长期施肥土壤微生物群落的剖面变化及其与土壤性质的关系

Effect of long-term fertilizing regime on soil microbial diversity and soil property

摘要:

摘要:【目的】认识不同施肥模式对土壤微生物群落的长期影响及其与土壤理化属性的联系。【方法】利用新一代高通量测序技术，研究绿洲农田20年单施化肥(N 300 kg/hm2、P2O5 150 kg/hm2与K2O 60 kg/hm2)与化肥配施秸秆(同量的N与P肥配施5.4 t秸秆)对土壤剖面(0－300 cm)微生物群落结构的影响。【结果】放线菌与α-变形菌为土壤表层(0－20 cm)的优势类群。随土壤剖面深度的增加，放线菌相对丰度减少，而变形菌，特别是γ-变形菌与β-变形菌相对丰度增加，逐渐成为深层(20－300 cm)土壤中的优势类群。长期施肥对整个土壤剖面的微生物群落结构均有显著影响，并且明显提高了0－40 cm土层中氨氧化古菌的相对丰度。此外，农田管理模式如灌溉可能是氨氧化细菌在土壤垂直剖面的重要驱动因素。统计分析表明土壤全氮含量对表层土壤中微生物群落结构的影响最大，而有机碳含量则是影响深层土壤微生物群落的最重要因子。【结论】长期施肥改变了土壤剖面碳源与氮源的可利用量，导致了施肥处理间土壤微生物群落结构的差异，特别在剖面深层更为明显。

Abstract:

Abstract:［Objective］To evaluate the effect of long-term fertilization on soil microbial community and soil chemical and physical properties． ［Methods］Using a high-throughput pyrosequencing technique，we studied microbial community in the 0－300 cm soil samples covering a 20-year field-experiment with different fertilization applications including inorganic fertilizer alone (N 300 kg/ hm2，P2O5 150 kg/hm2 and K2O 60 kg/hm2) and inorganic fertilizer combined with straw (same application rate of N and P fertilizer combined with 5. 4 t straw)．［Results］Actinobacteria and α-proteobacteria were the predominant groups in the topsoil (0－20cm)．As the soil depth increased，the relative abundance of actinobacteria decreased whereas that of proteobacteria，especially γ-proteobacteria and β-proteobacteria increased and gradually became the dominant groups in the subsoil (20－300 cm)．Long-term fertilizing applications significantly affected soil microbial communities throughout the soil profile，and increased the relative abundance of ammonia-oxidizing archaea at 0－40 cm depth．In addition，agriculture management，e． g．irrigation may be an important driving factor for the distribution of ammonia-oxidizing bacteria in soil profile． Total nitrogen and organic carbon contents were the most influential factors on microbial community in the topsoil and in the subsoil，respectively．［Conclusion］ Long-term fertilizer applications altered soil nutrient availability within the soil profile，which was likely to result in the different microbial community structure between the fertilizer treatments，especially for the subsoil．