Effect Of Special Fertilizer Combined With Nano Vermicompost Bio-organic Fertilizer On The Yield And Quality Of Apple And Tomato

Soil compaction,reduction in the number of microorganisms,and loss of nutrients are some of the main soil issues in orchards and vegetable farms that have been widespread for a long time,Which leds to the decrease in the yield and quality of fruits and vegetables.Increasing the application of organic fertilizer can effectively improve the soil and is an effective means to increase its yield and quality.Among the various organic fertilizers,vermicompost could effectively combine organic matter,microorganisms,and growth factors,and is more prominent in the retention of water and fertilizer in the soil and enhancing the quality and yield of fruit and vegetables.Nano-fertilizer has higher solubility,increasing fertilizer productivity,reducing biological and abiotic stresses,and increasing the accumulation of dry matter in fruits.Combining the advantages of both,applying nano vermicompost bio-organic fertilizer based on special fertilizer can more effectively enhance the quality of soil and increase the quality of fruit and vegetable.Based on this,three kinds of nano vermicompost bio-organic fertilizers were designed:nano vermicompost bio-organic fertilizer A₁（nano-carbon accounted for 0%of total carbon）,nano vermicompost bio-organic fertilizer A₂（nano-carbon accounted for 40%of total carbon）and nano vermicompost bio-organic fertilizer A₃（nano-carbon accounted for 80%of total carbon）,studied the effects of special fertilizer combined with nano vermicompost bio-organic fertilizer on the physical and chemical properties of apple and tomato rhizosphere soil,the appearance quality,flavour,antioxidant properties,and safety evaluation of heavy metals and pesticide residues of apple and tomato.The main findings were as follows:1.Special apple fertilizer combined with nanometer vermicompost bio-organic fertilizer A₂and A₃treatments（AT2 and AT3 treatments）could significantly increase the number of soil bacteria and actinomycetes.Among them,under the AT2 treatment,the number of bacteria increased most obviously,which was 41.80×10⁹cfu·g^-1,which was a significant increase of 70.48%compared to the single application of special apple fertilizer（ACF treatment）.Under AT3 treatment,the number of actinomycetes increased significantly,which was 31.4×10⁹cfu·g^-1;24.11%higher than that of ACF treatment.2.Special apple fertilizer combined with nanometer vermicompost bio-organic fertilizer A₁treatment（AT1）and AT3 treatment could significantly increase the yield of apples,which is 35.95%and 24.20%higher than that of ACF treatment.AT1 treatment has the highest plant yield,which is 24.77 kg,but there was no significant difference in AT3 treatment.3.AT3 treatment significantly increased the single fruit weight,soluble protein content,total flavonoid content and vitamin C content of apples,and reduced the carbendazim pesticide residue significantly in the fruit.Among them,under AT3 treatment,single fruit weight（267.40 g）,soluble protein content(172.86μg·g^-1),total flavonoid content(0.44mg·g^-1),vitamin C content(18.29 mg·100 g^-1),Compared with ACF treatment,it increased by17.26%,54.39%,55.78%and 21.74%,respectively.The residual amount of carbendazim was2.25μg·g^-1,which was reduced by 65.91%compared with the ACF treatment.4.The combined application of nano vermicompost bio-organic fertilizer could significantly increase the number of soil actinomycetes.Under the treatment of special tomato fertilizer combined with nano vermicompost bio-organic fertilizer A1,A2,and A3（TT1,TT2,and TT3 treatments）,the numbers of actinomycetes were 60.00×10⁹cfu·g^-1,97.00×10⁹cfu·g^-1and 193.00×10⁹cfu·g^-1respectively,which increased by 114.29%,246.43%,and 589.29%compared with the single application of special tomato fertilizer（TCF treatment）.TT1 and TT2 treatments could also significantly increase the number of bacteria in the soil,increasing by 33.00%and 56.00%compared with TCF treatment.5.Compared with ACF treatments,TT2 and TT3 treatments significantly increased the total proportion of"large fruit+middle fruit",total yield and total phenol content of tomatoes,and significantly reduced the residual amounts of arsenic（As）and cadmium（Cd）in the fruit.Under TT2 and TT3 treatments,the total proportion of"large fruit+middle fruit",total yield and total phenol content of tomato were 20.92%,19308 g,2.78μg·g^-1and 19.14%,18193 g,1.692.78μg^-1.The residual amounts of arsenic（As）and cadmium（Cd）in the fruits were24.80μg·kg^-1and 11.58μg·kg^-1respectively under TT2 and TT3 treatments,and TT2treatment>TT3 treatment.Treatment(36.15μg·kg^-1)decreased by 27.54%and 66.18%.6.Compared with TCF treatment,TT2 treatment could also significantly increase the soluble protein content and soluble sugar content and significantly reduce the residual procymidone in the fruit;TT3 treatment could also considerably increase the total flavonoid content in the fruit.Under TT2 treatment,the soluble protein content(86.51μg·g^-1)and soluble sugar content(3.54 mg·g^-1)were increased by 11.28%and 21.96%compared with TCF treatment,and the residual procymidone content was 0.66 mg·g^-1.Compared with TCF treatment,it was reduced by 51.82%;under TT3 treatment,the total flavonoid content was1.07 mg·g^-1,which was 2.71%higher than TCF treatment.In conclusion,nano vermicompost bio-organic fertilizer application into the soil can increase the number of soil microorganisms.The application of nano vermicompost bio-organic fertilizer with the special fertilizer for apple and tomato can improve the yield,flavor quality,antioxidant properties and reduce heavy metal and pesticide residues in fruits to a certain extent,promoting healthy and high-quality production of apples and tomatoes.