Effect of sources of phosphorus on "in vitro" digestibility of dry matter, organic matter and total digestible nutrients of Mombaça grass (Panicum maximum Jacq. Cv. Mombaça)

Abstract

The trial was performed to evaluate the effect of phosphorus sources on forage mass quality of Mombaça grass (Panicum maximum Jacq. cv. Mombaça), according to in vitro dry matter and organic matter digestibility and TDN concentration. Every month, samples of available forage mass were taken, from December, 2002 until April, 2003. The treatments were three phosphate sources (1-YoorinÃ†Ê magnesium thermophosphate; 2-GafsaÃ†Ê natural phosphate; 3-simple superphosphate + triple superphosphate) and the control (no fertilizer). They were arranged in a randomised block design with three replications. It was used 12 plots sized from 0,7 to 1,0 hectare, which were delimited by two-line eletric fence. The grazing method was continuous stocking and variable stocking rate ("put-and-take"). The IVDMD, IVOMD and TDN coefficients decreased along sampling period. IVDMD, IVOMD and TDN concentration didn't show significantly differences among treatments (P>0.05).