One of the major problems of planting tree saplings, e.g. for reforestation projects, is getting the nicely watered saplings, coming from the nursery, growing and surviving in a dry soil. In many cases survival rate of tree saplings in the field is rather low (even 30-40 % in some Western African countries) . Studying methods to improve these survival rates, we have set up some experiments with the soil conditioner TerraCottem, developed in my laboratory in 1982-1992. These experiments were set up in 1988 with my friend Gilbert Van Gampelaere, a skilled technician, at the Provincial Centre for Floriculture (PCS, Destelbergen).
Experiment 1. Testing root length of young Fuchsia plants in two long pipes, filled with a mixture of potting mix and thin layers of TerraCottem (TC) :
(a) Photo 1 Left: Fuchsia growing in a transparent plastic pipe (to be able to follow the roots during their growth. When filling the pipe with potting mix, thin layers of TC were positioned at different heights (see whitish stripes in the pipe). At the moment of pouring water in the pipe, the water absorbing polymers in TC are absorbing a lot of the percolating water and they are transformed into hydrogels, which keep the surrounding potting mix moistened for quite a long time. As plant root tips are easily discovering where water is present in the soil, the roots are growing swiftly from the upper TC-layers to the lowest ones in the pipe. Thus, root length is significantly stimulated within the shortest time (see Photo 2).