Effects of Potassium Fulvic Acid and DA-6 on the Growth and Yield of Tomato Cultivated with Rock Wool

Abstract

Potassium fulvic acid and diethyl aminoethyl hexanoate (DA-6) are two kinds of growth regulators with yield increasing and quality improving. There are few reports on the effects of adding potassium fulvic acid and DA-6 in nutrient solution on the growth of soilless culture of vegetables. In this study, tomato was used as the test material to add different concentrations of potassium fulvic acid (0, 15, 30 mg·L^-1) and DA-6 (0, 2.5, 5 mg·L^-1) into nutrient solution of total nutrient minerals, so as to study the effects of adding two growth-regulating substances to nutrient solution of total nutrient mineral on the growth, yield and quality of tomato in soilless cultivation with rock wool in solar greenhouse. The results showed that: With no addition of potassium fulvic acid and DA-6 as the control, in the early stage of bearing fruit, the potassium fulvic acid added with 30 mg·L^-1 nutrient solution alone had an inhibitory effect on tomato plant height and the inhibition could be alleviated by adding DA-6. When 30 mg·L^-1 potassium fulvic acid and DA-6 were added together, the fresh quality of single stem and dry quality of single leaf in the early and middle stage of tomato bearing fruit were significantly improved. 15 mg·L^-1 potassium fulvic acid and 2.5 mg·L^-1 DA-6 had the best effect on the total yield of a single plant, which was 21.77% higher than that of the control. 15 mg·L^-1 potassium fulvic acid and DA-6 could significantly increase the C content and sugar acid ratio of tomato fruit. To summarize, 15 mg·L^-1 potassium fulvic acid and 2.5 mg·L^-1 DA-6 showed synergistic effect, which has the best improvement effect on the growth, yield and quality of best.