Characteristics of Mineral Nutrient Absorption of Vegetable Crops in Water Culture

The study was carried out to clarify the effects of various compositions of nutrient solution on the growth, content of nitrogen, phosphorus, potassium, calcium, and magnesium in plant tissues and n/w (nutrient absorption (me)/water consumption (l)) of these five elements in head lettuce, tomato, eggplant, and sweet pepper. The crops were grown in a balanced solution at a horticultural experimental station in Japan (treatment 1) and in a nutrient solution which was based on the reports of recent experiments (treatments 2 and 3). The results are summarized as follows: 1. The differences of growth, yield, nutrient absorption and n/w of nitrogen, phosphorus, potassium, calcium, and magnesium among the experimental plots in each crop were not noticeable. But selective salt absorption by different crops was observed. 2. The differences of selective salt absorption of different crops were found in the n/w of nutrient elements. Especially, it was remarkable in the case of calcium absorption, and the n/w of calcium was found to occur in the following order: tomato>eggplant>sweet pepper>head lettuce. 3. A reverse tendency between the n/w of calcium and potassium was found at the growing stage of plants. 4. In tomato and head lettuce, the n/w of nutrient elements was found to be decreased as the age of plants advanced. But in eggplant and sweet pepper, the n/w of nitrogen and calcium was constantly increased when fruits were harvested at an immature stage. 5. The balanced solution of horticultural station in Japan could be used with no trouble for growing plants in this study. When the results of this study were scrutinized in detail, it seemed that the growth of head lettuce was not effected by a low calcium level solution. Moreover, the increase of calcium ratio of nutrient composition in tomato was favorable to the production of fruits.