Reconciling nitrogen fertilization effects on soil nitrification with acidification.
Where this comes from
- Record sourced from PubMed, PMID 42706253.
- Also identified by DOI 10.1038/s41467-026-76609-x.
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Abstract
Nitrogen (N) fertilization supports nearly half of the global population but disrupts the N cycle. While N addition is assumed to stimulate soil nitrification by increasing substrate supply and nitrifier activity, it may also inhibit nitrification via soil acidification. Resolving this paradox is key to understanding the nitrification response to N addition (β<sub>nit</sub>). Using a global dataset, we show that β<sub>nit</sub> is best explained by final soil pH and ecosystem type. The β<sub>nit</sub>-pH relationship is positive in croplands, weak in forests, and negative in grasslands. Notably, β<sub>nit</sub> shifts from negative to positive above a pH threshold of 5.7 in croplands. Structural equation modeling reveals that final pH affects β<sub>nit</sub> in croplands by altering ammonia-oxidizing bacteria abundance and ammonium concentration in response to N addition. Our findings underscore the critical role of pH in regulating β<sub>nit</sub> and improving predictions of ecosystem N dynamics and plant productivity under future N inputs.
Medical subject headings
- Soil
- Nitrogen
- Nitrification
- Fertilizers