Effects of Potash Applied at Different Growth Phases on Tomato Yield and Quality in Greenhouse

Potassium is a major mineral nutrient required in tomato plant. Applying potash can increase tomato yield obviously, especially in marketable yield. The content of soluble sugar, organic acid and soluble solid also increased when potash applied. Plant growth is restricted when potassium deficiency. The experiment on effects of potash applied at different growth phases on tomato yield and quality was conducted with tomato plants grown in pots in greenhouse. There were five treatments in this experiment: potash applied at seedling phase (treatment1); potash applied at flowering phase (treatment2); potash applied at fruit enlarging phase (treatment3); 40, 30 and 30% of total potash applied at seedling, flowering and fruit enlarging phases respectively (treatment4); no potash applied (CK). The results indicated that: potash promoted plant vegetative and generative growth significantly. Applying potash at flowering could obviously increase plant height and stem width, 11.4% and 4.4% higher than that of CK, respectively. Potash applied at flowering phase could obtain the highest yield and the total yield was 2.14 kg/plant, increased by 38.9% as compared with CK. Applying potash at seedling and SFE phases could also increase tomato yield to some extent, but it's not the optimum phases for potash application, but applying potash at fruit enlarging phase was similar to that of the control plants. Potash applied at different phases on tomato quality was also investigated, significant difference appeared. The content of soluble sugar, organic acid and soluble solid were the highest among all the five treatments, significantly increased by 44.7%, 28.8% and 7.1% as compared with CK, respectively. Potash applied at fruit enlarging phase got the highest ratio of sugar to acid. From this result, we concluded that flowering phase was the optimum phase to applying potash with fruit of the highest quality. The effective potash applied at different phases on tomato vegetable growth, yield and fruit quality were discussed.