Influence of nitrogen fertilization on the chemical composition of Paspalum plicatulum at differents phenological stages in the central plateau of Fouta-Djallon

The direct and residual effect of different levels of nitrogen fertilization on the chemical composition of Paspalum plicatulum at different phenological stages was conducted at the Bareng Agronomic Research Center in the Central Plateau of Fouta-Djallon between May 2014 and December 2015. A factorial design comparing six nitrogen doses (0 ; 50 ; 100 ; 150 ; 200 and 250 kg N/ha) combined with three phenological stages (bolting, flowering and after seedling) on plots of 8 m2 (4 m x 2 m) in four replicates, for a total of 72 experimental plots was used. In the second year, no fertilization was done. A representative sample of 500 g of P. plicatulum whole plants was collected on each plot, separated into stems and leaves, and then dried at 60 °C for the chemical composition evaluation. The results of this study showed that nitrogen fertilization influenced variably the chemical composition of P. plicatulum regardless of the phenological stage and the cutting year. In fact, crude protein, Ash, digestible organic matter, digestible nitrogenous matter and metabolizable energy increased significantly (p<0.05) with the direct and residual effect of nitrogen fertilization up to the optimum dose of 200 kg N/ha. However, dry matter and crude fiber contents of the plant were not significantly influenced by nitrogen fertilization irrespective of the phenological stage during the two years of cutting.