Neco 2021 Geography Question 50

The Universal Soil Loss Equation (USLE) estimates average annual soil loss \(A\) (ton ha\(^{-1}\) yr\(^{-1}\)) as \(A = R\,K\,L\,S\,C\,P\). For a field the following data are given: rainfall‑erosivity factor \(R = 300\), soil erodibility factor \(K = 0.25\), slope length \(\lambda = 150\) m, slope angle \(\theta = 5^{\circ}\), cover‑management factor \(C = 0.30\), and support practice factor \(P = 1.0\). The slope‑length factor \(L\) and slope factor \(S\) are combined as \(LS = \left(\frac{\lambda}{22.13}\right)^{m}\bigl(65.41\sin^{2}\theta + 4.56\sin\theta + 0.065\bigr)\), where \(m = 0.5\) if the slope percent is less than 5 % and \(m = 0.8\) otherwise. (Slope percent = \(\tan\theta \times 100\)).\n(a) Compute the combined \(LS\) factor for the field.\n(b) Using the USLE, calculate the original annual soil loss \(A_{1}\).\n(c) If a conservation practice reduces the support practice factor to \(P = 0.5\), compute the new soil loss \(A_{2}\) and the percentage reduction in soil loss.