Soil Conservation Flashcards
(25 cards)
What is soil?
A natural body comprised of solids (minerals & organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following: horizons that are distinguishable from the initial material and as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.
What essential services do soils provide to support basic ecosystem function?
Growing medium: Provides physical stability and support for plant roots
Sustaining plant and animal life: Diversity and productivity of living things depends on soil
Cycling nutrients: Carbon, nitrogen, and phosporus and other nutrients are stored, transformed, and cycled in soil
Regulating and filtering water: Helps control where rain, snowmelt, and irrigation water goes; water flows over land into and through soil
What ecosystem services do soils provide to benefit human society?
Basis of agro-ecosystems: Providing feed, fiber, food, and biofuels
Filtering/buffering pollutatnts: Soil minerals and microbes provide for filtering, buffering, degrading, immobilizing, and detoxifying industrial, household, and nonpoint source pollutants.
Foundation for our cities and towns
Source of antibiotics: most antibiotics used for fighting diseases are derived from soil microbes
Why should we care about soils?
They provide support to basic ecosystem function, benefit human life, and support landscapes that are more resilient to impacts of environmental stressors like drought, flood, and fire.
List some crops dependent on soils.
Corn, potato, wheat, cassava, soybeans, sorghum, rice, and plantains.
What are distinct horizons in a soil profile?
A soil profile extends from the soil surface to underlying parent rock material
What is in the USDA soil texture triangle?
Sand/Silt/Clay but also more specific categories like sandy clay, clay loam, silty clay, silt loam, and sandy loam, ect.
Why is soil texture important?
It influences water retention, water movement, and soil fertility
Whats the soil landscape like in the Santa Rita mountains?
Small Pleistocence-Age surfaces and inclusions with high clay % and shallow bedrock, and holocene-age surfaces with low clay % and deep bedrock
What are mollisols?
“Black earth” some of the most fertile soils; great for agriculture. Soils of grassland ecosystems; associated with the steepe biomes, where cold winters are followed by hot summers
What is Peat (Histosols)?
Thick soil dominated by organic matter that develops in wet conditions without permafrost. Associated with marshes, swamps, and bogs and are most prevalent in cooler climates.
What is Permafrost (Gelisols)?
Solids of very cold climates that contain permafrost within 2 m of the surface. Geographically limited to high-latitude polar regions and localized areas at high mountain elevations.
Is soil a renewable natural resource?
Although renewable, soil takes a very long time to form - up to millions of years. For human purposes, soil is a nonrenewable resource. Soil is constantly eroded by wind and water, and depleted of nutrients through careless use.
How much topsoil on earth has been lost in the last 150 years?
Half
What are the causes of soil degredation?
Erosion processes: Water driven; wind driven (Influenced by: climate, topography, vegetation, land use)
Chemical degradation: Nutrient depletion, salinization, acidification, pollution (e.g. heavy metals, pesticides)
Physical degradation: Compaction, loss of soil structure, reduced water infiltration
What are consequences of soil degradation?
Reduced crop yields, water pollution, increased flooding and sedimentation, loss of biodiversity, and loss of ecosystem function.
What does excessive use of chemical fertilizers lead to?
Reduction in soil organic matter, loss of soil carbon
When and what was the Dust Bowl?
1934-1939; the worst human-influenced environmental disaster in U.S. history. Happened because of farmers plowing up millions of acres of natural grasslands on the plains. Droughts began during the summer and continued through the decade, leading to huge dust storms. Led to the creation of the Soil Erosion Service in the Department of the Interior. Great Black Blizzard causes dramatic destruction of farmlands. It rendered 35 million acres of farmland useless for farming and left 500,000 people homleess.
How much soil is lost to soil erosion every year globally?
24 billion tons
What are the consequences of tilling the sonoran desert for cattle?
This doesn’t work in a desert environment and forage is reduced in the long term. Natural soil ecosystem is disrupted, native plant roots of plants are torn up, and soil is exposed leading to desiccation, a way to kill desert plants.
What are the four main principles of managing for soil health?
Minimize disturbance, maximize biodiversity, maximize soil cover, and maximize living roots.
What are the goals of soil conservation practices?
Control soil erosion, enhance crop productivity, improve water quality, increase biodiversity, improve soil health, and reduce dust emissions
What are agronomic practices to help conserve soil?
Crop rotation, cover cropping, conservation tillage, contour farming, and strip cropping
Why are the world’s drylands susceptible to desertification?
Land mis-management activties: Deforestation, overgrazing of livestock, and overcultivaton of crops.
Climate change: Greenhouse gas emissions, natural climate fluctuations
