不同施肥处理对高粱根际土壤微生物功能多样性的影响

Effect of Different Fertilization Treatments on Soil Microbial Function Diversity in Rhizosphere of Sorghum

根际土壤微生物在调控土壤根际环境和养分转化中发挥着重要的作用。高粱已被广泛用作饲料且耐瘠薄性较强,探明根际微生物对不同养分的生态响应,可为不同土壤养分条件下高粱的养分管理提供理论依据。以高粱/玉米轮作的长期定位大田试验为基础,结合人工温室的盆栽试验,采用BIOLOG微平板法研究了NPK、PK、NK、NP、CK(无肥处理) 5种长期不同施肥条件对高粱根际土壤微生物功能多样性的影响。结果表明,大田试验与盆栽试验的结果一致,PK处理提高了根际微生物的代谢活性,提高了微生物对氨基酸类、羧酸类、胺类、糖类和聚合物的利用,降低了对双亲化合物的利用,其多样性指数、丰富度指数和Simpson(优势度指数)均高于其他处理; NK和NP处理对根际微生物功能多样性的影响不显著,但NK处理降低了培养后期根际微生物代谢活性; CK处理显著降低了根际微生物对碳源的利用能力,其多样性指数、丰富度指数和优势度指数均低于其他处理,均匀度指数高于其他处理。主成分分析表明,大田试验中,NPK和NP处理根际土壤微生物碳源利用能力和类型差异不显著,其余处理间差异显著;盆栽试验中施氮处理NPK、NK和NP利用碳源能力和类型差异不显著,其余处理间差异显著。综上所述,施肥有利于改善土壤微生物特性。高粱根际微生物对氮、磷、钾胁迫的响应不同,氮胁迫时,微生物活性的增强可能是高粱耐氮的原因。

Rhizosphere soil microorganisms play an important role in the regulation of soil rhizosphere environment and nutrient transformation.Sorghum has been widely used as forage and strong barren tolerance.Study of rhizosphere microorganisms on the ecological response of different nutrients,which can provide the theoretical basis for nutrient management of different soil nutrients under conditions of sorghum.This paper was based on the long-term field test of sorghum/corn rotation,combined with the pot experiment of artificial greenhouse.BIOLOG micro plate was applied to test the effect of NPK,PK,NK,NP fertilizers and CK(without fertilization)on sorghum rhizosphere soil microbial functional diversity.The results showed that the field test was in agreement with the pot experiment.PK treatment increased the metabolic activity of rhizosphere microorganisms,and improved the utilization of amino acids,carboxylic acids,amines,sugars and polymers,and reduced the utilization of amphiphilic compounds.The Shannon-Wiener index(H),Richness index(S)and Simpson index(Ds)were higher than other treatments.The effects of NK and NP on the functional diversity of rhizosphere microorganisms were not significant,but NK treatment reduced the microbial metabolic activity in the rhizosphere of the late culture.CK treatment significantly decreased the rhizosphere microbial utilization of carbon sources,the Shannon-Wiener index(H),Richness index(S)and Simpson index(Ds)were lower than other treatments,Substrate evenness(E)higher than other treatments.Principal component analysis showed that there was no significant difference in rhizosphere soil microbial carbon source utilization capacity and type between NPK and NP treatments,and the rest treatments showed significant difference in the field test.In pot experiment,the difference of carbon source ability and type of NPK,NK and NP treatment was not significant,and the difference between the other treatments was significant.In summary,fertilization was conducive to improving soil microbial characteristics.The responses of sorghum rhizosphere microorganisms to nitrogen,phosphorus and potassium stress were different.When nitrogen stress was applied,the increase of soil microbial activities in sorghum rhizosphere was probably the cause of nitrogen tolerance in sorghum.