不同施肥措施对华北潮土区玉米田土壤微生物碳源代谢多样性的影响

探讨长期不同施肥措施下华北潮土区玉米田土壤微生物碳源代谢多样性特征，为华北地区可持续性施肥管理提供理论依据和数据支持。以农业农村部环境保护科研监测所建立的武清长期定位试验站为平台，采用Biolog生态板技术，研究6种不同施肥处理[不施肥对照（A0）、单施有机肥（A1）、氮肥减量配施有机肥（A2）、常量化肥配施有机肥（A3）、氮肥增量配施有机肥（A4）和单施化肥（A5）]对华北潮土区土壤微生物碳源代谢多样性的影响。结果表明，与不施肥对照相比，A1、A2、A3、A4和A5处理显著提高了土壤全氮和硝态氮含量，显著降低了土壤碳氮比和pH；施用有机肥处理（A1、A2、A3和A4）显著增加了有机碳和微生物量氮含量。培养96 h时，反映土壤微生物活性的平均颜色变化率（AWCD）变化顺序为： A2 > A3 > A4 > A5 >A1 > A0。A2的土壤微生物Shannon指数H显著高于其他施肥处理。主成分分析表明，不同施肥处理显著影响土壤微生物的碳源利用特征，A2和A3集中在第1主成分正方向，得分系数在1.125~1.473，土壤微生物碳源利用特征相似；A0、A1、A4和A5位于第1主成分负方向，得分系数在-1.157~-0.167。土壤微生物利用的碳源主要为碳水类、羧酸类、氨基酸和聚合物类。相关分析表明，土壤碳氮比、铵态氮、硝态氮、pH和微生物量氮是影响土壤微生物碳源代谢多样性的主要因素。氮肥减量配施有机肥有利于提高土壤微生物代谢活性和碳源代谢多样性。

Effects of fertilization regimes on the metabolic diversity of microbial carbon sources in a maize field of fluvoaquic soil in North China

To reveal the effects of long-term fertilization regimes on the metabolic diversity of the soil microbial community of a maize field in North China in order to provide a theoretical basis and data support for sustainable fertilization management in North China. This study was conducted in the Wuqing Experimental Station of the Agro-Environmental Protection Institute of the Ministry of Agriculture and Rural Affairs. The field experiment included six treatments, no fertilizer(A0), organic fertilizer(A1), reduced nitrogen fertilizer plus organic fertilizer(A2), normal chemical fertilizer plus organic fertilizer(A3), increased nitrogen fertilizer plus organic fertilizer(A4), and chemical fertilizer(A5). Soil samples were separately collected from the 0~20 cm soil layer. A Biolog EcoPlate was applied to test the changes in the soil microbial diversity under different fertilization treatments. The results showed that compared with the A0 treatment, the A1, A2, A3, A4, and A5 treatments significantly increased the contents of total nitrogen and nitrate nitrogen and significantly decreased the soil carbon/nitrogen ratio and pH. The application of organic fertilizer treatments(A1, A2, A3, and A4)significantly increased the organic carbon and microbial biomass nitrogen content. The average well color development values of the soil microbial communities in culture for 96 h were as follows:A2 > A3 > A4 > A5 > A1 > A0. The Shannon index of the A2 treatment was significantly higher than that of the other fertilization treatments. The results of the principal component analysis showed that there were significant differences in the microbial utilization of carbon in the different fertilization treatments. The A2 and A3 treatments were concentrated in the positive direction of the first principal component with score coefficients ranging from 1.125 to 1.473, and had similar carbon utilization. Conversely, the A0, A1, A4, and A5 treatments were concentrated in the negative direction of the first principal component, and the score coefficients ranged from -1.157 to -0.167. The carbon sources mostly used by soil microbes were carbohydrates, carboxylic acids, amino acids, and polymers. The correlation analysis showed that the soil carbon/nitrogen ratio, ammonium nitrogen, nitrate nitrogen, pH, and microbial biomass nitrogen were the main factors affecting the metabolic diversity of the soil microbial carbon sources. The A2 treatment improved the activity and functional diversity of the soil microbial community.