Crop Management Flashcards
7 cards from real CCA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Crop Management flashcards as text
Which of the following best describes the concept of 'optimum plant population' for a crop?
Answer: The density at which yield per unit area is maximized given economic and environmental constraints
Optimum plant population balances yield per plant against yield per area, considering factors like row spacing, hybrid, fertility, and moisture.
A corn hybrid with a flex ear responds to high plant population compared to a fixed-ear hybrid by:
Answer: Reducing kernel number and row number per ear to accommodate crowding
Flex-ear hybrids adjust ear size (kernel rows and length) in response to growing conditions, producing smaller ears at high populations.
Which of the following is a symptom of calcium deficiency in crops?
Answer: Tip burn and death of young leaves and growing points
Calcium is immobile in the plant, so deficiency affects new growth first, causing tip burn, blossom end rot, or distorted young leaves.
What is the agronomic rationale for strip-till compared to no-till in corn production?
Answer: Strip-till warms and dries a narrow seed zone while leaving residue between rows intact
Strip-till disturbs only the narrow strip where seeds will be planted, creating a warmer, drier seedbed while conserving residue and reducing erosion between rows.
Which environmental condition most favors development of gray leaf spot in corn?
Answer: High humidity, warm nights, and reduced air circulation in dense canopies
Gray leaf spot caused by Cercospora zeae-maydis thrives under prolonged periods of high humidity and warm temperatures, especially in dense canopies with poor air movement.
A farmer applies 180 lb N/acre to corn but achieves only 60% of expected yield response. Denitrification is suspected. Which field condition most supports this diagnosis?
Answer: Clay soil that was saturated for more than 3 days after application
Denitrification converts nitrate to nitrogen gases under anaerobic conditions; saturated clay soils create ideal oxygen-depleted environments for denitrifying bacteria.
Which of the following describes the concept of 'harvest index' in crop science?
Answer: The ratio of harvestable product (grain) to total aboveground biomass
Harvest index (HI) is the proportion of total above-ground dry matter partitioned into the harvested organ (grain), typically ranging from 0.45–0.55 in modern corn.