OXYGEN CONCENTRATION OF NUTRIENT SOLUTION IN MINERAL WOOLS

The importance of the oxygen supply to the root system has been well known for a long time. In this study, our purpose was to follow the oxygen variations in nutrient solutions sampled in a mineral substrate.

Micro sample analysis allowed to follow the evolution of the oxygen concentration of the nutrient solution in mineral wool. Supply solution, relatively little aerated, is saturated in oxygen by transfer through the upper layers of the wool. At the bottom of the slab, in the neighbourhood of the roots, the first measurements, carried immediately after irrigation, give value near saturation.

When the physiological activity is intensive (clear sky days), the oxygen concentration quickly decreases. Then, a steady state regime keeps the concentration at about 4 mg/l.

Further experiments are needed to determine if this concentration is high enough to satisfy the needs of the plants.