| The total area of acidic soil in China is up to2x 108 hm2, accounts for about 23% of the national soil area, more than half of the soil use for agriculture or has potential value of agriculture. As human demand for efficiency of land use and agricultural economic benefits is increasing, agricultural production going with large amounts of fertilizer inputs, but the utilization rate of nitrogen fertilizer for economic crops is generally lower than 40%, high nitrogen input result in soil nitrogen cycle imbalances, aggravating soil acidification and reducing the agricultural economic benefits. Nitrification is an important process of soil nitrogen cycle which driven by nitrifying microorganism,ammonia oxidation process is the limiting step of nitrification. However, the influence of ammonia oxidation under acid condition in soil nitrification is disputed, the intensity of soil nitrification and the ammonia oxidation microorganism are affected by comprehensive regulation of multiple environmental factors, the seasonal evolution of long-term fertilization acidic soil nitrification and its functional microorganism are not yet clear,in addition,the soil microbial community diversity of long-term use of inorganic fertilizer and organic fertilizer in acid upland are also different.The studied soil were collected from long-term fertilization experimental plots of Jiangxi Institute of Red Soil in China which was established 30 years ago. We chose three fertilizing treatments,(1)CK treatment (without fertilization),(2)NPK treatment (amended with mineral NPK fertilization),(3)OM treatment (amended with organic manure),established soil microcosms incubation in laboratory and analysis of oringin soil experiments.Microcosms incubation with nitrification inhibitors, molecular ecology techniques including denaturing gradient gel electrophoresis and Illumina MiSeq high-throughput sequencing,and bioinformatics analysis were carried out to investigate the active microbial groups in soil nitrification.We explored the feature of autotrophic nitrification microbial community and the relationship between them and soil characteristics, analysed the seasonal evolution features of nitrifying activity in long-term fertilization acidic upland soil and the relative contribution to ammonia oxidation process of ammonia oxidation archaea (Ammonia -oxidizing archaea, AOA) and bacteria (Ammonia - oxidizing bacteria, AOB) under the different temperature condition,discussed the total microbial communities diversity change which resault from long-term inorganic fertilizer and organic fertilizer and compared both similarities and differences, analysed the main environmental factors which affecting the change of communities.The result shows that fertilization had a significant effect on soil characteristics, The autotrophic nitrification dominated the soil nitrification, and accounted for 73.60-85.32%.Fertilization significantly increased soil autotrophic nitrification activity and the highest value was observed in OM soil. During the microcosm incubation, the absolute abundances of amoA genes and the relative abundances of 16S rRNA genes of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in OM soil significantly increased. The relative abundances of 16S rRNA genes of AOA greatly increased in both CK and NPK soils. These results suggested the remarkable activity of AOA in three soils (the predominant population was Nitrososphaera, > 99.30%), and also found that AOB was active in OM soil (the predominant population was Nitrosospira, > 99.99%). We also found the activity of nitrite-oxidizing bacteria (NOB) in OM soil, and the predominant population was Nitrospira(>96.69%). Stepwise regression analysis demonstrated that soil autotrophic nitrification activity was significantly affected by soil total nitrogen content, while the abundances of archaeal and bacterial amoA genes were significantly affected by soil organic carbon content and soil pH, respectively. We also found a significant positive correlation between the relative abundance of Nitrososphaera and soil nitrate content, and a negative correlation between the relative abundance of Nitrosospira and Nitrospira with soil C/N. Soil nitrifying activity increased in 4 ??28? and decreased in 28 ?-35 ? while temperature rising. The autotrophic nitrification contributed by AOB peaked at 28 ??18 ? and 18 ? respectively in CK,NPK and OM soils, as well the autotrophic nitrification contributed by AOA peaked at 35 ? in the three soils. With the increase of temperature, the contribution of AOA to autotrophic nitrification was gradually increased and dominated, and the inorganic fertilizer and organic fertilizer did not change the response of soil AOA to temperature, but the temperature of highest activity of AOB was significantly decreased. The inhibitory effect of C8H14 was positively correlated with the concentration,the best concentration of C8H14 in this study is 0.5% for distinguishing the relative contribution of AOA and AOB to nitrification in CKand NPK soils. These results suggested that long-term manure fertilization rather than chemical fertilization strongly changed red soil prokaryotic community composition and diversity. The aggregated boosted tree analysis found that the soil pH was the most important environmental factor influencing the prokaryotic communities. In addition, long-term organic manure rather than mineral fertilization also significant altered the relative proportion of predicted functional genes encoding enzymes of the metabolic pathways such as metabolism and genetic information processing. Our results provide field-based evidence that long-term fertilization with organic manure rather mineral fertilizer significantly changed acidic red soil prokaryotic community composition and diversity,which was crucial duo to the neutralization of soil acidity.The research on the evolution of the long-term fertilization acidic upland soil nitrification and microbial community, not only provided experimental data for understanding the nitrifying microbial community and diversity, but also provided a reference for acid soil fertilization management. |
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