Effect of Fertilizer Type and Method of Application on Nutrient Composition and <em>In-Situ</em> Rumen Degradability of Maize Straw

Abstract

The effects of fertilizer types and methods of application on the nutritive value and in situ rumen degradability of maize straw were assessed. The fertilizer types were; Low analysis fertilizer (LAF), with nutrient contents of less than 41% and High analysis fertilizer (HAF), with nutrient contents greater than 41%. The methods of fertilizer application used include A= beneath the seed at planting; B= beside the seedlings; C= in-between the seedlings; D= surface application; O= zero application or control. The LAF and HAF produced plant residues with high crude protein (CP) levels of 10.96 and 11.74% respectively compared to the 5.57% observed for the control. Crude fibre (CF) levels were however; lower in both LAF (40.26%) and HAF (36.68%) plant residues compared to that observed for the zero application (48.37%). Interaction of fertilizer types, and methods of application, influenced CP and CF values; with application method B recording high CP and comparatively low CF irrespective of fertilizer type. Rumen dry matter (DM) degradability of maize straw having HAF was consistently high across incubation periods. Application method B, recorded high DM degradability. The rate constant (c) and potential degradability (a +b) across fertilizer types and application methods ranged from 0.021-0.033 fraction/hr and, 61.95-74.12%. The results of this study therefore showed that both LAF and HAF can improve the feeding value of crop residues. However, application method is very critical in enhancing crop residues. Application of fertilizers beside the seedlings after seed emergence will increase CP and decrease CF contents of crop residues thus enhancing efficient utilization by livestock.

Keywords: Fertilizer, application method, nutrient, in-situ, degradability, maize straw