Effect of substrates on the growth and yield of tomato [Lycopersicon esculentum] in a closed hydroponic system
2008
Nakayama, C.(Tochigi-ken. Agricultural Experiment Station, Utsunomiya (Japan)) | Ishihara, Y.
We tested a rock wool (RW) substrate and cedar bark substrates (loose pieces and molded) for tomato in a closed hydroponic system. We studied how tomato growth and yield are related to physical properties of the substrates to evaluate how practicable cedar bark is for this system. 1. The RW substrate and the substrate composed of loose cedar bark pieces had less solid and higher porosity than the substrate made up of molded cedar bark pieces. The RW substrate had the least liquid when the substrates were adjusted to pF 1.5. At a lower pF of 2.7, the loose cedar bark substrate and the RW substrate had greater variations in moisture content. 2. Initial growth was vigorous with the RW substrate and weak with the molded cedar bark substrate but no difference in growth was observed after the fifth fruit trusses developed. In contrast, yield was high with the molded cedar bark substrate, followed by the RW substrate and the loose cedar bark substrate in the descending order. Also, fruit enlargement was somewhat smaller with the RW substrate and the loose cedar bark substrate after April. 3. A substrate for stable tomato cultivation by this system requires the following properties: strong capillary action for stable moisture content, little seasonal fluctuation in moisture content, and little deposition of fertilizer components that facilitates pH stability. The substrate made up of molded cedar bark pieces has those properties.
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