利用磷脂脂肪酸分析法和微平板测定法研究红壤荒地开垦为水田耕种20年后,不同施肥处理条件下土壤微生物群落结构和功能多样性变化,并分析土壤微生物学指标与土壤养分含量变化的关系。结果表明,与不施磷处理相比,施磷处理的水稻年产量、土壤有机碳、全氮、碱解氮、全磷和速效磷含量平均提高了196.6%、11.4%、19.4%、14.0%、100.6%和300.1%;而与未施有机肥处理相比,施有机肥处理上述各指标平均提高了85.4%、23.8%、25.0%、15.0%、38.6%和86.8%。与对照相比,施用磷肥和施用有机肥处理的微生物总磷脂脂肪酸(PLFA)含量提高了13.6%~68.9%。磷肥和有机肥的施用也提高了各菌群微生物的PLFA含量。不同施肥处理土壤微生物群落平均吸光度(AWCD)值、Shannon指数、Simpson指数和Mc Intosh指数分别为0.17~0.30、2.79~3.03、0.93~0.94和1.46~2.27。磷肥和有机肥的施用提高了微生物群落的AWCD值和功能多样性指数。主成分分析表明,施用磷肥和施用有机肥的处理微生物群落结构和碳源利用方式明显区别于对照、单施氮肥和施用氮钾肥的处理。逐步回归分析显示,有机碳、全磷、全氮和速效磷是影响土壤微生物群落结构和功能多样性的关键因素。磷肥和有机肥的施用有利于促进土壤微生物活性和多样性,提高土壤生物功能和生产力。
We investigated the influence of long-term fertilizations on microbial community struc- ture and functional diversity after 20 years of inorganic and organic fertilizer applications to a red paddy soil converted from an infertile wasteland, based on examining the phospholipid fatty acid (PLFA) profiles and community level physiological profiles (BIOLOG) of microorganisms. The relationship between microbial indicators and soil nutrient contents was also analyzed. After 20 years of cultivation, P fertilizer application increased total rice yield, soil organic C, total N, available N, total P and available P by 196.6%, 11.4%, 19.4%, 14.0%, 100.6% and 300.1% on average compared with P-omitted treatments, while organic manure application increased those by 85.4%, 23.8%, 25.0%, 15.0%, 38.6% and 86.8% on average compared with organic ma- nure-omitted treatments. Total microbial PLFA was 13.6%-68.9% higher in P fertilizer and or- ganic manure application treatments than in no fertilizer treatment. Phosphorus fertilizer and or- ganic manure application also increased PLFA of all microbial taxonomic groups. Average well color development (AWCD) values, Shannon index, Simpson index and McIntosh index of mi- crobial community under the different treatments was 0.17-0.30, 2.79-3.03, 0.93-0.94 and 1.46-2.27, respectively. The application of P fertilizer and organic manure increased AWCD val- ues and all microbial indices of microbial community. Principal component analysis showed that PLFA profiles and C source utilization patterns in treatments with P fertilizer and organic manure were clearly different from that in no fertilizer treatment, N treatment and NK treatment. Stepwise regression analysis revealed that soil organic C, total P, total N and available P significantly af- fected PLFA profiles and microbial functional diversity. The application of P fertilizer and organic manure could help promote soil microbial activity and diversity, and increase soil biological func- tion and productivity.