Production Et Croissance Des Plants D’acacia Sur Des Substrats à Base De Tamisat De Compost Dans Une Pépinière Hors Sol (tunisie)

This study proposes an attempt to optimize the forestry compost produced at the nursery forest aboveground Chott Mariem-Sousse in Tunisia, by varying the particles size using different techniques and different riddling methods, to develop a substrate based on forestry sieved product suitable for breeding in containers of hardwood plants of Acacia cyanophylla. Tamisats which have acceptable porosity and the current substrate not sieved (100 % crude forestry compost derived from Acacia homogenate) underwent an indirect morphological characterization based on assessments of germination and growth (height, diameter and robustness ratio) of produced plants. Regarding seed germination, the test results conducted in the laboratory have shown the good quality of seeds used. Similarly, the % germination is almost the same on all substrates tested, that’s why the riddling didn’t reveal significant effect. According to the results of the average evolution of the height and diameter of seedlings, it appears difficult to distinguish the effect of substrate on their behavior during the first month after seedbed. The other two followed observations of growth, made five and seven weeks after planting showed similar growth on crude compost and tamisats from the simple sifting respectively 6, 8 and 12 mm, however, we can note a small difference in favor of coarse tamisats from double riddling of refusal, respectively of the mesh 6 mm on the mesh 8 mm and of the mesh 8 mm to the mesh 12 mm. The measured values of robustness ratio are in favor of the tamisat stem from the double riddling of refusal of the mesh 6 mm on the mesh 8 mm, however, this judgment remains to be confirmed as the vegetative development stage considered was not advanced.