WAEC Agriculture 2021 Paper

Concept:When soil is burned, organic matter is oxidised and lost as gases, so the reduction in soil weight represents the organic matter content.Explanation:Weight of over-dried soil before burning = $50\,g$Weight of over-dried soil after burning = $28\,g$Loss in weight due to burning = $50 - 28 = 22\,g$This loss equals the amount of organic matter present in the soil sample.Percentage of organic matter in the soil = $\frac{\text{loss in weight}}{\text{original weight}} \times 100$Percentage of organic matter = $\frac{22}{50} \times 100 = 44\%$Answer:$44\%$Therefore, the correct option is C.