Phosphorus Supply Increases Nitrogen Transformation Rates and Retention in Soil: A Global Meta‐Analysis

Abstract

Nitrogen (N) is one of the most limiting nutrients for plant growth worldwide (Elser et al., 2007). It enters the biosphere primarily by biological N fixation, atmospheric reactive N deposition, and application of N fertilizers (Galloway et al., 2008;Peñuelas et al., 2013). After plant uptake, it is returned to soil in organic forms. Mineralization of organic N in soil is the main process of recycling organic N into mineral forms, which strongly drives N availability, distribution between biological and non-biological pools, and the cascading pathways of N leaving terrestrial ecosystems (Booth et al., 2005;Dai et al., 2020;Fang et al., 2015). For instance, ammonium (NH 4 + ) and nitrate (NO 3 − ) are favorable forms of N taken up by plants and microbes, and are mainly replenished by ammonification and nitrification processes, respectively, with the two processes covarying with each other and fundamentally driving organic N recycling (Figure S1 in Supporting Information S1;Booth et al., 2005). On the other hand, gaseous N emissions from denitrification and nitrification, and NO 3 − leaching, are essential ecosystem N output pathways that can strongly reduce plant N availability and the soil total nitrogen (TN) pool (Figure

Effects of biochar and arbuscular mycorrhizal fungi on winter wheat growth and soil N2O emissions in different phosphorus environments

“…For instance, N 2 O emission had a negative correlation with nosZ gene and positive correlation with nirK genes in the field experiment ( Figure S2B ), which was consistent with our previous research in the field ( Liu et al., 2020 ). In addition, biochar application could significantly reduce P availability in soil, especially in low P environment, which might bring about P deficiency stress, and then reduced activity of denitrifying microorganisms led to decreased soil N 2 O emissions ( Wang et al., 2022 ).…”

“…Different P conditions can influence soil N pools and cycling processes via regulating plant growth and microbial activity ( Xiao et al., 2022a ; Xiao et al., 2022b ). In P-limited environments, P addition enhanced soil N immobilization and retained more N in the plant-soil system by promoting plant and microbial growth, thus suppressing N 2 O emission ( Shen and Zhu, 2022 ; Wang et al., 2022 ). In soils with different P supplies, plants can adjust P-acquisition strategies by regulating root morphology (e.g.…”

Phosphorus additions imbalance terrestrial ecosystem C:N:P stoichiometry

“…[Colour figure can be viewed at wileyonlinelibrary.com] hypothesis (Tian et al, 2021). The contents of ammonium and nitrate declined with decreased plant N:P and C:P ratios (Figure 7c,d,g,h), likely because plant uptake more ammonium and nitrate to support plant growth (Wang et al, 2022), which in turn reduced the contents of soil ammonium and nitrate (Figure 2a). This coherent response is mirrored by unchanged plant N contents (Figure S2) and increased N mineralization rates (Figure 2b) in our analysis.…”

“…After the industrial era, P addition by fertilizer applications changed from 1.7 Tg P year −1 to approximately 3.5 Tg year −1 , which is two to fivefold its natural background value at the global scale (Smil, 2000). Importantly, due to P fertilizers are not volatile (Feng & Zhu, 2019), P additions remarkably affect various ecosystem functions, such as ecosystem C‐cycling (Jiang et al, 2021), soil respiration (Liu et al, 2012), and ecosystem N‐cycling (Wang et al, 2022).…”

“…fertilizers are not volatile (Feng & Zhu, 2019), P additions remarkably affect various ecosystem functions, such as ecosystem C-cycling (Jiang et al, 2021), soil respiration (Liu et al, 2012), and ecosystem N-cycling (Wang et al, 2022).…”