PBL 3: Cropping systems and tillage Flashcards

1
Q

Cropping systems: crop rotations

A

A planned sequence of different crops grown over years on the same land. Crop rotations vary in length and diversity of crop species.

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2
Q

Crop rotation advantages

A

e.g. corn, soybean, alfalfa alfalfa

-Weed control: switching crops helps break weed cycles and reduces weed populations

-Disease and insect control: rotations remove the hosts for diseases and insects (can also be useful habitat for other insects to eat)

-Increase in soil fertility and quality: nitrogen-fixing legume can add nitrogen. Perennial crops that do not require annual tillage increase SOM

-Reduced soil erosion

-Rotation effects

-Less risk, increased diversity:

-Recycling of nutrients

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3
Q

Continuous cropping

A

same crop is grown for 2 or more years on the same land.
-typically practices when there are economic incentives for growing that single crop or there is a limited market for alternative crops.

-allows for greater specialisation, in management too.

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4
Q

Monoculture systems

A

involve growing a single crop within a field during the GROWING SEASON.

-simplify crop management
-concentrates efforts and resources on a single crop

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5
Q

Advantages of Monoculture systems

A

-Machinery specialized for the crop can maximise efficiency of crop planting/harvest

-Chemi “cides” can target specific pests

-Maturity and dry down of all plants within a variety is synchronised.

-Specialized varieties are developed to efficiently use light, moisture, other environmental resources

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6
Q

Polyculture systems (Intercropping)

A

growing of two or more crops together on the same piece of land during a GROWING SEASON.

-allows for spatial diversification of plant species

-can be challenging to grow due to competition of resources and environment.

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7
Q

Polyculture systems: advantages

A

-Yield stability

-Greater tolerance to environmental+pest stress

-Income diversification (long-term and short term income of different species)

-Greater overall productivity per acre (potential)

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8
Q

Polyculture systems: Strip cropping

A

Involves growing crops in monocultures, in adjacent strips planted within a field.

-Can involve alternate rows of annual crops often harvested at different times.

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9
Q

Polyculture systems: Living mulch

A

Involve planting annual grain crops into a living, but suppressed perennial sod that can recover following harvest of the grain crop.

-provides year-round ground cover for soil conservation and weed suppression.

-Must be suppressed and controlled to avoid competition (otherwise no good :()

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10
Q

Multiple cropping

A

the sequential production of two or more different crops from the same piece of land each year.

-provides for maximum use of the land and the environment for crop production.

-most practised in regions with a long growing season.

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11
Q

Multiple cropping: Cover cropping

A

A crop is introduced during or following harvest of the cash crop.

-Can be used to cover the soil during the winter months between annual grain crops, or cool-season harvest.

-Before the next crop is seeded, cover crops are killed before maturity by mowing/tillage/herbicide

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12
Q

Cover cropping advantages:

A

-protects the soil from wind/water erosion

-absorb excess fertiliser nutrients from the soil

-enhance soil fertility via nitrogen fixation

-reduces weed growth

-control soil moisture levels

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13
Q

Green manure

A

crops that are grown for the primary purpose of plowing under to improve the soil quality through the addition of SOM and nutrients.
linked to cover cropping

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14
Q

Agroforestry

A

A type of agricultural system where trees/perennial shrubs are grown for harvest alongside other annual/perennial crops or grazing livestock.

-Can generate additional sources of income, provide species habitat, carbon fixation, environment protection.

Two types of systems: alley cropping and silvopasture

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15
Q

Alley cropping

A

Trees are grown in rows with other crops between them in the inter-row area. Alleys need to accommodate the size of mature tree crops so enough light can reach the alley crop without shading.

-protects from wind/water

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16
Q

Silvopasture

A

Combines trees with pastures for livestock utilisation. Trees+livestock both must be intensively managed for production.

-Livestock provides income while trees mature.

-Trees used for timber, nut/fruit crops, etc.

17
Q

Tillage

A

land preparation before planting crops. Tillage goals include:
-Incorporation of residues (SOM up)
-Control of crop pests
-Incorporation of manures, fertilisers, lime
-Preparation of seedbed
-Alteration of soil temp+color

18
Q

Conventional tillage

A

-Traditional two-step process:

  1. Primary tillage: uses plowing to disrupt

(Moldboard plowing >15% of previous residue remains/ excess can disrupt SOM+Disks

  1. Secondary tillage: uses harrows to smooth
19
Q

Conservation tillage

A

creates variable levels of soil disturbance, leaves >30% of crop residue on the soil surface.

-important for reducing soil+water erosion
-protects from rainfall impact
-enhances SOM
-less time+energy required

20
Q

No-till

A

Conservation tillage method that does not use primary tillage

-specialised planters with disk openers slice through residues and precisely deposit seed at a desired depth

21
Q

Methods of increasing diversity in Agricultural systems

A
  1. Fallows
  2. High organic matter inputs
  3. Reduction in Use of Chemical Inputs
22
Q

Fallows

A

Allow a period in the cropping sequence where the land is simply left uncultivatived/fallow.

-allows the soil to “rest”
-secondary succession and diversity revovery

23
Q

High organic matter inputs

A

High levels of OM are crucial for stimulating species diversification.

Can be increased by:
-composts
-covercropping
-diversifying, etc.

24
Q

Reduction in the use of Chemical Inputs

A

-Many agricultural pesticides either harm/kill many non target organisms in crop systems.

Best to minimise usage.