Natural Resources and Environmental Science
Domain 6: Natural Resources and Environmental Science
This domain tests ecosystems, watersheds, soil and water conservation, wildlife habitat, forestry, air and water quality, and renewable and nonrenewable energy. Questions often ask you to select conservation practices, interpret water-quality data, or calculate stocking rates.
Core rules and concepts
- A watershed is all land that drains to a common water body. Nonpoint-source pollution comes from diffuse runoff; point-source pollution comes from a specific outlet.
- Erosion occurs when soil detachment exceeds deposition. Conservation practices include contour farming, terraces, strip cropping, cover crops, and riparian buffers.
- Water quality is assessed by temperature, dissolved oxygen, pH, turbidity, nitrates, and biological indicators.
- Wildlife habitat requires food, water, cover, and space. Carrying capacity is the maximum sustainable population; stocking rate is the number of animals placed on an area.
- Renewable energy includes solar, wind, and biomass; fossil fuels are nonrenewable.
Worked example
A 1,000-lb cow eats 2.5% of body weight daily: 25 lb/day × 365 = 9,125 lb forage/year. If the pasture produces 1,000 lb forage/acre and half is harvested, available forage is 500 lb/acre. Acres per cow = 9,125 ÷ 500 = 18.25 acres. The reasoning is to use available forage, not total growth, and to account for grazing utilization.
Traps that cost marks
- Confusing point-source and nonpoint-source pollution.
- Using total forage production without accounting for utilization.
- Confusing weather with climate or carrying capacity with stocking rate.
- Ignoring riparian buffers when recommending erosion control.