Practice Test Geeks(GAP) Good Agricultural Practices Certified Practice Test
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Soil Science & Analysis Flashcards

7 cards from real GAP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Soil Science & Analysis flashcards as text

  1. A soil test indicates a base saturation of 65% calcium, 15% magnesium, 4% potassium, and 16% hydrogen. What does the hydrogen saturation level suggest?

    Answer: The soil is acidic and likely needs liming to raise pH

    Hydrogen occupying 16% of cation exchange sites indicates significant acidity; ideal productive soils have very low hydrogen saturation, typically below 5–10%.

  2. Which of the following soil organisms plays the most direct role in converting raw organic residues into stable humus?

    Answer: Earthworms and decomposer bacteria working together

    Earthworms shred and mix residues while decomposer bacteria and fungi break organic material into smaller compounds, collectively building stable humus through combined activity.

  3. A GAP farm near a former orchard is concerned about arsenic contamination in soil. What is the recommended first step?

    Answer: Conduct certified laboratory soil testing for arsenic levels before production

    The first step is always laboratory testing to determine actual arsenic levels, as historic pesticide use in orchards (e.g., lead arsenate) can leave persistent contamination.

  4. What is the recommended soil sampling depth for most annual vegetable crop nutrient analysis under GAP guidelines?

    Answer: 0–6 to 0–8 inches (plow layer)

    The standard 0–6 or 0–8 inch sample depth captures the plow layer where most nutrient availability and crop root activity occurs in annual vegetable production.

  5. Which of the following is the most reliable indicator of long-term soil health improvement on a GAP farm?

    Answer: Increasing soil organic matter percentage measured over multiple years

    Rising soil organic matter percentage over time is the most reliable composite indicator of improving soil biology, structure, fertility, and long-term productivity.

  6. When interpreting a soil texture triangle, a soil with 40% sand, 40% silt, and 20% clay would be classified as:

    Answer: Loam

    Plotting 40% sand, 40% silt, and 20% clay on the USDA soil texture triangle places the sample squarely within the 'loam' classification.

  7. Under GAP principles, which situation would most justify delaying harvest to protect food safety from a soil-related hazard?

    Answer: Recent flooding event has deposited sediment and potential pathogens on produce surfaces

    Flooding can deposit fecal pathogens from upstream sources directly onto produce; GAP guidelines recommend withholding harvest and testing for contamination after flood events.