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Published byNathan Woods Modified over 6 years ago
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Soil and Minerals https://www.soils.org/iys/monthly-videos
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Where does soil come from?
Rocks Minerals Organic Matter
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Ecological definition of soil
Soil is a mixture of mineral particles, organic matter, water, and air that is capable of supporting plant life
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Three Characteristics
1) Naturally occuring 2) Characteristic chemical compound 3) orderly internal structure Gold, copper, and Silver are considered native elements Mineral Quartz (silica and O2) is considered a compound
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a vertical section of soil from the ground surface to the parent rock
What is a Soil Profile? a vertical section of soil from the ground surface to the parent rock
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Bedrock Igneous, metamorphic and sedimentary rock of the lithosphere
Bedrock is the parent rock For soil (as it breaks down) Pavement is the bedrock of the desert
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How are climate and soil thickness related?
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Sagebrush-Cold Desert
Mollisol Profile Profile is only a few cm thick due to lack of water to break down the bedrock
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Desert Varnish—leaching of minerals and flowing over rocks
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Soil Properties in Biomes
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Permafrost
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Soil Horizons
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What are the main components of soil?
Mineral Matter Air Water Organic Matter
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Mineral component • Anchorage for plant roots. • Pore space for water and air. • Source of many plant nutrients through weathering. • Exchange sites for plant nutrients.
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Organic component • Source and exchange site for nutrient cycling. • Influences soil structure, pore space, and water holding capacity. • Energy source for soil microbes and other heterotrophs.
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Water component • Solvent for many essential plant nutrients. • Maintains equilibrium between cation and and anions that are held on exchange sites.
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Air component • Contains O2 for aerobic metabolism of plant roots and soil organisms. • Exchange of CO2 from soil respiration and which facilitates weathering. • Provides N2 for N-fixing soil organisms.
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Why are soils so crucial to ecological studies?
• They provide all or part of all essential factors for plant growth except light. • Rooting material for the plants: the platform on which trophic levels of the ecosystem are built. • Contains most of the decomposers that recycle energy and nutrients of the ecosystem. • Contain the history of the site, which can be interpreted through paleoecological reconstructions. • The soil is an ecosystem in itself (producers, consumers, and decomposers
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What are the FACTORS that make SOIL? TIME LAY OF THE LAND
1000’S TO 10,000’S OF YEARS LAY OF THE LAND TOPOGRAPHY LIVING ORGANISMS ANIMALS AND PLANTS CLIMATE HOT/COLD, WIND/RAIN PARENT MATERIAL ROCKS AND MINERALS
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Major process of soil development
Physical weathering Chemical weathering Decomposition Mineralization Nitrification
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Physical weathering: The breakdown of rock (the regolith) into finer particles through weathering
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Chemical weathering: The breakdown and redeposition of
organic and inorganic substances primarily through the processes of oxidation, dissolving, and leaching.
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Decomposition: The breakdown of organic matter by bacteria
and fungi into simpler organic substances (carbohydrates, lignins, proteins).
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Mineralization: The ultimate breakdown of organic substances into nonorganic substances (minerals, carbon dioxide, water, salts).
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Nitrification: The transformation by soil bacteria of ammonia compounds into nitrates and nitrites.
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What causes soil erosion?
Water Wind No Vegetation
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Soil and Erosion Consequences
-Topsoil loss (90% of soil fertility) – Sedimentation (rivers and coastal ecosystems) – Desertification – loss of water-holding properties of soils
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My Neighbor has my soil!
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SOIL CONSERVATION? Terracing Strip Cropping Contour Plowing Tilling
What are some practices Of SOIL CONSERVATION? Terracing Strip Cropping Contour Plowing Tilling Wind Breaks Ground Covers
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Tilling Soil on flat land
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Furrow Irrigation
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Minimum Tillage
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Strip Crop Farming
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Organic Farming Ecosystem management rather than external inputs • Considers environmental and social impacts of fertilizer and pesticide use • Conserves water and soil • Certification: USDA accreditation (farms must be certified) • Organic products: 100%organic, organic (95%), > 70% organic, < 70% organic
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Does Organic Farming Work?
21-y Swiss study (2002) – Yield – 20% less – Resource use reduced Fertilizer (34-53%) Pesticides (97%) – Increased biodiversity • Health benefits – WHO: million pesticide poisonings per y – Nutrient content – Benefits to consumers?
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Rain drop erosion
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The Great Dust Bowl Wind Erosion
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Wind Erosion removed topsoil
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Rill Erosion
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Gully Erosion How did the Canyon Lands of Utah form?
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Construction
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Overgrazing
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Vegetation protects soil
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Our lives depend on preserving our topsoils.
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Soil - We cannot live without it!
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Give a hand to the land
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