Do tropical climatic conditions reduce the effectiveness of nitrification inhibitors? A meta-analysis of studies carried out in Brazil.

Extensive research has been performed into the effectiveness of nitrification inhibitors (NIs) in preventing N losses; however, tropical agriculture has been underrepresented in recent meta-analyses. Here, we apply a meta-analytic approach using data from 50 articles to identify the impact of NIs (DMPP, DCD, and DCD + NBPT) on crop yield, N₂O emissions, soil NH₄⁺ and NO₃⁻ concentrations, and NH₃ volatilization in subtropical and tropical regions of Brazil. In addition, the survey includes information about location; climate zone; cultivated crops; soil pH; soil organic carbon; soil texture; experimental method; soil management; irrigation; fertilizer source, rate, and type; and NI type and rate. Overall, the data set showed that NIs increased crop yield and soil NH₄⁺ concentrations by 3 and 60%, respectively, whereas N₂O emissions and soil NO₃⁻ concentrations were reduced by 62 and 31%, respectively. Ammonia volatilization was not changed by NI application. However, the combination of a NI with a urease inhibitor decreased such losses by 39%. The effectiveness of the NIs was highest in irrigated fields, fine-textured soils, and mineral N sources. Moreover, NI performance in Brazil was found to be similar in tropical and subtropical climates, and was also comparable to values previously reported in meta-analyses, including those conducted in temperate climates. Therefore, NI application is indicated to be an efficient strategy to delay nitrification and mitigate N₂O emissions in tropical agroecosystems. [ABSTRACT FROM AUTHOR]