Concept:Soil depletion is the loss of soil fertility or nutrients due to natural and human activities.Explanation:Erosion washes or blows away fertile topsoil.Leaching removes nutrients as water drains through the soil.Illegal mining disturbs and degrades the soil.Afforestation means planting trees in areas that were not previously forested.Trees protect the soil and add organic matter, so afforestation does not deplete the soil; it improves it.Answer:B. afforestation.