SOIL ACIDITY AND POTENTIAL NITRIFICATION ACTIVITY IN PRECARPATHIAN AGROECOSYSTEMS: A METHODOLOGICAL APPROACH
DOI:
https://doi.org/10.31861/biosystems2026.02.318Keywords:
ammonia-oxidizing archaea, ammonia-oxidizing bacteria, comammox Nitrospira, pH-H₂O, pH-KCl, potential nitrificationAbstract
This paper synthesizes current evidence on the relationship between soil acidity and potential nitrification activity and proposes a methodological framework for planning field and laboratory studies of this relationship in Precarpathian agroecosystems. It is a narrative review and methodological synthesis of peer-reviewed studies published in 2021–2025, regional soil-fertility assessments, and standards for soil pH and potential nitrification measurements. The review includes 21 sources; effects were not quantitatively pooled. The operational meanings of pH-H₂O, pH-KCl, and a field electrochemical signal are distinguished. Because measured pH depends on the extractant and procedure, pH-H₂O and pH-KCl are not interchangeable. A field sensor is not a laboratory measurement and requires independent validation using paired soil samples. The response of nitrifying communities to acidity is shaped jointly by ammonium availability, moisture, temperature, aeration, organic carbon, soil texture, and fertilization practices. Comparison of four primary studies showed that reported roles of AOA, AOB, and comammox Nitrospira depend on soil, nitrogen regime, and endpoint (abundance, functional contribution, or rate); they cannot be transferred to a new region based on similar pH or amoA copy number alone. Potential nitrification activity is therefore interpreted as the functional potential of a sample under standardized incubation conditions, not as a measured in situ process rate. For a future regional study, the paper outlines stratified spatial sampling, pilot estimation of variance, seasonal resampling, and event-based sampling defined in advance. The minimum measurement set includes laboratory pH (H₂O and KCl), potential nitrification, NH₄⁺ and NO₃⁻, soil moisture, and temperature. Where resources permit, it should be complemented by organic carbon, texture, and molecular markers. Without carbon and texture data, adjusted estimates cannot account for their potential influence. A sensor time series may help schedule additional sampling only after its measurement error has been evaluated and calibration observations have been separated from independent validation data. The proposed framework contains no original experimental results and does not establish a causal effect of acidity. Its purpose is to support valid comparisons among sites, transparent adjustment for covariates, and subsequent local hypothesis testing of soil acidity and potential nitrification in the Precarpathian region.
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