Urea Promotes Ammonia Oxidation in Acidic Soils by Increasing the Abun-dance of Nitrosospira
The purpose of this study is to provide scientific basis for formulating rational fertilization strategy by exploring the ammonia oxidation in acidic soil.The effects of urea on ammonia oxidation and microbial communi-ty in acidic soil were studied by soil microcosmic experiment,liquid culture and subculture.The results showed that the average nitrification rate of three acid soil urea groups was significantly higher than that of blank control group and ammonium nitrogen fertilizer group(P＜0.05).Urea application significantly increased amoA gene abun-dance of ammonia oxidizing bacteria(AOB)(P＜0.05).However,amoA gene abundance of ammonia oxidizing ar-chaea(AOA)was not found(P＜0.05),indicating that urea promoted ammonia oxidation in acid soils by increasing AOB abundance.The results of liquid culture showed that urea promoted the ammonia oxidation activity of differ-ent acidic soil suspensions,and this promotion effect was not related to the rise of pH during urea hydrolysis.The passage culture showed that the culture method with urea as the initial substrate under acidic conditions was bene-ficial to the reproduction of AOB,especially uncultured Nitrosospira.This study confirmed that urea promoted am-monia oxidation in acidic soil by increasing the abundance of Nitrosospira,which provided a scientific basis for formulating a reasonable nitrogen fertilizer application strategy.
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维普
