Effects of Varying Levels of Inorganic Fertilizer Application on the Underground and Nutritive Response of Panicum maximum cv. T58 (Guinea Grass)

Abstract

A pot experiment was conducted at the pasture unit of Ladoke Akintola University of Technology Ogbomoso, Nigeria, Teaching and Research Farm, to study the effect of inorganic fertilizer application levels on the underground response of Panicum maximum. The varying levels were 0 (control), 50, 100 and 200kg/ha NPK 15:15:15. Four cutting frequencies at 4^th, 8^th, 12^th and 16^th weeks were done. It was observed that the shortest and longest root length in week 16 for the control treatment has the value of 3.63cm and 62.70cm respectively. At inclusion level of 50kg/ha (1.5g/pot), 100kg/ha (3g/pot) and 200kg/ha (6g/pot) there were significant differences (P<0.05) between root lengths and Biomass yield for the weeks examined. The root length and biomass yield were observed to increase as the week increased. The possible increase in root length will ascertain the potential of the plant to be able to draw up nutrient from the deep soil and also withstand possible adverse weather conditions. The interactive effect of varying levels of inorganic fertilizer application on the chemical composition of the plant at various weeks revealed an increase in the Dry Matter, Crude Protein and Ash content with increase in fertilizer level and age at harvest. At week 12 of 100kg/ha, values for the crude fibre decreased with increase in the level of fertilizer applied. The Ether Extract was inconsistent with application rate and age at harvest as the highest value (2.95%) was observed at week 12 with 200kg/ha (6g/pot).The potassium and phosphorus levels in the forages increased with increase in fertilizer and age at harvest. From the result it is evident that inorganic fertilizer application at varying levels and age at harvest has effect on the nutrient content of the root and biomass yield of Panicum maximum. The root length (shortest and longest) and biomass yield also increased significantly as levels of fertilizer application increased and with age of harvest. . Increase in biomass yield will ensure forage availability for ruminant animals.

Keywords: Panicum maximum, roots length, biomass yield.