Orange Chill Shield Quiz Quiz

Explore essential knowledge about protecting citrus crops from frost damage with practical and science-based methods. Each question covers a unique aspect of citrus frost protection strategies applied in horticulture.

1. Identifying Critical Temperatures

   At what minimum temperature (in Celsius) are many citrus varieties generally at risk of frost damage, requiring protection measures to be considered?

   1. 5°C
   2. -5°C
   3. 0°C
   4. 10°C

   Explanation: Citrus crops typically begin suffering frost damage at or just below 0°C. -5°C is more likely to cause severe injury, but preventive action is needed before these lower temperatures. 10°C and 5°C are higher than critical thresholds for most citrus; damage rarely begins here.

2. Microclimate Modification Technique

   Which common method effectively protects citrus orchards from light frost by increasing air temperature near the ground?

   1. Applying mulch
   2. Overhead sprinkler irrigation
   3. Removing tree canopies
   4. Exposing bare soil

   Explanation: Overhead sprinklers protect plants by releasing latent heat as water freezes, keeping tissues near 0°C. Mulch insulates roots but doesn't address air temperature. Removing canopies exposes trees to more frost. Exposing bare soil may slightly increase ground heat release but offers limited protection.

3. Site Selection for Frost Protection

   When establishing a citrus orchard, what site feature BEST minimizes frost risk?

   1. South-facing gentle slope
   2. Dense woodland
   3. Low-lying valley floor
   4. Ridge with poor air flow

   Explanation: A south-facing gentle slope provides better sun exposure and allows cold air to drain away, reducing frost risk. Low-lying valley floors can trap cold air, increasing risk. Dense woodland may limit sun and air movement. Ridges with poor air flow can still allow frost pockets.

4. Physical Plant Protection

   Which material is commonly used to physically cover and protect young citrus trees from frost at night?

   1. Burlap sacks
   2. Cotton sheets
   3. Plastic tarps
   4. Aluminum foil

   Explanation: Cotton sheets trap warmth and provide insulation without overheating the trees. Plastic tarps can retain moisture and damage foliage. Aluminum foil is not practical for covering whole trees. Burlap sacks may be too heavy or insufficiently insulative for effective overnight protection.

5. Wind Machines Usage

   How do wind machines help in citrus frost protection during calm, clear nights?

   1. Dispersing cold air with warmer air
   2. Increasing fruit sugar content
   3. Removing humidity
   4. Simulating rainfall

   Explanation: Wind machines mix warmer air from above with colder ground air, reducing the likelihood of frost near tree canopies. They do not remove humidity or simulate rain. Increasing sugar content is unrelated to their mechanical function.