烟沫有机肥部分替代化肥对玉米生长和根系分泌物及土壤微生物群落结构的影响

Effect of Partial Substitution of Chemical Fertilizer with Tobacco Foam Organic Fertilizer on Corn Growth,Microbial Community Structure and Root Exudates

【目的】通过研究施用不同比例烟沫有机肥替代化肥对玉米生长和根系分泌物及土壤微生物群落结构的影响,旨在减少化肥用量,为烟沫废弃物合理农用提供科学依据。【方法】以富甜糯2号玉米为研究对象,通过盆栽试验,采用田间土壤耕层(0~20 cm)黄棕壤作为供试土壤,设计6个处理(CK,100%无机肥;T1,80%无机肥+20%烟沫有机肥;T2,60%无机肥+40%烟沫有机肥;T3,40%无机肥+60%烟沫有机肥;T4,20%无机肥+80%烟沫有机肥;T5,100%烟沫有机肥),探究烟沫有机肥不同比例替代化肥中的氮素,对玉米生物量、土壤微生物、根系有机酸分泌物的影响及其相互作用。【结果】与CK处理比较,T1处理地上、下部鲜重增效最明显,且土壤中硝化细菌数量提高显著(增幅为22.84%);T2处理株高和穗位数数值最大,且土壤中氨化细菌数量提升最显著(72.70%)。不同比例烟沫有机肥替代化肥处理中,变形菌门(Proteobacteria)、拟杆菌门(Bacteroidota)相对丰度均增加,绿弯菌门(Chloroflexi)相对丰度降低。其中,T1处理放线菌门(Actinobacteriota)、厚壁菌门(Firmicutes)相对丰度增加显著。烟沫有机肥不同比例替代化肥,根系有机酸分泌总量有一定程度提高,且T1处理有机酸总量改变最显著,增加17.82%。液相色谱(HPLC)分析发现,T1和T2处理中,酒石酸、苹果酸、丁二酸、草酸分泌量分别增加,乙酸,柠檬酸分泌量较低。将根系有机酸分泌物与门水平前10种细菌群落进行相关性分析发现,放线菌门(Actinobacteriota)与丁二酸呈极显著正相关;芽单胞菌门(Gemmatimonadota)与乙酸呈显著负相关;髌骨细菌门(Patescibacteria)与柠檬酸呈显著正相关,与苹果酸呈极显著负相关。冗余分析发现,丁二酸、酒石酸、苹果酸与放线菌门(Actinobacteriota)、芽单胞菌门(Gemmatimonadota)及土壤全氮、铵态氮、穗位高、氨化细菌、地上部鲜重、地上部干重成显著正相关,【结论】20%~40%烟沫有机肥替代化肥可显著改变土壤微生物结构和玉米根系有机酸分泌含量,从而促进玉米的生长。

[Objective]The aims were to study the effects of the application of tobacco and foam waste on corn growth,root secretion and soil microbial community structure,in order to reduce the amount of chemical fertilizer in agriculture.[Method]Futiannuo No.2 corn was taken as the research object,The yellow-brown soil(0-20 cm)in the topsoil layer was used as the test soil,the treatments included:CK(100%inorganic fertilizer),T1(80%inorganic fertilizer+20%tobacco and foam organic fertilizer),T2(60%inorganic fertilizer+40%tobacco and foam organic fertilizer),T3(40%inorganic fertilizer+60%tobacco and foam organic fertilizer),T4(20%inorganic fertilizer+80%tobacco and foam organic fertilizer),T5(100%tobacco and foam organic fertilizer).Soil microorganisms,root organic acid secretion and their interaction were explored through pot experiments.[Result]Compared with CK,the results showed that the above-ground and under-ground fresh weight efficiency in T1 treatment was the most obvious,and the number of nitrifying bacteria in the soil increased most significantly,with an increase of 22.84%.T2 treatment had the highest plant height and panicle height,and the number of ammonifying bacteria in soil was increased most significantly,with an increase of 72.70%.In the treatment of foam organic fertilizer with different proportions,the relative abundance of Proteobacteria and Bacteroidota increased,and the relative abundance of Chloroflexi decreased.Among them,the relative abundance of Actinobacteriota and Firmicutes increased strikingly.The total amount of organic acids secreted by roots increased to a certain extent,and the total amount of organic acids in T1 treatment significantly increased by 17.82%.High-Performance Liquid Chromatography(HPLC)analysis showed that the secretion of tartaric acid,malic acid,succinic acid,and oxalic acid increased respectively in T1 and T2 treatments compared with CK,acetic acid,and citric acid secretion was lower.The correlation analysis between the organic acid components secreted by roots and the top 10 bacterial communities at the phylum level showed that Actinobacteriota was significantly positively correlated with succinic acid.Gemmatimonadota was negatively correlated with acetic acid.Patescibacteria were significantly positively correlated with citric acid and negatively correlated with malic acid.The redundancy analysis showed that succinic acid,tartaric acid,and malic acid were significant positively correlated with Actinobacteriota,Gemmatimonadota,soil total nitrogen,ammonium nitrogen,panicle height,ammonifying bacteria,fresh weight of the above-ground part,and the dry weight of the above-ground part.[Conclusion]The results showed that 20%~40%organic fertilizer instead of chemical fertilizer can significantly increase the number of soil microorganisms and the content of organic acid secreted by corn roots,and promote the growth of corn.