The determination of the dry mass of all substrate pots by drying in the ventilated oven at 60°C (Heraeus, Hanau, Germany) for seven times at first and stop of lettuce cultivation permitted the calculation in the mineralized natural and organic matter during the experiment. This process was used based on https://zanerhviu.blogpixi.com/33319567/5-tips-about-ventilation-system-you-can-use-today