4 - Agriculture Impacts on the Lithosphere Flashcards
what are the six main negative impacts of agriculture on the Lithosphere?
- Compaction
- Decline in SOM
- Erosion
- Loss of Soil Biodiversity
- Soil Contamination
- Soil Salinization
What are the main causes of wind erosion in the 1930s Dust Bowl?
- Failure to understand ecology of dry prairies
- Frequent and extended droughts
- Inappropriate Soil Management Practices
- Poor Land Use Policies
What are three types of inappropriate soil management practices?
- Extensive Deep Plowing
- Heavy Use of Farm Machinery
- Residue Burning
What did the Dust Bowl impact?
- Desertification
- Financial Loss
- Loss of Fertile top soil
- Land Abandonment and human displacement
Approximately how much money was lost during the 1930s Dust Bowl?
$25 million per day ($400 million today)
Impacts of the Dust Bowl led to the establishment of _________________ in the US.
Soil Conservation Services (SCS)
What is the SCS?
Soil Conservation Services
What is the PFRA?
Prairie Farm Rehabilitation Administration
Is the PFRA Canadian or American?
Canadian
When was the PFRA established?
1935, in response to the drought crisis.
Who is considered the Father of Soil Conservation?
H.H. Bennet
What did the PFRA intend to do?
- Farmers conserve soil
- Prevent erosion
- Manage water resources and pasture land
When was the PFRA dissolved?
2009
Provide the causes of Soil Erosion (10):
- Burning Crop Residue
- Clean Weeding
- Clear Cutting
- Cultivation of Arable Crops
- Excessive Tillage
- High Intensity Rain
- Lack of Proper Soil Conservation Measures
- Overgrazing
- Steep Sloping Land
- Wind with High Velocity
What are the two main mitigations for soil erosion?
- Decrease Detachment of Soil
- Decrease Transport
What are the ways to decrease soil detachment?
- Avoid Fallowing
- Conservation Tillage
- Crop Cover
- Mixed Cropping
- Mulching
What are the ways to decrease soil transport when mitigating soil erosion?
- Contour Farming
- Cover Crops
- Strip Cropping
- Terracing
- Wind Breaks
- Vegetative Buffer
Define Conservation Tillage:
Disturbing the soil as little as possible.
Define Conventional Tillage:
Normal tilling of land before seeding.
What does Conservation Tillage aim to do?
- Conserve Soil Erosion
- Minimizes Soil Erosion
- Reduce Compaction
What does Conventional Tillage aim to do?
- Lead to Soil Compaction
- Increases Soil Erosion
- Increase Moisture Loss
Any agricultural practices which affect such factors will duly influence biodiversity, and can therefore have both ________ and __________ effects upon the soil.
direct, indirect
What are the 5 factors governing Soil Biodiversity?
- Air
- Food
- Environmental Conditions
- Space
- Water
What are the 2 directs of agriculture on biodiversity?
- Application of pesticides which target specific biotic groups
- Often effects on non-target organisms within the same and other biotic groups
What is an indirect effect of agriculture on biodiversity?
Greater influence on biodiversity; operate at abroad system-level.
Define Soil Contamination:
Various sources of contaminants which decreases soil quality.
Soil contamination could get into _____________, which affects humans and other top predators.
food chains
Contamination affects the soils’ ability to __________, ___________ and _________ chemicals.
filter, buffer, transform
True or False: Contaminants can move into groundwater and surface water supplies.
True
What are the four types of soil contaminant?
- Fertilizer Nutrients
- Heavy Metals
- Pesticides
- Antibiotics
How are Fertilizer Nutrients a soil contaminant?
When excess nutrients are added beyond what is needed by the crop.
What is the main source of Heavy Metals as a soil contaminant?
From various sources including livestock manures, inorganic fertilizers, lime, and composts.
Define Soil Salinization:
Accumulation of soluble salts (salt pollution)
Where is soil Salinization common?
Arid Environments
What two agricultural activities result in soil salinization?
- Irrigated Land
- Over fertilization with inorganic and organic fertilizers
True or False: Most salts are not toxic to plants, humans or animals.
True
What is Physiological Droughtness?
When there is soil salinity, plants cannot uptake water.
Soil Salinity can affect beneficial ____________.
Microorganisms
Salts are ___________; can be leached with good quality irrigation water.
solube
What are the two ways of reclaiming salt-affected soils?
- Salts are soluble; can be leached with good quality irrigation water
- May need to add amendments prior to leaching depending on the type of salt
What 4 points are included in Sustainable Soil Management?
- Better diversity maintaining live plants
- Good Crop Cover
- Integrated Farming
- Minimum Disturbance
Define Soil Restoration:
To return to a biological community to its pre-disturbance structure.
Define Soil Remediation:
Remove pollution using chemical, physical, or biological methods causing as little disturbance as possible.
What are the two key positive impacts of agriculture on the lithosphere?
- Nutrient / Water Storage and Cycling
- Crop Residue Effects
What are the three key negative impacts of agriculture on the lithosphere?
Soil Erosion, Degradation and Desertification
Why is nutrient storage and cycling important?
Because plant nutrients are stored in the soil and nutrients are cycled through the:
- Biosphere
- Hydrosphere
- Atmosphere; and
- Pedosphere
How does agriculture contribute to nutrient storage?
- Cropping BNF Plants
- Fertilizer / Manure Application
- Improving soil’s ability to retain nutrients
- Incorporation of Crop Residue
What are the 3 main fertilizers?
