Growth and development of komatsuna (iBrassica rapa/iL. Nothovar) in NFT (nutrient film technique) system, as influenced by natural mineral

摘要

The cultivation of komatsuna (Brassica rapa L. Nothovar) was carried out hydroponically using a nutrient film technique (NFT) system inside a greenhouse, applying a quartz porphyry (QP) treated nutrient solution. Quartz porphyry is a natural mineral containing many substances that easily ionize with water to improve water quality. Different growth attributes of komatsuna such as leaf length, leaf width and plant fresh weight increased in plants that received QP treated nutrient solution. The coefficient of variation was smaller for QP treated nutrient solution plants when compared to the control. High light intensity, long duration of solar radiation and higher temperatures in the summer (July-Aug.) promoted plant growth compare to winter (Dec.-Feb.). In contrast, plants grown in the winter accumulated more fresh weight compare to plants grown in the summer. Results also showed that the rapid exchange of ion in the nutrient solution due to the QP treatment enabled the solution to maintain the ion balance, and thus plants grew uniformly and vigorously. The cations Na+ and Ca2+ and the anions Cl- and were dominant and made the media saline. There was a decrease of Na+ ion concentration in the recirculating nutrient solution (NFT) due to ion exchange by QP. Results suggest that water treatment with QP could be used for production of high quality vegetables.