| With the development of modern facility agriculture,the seedling industry has also developed rapidly.Biological seedling substrates containing beneficial microorganisms have become a research hotspot in the seedling industry because of their advantages in effectively promoting the growth of seedlings,enhancing seedling lodging resistance,disease resistance,and effectively promoting the crop growth after seedlings transplantated into field.Among the many organic(type)fertilizers,bio-organic fertilizer containing functional Trichoderma strain has been widely used to imporve soil fertility,crop yield and quality due to the ability of manipulating soil microflora and improving soil microbiome since the functional Trichoderma strain can produce a variety of enzymes and secondary metabolites,and have the antagonistic effects on a variety of pathogens.However,under natural conditions,the growth of Trichoderma strains is susceptible to environmental factors such as light,humidity,chemicals,especially temperature.Therefore,the effects of biological seedling substrates containing different Trichoderma strinas with different optimal growth temperatures on the growth of pepper seedlings under different temperature conditions were comared in this study to explore the promoting effects of biological seedling substrates containing thermostable Trichoderma strains on pepper seedlings under different temperature conditions.Then the effects of biological seedling substrates containing different microbial consortium based on the different combinations of different Trichoderma strains and rhizosphere growth-promoting bacteria on the growth of papper seedlings were performed using two-seasonal greenhouse trials to explore the promoting effects of biological seedling substrates containing different microbial consortium on pepper seedlings.Finally,in order to explore the best combination of thermostable Trichoderma strain with organic(type)fertilizers to produce bio-organic fertilizers and their growth-promoting effect,the effects of bio-organic fertilizers produced by the combination of thermostable Trichoderma strain with different organic(type)fertilizers applied to different type soils(yellow brown soil and aeolian sandy soil)on the growth of bok choy was conducted by the two-season pot experiment.The main results are as follows:1)The results of biological seedling substrates containing different functional Trichoderma strains on the growth of pepper seedlings under different temperature conditions based on three seasonal experiments all showed that compared with the common seedling substrate control(CK),the biological seedling substrate treatments containing Trichoderma guizhouensis NJAU4742(NJAU4742)and thermostable strains of T.longibrachiatum MD30(MD30)and T.citrinoviride JS84(JS84)displayed significant higher promotion effects on the plant height,stem diameter,fresh weight and dry weight of the shoots and the fresh weight of the roots of pepper seedlings.The average daily temperature during the first season of seedling experiment was about 36.4℃.Compared to the NJAU4742 treatment,the shoots dry matter of the the pepper seedlings treated with MD30 and JS84 increased significantly,with an average increase rate of 47% and 23%respectively.For the second season of seedling experiment,the average daily temperature was 26.9℃.Only the shoot dry matter of pepper seedlings treated with JS84 increased significantly,with an increase rate of 35% compared with NJAU4742 tretment.During the third season seedling experiment,the average daily temperature was 20.2℃,with no significant differences in the shoots dry matter of pepper seedlings among JS84,MD30 and NJAU4742 treatments were observed.All above results from the three-season seedling experiment showed that the growth-promoting effect of the biological seedling substrate containing the thermostable Trichoderma strain was more obvious with the increase of seedling temperaturein the range of daily average temperature of 20.2℃ to 36.4℃.2)The results of biological seedling substrates containing different groups of fuctional strains on the growth of pepper seedlings based on two-season seedling experiment all showed that biological seedling substrates containing the group of allfour functional strains(T.guizhouensis NJAU4742,thermostable strains of T.longibrachiatum MD30 and T.citrinoviride JS84,Bacillus amyloliquefaciens SQR9)and biological seedling substrates containing the group of three strains from four functional strains(NJAU4742,MD30,JS84,SQR9)exhibited the promoting effects on plant height,stem diameter,fresh and fry weight of shootsof peper seedlings compared to comon seedling substrates control(CK)and biological seedling substrates containing single fuctional strain.Moreover,the promoting effects of biological seedling substrates containing single fuctional strain was better than CK.However,the promoting effects for treatment of biological seedling substrates containing the group of allfour functional strains was not significant in comparsion with the treatments of biological seedling substrates containing the group of three strains.Among all treaments,the treatment of biological seedling substrate containing the microbialcombination of four fuctional strains(T4-1,SQR9+MD30+JS84+4742)displayed the best growth-promoting effect.Comparedto CK,the T11 treatmentshowed singnificant increases of 62% and 38% for plant hight,42% and 25% for the stem diameter,103% and70% for the fresh weight of the shoots,61% and 80% for the dry weight of the shoots,respectively for first and sceond experiment.3)The results of the effects of bio-organic feritlizers produced by adding thermostable Trichoderma types of organic fertilizer on the grwoth of bok choy when applied to different soil types based on two-season greenhouse experiment showed all that under the design of equal nutrients among different treatments,bio-organic fertilizers developed by the combination of Trichoderma strain with sheep manure and chicken manure,displayed better growth-promoting effects on bok choy when both applied to yellow brown soil and aeolian sandy soil than the bio-organic fertilizers developed by the combination of Trichoderma strain with other organic fertilizers.Meanwhile,bio-organic fertilizer treatment produced by adding Trichoderma to sheep compost showed the most significant growth-promoting effect.Compared to the control of amended with only chemical fertilizer(CF),the bio-organic fertilizer without fertilization,the treatment produced by adding Trichoderma to sheep compost significantly promoted the biomass of bok choy grown on yellow-brown soil and aeolian sandy soil.For example,the dry weight of the shoots of bok choy grown in the yellow brown soil and aeolian sandy soilsignificantly increased by 51%and 32% for for the first seasonand 66% and 54% for the second season respectively.In addition,the the treatment produced by adding Trichoderma to sheep compost could also significantly increase the content of soil total carbon,total nitrogen,total phosphorus,total potassium,available phosphorus,and available potassium andthe number of culturable Trichoderma strains forboth the two season.In summary,the biological seedling substrates developed with T.guizhouensis NJAU4742 and thermostable strains T.longiflorum MD30 and T.citrinoviride JS84 all can significantly promote the growth of pepper seedlings.Moreover,the growth-promoting effect of the biological seedling substrate of thermostable Trichodermastrainwas more obvious with the rises of temperature during seedling.With the diversity of functional stains in thecombination of microbial consortia,which was made up of PGPR strains of SQR9,NJAU4742,MD30 and JS84,added into biological seedling substrates,the growth-promoting effect was more excellent.Among them,the treatment developped by adding all four functional strains intobiological seedling substrates(SQR9+MD30+JS84+4742)showed the best growth-promoting effects during seedling.The bio-organic fertilizer produced by adding thermostable Trichoderma strains into sheep manure exhibited the most significant growth-promoting effect on bok choy when applied both to yellow brown soil and aeolian sandy soil.And this bio-organic fertilizer could increase the accumulation of crop biomass by increasing the content of soil nutrients such as total carbon and total nitrogen in the soil and the number of culturable Trichoderma in soil. |
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