Evaluation of Poultry Manure Application Rates on the Nutrient Composition of Dioscorea bulbifera (Aerial yam)
An experiment was conducted to evaluate the effect of various levels of poultry manure application on the nutritional value and functional properties of Dioscorea bulbifera. The experiment was a randomised complete block design on a plot size of 8 m2 with a planting space of 50 cm x 1 m, using 5 levels of poultry manure: 0, 1, 2, 3 and 4 tonnes/ hectare. Standard analytical methods were used to determine the proximate and mineral composition as well as the functional properties of the bulbils. Poultry manure application significantly increased the starch content. The highest starch yield (13.50%) was observed at 4 tonnes/hectare poultry manure application. The dry matter and fat contents were not significantly affected by poultry manure application. Crude fibre, ash and crude protein contents were significantly affected by poultry manure application. Ash content ranged from 3.41 – 4.68% with 4 t/ha level of application having the highest ash content. The crude protein content ranged from 2.48 – 6.28%. The highest crude protein content was observed at 3 t/ha. The total carotenoid content was not significantly affected by poultry manure application. The phosphorus, calcium and magnesium contents were significantly affected by poultry manure application. Water and oil absorption capacity increased with increase in the level of poultry manure while the bulk density was not significantly affected by the level of poultry manure. Application of poultry manure was found to significantly influence the nutrient content and functional properties of D. bulbifera.
Keywords: Dioscorea bulbifera, poultry manure, proximate composition, functional properties.