Sustainable Agriculture and Conservation Flashcards

What is nitrogen use efficiency (NUE) in crop production?

Answer: The proportion of applied nitrogen that is taken up and used by the crop

NUE measures what fraction of the nitrogen applied as fertilizer is actually taken up and utilized by the crop, with typical values around 50% for corn.

Which soil conservation practice involves planting alternating strips of different crops across a slope?

Answer: Strip cropping

Strip cropping alternates strips of row crops with close-growing crops or sod across a slope, reducing water velocity and trapping sediment eroded from row crop strips.

What is biological nitrogen fixation (BNF) in agriculture?

Answer: The conversion of atmospheric N2 to plant-available ammonia by symbiotic or free-living bacteria

BNF is the microbial process by which certain bacteria, notably Rhizobium in legume root nodules, convert atmospheric N2 gas into ammonia available for plant nutrition.

What is the Universal Soil Loss Equation (USLE) used to estimate?

Answer: Average annual soil erosion from rainfall and runoff on cropland

The USLE estimates average annual soil loss (tons/acre/year) from sheet and rill erosion on cropland based on rainfall, soil erodibility, slope, and management factors.

Which soil health indicator is most directly improved by increasing crop diversity in a rotation?

Answer: Soil biological diversity and microbial biomass

Diverse crop rotations feed a wider variety of soil microorganisms through different root exudates and residue qualities, increasing soil biological diversity and activity.

What is the primary environmental concern associated with excess nitrate leaching from agricultural soils?

Answer: Groundwater and surface water contamination causing hypoxia and health risks

Nitrate leaches readily through soil into groundwater and streams, contaminating drinking water and contributing to aquatic hypoxia (dead zones) in water bodies.