| Biofertilizer is a new type of environment-friendly fertilizer that was made from p lant growth promoting rhizobacteria(PGPR).These beneficial microorganisms could not only provide plants with nutrition,reduce the occurrence of pests and diseases with plants,and increase yield,but also improve soil quality and prevent secondary soil pollution.At present,PGPR had become one of the research hotspots in biofertilizer.However,the different plants had different kind of plant growth promoting rhizobacteria,and its promotion effects had differences in different plants.Therefore,the resource library of PGPR strains needed to be further improved.The PGPR of Brassica oleracea,Brassica campestris,Capsicum annuum and Allium fistulosum were isolated and screened to enrich strains resource library and know the effect of PGPR on the different plants growth.The excellent strains were identified by the morphological characteristics and 16 S r DNA gene sequence analysis.The antagonistic function's the excellent PGPR strains were determined by the Oxford C up method,and obtained the best strains combination.In this study,the growth indexes of Triticale(Triticosecale)and Phleum pretense were determined by setting four experiment treatments(CK:Control;NF1:Pre-developed biofertilizer;NF2:New production of biofertilizer)to verify the effect of the best strains combination.The effects of microbial fertilizer on broccoli(Brassica oleracea)biological indicators and soil microbial biomass by field experiment under different treatments(A: Control;B: Microbial fertilizer;C : 70%C hemical fertilizer + microbial fertilizer;D: 100 %Chemical fertilizer).The main results were obtained as follows:(1)There were 57 strains of PGPR screened from the rhizosphere of four different plants,consist of 24 strains nitrogen fixing bacteria and 33 strains dissolving phosphate strains.(2)The nitrogen fixaton ability of PGPR strains were between 0.14 and 3664.97 nmol(C2H4)/h/m L.There are four strains which nitrogenase activity were more than 100 nmol(C2H4)/h/m L,included strains NCRS1,PYRS1,NYRS2 and PCHP1,the values were 3664.97,1557.63,160.03 and 108.90 nmol(C2H4)/h/m L,respectively.The others strains were less than 100 nmol(C2H4)/h/m L.(3)The value of D/d in dissolved inorganic phosphorus strains were between 1.25 and 2.73,the soluble phosphorus content of PGPR strains were between 36.99 and 362.60 ?g/m L,the value of p H in culture medium of strains were between 4.57 and 5.75,and the dissolved phosphorus maximum strain was NCRP2.The value of D/d in dissolved organic phosphorus strains were between 1.22 and 2.81,the soluble phosphorus content of PGPR strains were between 5.62 and 55.21 ?g/m L,the value of p H in culture medium of strains were between 5.89 and 7.85,and the dissolved phosphorus maximum strain was PPRS3.There were strains that dissolve inorganic phosphorus and organic phosphorusthat can dissolve inorganic phosphorus and organophosphate at the same time,included strains NYRS3,NCRS1,NPRS1,MBHP1,MPHP1,MC RP1,MYRS2,MC RP2,MCRS1,MC RS4,PCHP1,PYRS2,PYRS1,PCRP1,PCRS2,PBRP1,PCRS1 and PPHP1.(4)The secretion amount of IAA were less than 4 ?g/m L.The NCRP2 and NCRP3 strains showed obvious antibacterial activity to Helminthosporium tritici-vulgaris,Alternariasolani,Fusarium oxysporumn,Rhizoctonia solani,Sclerotiniasclerotiorumand Bipolaria maydis.The antibacterial rates of NCRP2 strain reached 61.23%,53.41%,51.52%,53.16%,77.44%,59.87%,and NCRP3 strain rose up 66.44%,52.63%,52.44%,62.27%,67.48% and 57.02%,respectively.(5)The 21 excellent PGPR strains were identified by morphological features and 16 S r DNA gene sequence analysis method.The results showed that PYRS1 strain was Pseudomonas syringae,NCRS1 and PBRS2 strains were Pseudomonas migulae,PCRP1 strain was Pseudomonas brassicacearum,MPHP1 strain was Pseudomonas thivervalensis,MCRS1,PCRS2,MCRP1,PYRS2 and PPRS3 strains were Acinetobacter calcoaceticus,MCRS4 strain was Advenella kashmirensis,NCRP1 strain was Rhizobium sphaerophysae,NCRP2 and NCRS2 strains were Phyllobacterium ifriqiyense,N YRS3 strain was Microbacterium binotii,NBRP2 strain was Microbacterium profundi,MBHP1,MYRS2,NYRS2,MCRP2 and PCHP1 strains were Bacillus pumilus.(6)The main results obtained as follow by potting experiment,compared with the control,NF2 could increase the stems and fresh weight of ground biomass in Triticale,they were increased by 6.79% and 0.89%,the stems and chlorophyll content in Phleum pretensewere increased by 33.74% and 13.72%,and there were no significant difference under different treatments(P>0.05).The root length,root surface area and root volume maximum treatment was NF2,the value were 217.94 cm,11.78 cm2,and 0.35 cm3,respectively.There was significant difference at root length in 0.5-1.0 mm of Triticale under NF2 treatment(P<0.05).There were no significant difference between root form and root length under different treatments(P>0.05).(7)The results showed that the numbers of soil bacteria,fungi,and actinomycete decreased with soil depth increased under different fertilizer treatments.The numbers of microbe showed a tendency of bacteria> actinomycete> fungi with different fertilizer treatments.The 70%chemical fertilizer + NF2 treatment was the best fertilizer treatment for broccoli's biological indicators and soil microbial biomass.Plant height,stem diameter,leaves number,aboveground fresh weight,aboveground dry weight,belowground fresh weight,belowground fresh dry weight,bacteria,actinomycetes,microbial total,soil microbial biomass carbon,soil microbial biomass nitrogen and soil microbial biomass phosphorus increased by 6.82%,11.53%,11.76%,9.68%,33.33%,62.5%,33.33%,34.04%-37.61%,8.42%-15.87%,32.53%-33.86%,13.56%-18.6%,3.99% and 12.81%-17.99%,respectively.Meanwhile,the numbers of fungi decreased 26.23%-32.89%.Moreover,the resulted of correlation analysis showed that there were significant positive correlations among soil microbial biomass and the number of soil microorganism.70%C hemical fertilizer +NF2 showed good promoting effects on broccoli growth. |
PDF Full Text Request