7 - Impacts of Agriculture on the Hydrosphere Flashcards
What are the two key impacts of agriculture on the hydrosphere?
- Water Storage and Cycling
- Crop Cover Effects
What is the percentage of Ocean and Saline Lakes vs. Freshwater in the world?
- Oceans and Saline Lakes: 97.4%
- Freshwater: 2.6%
75% of freshwater is tied up in ______________ and ______________.
Ice caps and glaciers
What is a major source of freshwater?
Soil Water (>30%)
What can increase the water storing capacity of agricultural soils?
Cultivation and Management practices
Provide the equation of the Water Budget:
S = I + P + C - ET - DP - R
What are the components of the Water Budget? (SCRIP-DPET)
- S = Storage
- C = Capillary Rise
- R = Runoff
- I = Irrigation
- P = Precipitation
- DP = Deep Percolation
- ET = Evaporation
What are the two key affects of agriculture on the water cycle?
- Land Preparation
- Irrigatoin
Why does land preparation increase the runoff and drainage of the land?
- Reduced vegetation cover
- Soil compaction from machinery use
- Increase in soil erosion, silting of water bodies.
If groundwater is used from aquifer faster than it is replaced, then the water table will be _____________,
lowered
What are the four examples of agricultural water consumption and water deficits?
- Aral Sea Crisis
- Ogallala Aquifer
- Lake Chad
- Nile, Jordan, and Euphrates-Tigris River Basins
Up until the third quarter of the 20th century, ________ was the worlds fourth largest saline lake.
The Aral Sea
What was the main cause of the Aral Sea crisis?
The soviet government diverted those rivers to irrigate the desert region to grow cotton.
What are the four key effects of the Aral Sea crisis?
- Change in the Sea Surface Temperature. Summer SSTs have increased, while winter SSTs have decreased.
- The Aral Sea region experienced significant desertification during the desiccation period.
- A sharp increase in salinization of lands - one of the most negative consequences of Aral Sea crisis.
- An increase in the number of dust and salt storms in the area.
Where is the Ogallala Aquifer located?
Occupies the High Plains of US, from Texas to South Dakota (450,000km2 of 8 states).
What is the cause of the Ogallala Aquifer crisis?
- Irrigated farming accounts for 94% of the groundwater use, 5.5 million hectares are irrigated in the region (Nebraska = 46%, Texas = 30% and Kansas = 14%)
State governments and local water districts throughout the region have developed what kind of policies?
- To promote groundwater conservation
- Slow or eliminate the expansion of irrigation.
What are the three key causes of the Lake Chad shrinkage?
- Overgrazing resulting in a loss of vegetation
- Deforestation, contributing to a drier climate
- Large and unsustainable irrigation projects built by Niger, Nigeria, Cameroon, and Chad which have diverted water from both the lake and the Chari and Logone rivers.
What three basins are in main focus for water shortages and conflict in the Middle East?
Nile, Jordan and Tigris
Who of the Nile, Jordan, or Tigris reservoir uses the most water?
Starts in Ethiopia, Sudan and Egypt uses most of the water flows in the Nile River.
Ethiopia and Sudan divert water from the Nile, this reduced the amount available to Egypt.
Of the three, Nile, Jordan and Tigris, who is the most water short in the region?
Jordan Basin
Why does Jordan experience a decreased downstream water supply?
From hydro-electricity dams in Syria
What are four proposed solutions to the issues faced by the Nile, Jordan, and Tigris water basins?
- Regional cooperation in allocating water supplies.
- Improve water use efficiency
- Higher water prices (to help increase efficiency)
- Import more grain to cut down the need for irrigation water
_______________ is a major cause of degradation of surface and groundwater resources.
Agriculture
_____________ people die annually from water-borne diseases.
Five million
What are four consequences of degraded surface and groundwater resources?
- Ecosystem dysfunction and loss of biodiversity.
- Contamination of marine ecosystems from land-based activities.
- Contamination of groundwater resources.
- Global contamination by Persistent Organic Pollutants (POP).
What are the six non-point source pollutions through agriculture?
- Animal Feedlots
- Animal Grazing
- Aquaculture
- Cultivation
- Dairy Farming
- Irrigation
What are the seven types of water pollution through agricultural activities?
- Nutrients
- Metals
- Oxygen demanding Wastes
- Organic Chemical
- Pathogens
- Sediments
- Salt
What are the two types of nutrient pollutions in water?
Phosphorus and Nitrogen
What are the two types of metal pollutants to water?
Selenium and Cadmium
What are the two types of Organic Chemicals in water?
