Dose Wise! Fertilizer Facts Quiz Quiz

Explore essential knowledge of recommended fertilizer application rates and methods for effective agriculture. Understand how to match crop needs and minimize waste for sustainable growth.

1. Nitrogen Rate Basics

   What is the main reason for adjusting nitrogen fertilizer application rates based on crop type and soil test results?

   1. To make fertilizers available year-round
   2. To match nutrient demand and prevent over-fertilization
   3. To grow crops with identical yields every season
   4. To increase fertilizer company profits

   Explanation: Application rates are adjusted to ensure plants receive enough nutrients without excess waste, reducing environmental impacts. Increasing profits or guaranteeing identical yields are not direct reasons for adjusting rates. Fertilizer availability is a logistical, not agronomic, concern.

2. Phosphorus Application Examples

   If a soil test shows low phosphorus and you are planting corn, which action promotes optimal growth?

   1. Avoid phosphorus fertilizer entirely
   2. Double the standard rate for insurance
   3. Use a rate intended for soybean fields regardless of soil
   4. Apply a phosphorus rate recommended for low-testing soils and corn needs

   Explanation: The recommended rate based on both soil test and crop ensures adequacy. Using rates for other crops or ignoring soil phosphorus can lead to deficiencies or inefficiency. Doubling the rate wastes inputs and can cause environmental harm.

3. Potassium Rate Considerations

   Why should potassium application rates be adjusted in sandy soils?

   1. Because sandy soils are always high in potassium
   2. Because potassium is unused by most plants
   3. To make the fertilizer last longer
   4. Because sandy soils have a lower nutrient-holding capacity

   Explanation: Sandy soils retain less potassium, requiring rate adjustments. They are not always high in potassium, and potassium is essential for plant growth. Adjusting to make fertilizer last longer is unrelated to the soil's nutrient-holding capacity.

4. Fertilizer Timing

   For most field crops, why is it important to split nitrogen applications during the growing season?

   1. To limit crop water uptake
   2. To double the application workload
   3. To reduce leaching losses and match nutrient uptake periods
   4. To maximize fertilizer bag sales

   Explanation: Splitting nitrogen applications helps plants absorb nutrients when needed and reduces loss through leaching. It does not intentionally increase work or costs, and it does not aim to limit water uptake.

5. Calculating Application Rates

   If a recommendation calls for 60 kg nitrogen per hectare and your fertilizer contains 30% nitrogen, how many kg of fertilizer per hectare should you apply?

   1. 200
   2. 20
   3. 180
   4. 30

   Explanation: Applying 200 kg of 30% nitrogen fertilizer provides 60 kg nitrogen (0.3 x 200 = 60). Lower rates would provide insufficient nitrogen, and 180 or 30 kg do not meet the required amount.