Neco 2020 Agricultural Science Question 5

A farmer intends to implement a three‑year crop rotation on a 9‑hectare farm. The rotation will consist of maize (Year 1), cowpea (Year 2) and cassava (Year 3), each cultivated on 3 ha. Soil analysis of the field gave the following results: pH = 5.5, organic matter = 2 %, available nitrogen = 45 kg ha⁻¹, available phosphorus = 12 kg ha⁻¹ and available potassium = 90 kg ha⁻¹. The target soil pH for optimal maize production is 6.5. The recommended lime requirement for a sandy‑loam soil is 2.5 t ha⁻¹ for each unit increase in pH. Recommended fertilizer rates are: - Maize: 120 kg N, 60 kg P₂O₅ and 40 kg K₂O per hectare, - Cowpea: 30 kg N, 20 kg P₂O₅ and 15 kg K₂O per hectare, - Cassava: 50 kg N, 25 kg P₂O₅ and 30 kg K₂O per hectare. Expected yields after proper soil amendment are 4.5 t ha⁻¹ for maize, 1.8 t ha⁻¹ for cowpea and 12 t ha⁻¹ for cassava. Answer the following: