DOLOMITE, PHOSPHORUS AND NITROGEN FERTILIZATION AFFECT BIOMASS PRODUCTION AND SEED QUALITY OF FODDER SPECIES BRACHIARIA RUZIZIENSIS GERM. and EVRARD, STYLOSANTHES HAMATA (L.) AND STYLOSANTHES GUIANENSIS (AUBL.).

Seed production of forage species in the natural rangelands reflects its ability to reseed and enrich the rangeland. This study aims to evaluate the effect of dolomite and phospho-nitrogen fertilization on the biomass production and seed quality of Brachiaria ruziziensis, Stylosanthes hamata, and Stylosanthes guianensis in Burkina Faso. Thus, two split plots experimental setups were established in the Farako-Bâ, Burkina Faso. The first block without dolomite was composed of nine treatments in four repetitions. The experiment involved the cultivation of Brachiaria ruziziensis (Ruzi, Congo grass) on elementary plots of 30 m2, with treatments consisting of two doses of dolomite (0 and 400 kg. ha-1), three doses of nitrogen (N) (0; 50; and 100 kg N. ha-1) and three doses of phosphorus (P) (0; 50 and 100 kg P2O5.ha-1). In the second experiment design, two varieties of Stylosanthes were grown, with treatments including two doses of dolomite (0 and 400 kg. ha-1) and three doses of P (0; 50; and 100 kg P2O5.ha-1). Each elementary treatment was repeated 4 times in the experimental design. The results showed that the application of dolomite, P and N significantly influenced the biomass of Brachiaria ruziziensis. The plot treated with dolomite and fertilized at doses of 50 P/ha and 100 N. ha-1 provided a biomass (7403 kg DM. ha-1) ten times greater than that treated with dolomite and fertilized at doses of 100 kg P. ha-1and 100 N. ha-1 (734 kg DM. ha-1). For seed quality, N influenced the rate and germination speed of Brachiaria ruziziensis. In addition, the contribution of dolomite to the variety of Stylosanthes hamata influenced grain yield and 1000-grain weight respectively (P<0.05). S. hamata variety showed better performance with grain yield of 191 kg. ha-1and 3.81 g/1000 seeds. Based on these results, phospho-nitrogen fertilization seems necessary to increase the biomass production and the grain yield of Brachiaria ruziziensis. This implies that a combination of P and N fertilizers with dolomite would be beneficial for enhancing the productivity of this species. [ABSTRACT FROM AUTHOR]