Neco Model Questions Vol1 2023 Agricultural Science Question 38

Soil tests show available nutrients of \(N=30\) kg ha\(^{-1}\), \(P=15\) kg ha\(^{-1}\), and \(K=20\) kg ha\(^{-1}\). The target maize yield is \(8\) t ha\(^{-1}\). Nutrient removal per tonne of maize is \(20\) kg N, \(5\) kg P, and \(15\) kg K. After harvest the farmer wants to have at least \(N=40\) kg ha\(^{-1}\), \(P=25\) kg ha\(^{-1}\), and \(K=30\) kg ha\(^{-1}\) remaining in the soil. Fertiliser sources are urea (46 % N), single superphosphate (20 % P\(_2\)O\(_5\)), and muriate of potash (60 % K\(_2\)O). Their use efficiencies are \(70\%\) for N, \(60\%\) for P, and \(50\%\) for K. Calculate the amounts of urea, single superphosphate and muriate of potash (in kg ha\(^{-1}\), rounded to the nearest kilogram) that should be applied.