Effect of manure type and season of harvest on the forage yield, quality and macro-elements of two <i>Panicum maximum</i> varieties

Abstract

A two year study was carried out to evaluate the effect of manure type and season on forage yield, quality and macro elements of two Panicum maximum varieties. The manures used are those of cattle, swine and poultry, the two P. maximum varieties are Local and Ntchisi whereas the seasons are the rainy and dry seasons. The grass samples were harvested and yield measured from each plot, the samples harvested were used in the determination of the dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and macro-elements (P, Ca, K, Mg and Na). The grasses harvested in the rainy season (14.55 vs 15.76 tha^-1 for 2010 and 2011 respectively) had better yield (P<0.05) than those of the dry season (12.2 vs 13.32 tha^-1 for 2010 and 2011 respectively) in both year of the study. Grasses fertilized with swine manure outweighed others in both years  (16.65 vs 18.51 tha^-1 for 2010 and 2011 respectively) and P. maximum Ntchisi was  performed better than P. maximum Local. The crude protein (CP) content of grasses harvested in the rainy season (104.20 vs 110.30 g kg^-1DM for 2010 and 2011  respectively) was higher than those of dry season, the CP content of grasses  fertilized with cattle dung was highest in the first year and grasses fertilized with swine manure had the highest CP content in the second year, though statistically similar to those fertilized with cattle dung. The neutral detergent fibre (NDF) of the grasses fertilized with poultry manure (594.01 vs 580.12 g kg-1DM for 2010 and 2011 respectively) was the least (P<0.05) for both years and P. maximum Ntchisi had the least NDF  content. The grasses harvested in the dry season in both years recorded higher (P<0.05) values for P (3.18 vs 3.21 g kg^-1DM), Ca (5.99 vs 5.82 g kg^-1DM) and Mg (2.23 vs 2.25 g kg^-1DM) concentrations for 2010 and 2011  respectively, while the grasses harvested in the rainy season had higher (P<0.05) values for K (8.79 vs 8.83 g kg^-1DM) and Na (1.63 vs 1.52 g kg^-1DM)    concentrations for 2010 and 2011 respectively. Grasses fertilized with swine manure had the highest P concentration, Ca   concentration in the first year was  recorded for unfertilized grasses. Grasses fertilized with cattle dung had the highest Mg (2.13 vs 2.18 g kg^-1DM) concentration in 2010 and 2011 respectively whereas the K (8.87 vs 8.61 g kg^-1DM) and Na (1.71 vs 1.90 g kg^-1DM) concentrations for 2010 and 2011 respectively were recorded for grasses fertilized with swine manure and unfertilized ones respectively. Panicum maximum Ntchisi had higher values of Ca (5.63 vs 5.49 g kg^-1DM), Mg (2.23 vs 2.01 g kg^-1DM), K (8.38 vs 7.93 g kg^-1DM) and Na (1.34 vs 1.29 g kg^-1DM) concentration for 2010 and 2011 respectively. It could be concluded that manured P. maximum varieties are a very good source of macro minerals for ruminant livestock.

Keywords: Mineral, grasses, ruminant, Guinea grass, concentration.