WATER QUALITY, CLIMATIC ENVIRONMENT AND MINERAL NUTRITION OF TOMATO (LYCOPERSICON ESCULENTUM) IN CLOSED SOILLESS CROPPING SYSTEM

A tomato crop (Lycopersicon esculentum Mill. cv.
Recento) grown on rockwool with fully recirculated nutrient solution yielded 33 kg.m^-2 (2.2 pl.m^-2) within 130 days.
Nutrient concentration and balance adjustments were based on solution and tap water analyses.
The latter’s electrical conductivity (EC 0.3 mS.cm^-1) showed slight variation but it contained sufficient Ca Mg and SO₄ to supply the crop’s needs for most of the growing period.
NO₃, SO₄, Ca and Mg concentrations in the recirculated solution increased from the end of May and to the beginning of July; plant uptake resumed by the end of July.
K uptake was weak from the beginning of July through to the end of August as shown by accumulation in the solution; plant uptake then increased strongly for a short period in September.
The electrical conductivity of the nutrient solution fluctuated from a minimum of 1.4 (May) to a maximum of 3.13 mS.cm^-1 (mid-August).

The mineral contents of the fruits showed too high a K/Ca+Mg ratio.
Fruit blossom-end rot occurred increasingly from the end of August, the main causes of which were high day and night air humidity, poor root renewal and excess K relative to Ca and Mg uptake.

International Symposium on Water Quality & Quantity-Greenhouse

D. Pivot, A. Reist, J.-M. Gillioz, J.-P. Ryser

drainage, nutrient solution adjustment, rockwool, salinity

https://doi.org/10.17660/ActaHortic.1998.458.24