- Nitrogen
- Phosphorus
- Potassium
Where are Nitrogen fertilizers sourced from?
Nitrogen gas from the atmosphere
Where are Phosphorus fertilizers sourced from?
Rock phosphate deposits
Where are Potassium fertilizers sourced from?
Potash Deposits
Adding fertilizers influence ______________.
nutrient cycling
How do Nutrient Cycles describe the movement of nutrients? Describe how they move:
How nutrients move from the physical environment into living organisms, ad subsequently are recycled back to the physical environment.
Nutrient flow moves from one place to another, they can be either ______________ or _______________.
Intentional, unintentional
What are some examples of an intentional flow of nutrients?
- Fertilizer Application
- Cropping Nitrogen Fixing Plants
What are some examples of an unintentional flow of nutrients?
- Gaseous Loss
- Nutrient Leaching
- Nutrient Runoff
In the early stages of agriculture, nutrient cycling was _____________.
efficient
What are 3 reasons why there is little cycling of nutrients in industrial agriculture?
- Nutrients in produce are shipped off the farm.
- Nutrients in crop residues are not returned efficiently
- Nutrient runoff and leaching losses are much larger than from natural systems.
What was the first major break in nutrient cycling?
Occurred as cities developed. Nutrients began to travel with farm products to feed the urban populations. Thus, nutrients have accumulated in urban sewage and polluted waterways around the world.
What was the second major break in nutrient cycling?
Through farm specialization; separating animals from the land that grows their feed. Thus nutrients accumulate in manure while crop farmers purchase fertilizers to keep their fields from becoming nutrient deficient.
What are the six negative impacts of agriculture on soil quality?
- Compaction
- Contamination
- Decline in SOM
- Erosion
- Loss of Soil Biodiversity
- Salinization
What does SOM stand for?
Soil Organic Matter
Why is soil organic matter important? (4)
- Represents the Largest Stock of terrestrial C.
- SOM has N, P, and S.
- SOM is essential for soil microbes which support a range of processes essential of the overall functioning of the soil system
- SOM influences other soil physical and chemical properties.
Traditional cropping practices have dramatically reduced ____________________.
SOM levels
What are the main aspects to overcome from the decline in SOM?
- Application of Organic Manure
- Avoiding Burning
- Better Crop Varieties
- Crop Rotation
- Conservation Tillage
- Cover Crops
- Mulching
- Pasture Rotaions
- Rotational Grazing
What is Soil Compaction?
A physical reduction in pore space expressed on a volume basis.
How does Soil Compaction affect productivity and soil functions?
- Increases Soil Resistance
- Increases the Overload Runoff Following Rainfall
- Increases the Risk of Flooding and Soil Erosion
- May Affect Nutrient Cycles
- May Increase GHG Emissions
- Reduces Water Storage Capacity
- Reduces Water Infiltration and Drainage
Why does soil resistance improve soil compaction?
It makes it harder for roots to penetrate.
What are 3 main ways to deal with Soil Compaction?
- Alleviating Compaction
- Prevention
- Protecting the Soil Compaction
What is included in the Soil Compaction Prevention?
Improving equipment design and better soil management practices.
Making soil more resilient is a way to mediate ___________.
Soil Compaction
What are 3 ways to make soil more resilient?
- Increasing the SOM Content
- Improving drainage
- Minimizing Tillage Operations
Alleviating compaction is done through _______________.
mechanical intervention
Define Soil Erosion:
Removal of soil from a location resulting in a reduction of soil mass and soil volume.
Soil Erosion involves the detachment and transport of soil by __________, ____________, ___________, and _____________.
Glacier, Tillage, Water, Wind
On what scale does Soil Erosion occur?
Globally
Soil Erosion is accelerated by what four human activities?
- Agriculture
- Construction
- Deforestation
- Mining
Wha are the two-folds of the Soil Erosion Problem?
- Lost Productivity
- Sediment Pollution
Lost Productivity has ___________ effects.
On-site
Sediment Pollution has ____________ effects.
off-site
Provide the six on-site effects of soil erosion:
- Changes the Landform
- Destroys man made structures
- Exposes the less fertile subsoil, thus reduce soil fertility and productivity
- Leads to land degradation
- Topsoil removal
- Yield Reductions
In North America there was a ___% in corn yield reductions and _____% in soybean yield reductions.
9-18% and 17-24%
What are the five Off-Site effects of soil erosion?
- Causes Flooding
- Makes lakes and rivers more shallow
- Reduces Capacity of Reservoirs
- Siltation of Lakes & Reservoirs
- Sediments
Erosion Mechanisms involved which two physical processes?
- Detachment
- Transport of Sediments
Detaching forces of soil erosion include:
- Rain drops
- Tillage
- Wind
Transporting forces of soil erosion include:
- Flowing water
- Wind
Define an Aggregate:
Groups of soil particles that bind to each other.
If aggregates are stable when wet, they have _________________.
a resistance to erosion
If aggregates fall apart, they are _________________.
more susceptible for erosion
Wet aggregate stability is a ______________________.
measure of susceptibility to erosion loss
Define Tillage Erosion:
The movement of soil during tillage
Tillage Erosion can result in:
Net losses and accumulations of soil within the landscape.
The “loss of topsoil from upper slopes leading to decrease in productivity” is an example of what?
Tillage Erosion
