An Agronomic test of a period of eighteen month, was conducted in the town of Bonoua, to study the effect of organic fertilizer on the vegetative growth of immature plants of rubber trees (Hevea brasiliensis Müll Arg.), and the effect on chemical soil characteristics. A randomized complete block (BCR) of eight treatments and three repetitions, using two sources of organic manure with three levels of doses each, has been set up. The data on the growth unit (CPU), the diameter of the scion (DS) and the height (H) of plants, were observed every six months, starting from the implementation of the tests. Soil samples were also collected, with the same frequencies for analysis. The results showed that, on chemical soil characteristics, some differences relative to control without fertilizers, thus indicating some improved effects of the two types of compost on the studied soil, concerning pH, organic matter content and the cation exchange capacity. Unlike the cow manure-based compost, the increasing of the dose of compost made from chicken droppings resulted lesser effects on soil pH. Vegetative growth in plant height and diameter of the scion were also improved respectively with 24.45% and 15.60%, compared to the control (without fertilizer), through the used of 1.2 t ha-1 of compost of chicken manure. So, under the conditions of this study, this manure, at this level, can be recommended on immature rubber plants.