ISHS Acta Horticulturae 644: International Symposium on Growing Media and Hydroponics
CRITICAL NUTRIENT CONCENTRATIONS FOR ABSORPTION OF SOME VEGETABLES |
| Authors: | T. Maruo, M. Takagaki, Y. Shinohara |
| Keywords: | low concentration, nutrient absorption, euthrophic water, environmental stress, Lactuca sativa, Lycopersicon esculentum, Ipomea aquatica |
| DOI: | 10.17660/ActaHortic.2004.644.66 |
| Abstract:
The critical concentrations of each inorganic component for nutrient absorption were investigated in tomato (Lycopersicon esculentum Mill.), lettuce (Lactuca sativa L.) and water convolvulus (Ipomea aquatica Forsk.) plants. The nutrient absorption rate was calculated from the decreasing rate of the nutrient concentration in the system. The water volume in the measuring system was maintained at a constant level by supplying ion-free water. In the experiments using tomato and lettuce plants, the absorption concentration of each component was gradually decreasing (about 30%) with the given nutrient concentration decreased 3-4 times except when the nutrient concentration is very low. When the nutrient concentration fell below the critical concentration, the nutrient absorption concentration fell off rapidly. The absorption rates were also checked at low nutrient concentration condition. The critical nutrient concentrations for water convolvulus were obtained as follows, NO3-N: 0.2 me L-1, PO4-P: 0.05 me L-1, K: 0.06 me L-1, Ca: 0.03 me L-1. These concentrations were much lower than those in commercial systems. Therefore, these results suggest that the cultivation with low nutrient concentration could be achieved if each nutrient was supplied continuously. | |
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