Gce Model Questions Vol1 2022 Geography Question 20

Using the Universal Soil Loss Equation (USLE), estimate the average annual soil loss for a field with the following parameters: - Rainfall erosivity factor \(R = 300\) (MJ·mm ha⁻¹ h⁻¹ yr⁻¹) - Soil erodibility factor \(K = 0.03\) (t·ha·h·ha⁻¹·MJ⁻¹·mm⁻¹) - Slope length \(\lambda = 150\) m - Slope gradient = 12%\n- Cover‑management factor \(C = 0.2\) - Support practice factor \(P = 0.5\) The slope length‑steepness factor \(LS\) is to be calculated with the empirical formula \(LS = \left(\frac{\lambda}{22.13}\right)^{0.5} \times \left(\frac{\sin \theta}{0.0896}\right)^{1.3}\), where \(\theta\) is the slope angle (\(\theta = \arctan(\text{slope%}/100)\)). Calculate \(LS\), then the predicted soil loss \(A = R \times K \times LS \times C \times P\) (t·ha⁻¹·yr⁻¹). Is the predicted loss above the critical threshold of 5 t·ha⁻¹·yr⁻¹?