Articles
WATER USE EFFICIENCY AND NUTRIENT CONSUMPTION OF A GREENHOUSE ROSE CROP GROWN IN ROCKWOOL
Results show that, during spring and summer, high levels of temperature (air and substrate) and VPD (vapour pressure deficit) have a negative effect on both transpiration rate and water use efficiency.
Temperature of the rockwool slabs seemed to have a strong influence on the uptake of the main macroelements during the warm season.
The ratio of the uptake rates of NO3, K and P to transpiration rate decreased through May to September, indicating that the substrate temperature affected more severely nutrient uptake than water absorption.
This can induce unbalanced concentrations and accumulation of salts in the substrate, that must be corrected by continuous adjustment of the nutrient solution.
An other alternative would be to cool the substrate in order to keep its temperature within an optimal range.
Then, cooling devices that are effective in reducing substrate temperature could be a solution to maintain adequate levels of nutrient uptake during late spring and summer periods.