Natural Resources and Their Conservation
What this domain tests
This domain covers renewable and non-renewable resources, forest, water, soil, mineral, energy and food resources, and conservation methods. The exam tests sustainable use, resource conflicts, watershed management, soil conservation and energy alternatives.
Core rules and concepts
- A resource is renewable only if its use rate stays below its regeneration rate; otherwise it is being mined.
- Forests provide timber, fuel, fodder, watershed protection, carbon storage and biodiversity habitat. Conservation includes afforestation, social forestry, agroforestry and protected areas.
- Soil erosion is controlled by contour ploughing, terracing, strip cropping, check dams, mulching and vegetative cover.
- Groundwater is a stock resource: recharge, discharge and extraction must balance. Watershed management links land use, water harvesting and soil conservation.
- Non-renewable minerals and fossil fuels need efficient use, recycling, substitution and extended producer responsibility.
Worked example
A watershed has recharge of 80 mm yr⁻¹ and extraction of 110 mm yr⁻¹, a deficit of 30 mm yr⁻¹. Over 10 years the water equivalent lost is 300 mm. If the aquifer's specific yield is 0.1, the water-table decline is 300 ÷ 0.1 = 3,000 mm = 3 m. Reason: specific yield converts water volume per area into water-table drop. This shows why a small annual deficit can cause serious groundwater mining.
Traps that cost marks
Do not call all natural resources renewable. Distinguish soil erosion from soil fertility loss. Reforestation is not automatically equivalent to conserving an old-growth forest. In water budgets, separate rainfall, runoff, recharge and evapotranspiration. Conservation is not non-use; it is wise, sustainable use.