ISHS Acta Horticulturae 710: International Symposium on Greenhouses, Environmental Controls and In-house Mechanization for Crop Production in the Tropics and Sub-Tropics
SALINITY MANAGEMENT OF MEDIA GROWN HYDROPONIC TOMATOES |
| Author: | R.A.J. White |
| Keywords: | planter bags, pumice, sawdust, EC, 1:1.5 water extracts |
| Abstract:
Trickle irrigation of media such as pumice, sawdust or similar materials in pots, buckets or planter bags results in the development of zones of high and low salinity within the media. Analyses of samples of media from commercial tomato growers show that very high EC can be reached in the zones of nutrient salt accumulation, yet many of the crops with high EC in the root zones produce excellent fruit quality and with no apparent yield reduction due to the high salinity. It is usually accepted that high salinity improves fruit quality at the cost of reduced yield. Some recent experiments in the UK using split root zones showed that using high and low EC in different parts of the root zone allowed high quality fruit to be produced without the expected yield reduction. This also appears to occur with commercial crops in trickle irrigated bag growing systems. The particular mechanism of salt accumulation in this growing system is discussed and survey data on the incidence of high EC in New Zealand crops is presented. Watering and nutritional management in this situation is discussed and compared with management of growing systems using slabs and horizontal tubes of media. | |
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