CCA Crop Management 3 — Questions and Answers
Question 1: In integrated pest management (IPM), what is the correct order of pest management tactics by preference?
- Chemical, biological, cultural, prevention
- Prevention, cultural, biological, chemical (Correct answer)
- Biological, prevention, chemical, cultural
- Cultural, chemical, prevention, biological
Correct answer: Prevention, cultural, biological, chemical
IPM prioritizes prevention first, then cultural controls, biological controls, and uses chemical controls as a last resort.
Question 2: Which soil water potential range is generally considered optimal for crop water uptake?
- -0.01 to -0.03 MPa
- -0.03 to -1.5 MPa (Correct answer)
- -1.5 to -3.0 MPa
- 0 to -0.01 MPa
Correct answer: -0.03 to -1.5 MPa
Soil water potential between -0.03 MPa (field capacity) and -1.5 MPa (permanent wilting point) represents plant-available water.
Question 3: A soybean crop is showing nitrogen deficiency symptoms despite adequate soil nitrogen. Which condition could cause this?
- High soil pH above 7.5
- Waterlogged soils reducing root function and nodule activity (Correct answer)
- Excess phosphorus
- Low air temperature during vegetative growth
Correct answer: Waterlogged soils reducing root function and nodule activity
Waterlogged soils kill rhizobium nodules and reduce root function, preventing nitrogen fixation even when soil nitrate is present.
Question 4: What is the recommended practice when planting corn after corn (continuous corn) to manage northern corn leaf blight?
- Apply fungicide at planting
- Select resistant hybrids and bury residue with tillage (Correct answer)
- Increase plant population
- Apply high rates of potassium
Correct answer: Select resistant hybrids and bury residue with tillage
Using resistant hybrids and incorporating residue reduces northern corn leaf blight inoculum, since the pathogen overwinters in infected crop debris.
Question 5: Which seeding depth is generally recommended for small-seeded crops like alfalfa?
- 0.5 to 1.0 inch (Correct answer)
- 1.5 to 2.0 inches
- 2.5 to 3.0 inches
- 3.5 to 4.0 inches
Correct answer: 0.5 to 1.0 inch
Small-seeded crops like alfalfa have limited seed energy reserves and should be planted at 0.5–1.0 inch to ensure rapid emergence.
Question 6: What does the leaf area index (LAI) represent in crop physiology?
- Total root surface area per unit soil area
- Total leaf surface area per unit ground area (Correct answer)
- Ratio of leaf length to leaf width
- Number of leaves per plant
Correct answer: Total leaf surface area per unit ground area
LAI is the ratio of total one-sided leaf area to the ground surface area beneath the crop canopy, reflecting light interception capacity.
Question 7: Which practice best prevents development of herbicide-resistant weed populations?
- Applying the same effective herbicide every year for consistency
- Rotating herbicide modes of action and integrating non-chemical weed control (Correct answer)
- Doubling herbicide rates when resistance is suspected
- Applying herbicides only in wet conditions
Correct answer: Rotating herbicide modes of action and integrating non-chemical weed control
Rotating herbicide modes of action and incorporating mechanical or cultural controls prevents selection pressure that leads to resistance.
CCA Crop Management 3
In integrated pest management (IPM), what is the correct order of pest management tactics by preference?