ROOT LENGTH DENSITY OF Acacia mangium Willd IN SAVANNAH SOIL

Abstract

To understand the chemical fertility of a Savannah soil in an Acacia mangium (Fabaceae) plantation, which is a timber-yielding species of rapid growth that fixes nitrogen and restores the natural properties of the soil, the pH, MO, CIC, P and exchange bases were analyzed during three seasons of the year (dry, rainy and north wind) at two depths (0-30 and 30-60 cm); in addition, the vertical and horizontal behavior of the fine root length density of the trees was estimated. Results showed that soil acidity increases with depth and during the rainy season. The highest MO content was observed during drought season, and it decreases with depth. The P content was low in general, as was the CIC for both parameters; the lowest values were found during the rainy season and at greater depth. All the exchange bases showed very low contents that tended to increase with depth and during the moist seasons, except for K. The vertical DR showed a greater development (51.5 %) in the first 20 cm, while the horizontal one was similar at all distances from the tree.