Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, 430074, China.
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
Environ Pollut. 2020 Oct;265(Pt B):115065. doi: 10.1016/j.envpol.2020.115065. Epub 2020 Jun 25.
Potassium (K) fertilizer plays an important role in increasing crop yield, quality, and nitrogen use efficiency. However, little is known about its environmental impacts, such as its effects on emissions of the greenhouse gas nitrous oxide (NO). A nitrogen-15 (N) tracer laboratory experiment was therefore performed in an acidic agricultural soil in the suburbs of Wuhan, central China, to determine the effects of K fertilizer on NO emissions and nitrification/denitrification product ratios under N fertilization. During 15-d incubation periods with a fixed initial N concentration (80 mg kg), K application increased average NO emission rates significantly (1.6-10.8-fold) compared to the control treatment. NO emissions derived from nitrification and denitrification both increased in K-treated soil, and denitrification contributed more to the increase; its contribution ratio rose from 32% without K fertilizer to 53% with 300 mg kg of K applied. The increase in NO emissions under K fertilization is probably due to an increase in the activity of denitrifying microorganisms and acid-resistant nitrifying microorganisms caused by higher K concentrations and lower soil pH. Combined treatment with potassium chloride (KCl) and N fertilizer produced lower NO emissions than combined treatment with potassium sulfate (KSO) and N fertilizer during 15-d incubation periods. Our results imply that there are significant interaction effects between N fertilizers and K fertilizers on NO emissions. In particular, combining N fertilizers with fertilizers that reduce soil acidity or contain Cl or K ions may significantly affect agricultural NO emissions.
钾（K）肥在提高作物产量、质量和氮素利用效率方面起着重要作用。然而，人们对其环境影响知之甚少，例如对温室气体氧化亚氮（NO）排放的影响。因此，在中国中部武汉市郊区的酸性农业土壤中进行了氮-15（N）示踪实验室实验，以确定在氮施肥条件下 K 肥对 NO 排放和硝化/反硝化产物比的影响。在固定初始 N 浓度（80mgkg）的 15d 孵育期间，与对照处理相比，K 肥的施用显著增加了平均 NO 排放速率（1.6-10.8 倍）。硝化和反硝化过程中产生的 NO 排放均增加，反硝化的贡献更大；其贡献率从无 K 肥时的 32%上升到施用 300mgkg K 时的 53%。K 肥处理下 NO 排放的增加可能是由于较高的 K 浓度和较低的土壤 pH 值导致反硝化微生物和耐酸硝化微生物活性增加所致。在 15d 的孵育期间，KCl 和 N 肥的联合处理比 KSO 和 N 肥的联合处理产生的 NO 排放更低。我们的研究结果表明，N 肥和 K 肥之间存在显著的相互作用效应，对 NO 排放有影响。特别是，将 N 肥与降低土壤酸度或含有 Cl 或 K 离子的肥料结合使用，可能会显著影响农业 NO 排放。
