DYNAMIC CHANGE OF PH AND EC VALUE IN SUBSTRATE CULTURE USING DIRECTLY SOLID FERTILIZERS INSTEAD OF NUTRIENT SOLUTION

     In eco-organic soilless cultures (EOSC the crop is fed by means of solid fertilizers and irrigation with fresh water only and non by supplying complete nutrient solution as in conventional hydroponics. EOSC is quite common for greenhouse production in China, accounting for more than 60% of total area cultivated with hydroponics. This paper reports the results of an experiment carried out with tomato and cucumber grown in EOSC to study the dynamic changes of pH and electrical conductivity (EC) in the substrate, which was a mixture of perlite and vermiculite. In EOSC top dressing fertilization maintained more favorable pH in the root zone by increasing the substrate’s buffering capacity, which could avoid the alkalinizing effect of irrigation water. The result of this work suggest that in EOSC the range of pH and EC in the substrate may remain within the optimal values, if top-dressing applications are provided at 10-day interval.

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