Abstract:

To investigate the synergistic enhancement mechanism of applying fulvic acid-potassium organic complex on tomato yield,quality,and soil microenvironment under supplemental lighting,two light environments(white light, W;red-blue light, T)and four amendment treatments(no amendment,KB;decomposed corn straw,KF;ordinary fulvic acid, KP;fulvic acid potassium organic complex,KS)were established.The effects of different treatments on soil enzyme activities,physicochemical properties,rhizosphere solution nutrients,root morphology and physiology,photosynthetic characteristics,and fruit yield and quality were systematically studied.The results showed that compared with the W-KB treatment,the T-KS treatment increased soil urease,sucrase,and catalase activities by 45.71%,57.88%,and 17.25%,respectively.The contents of soil organic matter,available zinc and iron increased by 63.61%,53.55% and 46.85% respectively, while the pH value and EC value decreased by 3.62% and 15.65%, respectively. The concentrations of zinc and iron in the rhizosphere solution increased by 75.12% and 88.18% respectively,and the pH of the solution decreased by 4.22%.The root length and root system vitality increased by 27.86% and 85.93% respectively.The net photosynthetic rate and maximum photochemical efficiency increased by 40.94% and 3.40% respectively. Ultimately,T-KS treatment increased the number of fruits per plant,the single fruit weight,and the yield per plant by 25.46%,16.54%,and 45.93% respectively. At the same time,it significantly improved the fruit quality,increasing the contents of soluble solids,vitamin C,lycopene and soluble sugar by 20.61%, 32.27%, 30.75%, and 29.56% respectively. The titratable acid content decreased by 10.93%,while the sugar-acid ratio increased by 45.42%.Correlation and principal component analyses showed that all measured indicators had significant effects on yield and quality.Structural equation modeling revealed that,under red-blue light,the complex exerts synergistic effects through the pathway of “soil enzyme activity—rhizosphere micro-environment—root development—photosynthetic performance—fruit enhancement”.In conclusion,applying the complex under red-blue light improves soil nutrients,promotes root development and photosynthetic performance,and thereby enhances tomato yield and quality.

Key words: Tomato, Supplementary lighting, Potassium fulvate, Organic materials, Quality and yield

CLC Number: 

• S641.2

• S627瓜果设施园艺