GAP Soil Science & Analysis 2

Question 1

A soil test reports a cation exchange capacity (CEC) of 5 meq/100g. This soil is best described as:

Accepted Answer

Sandy with low nutrient-holding capacity

Answer

A CEC of 5 meq/100g indicates a coarse, sandy soil with limited ability to retain cations like calcium, magnesium, and potassium.

Question 2

Which nutrient is most commonly tied up and unavailable to plants when soil pH drops below 5.5?

Accepted Answer

Phosphorus

Answer

Phosphorus becomes fixed by iron and aluminum compounds in acidic soils below pH 5.5, making it largely unavailable to plants.

Question 3

What does a high electrical conductivity (EC) reading in a soil test indicate?

Accepted Answer

Excessive soluble salts that may harm crops

Answer

High EC indicates excessive soluble salts in the soil, which can cause osmotic stress, reducing water uptake and crop yields.

Question 4

In the context of GAP, why is it important to test soil for heavy metals before growing fresh produce?

Accepted Answer

Contaminated soil can transfer heavy metals to edible crops, posing food safety risks

Answer

Heavy metals like lead, cadmium, and arsenic can accumulate in produce grown in contaminated soil and pose serious health risks to consumers.

Question 5

Which soil texture has the best balance of drainage and water-holding capacity for most vegetable crops?

Accepted Answer

Silt loam

Answer

Silt loam provides a good balance of pore sizes, allowing adequate drainage while retaining sufficient moisture and nutrients for vegetable production.

(GAP) Good Agricultural Practices Certified Practice Test

(GAP) Good Agricultural Practices Certified Practice Test

GAP Soil Science & Analysis 2