Ecological characteristics of hyparhhenia diplandra (hack) stapf savannah in ignie area, north of brazzaville, Congo

The knowledge of the Congo savannahs requires studies on the floristics and the production of herbaceous aerial phytomass, in relation to the soils. The general objective of this study was to characterise Hyparrhenia diplandra(Hack) Stapf savannah in Ignié zone in terms of floristics and herbaceous above-ground production in relation to soils. Four plots of 50 m each were delimited. The floristic inventory was carried out by the method of aligned quadrat points. Shrub density was determined by counting individuals per species in an area of 100 m2 with 5 replicates. Floristic diversity was estimated by calculating diversity indices. Herbaceous above-ground phytomass was measured by the integral harvesting method. Soil samples were collected and air-dried and analysed for grain size and chemical composition. The results showed that the flora i was less diverse (Shannon index ranging from 1.39 to 3.02) and the distribution of species was not equitable (equitability index ranging from 0.42 to 0.67). Herbaceous above-ground phytomass and shrub density ranged from 4.75 to 6.85 t DM/ha and from 4.8 to 9.8 shrubs/100 m2 respectively. The soils are sandy, acidic, with average levels of organic matter (2.16 to 2.77%). These results indicate that the savannah studied could be used for agricultural and pastoral activities.