Pesticides and Antibiotics
What are the two main nutrient pollution through agriculture activities?
- Phosphorus
- Nitrogen
What are the 3 main sources of phosphorus pollution?
- Fertilizer
- Manure
- Aquaculture
Nitrogen and Phosphorus contribute to the ______________ of surface water.
eutrophication
Define Eutrophication:
Excessive richness of nutrients in a lake or other water body, frequently due to runoff from the land, which causes a dense growth of algae and other aquatic plants and death of animal life from lack of oxygen
True or False: In 2013, Lake Winnipeg was classified as the most threatened lake of the year.
True
P is often the most limiting nutrient for algae growth, why?
Some algae have the ability to fix their own nitrogen, but they cannot do the same for phosphorus.
How does excess algae growth affect water quality?
When algae dies and decomposes, oxygen concentrations in water gets developed.
What are the pathways of phosphorus loss?
- Erosion of particulate P
- Release of soil and plant P to surface runoff
- Particulate O loss is high in regions of high intensity rainfall and steep slopes.
What are the two main drawbacks of nitrogen in the groundwater?
- Leaching of nitrate to groundwater, excessive levels are a threat to public health.
- Drinking groundwater with high nitrate can result in decreased oxygen carrying capacity of hemoglobin in babies leading to death (Blue Baby Syndrome).
What are the 3 main sources of Pathogens?
- Aquaculture
- Feed Lots
- Manure Spreading
What is an example of a pathogen entering a water body?
Walkerton Water Pollution
What is the Walkerton Water Pollution? Define:
In May 2000, drinking water contaminated with E.coli and campylobacter bacteria in Walkerton, Ontario.
What are the three main sources of Oxygen demanding Waste?
- Food Waste
- Manure
- Organic Waste
Provide the three effects of Oxygen demanding Waste on surface water:
- Decomposing organic waste increases biological activity in water.
- Increase the demand for oxygen (for respiration and oxygen consuming processes).
- Dissolved oxygen in water is depleted
What are the two key metal pollutants?
- Selenium
- Cadmium
How are metals pollutants introduced into water bodies?
- Fertilizers
- Feedlots
- Manure
Provide five effects of metals on surface water and ground water:
- Contamination with toxic heavy metals
- Some fertilizers contain metals as impurities
- Manure contains metals as animals are fed with copper, zinc, arsenic, etc.
- Toxic metals in drinking water can cause health issues such as kidney disease.
- Metals get into the food chain and affects the ecosystem and human health.
What are the two Organic Chemical pollutants considered in this course?
- Pesticides
- Antibiotics
What is a source of antibiotics in water ways?
Manure
How do antibiotics effect water ways?
- Runoff - contamination of surface water
- Loss of top predators due to growth inhibition and reproductive failure.
- Dysfunction of ecological system
- Public health impacts from eating contaminated fish.
How are sediments introduced into surface water?
Soil Erosion
What three effects do sediments have on surface water?
- Sediments increase turbidity
- Sediments carry phosphorus and pesticides absorbed to sediment particles.
- Siltation of river beds and loss of habitat and spawning ground, etc.
What is the source of salt in water bodies from agricultural practices?
Irrigation
What are the two effects of salt in water bodies?
- Runoff of salts leading to salinization of surface waters.
- Enrichment of groundwater with salts by leaching.
What are the three key practices to sustainable water management?
- Use of agronomic practices that increase water storage in soils and water use efficiency by crops.
- Nutrient management to reduce pollution with N and P.
- Low input agriculture / organic farming.
What are the 8 ways of that increasing water storage in soils and water use efficiency by crops?
- Cover Crops
- Crop Rotation
- Conservation Terraces
- Fallow
- Irrigation
- Improved SOM
- Mulches
- Strip Cropping
How does mulch increase water storage in soils and water use efficiency by crops?
Barriers to moisture moving out of soil and keeps temperature cool.
How do Conservation Terraces increase water storage in soils and water use efficiency by crops?
Slow water runoff and Catch basins to collect water
In what four ways can converting to grasslands help conserve soil water?
- Grasses root less deeply
- Grasses go dormant earlier in the fall
- Grasses intercept less precipitation
- More protection from soil erosion
What is the 4R Nutrient Management?
- Right Source
- Right Rate
- Rate Time
- Rate Place
True or False: Erosion control measures are not effective to reduce P losses in Manitoba; may even enhance losses.
True
In reducing phosphorus losses, what are the two main considerations?
- High P Source
- High Transport
What is the “Critical Source Area for P Loss”?
Where the High P Source and High Transport interact
