Solid State Fermentation Of Trichoderma NJAU 4742 With Stevia Resvia Residue And Its Effects On Corn Growth In Seeding Stage

Trichoderma SPP.,as an important plant growth promoting fungi,is widely used to promote plant growth and control plant soil-borne disease.In addition,the spore of Trichoderma SPP.has high ability in adapting to environmental stress,which as a result as the main application form in agricultural production process.Due to solid state fermentation is closer to the growth habit of Trichoderma SPP.,as compared with liquid fermentation,it can obtain higher density and quality Trichoderma seeds.Meanwhile,stevia residue is an agricultural solid waste with abundant fiber and protein,which can be used as carbon and nitrogen resource for solid state fermentation.Thus,stevia dregs were used as the solid material for fermentation of Trichoderma guizhou NJAU 4742 in this study.Moreover,the solid Trichoderma seeds were further used to evaluate the effects of corn grown under different fertilization conditions.The findings are as follows:The solid-state fermentation of Trichoderma guizhou NJAU 4742 were conducted by 100%stevia residue,70%stevia residue+30%rice bran,70%stevia residue+30%bran,70%stevia residue+30%rice chaff and 70%stevia residue+30%rice straw powder.Results showed that 70%stevia residue+30%rice bran got the highest amount of solid Trichoderma seeds with the pH value 2.5-3.0,which adjusted by acid hydrolysis amino acids.Then,the single-factor test was used to explore the optimal solid state fermentation conditions:adjusting the addition ratio of rice bran to 50%,adjusting the water content to 60%,sterilizing the solid mixture at 115℃ for 40 minutes,and transferring 10%(v/m)Trichoderma spp.liquid fermentation via a sterile tube system after cooling the solid culture medium to 28-30℃.Moreover,the solid-state fermentation thickness is 2-3 cm,the temperature is 26-28℃,the humidity is 70-90%,and the cultured time is 4-6 days under sterile environment.Notably,the density of Trichoderma under such conditions can steadily be as high as a fresh weight of 7×109 cfu/g.The pot experiment contains six treatments:(1)CK,soil amended with none fertilizer;(2)CK+B,soil amended with solid Trichoderma seeds;(3)CF,soil amended with chemical fertilizer;(4)CF+B,soil amended with chemical fertilizer plus solid Trichoderma seeds;(5)OF,soil amended with organic fertilizer;(6)OF+B,soil amended with organic fertilizer plus solid Trichoderma seeds.There was none significant difference in corn biomass observed between CK and CK+B treatments and between CF and CF+B treatments.However,OF+B treatment significantly increased aboveground biomass as compared to OF treatment,while did not influence the belowground biomass.Moreover,OF+B treatment got the highest aboveground biomass among all the treatments.These results mean that the solid Trichoderma seeds promote corn growth through combination used with organic fertilizers.Compared with CK+B and CF+B treatments,OF+B treatment significantly improved the soil available P,total P,ammonium N and organic matters.Different application methods of solid Trichoderma seeds significantly influenced the fungal microbial communities in both bulk and rhizosphere soil,to a certain extent,the treatments with solid seeds added some crop growth beneficial bacteria in the soil,this indicates that solid Trichoderma seeds can change the community structure of fungi in soil.Therefore,application of soil amended with organic fertilizer plus solid Trichoderma seeds treatment significantly promoted the growth of corn,maybe through regulating the fungal microbial community.