Determination of Mineralization Rate of Organic Materials Using Carbon Dioxide Evolution as an Index

A study was conducted on a sandy loam soil to determine the rate of CO2 release by Kola Pod Husk (KPH) and Pacesetter Grade B (PGB) (sorted city waste plus cow dung) in southwest Nigeria. Each of KPH and PGB was applied at 0.25 g to 50 g soil; and control without treatment application was incubated for 16 weeks. The treatments were replicated four times on a completely randomized design. Evolution of CO2 by all the treatments increased as the period of incubation increased from the first week to the 5th week of the experiment. After the 6th week, PGB decreased CO2 at 7th and 8th week and increased it between 9th and 11th week and thereafter finally decreased it as incubation period progressed. KPH decreased CO2 between 7th and 8th week and then increased it from 9th - 11th week before the CO2 finally declined till the termination of the experiment. Compared with control, KPH and PGB significantly (P< 0.05) increased CO2evolution. The rate of mineralization in the first 1-7 weeks of incubation was in the order of PGB > KPH> control, while the last 12-16 weeks of incubation was in the order of KPH>PGB> control. Pacesetter Grade B reached its peak of CO2 evolution at 9th week of incubation while KPH reached its peak at 13th week of incubation. Grade B pacesetter had the highest CO2 emission.