ISHS Acta Horticulturae 648: South Pacific Soilless Culture Conference - SPSCC
EFFECT OF PYROPHYLLITIC CLAY SUSPENSION ON SALINITY TOLERANCE OF TOMATO IN NFT |
| Author: | S. Lennard |
| Keywords: | oilless culture, hydroponics, silicon, blossom end rot, brix |
| Abstract:
Soilless culture offers the potential to extend horticultural cropping into areas of the world where conventional horticulture is not possible. However, in many of these areas soilless culture is made difficult by the salinity of the local water supplies. In a project intended for establishment in the United Arab Emirates progress was hindered by the water supply containing (among other elements) sodium levels exceeding 2000 mg/l. A pyrophillitic clay suspension manufactured in New Zealand (Pyrosol) had previously demonstrated an ability to overcome the effects of moderately high salinity in strawberries in NFT hydroponics. A trial was carried out in New Zealand to replicate this water supply, and test the effects of Pyrosol on the growth, yield and quality of tomatoes growing in NFT. The two treatments both used the same water supply, which consisted of rain water amended with sodium chloride, sodium bicarbonate, calcium carbonate, magnesium carbonate, magnesium sulphate, manganese sulphate and boric acid to replicate the ionic content of the UAE water supply (EC=3.5 mmho). One nutrient tank was further amended with 75 g per 100 litres of Pyrosol, the other nutrient tank was left untreated. The trial was set up using three ‘Panda film’ gullies 5 m in length for each of the two treatments. The nutrient formulation was identical for both treatments but was corrected for the high levels of magnesium, boron and manganese in the replica water supply. Results indicated that the addition of Pyrosol to the treated water supply, significantly improved fresh weight of the fruit, significantly reduced the incidence of ‘blossom end rot’, and increased brix readings of the fruit. Pyrosol resulted in higher numbers of fruit which had a greater weight and higher marketable yield. This data is presented along with a possible explanation for the mode of action. | |
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