| Summary: | Ureolytic microbes in soil produce urease to catalyze the hydrolysis of urea to NH<sub>3</sub>/NH<sub>4</sub><sup>+</sup>. Manure is widely applied in agriculture and has the potential to influence soil urease activity. In this study, we examined the responses of the ureolytic microbial community to manure application in two agricultural soils from north (N) and south (S) China using high-throughput sequencing of the <i>ureC</i> genes. We found that N soil and S soil harbored significantly distinct ureolytic communities, as no OTU was shared between two locations. The slight variation of the ureolytic community (32.2%, Adonis) was observed in N soil where low rates of manure were applied. However, dramatic alteration of the structure of ureolytic community (83.4%, Adonis) was found, possibly by promoting the growth of <i>Betaproteobacteria</i> and <i>Deltaproteobacteria</i> and the suppression of the growth of <i>Actinobacteria</i> in S soil where high rates of manure were inputted. The total C and C/N ratio were the main environmental factors driving the microbial communities. The relative ratios of <i>ureC</i> to <i>16S rRNA</i> genes ranged from 1.5 to 3.5% among the two soils. The abundance of <i>ureC</i> genes was significantly and positively correlated with total phosphorus (TP, <i>r</i> = 0.87, <i>p</i> < 0.001). Positive correlations between the urease activity and soil available NH<sub>4</sub><sup>+</sup> (<i>r</i> = 0.81, <i>p</i> = 0.001), TP (<i>r</i> = 0.84, <i>p</i> = 0.001), and the abundance of <i>ureC</i> (<i>r</i> = 0.87, <i>p</i> < 0.001) were observed in our study. We speculate that sufficient soil phosphorus promotes the growth of ureolytic microbes, which results in higher urease activity and the greater release of available NH<sub>4</sub><sup>+</sup>.
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