| Trichoderma is a well-known plant growth-promoting fungi(PGPF)and widely distributed in soils,and it has the abilities of promoting in plant growth,thus suppressing soil-borne diseases,and enhancing crop productivity.We conducted the study in order to solve the problems of soil fertility declined,serious crop diseases,declining watermelon yields and so on.Combined the field effect of trichoderma bio-organic fertilizer on watermelon grown on sand-stone covered soils in ningxia with soil culture experiment and greenhouse experiment,we want to explore the biological effect of trichoderma bio-organic fertilizer on watermelon grown on sand-stone covered soils and the effects of soil microflora in ningxia,inorder to provide theoretical support for the promotion of trichoderma bio-organic fertilizer.The main research results are obtained as follow:1.The application of trichoderma bio-organic fertilizer can significantly(P<0.05)promote the growth of watermelon grown on sand-stone covered soils and increase its yield.Compared with CF treatment,trichoderma bio-organic fertilizer treatment increased the vine length by 40.2%?81.3%;the thickness of stems by 26.6%?33.2%;the number of leaves by 32.8%?239.7%;the number of branches by 28.1%?30.0%;the yield by 33.2%?69.3%.2.The application of trichoderma bio-organic fertilizer can significantly(P<0.05)improve soil physical and chemical properties,promote soil enzyme activity,increase the number of bacteria and actinomycetes and decrease the number of fusarium oxysporum in soil.Compared with the CF treatment,trichoderma bio-organic fertilizer treatment increased the activity of ?-glucosidase by 82.7%?198.1%;the activity of ?-glucosidase by 52.6%?76.6%;the activity of ?-cellobiosidase by 459%?200.0%;the activity of phosphatase by 56.6%?65.0%;the activity of sulfatase by 15.3%?54.5%;the activity of N-acety-?-glucosaminidase by 71.9%?350.9%;the activity of urease by 21.0%?102.9%;the activity of catalease by 20.5%?25.9%and the activity of invertase by 95.3%?167.3%.At the same time,the trichoderma bio-organic fertilizer treatment increased the number of bacteria in soil by 62.0%?156.5%;the number of actinomycetes in soil by 119.3%?180.3%;decreased the number of fungi by 39.5%?58.0%;decreased the number of fusarium oxysporum by 68.7%?74.1%.Also,it helped increase the B/F value in soil,which optimized the community structure of culturable microorganisms in soil.3.The result of culture experiment shows that continues application of trichoderma bio-organic fertilizer can increase the number of bacteria,actinomycetes and beneficial fungi such as trichoderma in soil.It can decrease the number of fusarium oxysporum and maintain at a lower and more stable level.After six successive applications of fertilizer,the number of bacteria treated with trichoderma bio-organic fertilizer was 13.2 times and 15.7 times higher than that treated with chemical fertilizer.The number of fungi treated with trichoderma bio-organic fertilizer was 24.6 times and 37.6 times higher than that treated with chemical fertilizer.The number of actinomycetes treated with trichoderma bio-organic fertilizer was 5.8 times and 2.1 times higher than that treated with chemical fertilizer.The number of fusarium oxysporum treated with chemical fertilizer was 7.9 times and 10.1 times higher than that treated with trichoderma bio-organic fertilizer.4.The continues application of trichoderma bio-organic fertilizer can promote the growth of watermelon,improve soil physical and chemical properties,promote soil enzyme activity,increase the number of bacteria and actinomycetes and decrease the number of fusarium oxysporum in soil.The results of pot experiment showed that compared with the CF-CF treatment,the BOF 4742-BOF 4742 treatment can increase the vine length by 9.1%;the thickness of stems by 21.3%;the number of branches by 200.0%;the SPAD value by 33.2%?69.3%;fresh weight by 137.4%;dry weight by 39.2%.In three sampling periods,compared with the CF-CF treatment,the pH value of the BOF 4742-BOF 4742 treatment decreased by 0.21,0.31 and 0.28 units,respectively.The content of available nitrogen in the CF-CF treatment was significantly(P<0.05)higher than that in the BOF 4742-BOF 4742 treatment.But The content of AK(Available potassium)and AP(Available phosphorus)in the CF-CF treatment was significantly(P<0.05)lower than that in the BOF 4742-BOF 4742 treatment.The activities of ?-glucosidase,?-xylanase,?-glucosidase,?-cellobioglycerase,phosphatase,N-acety-?-glucosaminidase and invertase in soil treated with trichoderma bio-organic fertilizer were significantly(P<0.05)higher than those in the CF-CF treatment,which were 1.5,1.4,1.3,1.5,1.1,2.9,1.8 and 1.8 times respectively.There was no significant difference between urease and catalase.Compared with the continuous application of chemical fertilizer(CF-CF),the number of bacteria in soil treated with BOF 4742-BOF 4742 was 1.9,3.0 and 2.9 times in 40 days,70 days and 90 days,respectively.The number of culturable fungi was 11.2,8.2 and 9.0 times,and the number of culturable actinomycetes was 1.5,4.0 and 2.1 times.The number of Fusarium oxysporum in soil treated with CF-CF was 2.5,4.2 and 5.1 times higher than that treated with BOF 4742-BOF 4742 at 40 days,70 days and 90 days,respectively.5.Illumina MiSeq high-throughput sequencing was used to sequence the 16S rRNA V3-V4 region of soil bacteria and culturable bacteria.The results showed that tillage could reduce the diversity of soil bacteria and culturable bacteria,but the continuous application of Trichoderma bio-organic fertilizer could alleviate the loss of diversity caused by watermelon tillage compared with the continuous application of chemical fertilizer,and it could relatively improve the soil Alpha diversity index,which was conducive to the construction of more stable bacterial groups.Continuous application of Trichoderma bio-organic fertilizer can change the community structure of soil bacteria and cultured bacteria,and increase the relative abundance of some beneficial microorganisms in soil,such as rhizobium,bacillus,etc.In conclusion,application of Trichoderma bio-organic fertilizer can significantly promote the growth of sand-pressed watermelon,increase its yield,and promote soil physical and chemical properties and soil enzyme activities.Under the condition of continuous application,soil microbial activity can be improved,soil bacterial community structure can be effectively improved,more stable bacterial groups can be constructed and the relative abundance of beneficial microorganisms can be increased. |
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