The emission pathways and intensities of nitrous oxide (N2O) vary across land uses, and the efficacy of mitigation measures may also differ. To investigate the key factors influencing the effectiveness of the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) in mitigating N2O under various land use conditions, we collected ten pairs of soils from tea plantations and adjacent cultivated land for laboratory incubation. As a complementary study, we conducted a meta-analysis based on 261 pairs of observations from 40 incubation studies to investigate the determinants of soil N2O mitigation by DMPP and to validate our experimental results. Results of the incubation experiment showed that DMPP was significantly less effective in mitigating N2O in tea plantation soils (73%) than in cropland soils (82%). Soil pH is a key factor influencing DMPP efficiency under different land use conditions. The lower pH of acidic tea plantation soils resulted in lower abundance and activity of ammonia-oxidizing bacteria (AOB). Under these low pH conditions, heterotrophic nitrification became an important source of N2O emissions in acidic tea plantation soils. As DMPP primarily inhibits AOB, it was less effective against heterotrophic nitrification, which likely contributed to its reduced efficacy in tea plantation soils compared to cropland soils. Our meta-analysis further confirmed the critical role of soil pH in determining DMPP effectiveness. The effect of soil pH on DMPP efficacy was mainly attributed to its regulation of heterotrophic and AOB-derived nitrification. These findings suggest that the field efficacy of DMPP in N2O abatement in tea plantations requires further investigation. Given the significant contribution of heterotrophic nitrification to N2O emissions in strongly acidic tea plantation soils, alternative N2O mitigation strategies should be explored.

中文翻译：

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不同土地利用下 DMPP 缓解一氧化二氮的土壤 pH 依赖性功效


一氧化二氮 （N2O） 的排放途径和强度因土地用途而异，缓解措施的效果也可能不同。为了研究影响硝化抑制剂 3,4-二甲基吡唑磷酸酯 （DMPP） 在不同土地利用条件下减轻 N2O 有效性的关键因素，我们从茶园和邻近的耕地收集了 10 对土壤进行实验室孵化。作为一项补充研究，我们根据 261 项孵化研究的 40 对观察结果进行了一项荟萃分析，以调查 DMPP 缓解土壤 N2O 的决定因素并验证我们的实验结果。孵化实验结果表明，DMPP 在减轻茶园土壤 （73%） 中的 N2O 效果明显低于农田土壤 （82%）。在不同土地利用条件下，土壤 pH 值是影响 DMPP 效率的关键因素。酸性茶园土壤的较低 pH 值导致氨氧化菌 （AOB） 的丰度和活性较低。在这些低 pH 条件下，异养硝化成为酸性茶园土壤中 N2O 排放的重要来源。由于 DMPP 主要抑制 AOB，因此它对异养硝化作用的效果较差，这可能导致与农田土壤相比，它在茶园土壤中的功效降低。我们的荟萃分析进一步证实了土壤 pH 值在决定 DMPP 有效性方面的关键作用。土壤 pH 值对 DMPP 功效的影响主要归因于其对异养和 AOB 衍生硝化作用的调节。这些发现表明，DMPP 在茶园 N2O 减排中的田间功效需要进一步研究。 鉴于异养硝化作用对强酸性茶园土壤中 N2O 排放的重大贡献，应探索替代的 N2O 缓解策略。