ASSESSMENT OF ENVIRONMENTAL IMPACT AND NUTRIENT CONTENT OF PALM OIL SLURRY IN LIVESTOCK NUTRITION IN NIGERIA

Abstract

TDump Sitehe aim of this study was to assess the nutrient content and environmental impact of palm oil slurry (POS) disposal on soil of some selected palm oil processing locations in South-western Nigeria. Soil samples were collected from three different dump sites (DS) and a non-dump site (NDS) in South-western Nigeria to determine the proximate, physico-chemical and microbiological characteristics. The POS was fermented at 24 hourly intervals for 72 hours to determine its nutrient content. Results revealed significant variation for chemical composition of slurry in dry matter, crude protein and neutral detergent fibre, (15.31 - 40.12; 6.21 – 9.05 and 46.03 - 52.14 % for 0 – 72 hours fermentation respectively). Significant variations for pH, water holding capacity, organic carbon, total nitrogen and available phosphorus, ranged from 5.75 - 6.68; 23.01 - 36.18 %; 2.58 - 3.31 %; 13.03 - 14.50 % and 22.02 - 28.00 ppm in NDS and DS respectively. Same trend was observed for the microbial count (log₁₀cfu/g): Total heterotrophic bacteria count, hydrocarbon utilizing bacteria count, hydrocarbon utilizing fungi count ranging from 6.89 – 8.28; 2.53 - 6.02 and 2.73 – 3.15 respectively. However, significant differences also occurred between the various slurry DS and NDS for total heterotrophic fungi count and nitrifying bacteria ranging from 8.01 – 4.00 and 3.84 – 2.89 in NDS and DS respectively. The biological oxygen demand (BOD) of the POS increased persistently over a period of five years in the range of 255 – 5000 mg/liter. Similarly, the chemical oxygen demand (COD)   took the range of 500 – 8000 mg/liter. Slurry DS were altered; however, proper use and safe disposal of POS on the soil could lead to improved soil fertility. Fermentation of POS increased protein content (maggot buildup) which could be beneficial to livestock, most especially fish farmers.