| heal.abstract |
The conventional Nutrient Film Technique system (NFT) is used for long time for growing short-term crops, like lettuce. Using NFT for long-term crops such as, tomatoes, cucumbers and peppers presents disadvantages. Extended measurements show that the oxygen content along the bed in NFT decreases from inlet to outlet. Also, the different oxygen content along the bed seems to influence nutrient uptake. A modified system using continuous recirculating drip system for growing in solution culture (NDT1) was designed, to provide precise nutrient control, consistent water potentials, uniform electric conductivity and oxygen concentration in root environment of all plants. The system was tested for tomato crop in comparison to NFT system. The results indicated that all tomato plants in the NDT1 system grew vigorously, were healthy and more productive than in the conventional NFT system. The measurements of oxygen concentration and electric conductivity in nutrient solution, near by the roots, showed that was high and uniform along the gully of NDT1. Fruit production showed a significant increase in the NDT1 system. Thus, the NDT1 appeared to approximate a well-drained porous substrate and was ideal for long-term greenhouse growth of vegetables. For a commercial culture, this system provides a better root environment control and independence of porous substrates. For experimentation, this system has the advantages that solution culture provides, like a better controlled abiotic-stress and easiness of root harvest. |
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