摘要
为探讨有机-无机肥配施对小麦-玉米轮作土壤细菌氮循环功能基因的影响,设置单施化肥(NPK)、化肥配施玉米秸秆(NPKS)和化肥配施有机肥(NPKO)3种施肥方式,采用16S rRNA基因的高通量测序技术并结合PICRUSt功能预测分析,探明不同施肥方式下小麦和玉米土壤细菌关键氮循环功能基因的变化特征。结果表明:对于KEGG的二级功能分类,NPKS处理下小麦土壤细菌排泄系统的相对丰度较NPK处理显著提高8.73%,而NPKO处理显著降低了辅酶和维生素代谢的相对丰度,降低幅度达到0.90%;NPKS、NPKO与NPK处理间玉米土壤细菌功能相对丰度差异均不显著。有机-无机肥配施下小麦土壤细菌中具有显著差异的三级功能分类数量明显多于玉米土壤细菌。与NPK处理相比,NPKS处理显著降低了小麦土壤细菌的氨基酸糖与核苷酸糖代谢,丙氨酸、天冬氨酸和谷氨酸代谢,硫胺素代谢,脂多糖生物合成,核黄素代谢和长寿调节途径的相对丰度和玉米土壤细菌Glioma和神经营养素信号通路的相对丰度,但显著提高了玉米土壤细菌突触囊泡循环的相对丰度;NPKO处理显著降低了小麦土壤细菌Cell cycle-Caulobacter、硫胺素代谢和核黄素代谢的相对丰度及玉米季甲烷代谢的相对丰度,但显著提高了小麦土壤细菌碱基切除修复的相对丰度。小麦和玉米土壤细菌均有23个功能基因参与氮循环的KO通路。小麦土壤细菌氮循环功能基因丰度与土壤SOM和TN显著正相关,与土壤NH+4-N显著负相关;玉米土壤细菌氮循环功能基因丰度与土壤TN和TP显著正相关。综上所述,小麦和玉米土壤细菌具有功能上的多样性,有机-无机肥配施下小麦土壤细菌发挥的代谢作用更为强烈。小麦和玉米土壤细菌的氮异化还原和氮同化还原潜力最高,反硝化潜力和固氮潜力次之,硝化潜力最弱。土壤细菌氮循环功能基因受轮作体系影响,SOM和TN促进小麦土壤细菌氮循环过程,而NH4^+-N对氮循环过程产生负面影响;TN和TP在玉米土壤细菌氮循环过程中发挥积极作用。
A field experiment was conducted in a wheat-maize rotation field to investigate the effects of combined organic and inorganic fertilizers on the functional genes involved in soil bacterial nitrogen cycling.Three fertilizer combinations were investigated,including single chemical fertilizer(NPK),chemical fertilizer with maize straw(NPKS),and chemical fertilizer with organic fertilizer(NPKO).The characteristics of the nitrogen cycling functional genes were explored using high-throughput sequencing of the bacterial 16S rRNA gene,followed by PICRUSt functional prediction analysis.Our results showed that,at the level 2 of Kyoto Encyclopedia of Genes and Genomes(KEGG)functional classification,the relative abundance of the wheat soil bacterial excretion system was significantly higher with the NPKS treatment compared to NPK(+8.73%),and the relative abundance of the metabolic cofactors and vitamins significantly decreased with the NPKO treatment(-0.90%).There were no significant differences in the maize soil bacterial functional abundances among treatments.When the organic and inorganic fertilizers were simultaneously applied,the number of level 3 bacterial functions with pronounced differences were significantly higher in wheat soil than in maize soil.Compared to the NPK treatment,the NPKS treatment significantly reduced the relative abundances of the wheat soil bacterial amino sugar and nucleotide sugar metabolism,alanine,aspartate and glutamate metabolism,thiamine metabolism,lipopolysaccharide biosynthesis,riboflavin metabolism and longevity regulating pathwayworm.In maize soil,the relative abundances of the bacterial glioma and neurotrophin signaling pathways were significantly reduced,and the relative abundance of the bacterial synaptic vesicle cycle significantly increased.The NPKO treatment significantly reduced the relative abundances of the wheat soil bacterial cell cycle-Caulobacter,thiamine metabolism and riboflavin metabolism,but significantly improved the relative abundance of the base excision repair.The relative abundance of the maize soil bacteria methane metabolism was also significantly reduced with the NPKO treatment.Twenty-three types of functional genes within the bacterial nitrogen cycling KEGG Orthology(KO)pathway were identified in the wheat and maize soils.The bacterial nitrogen cycling functional gene abundances in wheat soil were significantly positively correlated with the soil organic matter(SOM)and total nitrogen(TN),and significantly negatively correlated with the ammonium-nitrogen(NH+4-N)content.The functional gene abundances in maize soil had a significant positive correlation with TN and total phosphorus(TP).The bacteria in wheat and maize soils were functionally diverse,and the wheat soil bacterial metabolism was high when combined application organic and inorganic fertilizers was undertook.For both crops,the soil bacterial nitrogen dissimilation reduction and the nitrogen assimilation reduction potentials were high,the denitrification and nitrogen fixation potentials were less prominent,and the nitrification potential was low.The crop rotation system had a significant influence on the functional genes involved in soil bacterial nitrogen cycling.In wheat soil,SOM and TN promoted bacterial nitrogen cycling,but NH4^+-N had the opposite effect.In maize soil,TN and TP actively influenced bacterial nitrogen cycling.
作者
胡菏
吴宪
赵建宁
杨殿林
王丽丽
李刚
修伟明
HU He;WU Xian;ZHAO Jian-ning;YANG Dian-lin;WANG Li-li;LI Gang;XIU Wei-ming(Key Laboratory of Original Agro-environment Pollution Prevention and Control of Ministry of Agriculture and Rural Affairs,Tianjin Key Laboratory of Agro-environment and Agro-product Safety,Agro-Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2021年第1期144-154,共11页
Journal of Agro-Environment Science
基金
公益性行业(农业)科研专项(201503121-04)
中国农业科学院科技创新工程项目
国家重点研发计划项目(2016YFD0201009)。
关键词
有机-无机肥配施
氮循环
功能基因
小麦-玉米轮作
PICRUSt功能预测
combined organic and inorganic fertilizers
nitrogen cycling
functional genes
wheat-maize rotation
PICRUSt functional prediction
