Effects of Nitrogen Rate on the Growth, Yield and Quality of Tomato in Greenhouse Fertilization with Biogas Slurry

The experiment was conducted in the greenhouse with different nitrogen rates of biogas slurry as top-dressing fertilizer to investigate their effects on growth, yield and quality of tomato. Biogas slurry and organic fertilizer as supplemental fertilizations were both provided seven times in total during the growing period. 10 g per plant of organic fertilizer as a control was applied each time, of which the amount of total nitrogen was 541 mg per plant. In treatment 1 (T1), 143 ml per plant of biogas slurry was applied each time, which was based on supplying the same amount of total nitrogen as in the control, while biogas slurry of 215 ml per plant was provided each time in treatment 2 (T2), resulting in a total nitrogen supply which was 1.5 times higher than in the control. The results showed that T2 had better effect on the promotion of stem diameter growth and the fruit enlargement rate as compared with the control. The maximum of soluble sugar content in fresh weight of fruit and sugar-acid ratio was also recorded in T2.