due to higher biological N retention and lower N loss Accrual of soil total N was coupled with an increase in carbon (C) pool, demonstrating the fundamental role of P supply in promoting C sequestration