An interesting experiment
In May 1995 an experiment was set up in Zanona (Cadiz/Andalusia/Spain) to show the effect of the soil conditioner TerraCottem (TC) on seedlings of conifers.
A number of seedlings was acquired in a nearby nursery. Half of them were kept as control plants, the other half were treated with TerraCottem soil conditioner (see http://www.terracottem.com) at a dosage of 5 g TC per kg of potting soil. All plants were watered in the same way (all the same day, all the same small volume of water to create a certain hydric stress for the seedlings under very dry conditions in the area).