Composted Poultry Litter Effect on Tiller Dynamics, Herbage Mass and Crude Protein Concentration of BRACHIARIA BRIZANTHA CV. Mulato

Composted poultry litter (CPL) applied to field crops can be an important source of nutrients and organic matter to improve soil quality. However, little is known on the effects of CPL on tiller dynamics and forage yield of the tropical grass Brachiaria brizantha cv. mulatto. A study was conducted in the fall of 2003 and spring of 2004 to evaluate four CPL rates and their influence on number of tillers, herbage mass (g/plant), and crude protein (CP) concentration of cv. Mulato at three harvests at 30-d intervals. Treatments included 0 (Control; C), 16 (low; L), 31 (Medium; M), and 62 kg/ha of Ν (High; H) CPL rates. Grass seedlings (6-wk old) were established in pots (1-gl) filled with soil of the Consumo type (Fine, mixed, semi-active, isohyperthermic Typic Haplohumults). Composted poultry litter was broadcast-applied and incorporated into the first 2-cm of the soil in the pots. Plants were irrigated as needed. From first to the third harvest, there was a minimal increase in tiller count (8.4 to 11) for the control. Corresponding increases observed for the L and M CPL rates were 14 to 28 and 21 to 28 tillers/plant. However, the magnitude of change in tiller counts at the H CPL rate was much greater (21, 23, and 44) at first, second and third harvest, respectively. There was also a linear effect (P<0.05) of CPL rates on herbage mass (g/plant on dry matter basis). For C, there were no changes in herbage mass from first to last harvest (mean of 16 g per plant). For the L and M rates of CPL minimal changes in herbage mass were noted from the first to third harvest. Herbage mass increases from 31 to 56, and 81 g/plant at first, second, and third harvest, respectively at the H CPL rate. There were differences in CP of cv. Mulato with increasing rates of CPL. Crude protein averaged 7.2, 6.6, 7.2, and 9.1% for the C, L, M, and H rates, respectively (a 2 percentage unit increase over C with H CPL). An important aspect of this study is that cv. Mulato can serve as a sink for this nutrient-rich compost and can also provide a profitable and environmentally acceptable use of CPL.