laboratory experiment was conducted using the completely randomised design (CRD) to estimate CO2 released from the soil in one of the labs at the College of Agriculture and Forestry using two levels of fungus inoculant (without inoculation and inoculation with Trichoderma harzianum) with 10 cm3, and two levels of cow amendment (without manuring and 2% manure). This experiment was conducted in two types of soils, the first was taken from one of the fields at the College of Agriculture and Forestry and the second soil was taken from the Zaweetah area, which is planted with pine trees targeting the release of CO2 that is considered as an indicator of the biological decomposition of organic fertilisers. The experimental units were incubated for 10, 20, 40 and 60 days at a temperature of 28°C ±2. The results showed that inoculating the soil with T. harzianum fungus, in the presence of the organic amendment (cow manure), gave the highest value of CO2 release at the incubation period of 40 days for both soils as the CO2 release values were 52.9 and 57.7 mg.100 g–1 soil. Moreover, a decrease in the quantity of CO2 released was observed at the incubation period of 60 days in both soils.
