Shared Flashcard Set


Lecture 1
Organic Mulches
Undergraduate 4

Additional Agriculture Flashcards




What four factors must be considered in fruit crop management?
At what temperature does damage occur to strawberry crowns?
Define Organic Mulch
Any NATURAL material such as straw, sawfust, leaves or loose soil that is spread on the surface of the soil to protect the soil and plant roots from the effects of raindrops, soil crusting, freezing and evaporation

What are the 10 advantages to Organic Mulch?






1. Increases Organic Matter

- As straw breaks down, organic matter and water retention increases. Improves soil structure


2. Prevent Severe Freezing

- As air temperature increases, soil temperature increases

- Straw has a moderating effect, as soil underneath straw is barely changing with temperature changes


3. Prolong Winter Dormancy

- If soil warms slowly, plant will remain dormant longer


4. Conserve Moisture

- Mulch acts as a physical barrier to decrease evaporation (evapotranspiration)


5. Moderate Soil Temperature

- Reduces the cycles of thawing and freezing


6. Prevents Heaving

- As freezing and thawing occur, ice lens form. This causes soil to push up and brings the crown with it

- After melting, roots are exposed from heaving


7. Controls Weeds

- Physical barrier so weeds cannot penetrate the soil


8. Reduce Erosion

- Mulch absorbs moisture in rain, prevents movement of soil


9. Retain Snow

- Straw has irregular shape, which traps snow and causes snow to act like an insulator


10. Keeps Fruit Clean

- Fruit isn't sitting on soil

- Fruit isn't in contact with microorganisms in the soil (less chance of disease)


What are the 6 disadvantages to Organic Mulch?




1. Harbours Rodents

- Provides a home for pests


2. May Affect Soil Nitrogen

- Wide carbon to nitrogen ratio (bacteria and fungi decomposing will consume the nitrogen)


3. May Introduce Weeds

- Dirty straw can bring in weed seeds


4. May Prolong Growing Season

- If flowering is delayed, fruit is delayed

- Delays in harvest = disadvantage to reaching early market


5. Allelopathic Effect

- Compound secreted by neighbour plant to prevent other plant's growth

- Straw from rye may inhibit strawberry growth


6. Increase Chance of Frost

- Acts an an insulator


What are the 3 types of mulches?


- Cannot trap air, but can trap moisture

- If it gets wet, it is useless

- Use for blueberries

- Can have allelopathic effect



- Use for cranberries

- Cranberries are acid-loving (need acidic sand to grow)




- Cheap, plentiful and by-product of cereal crops

- Winter wheat has least allelopathic effect 

What Macro factors must be considered in site selection?

1. Market Location

- What is the distance to market?

- Dealing with perishable item, therefore want to be close to market


2. Labour Supply

- Fruits must be harvested by hand

- Often offshore labour is hired


3. Climate

- This will impact length of growing season

- Can select correct cultivar and management practices accordingly

- Compare Guelph and Niagara - Guelph has low winter temps, whereas Niagara has higher winter temps

What are the 7 Micro factors to be considered for site selection?

1. Soil Type

- Strawberries and Raspberries have problems with soil drainage

- These fruits are 89-90% water and without water, they cannot reach their potential

- Stay away from clay soils, unless using a raised bed (use soil diagram with soil type and drainage)


2. Water Supply

- Want pond or body of water in close proximity

- Water is critical from a physiological standpoint


3. Shelter (from wind)

- Not to stop air, but to slow it down

- Reduces water loss, less damange to plant

- Provides a shelter for pollinating insects


4. Air Drainage/Slope

-Radiative Frost occurs on cold clear night and no wind

- Heat absorbed is re-radiated and rises. Cold air falls. This causes an inversion layer to be created

- Good to plant strawberries on slope because cold air flows like water (cold air will drain away on slope)

- Air drainage is the movement of cold air down a slope


5. Directional Exposure

- Direct sun exposure causes plants to grow sooner

- Where it is shaded, growth is delayed


6. Previous Crop

- Important from a disease standpoint

- Never plant strawberries on potato or tomato land (similar disease pathogens) VERTICILLIUM WILT

7. Need to Fumigate?

- Nematode presence impacts crops (will bore into root of plant. Creates wound-like injury)

- At high fumigant rate, all fungi is killed (use low rate)

- Can tarp field 

Explain the soil selection diagram
What are some alternatives to fumigating?

Solarization (cover soil with plastic)


Incorporate crop that has antagonistic effect against nematodes (ex. Brassicas)


Memorize the following diagram


Heat absorbed is re-radiated and rises. At the same time, cold air is falling. An inversion layer is created, where the cold air falling meets the warm air rising


Small jog on the graph - see that close to soil surface, tempertaure jogs up. This is soil radiating heat up. Mulches are enough to do this, as they will not allow dip in temperature

Memorize the cold air drainage diagram
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