EFFECT OF SOLE AND COMBINED APPLICATION OF ANIMAL MANURE AND NPK FERTILIZERS ON SOIL PHYSICO-CHEMICAL PROPERTIES AND NUTRIENT STATUS OF YAM

The effects of sole and combined application of animal manure and NPK fertilizer on soil physic-chemical properties and nutrient status of yam were studied and compared in a research conducted in Akure, Ondo State (Latitude 71º81N and Longitude 5º151E) Nigeria in 2010, 2011 and 2012.

Seven treatments combinations were evaluated as to how amendments affects yam nutrient uptake. The amendments used during the second and the third amendments were dependents on the first experiments. Soil physical properties were improved by goat and poultry manure and their combined application with NPK fertilizer. Sole animal manures applied alone or applied in combined form at the rate of 2 to 12 tha-1 significantly reduced soil bulk density (1.11 g/cm3 to 0.89 g/cm3), temperature (31.7º to 28.7º) and increased moisture content (7.29%- 8.59%). Integrated application of animal manure and NPK fertilizer at reduced rate gave less values of leaf N, P K Mg and Ca. Integration of animal manures with NPK fertilizer reduces requirement for fertilizer to about 25%, manures at 6 to 12 tha-1 were effective in this regard.