article · Global Change Biology
Soil organic nitrogen mineralization supplies nutrients for plants but can also reduce overall nitrogen retention. Organic matter exists in recalcitrant forms, primarily bound to minerals, and labile forms, mainly particulate matter. An analysis of data from 57 isotope-tracing studies demonstrates that soil pH governs recalcitrant nitrogen mineralization, whilst total nitrogen regulates labile nitrogen mineralization. Recalcitrant nitrogen breakdown directly promotes microbial nitrogen retention and plant nitrogen uptake, operating more efficiently under warmer, drier conditions with higher soil pH. Conversely, labile nitrogen mineralization triggers autotrophic nitrification, accelerating nitrate production, deterring ammonium uptake, and increasing the risk of nitrogen loss. Consequently, managing soils to favour the breakdown of recalcitrant rather than labile organic nitrogen supports a more conservative nitrogen cycle and enhances ecosystem services.
Understanding how different soil nitrogen pools break down helps predict ecosystem nutrient retention and land productivity. Discovering that recalcitrant nitrogen mineralization directly enhances plant uptake while reducing nutrient loss can guide sustainable soil stewardship. This knowledge enables land managers and researchers to develop practices that retain nutrients in the soil more effectively, mitigating the risks of nitrate leaching and environmental degradation.
This early-stage research provides mechanistic insights that could guide the future design of soil management regimes and specialised soil amendments. Potential users include agricultural advisors, land managers, and fertiliser manufacturers seeking strategies to minimise nitrogen loss and enhance crop uptake. Because the work is based on an analytical synthesis of isotopic tracer studies rather than product testing, practical commercial tools remain at an early stage of development.
AI-generated from the published abstract. Always read the original work before citing.
Soil organic nitrogen (N) mineralization not only supports ecosystem productivity but also weakens carbon and N accumulation in soils. Recalcitrant (mainly mineral-associated organic matter) and labile (mainly particulate organic matter) organic materials differ dramatically in nature. Yet, the patterns and drivers of recalcitrant (M<sub>Nrec</sub>) and labile (M<sub>Nlab</sub>) organic N mineralization rates and their consequences on ecosystem N retention are still unclear. By collecting M<sub>Nrec</sub> (299 observations) and M<sub>Nlab</sub> (299 observations) from 57 <sup>15</sup>N tracing studies, we found that soil pH and total N were the master factors controlling M<sub>Nrec</sub> and M<sub>Nlab</sub>, respectively. This was consistent with the significantly higher rates of M<sub>Nrec</sub> in alkaline soils and of M<sub>Nlab</sub> in natural ecosystems. Interestingly, our analysis revealed that M<sub>Nrec</sub> directly stimulated microbial N immobilization and plant N uptake, while M<sub>Nlab</sub> stimulated the soil gross autotrophic nitrification which discouraged ammonium immobilization and accelerated nitrate production. We also noted that M<sub>Nrec</sub> was more efficient at lower precipitation and higher temperatures due to increased soil pH. In contrast, M<sub>Nlab</sub> was more efficient at higher precipitation and lower temperatures due to increased soil total N. Overall, we suggest that increasing M<sub>Nrec</sub> may lead to a conservative N cycle, improving the ecosystem services and functions, while increasing M<sub>Nlab</sub> may stimulate the potential risk of soil N loss.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.1111/gcb.17290
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
