ISHS Acta Horticulturae 133: Nutrient Film Technique and Substrates, XXI IHC
A CABLE SUPPORTED NFT TOMATO PRODUCTION SYSTEM FOR THE GREENHOUSE |
| Authors: | Gene A. Giacomelli, Harry W. Janes, David R. Mears, W. J. Roberts |
| Abstract:
Greenhouse tomatoes (cv. Vendor) have been grown within a modified, NFT culturing system. Each crop row consisted of a continuous, plastic film tube 15 cm in diameter and a 0.32 cm steel cable threaded within the tube. The cable was attached to a frame located at each end of the greenhouse through a roller mechanism. The roller mechanism could travel along the frame which traversed the width of the greenhouse. This provided a catenary structure, attached only at its ends, which supported the plant-growing tube above the floor and created a cropping system capable of variable row-to-row spacings. No intermediate supports were necessary, which simplified the problems of establishing a movable crop row. Seedlings were transplanted into the tube which carried nutrient solution and provided an environment for the growth of their root systems. Nutrient solution pumped to each end of the tube flowed to the center of the span where it was discharged into a return flume located in the floor below. The aerial portion of the plant was secured by a string to an additional cable located 2.1 m directly above the growing tube. This string and cable provided the physical support for the plant and its fruit. Both cables were attached to the frame such that they moved together when the row spacing was altered. More effective utilization of the greenhouse floor area for crop production was possible through increasing row-to-row distances as the seedlings matured. Plant density at transplant was 20 plants per square meter and could be decreased to 4.3 plants per square meter. With proper timing of successive crop plantings an increase of total yearly fruit production per unit floor area and a more continuous yearly harvest rate can be realized. Individual plant growth and yields have been comparable to those plants grown in the traditional floor-mounted NFT troughs for a growing period of 150 days. | |
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