Effects of Activated Charcoal and Dissolved Oxygen Levels in the Hydroponic Solution on the Growth and Yield of Cucumber Plants

Abstract

The effects of adding activated charcoal and different concentrations of dissolved oxygen to the hydroponic culture solution on the vegetative growth and yield of cucmber plants were studied. 1. The concentrations of dissolved oxygen in the culture solution after 6- and 24- hr aeration treatment were 1.7∿3.1 ppm and 5.0∿7.5 ppm, respectively. Adding activated charcoal to the culture solution with different aeration periods did not affect the concentrations of dissolved oxygen. 2. Whether the activated charcoal was added or not, the length of the primary lateral branch and its dry weight at the end of the experiment decreased slightly following 6-hr aeration compared to that following 24-hr aeration. 3. The yield per plant was unaffected by a 6-hr or 24-hr aeration but it was significantly increased by the addition of activated charcoal. Apparently root exudates, which are detrimental to vegetative growth and yield of cucumber plants are adsorbed by the activated charcoal.