WAEC Agriculture 2023 Paper

Concept:Yam and cassava need a nitrogen-rich fertilizer to support strong leafy growth, which later helps tuber formation.Explanation:The recommended NPK ratio for cultivating yam and cassava is $20:10:10$.This means the fertilizer contains $20$ parts nitrogen, $10$ parts phosphorus, and $10$ parts potassium.The percentage of nitrogen ($\mathrm{N}$) is therefore higher than that of phosphorus ($\mathrm{P}$) and potassium ($\mathrm{K}$).Nitrogen stimulates rapid vegetative growth and improves leaf development in yam and cassava, especially during the early growth stages.This strong canopy encourages better photosynthesis, which supports healthy root and tuber development.Answer:Option B: $20:10:10$.