AP Human Geography – Agriculture Practice Test

Protecting soil fertility on sloped or fragile lands relies on practices that reduce erosion and keep nutrients, organic matter, and soil structure in place. Terraces break a steep gradient into stepped levels, slowing water flow, trapping soil, and allowing farming without washing away the topsoil. Contour farming follows the land’s curves to form small ridges that disrupt runoff and keep soil and nutrients where plants can access them. Cover crops protect the soil surface during off-seasons or between main crops, add organic matter, and can fix nitrogen or otherwise improve soil fertility and structure. Reduced tillage disturbs the soil less, preserving its structure and reducing erosion, so nutrients stay near the surface where roots can reach them. Together, these methods keep soil depth and health on slopes.

In contrast, more intensive tillage and removing crop residues increase erosion and nutrient loss; planting only one crop with no rotation depletes specific nutrients and can raise pest and disease problems; burning fields after harvest removes protective cover and valuable organic matter, harming soil structure and fertility.