State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; China-Australia Research Laboratory on Environmental Biogeochemistry, Huazhong Agricultural University, China.
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; China-Australia Research Laboratory on Environmental Biogeochemistry, Huazhong Agricultural University, China.
Sci Total Environ. 2020 May 10;716:137103. doi: 10.1016/j.scitotenv.2020.137103. Epub 2020 Feb 3.
Ureolytic microorganisms play a crucial role in soil nitrogen transformation. Soil aggregates and associated microbes are reported to modify the impact of agricultural management on soil nutrient cycling. However, the responses of ureolytic microbial communities in various soil aggregates to long-term fertilization regimes are still unclear in acid soils. In this study, we characterized the ureolytic microflora as well as urease activity in three soil aggregate fractions (2-0.25, 0.25-0.053, <0.053 mm) from an Ultisol with 26-year fertilization experiment. The results showed that long-term chemical fertilization (NPK) significantly decreased the abundance, richness and activity of ureolytic microbial community across soil aggregates (P < .05) due to strong soil acidification. While manure application (M and MNPK) could mitigate these negative impacts and markedly (P < .05) improved the abundance, α-diversity and activity of soil ureolytic microflora. Long-term fertilization regimes also drove the differentiation of ureolytic microbial compositions in soil aggregates (Adonis, F = 17.4, P = .001, R = 33.6%), and manure application appeared to be the most important driver. This variation partly contributed to the aberrance of soil urease activity (structure equation model, path coefficient: 0.45, P = .008). No significant differences were found for ureolytic microbial community among soil aggregates, which was in accordance with the distribution patterns of soil nutrients, indicating the dominant role of resources availability in determining ureolytic microbiota in micro-environment. The ureolytic microbial community among different soil aggregates responded uniformly to long-term fertilizations. Our study revealed that manure application was a sustainable fertilization regime to alleviate the loss of soil ureolytic microbial diversity and activity in acid soils.
脲分解微生物在土壤氮转化中起着至关重要的作用。据报道，土壤团聚体及其相关微生物可以改变农业管理对土壤养分循环的影响。然而，在酸性土壤中，长期施肥对不同土壤团聚体中脲分解微生物群落的响应仍不清楚。本研究在一个 26 年施肥试验的风化土中，对三个土壤团聚体（2-0.25、0.25-0.053 和<0.053mm）的脲分解微生物菌群和脲酶活性进行了特征描述。结果表明，长期的化学施肥（NPK）由于强烈的土壤酸化，显著降低了土壤团聚体中脲分解微生物群落的丰度、丰富度和活性（P<0.05）。而施用有机肥（M 和 MNPK）可以减轻这些负面影响，并显著（P<0.05）提高土壤脲分解微生物的丰度、α多样性和活性。长期施肥还导致土壤团聚体中脲分解微生物组成的分化（Adonis，F=17.4，P=0.001，R=33.6%），而有机肥的施用似乎是最重要的驱动因素。这种变化部分导致了土壤脲酶活性的异常（结构方程模型，路径系数：0.45，P=0.008）。土壤团聚体之间的脲分解微生物群落没有发现显著差异，这与土壤养分的分布模式一致，表明资源可用性在决定微环境中的脲分解微生物群方面起着主导作用。不同土壤团聚体之间的脲分解微生物群落对长期施肥的响应是一致的。本研究表明，施用有机肥是一种可持续的施肥制度，可以减轻酸性土壤中土壤脲分解微生物多样性和活性的丧失。
