Stop Nutrient Loss! Quiz Quiz

Strengthen your understanding of effective soil fertility management strategies for sustainable agriculture. Explore key concepts on nutrient retention, soil amendments, and environmental impacts.

1. Organic Matter Benefits

   A farmer applies composted manure to her field; which major benefit does this action provide for soil fertility?

   1. Causes immediate nutrient leaching
   2. Decreases soil pH dramatically
   3. Sterilizes soil to remove pests
   4. Increases soil organic matter and nutrient holding capacity

   Explanation: Adding composted manure enriches soil organic matter and helps the soil retain nutrients. It does not dramatically decrease pH, which is more commonly affected by chemical amendments. Compost improves nutrient availability rather than causing leaching. It does not sterilize soil; instead, it enhances beneficial microbial activity.

2. Nitrogen Loss Mechanisms

   Which process is most responsible for loss of nitrogen from agricultural soils as a gas, especially after heavy rainfall?

   1. Mineralization
   2. Phosphorylation
   3. Denitrification
   4. Cation exchange

   Explanation: Denitrification converts soil nitrate to nitrogen gases, often increasing after rainfall due to low oxygen and high microbial activity. Mineralization releases nutrients from organic matter, not as gas. Phosphorylation is not a soil nitrogen process. Cation exchange involves nutrient retention, not loss as a gas.

3. Soil Testing Purpose

   Why is regular soil testing recommended as part of fertility management before applying fertilizers?

   1. To determine existing nutrient levels and avoid over-application
   2. To make soil more acidic automatically
   3. To ensure soil never contains organic matter
   4. To prevent the need for irrigation

   Explanation: Soil testing allows for informed fertilizer use, reducing excess input and environmental risk. It is not used to remove organic matter, eliminate irrigation needs, or acidify soil directly. Over-application wastes resources and can harm soil and water.

4. Cover Crop Function

   A grower uses a leguminous cover crop during the off-season; what is the primary soil fertility benefit of this practice?

   1. Biological nitrogen fixation for soil enrichment
   2. Heavy pesticide requirement
   3. Soil compaction
   4. Increased soil erosion

   Explanation: Leguminous cover crops fix atmospheric nitrogen, enriching the soil for subsequent crops. They do not cause compaction, promote pesticide use, or increase erosion; in fact, they often reduce erosion and improve soil structure.

5. Phosphorus Management Concern

   Why should phosphorus fertilizers be managed carefully in fields near streams or lakes?

   1. To avoid iron deficiency in crops
   2. To prevent water pollution from runoff leading to algal blooms
   3. Because phosphorus instantly evaporates from soil surfaces
   4. Phosphorus has no effect outside the field

   Explanation: Runoff of phosphorus from farm fields can contaminate water bodies and trigger algal blooms, harming aquatic systems. Phosphorus does not evaporate, and overapplication does not directly cause iron deficiency. Its effects outside the field, especially in water bodies, are significant.