土壤含水量和氮素水平是调控氨氧化微生物和硝化速率的重要因素。本研究以旱地红壤为对象，设置3个土壤含水量(40％WFPS、60％WFPS、80％WFPS，WFPS为土壤孔隙含水量)×4个氮添加水平(0、25、50和100 mg N·kg-1)，进行微宇宙培养试验，研究含水量和氮添加对土壤净硝化速率和氨氧化微生物功能基因丰度的影响。结果表明:土壤净硝化速率随土壤含水量和氮添加量的增加而增加。土壤含水量增加显著提高AOA和AOB amoA基因丰度，但降低完全氨氧化菌clade A amoA基因丰度，表明土壤含水量增加不利于完全氨氧化菌clade A生长。氮添加显著提高AOA和AOB amoA基因丰度，但对完全氨氧化菌clade A amoA基因丰度无显著影响。综上，土壤含水量增加不利于旱地农田红壤完全氨氧化菌生长，但氮添加对其丰度影响不显著。
Effects of soil water content and nitrogen addition on the abundance of functional genes of ammonia-oxidi-zing microorganisms in an Ultisol
Soil water content and nitrogen availability are important factors regulating nitrification rate and ammo-nia-oxidizing microorganisms.In this study,a microcosm experiment with three soil water content levels(40％WFPS,60％WFPS,80％WFPS;WFPS,water filled pore space)x four nitrogen addition levels(0,25,50 and 100 mg N·kg-1),was carried out using Ultisol to study the effects of soil water content and nitrogen addition on net nitrification rate and the abundance of functional gene(amoA)of ammonia-oxidizing microorganisms.Results showed that soil net nitrification rate increased with increasing soil water content and nitrogen addition levels.Increasing soil water content significantly increased the abundance of AOA and AOB amoA genes,but decreased the abundance of comammox Nitrospira clade A amoA gene,indicating that increasing soil water content suppressed the growth of comammox Nitrospira clade A.In contrast,nitrogen addition significantly increased the abundance of AOA and AOB,while did not affect the abundance of comammox Nitrospira clade A.Taken together,increasing soil water content was detrimental to the growth of comammox Nitrospira in upland agricultural Ultisol,while nitro-gen addition did not influence the abundance of comammox Nitrospira.
万方数据
维普
