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Studies of the impact of nitrification inhibitors (NIs), specifically DMPP and DMPSA, on N2O emissions during hot moments have produced conflicting results regarding their effectiveness after rewetting. This study aimed to clarify the effectiveness of NIs in reducing N2O emissions by assessing residual DMP concentration and its influence on ammonia-oxidizing bacteria (AOB) in two pot experiments using calcareous (Soil C, Calcic Haploxerept) and acidic soils (Soil A, Dystric Xerochrepts). Fertilizer treatments included urea (U), DMPP, and DMPSA. The experiments were divided into Phase I (water application to dry period, 44 days) and Phase II (rewetting from days 101 to 121). In both phases for Soil C, total N2O emissions were reduced by 88% and 90% for DMPP and DMPSA, respectively, compared with U alone. While in Phase I, the efficacy of NIs was linked to the regulation of AOB populations, in Phase II this group was not affected by NIs, suggesting that nitrification may not be the predominant process after rewetting. In Soil A, higher concentrations of DMP from DMPP were maintained compared to Soil C at the end of each phase. Despite this, NIs had no significant effect due to low nitrification rates and limited amoA gene abundance, indicating unfavorable conditions for nitrifiers. The study highlights the need to optimize NIs to reduce N2O emissions and improve nitrogen efficiency, while understanding their interactions with the soil. This knowledge is necessary in order to design fertilization strategies that improve the sustainability of agriculture under climate change.

期刊论文 2024-11-01 DOI: 10.3390/agronomy14112620

Glaciers retreating due to global warming create important new habitats, particularly suitable for studying ecosystem development where nitrogen is a limiting factor. Nitrogen availability mainly results from microbial decomposition and transformation processes, including nitrification. AOA and AOB perform the first and rate-limiting step of nitrification. Investigating the abundance and diversity of AOA and AOB is essential for understanding early ecosystem development. The dynamics of AOA and AOB community structure along a soil chronosequence in Tianshan No. 1 Glacier foreland were analyzed using qPCR and clone library methods. The results consistently showed low quantities of both AOA and AOB throughout the chronosequence. Initially, the copy numbers of AOB were higher than those of AOA, but they decreased in later stages. The AOB community was dominated by Nitrosospira cluster ME, while the AOA community was dominated by the soil and sediment 1. Both communities were potentially connected to supra- and subglacial microbial communities during early stages. Correlation analysis revealed a significant positive correlation between the ratios of AOA and AOB with soil ammonium and total nitrogen levels. These results suggest that variations in abundance and diversity of AOA and AOB along the chronosequences were influenced by ammonium availability during glacier retreat.

期刊论文 2022-12-01 DOI: http://dx.doi.org/10.3390/microorganisms11122871

Accompanying the seasonal soil freeze-thaw cycle, microbial decomposition of litter exhibited different dynamic response to various snow thicknesses. In this study, we used real-time qPCR to investigate the abundance of bacteria, archaea, ammonia-oxidizing archaea (AOA) and bacteria (AOB), and the amoA gene transcripts, during the decomposition of dwarf bamboo (Fargesia nitida) litter under different snow patches at various snow-cover stages in an alpine forest on the eastern Tibetan Plateau in China. The effects of snow thickness were significant, with thicker snow patches resulting in higher microbial abundance and the amoA gene transcripts, while the degree of the effects were different. Compared with AOB, AOA were more abundant on the majority of sampling dates during the freeze-thaw period, and as well as their amoA gene transcripts. AOA are more persistent and abundant than AOB, and the higher AOA/AOB ratios were observed clearly in shrub litter and continued to decrease as the snow thickness increased, meanwhile gradually increased under uniform snow thickness over time. Our results suggested that the reduced seasonal snow cover and shortened freeze-thaw cycle periods caused by winter warming would significantly affect the ammonia oxidizers particularly tied to the ammonia oxidation process, and then could contribute to N cycle as related to litter in alpine forest ecosystems.

期刊论文 2016-07-01 DOI: 10.1134/S106741361604010X ISSN: 1067-4136
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