DRY MATTER YIELDS AND BOTANICAL COMPOSITION OF THREE GRASSES AND TWO LEGUME MIXTURES GRAZED BY CATTLE IN A DERIVED SAVANNA AREA OF NIGERIA

Abstract

A field experiment was conducted at the International Livestock Research Institute Ibadan, Nigeria between July 1998 and August 2000 to evaluate the dry matter yields and botanical composition of Panicum maximum (local), Panicum maximum (Ntchisi) and Brachiaria ruziziensis planted in mixtures with Centrosema pubescens ILRI 152 and Stylosanthes guianensis ILRI 164 (CIAT 184 cv. Pucallpa) and these species in sole stands. The grass/legume and sole pasture species were mob-grazed by White Fulani and N’Dama cattle one year after planting beginning from March 1999. Thirty-two mature animals (average of 3 years old) of mixed sex, amounting to a stocking density of 250 head ha^-1 grazed the plots at each grazing period. The pastures were evaluated for dry matter yield, botanical composition, and response of the species components to grazing effects. The dry matter yields of the pastures were lower at the year of planting than the subsequent years and the mean dry matter values averaged over the three years indicated that P. maximum (Ntchisi)/S. guianensis (9.7 t/ha), Sole P. maximum Ntchisi (10.2 t/ha) and sole S. guianensis (9.9 t/ha) produced significantly more than the other pastures. The yields by pastures that had B. ruziziensis (6.4 - 7.1 kg/ha) as sole crop or as grass/legume mixtures were among the lowest. During grazing, dry matter yields declined from March to December, apparently in response to effects of the intensive grazing. The mean values for dry matter yield indicated that P. maximum Ntchisi/S. guianensis mixture was more persistent under the heavy grazing effects with the value of 16.9 t/ha compared to 10.6 t/ha for sole B. ruziziensis. S. guianensis and C. pubescens constituted 18-21% and 24-25% respectively of the biomass of the grass/legume pastures one year after mob-grazing indicating that C. pubescens could be more resilient under intensive grazing in the derived savanna area of southwest Nigeria.