Criado por abby Radske
mais de 6 anos atrás
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Questão | Responda |
What does soil consist of? | mineral matter, organic matter, air, water dead and living microorganisms, decaying material bateria, algae, earthworms, insects, mammals, amphibians, and reptiles |
What is Parent Material? | the base geologic material of soil lava, volcanic ash, rock, dunes, bedrock |
Physical (mechanical) Weathering | Wind and rain, no chemical changes in the parent material |
Weathering | The physical, chemical, biological processes that break down rocks to form soil |
Chemical Weathering | Substances chemically interact with parent material |
Biological Weathering | Organisms break down parent material |
Erosion | the dislodging and movement of soil by wind or water occurs when vegetation is absent |
What are some biological processes that affect soil? | biological activity includes deposition, decomposition, and accumulation of organic matter |
Humus | a dark, spongy, crumbly mass of material formed by partial decomposition a very complex system of strange molecules, abundant in oxygen humus, overall, contains a negative charge. Since nutrients are positively charged, humus is good at holding onto them. |
What is Lignin and what is it's role with bacteria & humus? | Lignin is a class of complex organic polymers that form important structural materials in the support tissues of vascular plants and some algae Bacteria cannot digest the humus' lignin polymer because Its too large, so some will release a lignin modifying enzyme, which will turn it into a monomer |
Soil Profile Horizons | Ostriches --> O Horizon: Litter Always --> A Horizon: rich in nutrients Eat --> E Horizon: poor because of leaching (Elluviation) Bananas --> B Horizon: very rich in nutrients/minerals (Illuviation) |
Soil profile | the cross section of soil as a whole |
Topsoil | inorganic and organic material most nutritive for plants |
Leaching | dissolved particles move down through horizons |
What are the properties that classify soils | colour texture structure pH |
Soil Colour | indicates its composition and fertility black/dark brown : rich in organic matter Pale grey/white : indicates leaching |
Soil Texture Classification | the size of particles Clay = smallest silt = middle Sand = largest |
Loam | a soil with roughly equal proportions of sand, silt, and clay. influences how easy it is to cultivate and let air and water travel through the soil |
Which types of soils are best for plant growth and crop agriculture? | Silty soils with medium sized pores, or loamy soils with mixtures of pore sizes |
Soil Structures | a measure of soil's "clumsiness", facilitates bioactivity large clumps can discourage plant roots repeated tilting compacts soil |
Plow Pan | a subsurface horizon or soil layer having a high bulk density and a lower total porosity than the soil directly above or below it as a result of pressure applied by normal tillage operations |
Soil pH | influences a soil's ability to support plant growth soils that are too acidic or basic can kill plants |
Soil Clump | Mix of sand, silt, and clay that are held together by organic matter and microbes, host bacteria, and contains water and air |
What is Cation Exchange? | process that allows plants to gain nutrients negatively charged soils hold cations of calcium, magnesium, and potassium |
What is Cation Exchange Capacity? | A soils ability to hold cations, preventing them from leaching, therefore increasing their availability to plants a useful measure of soil fertility greatest in fine soils |
How is cation exchange vital for plant growth? | The higher the CEC, the higher the negative charge of the soil and the more cations that can be held. CEC indicates how well your soil will hold onto anything, including nutrients and water the negative charge not only holds nutrients, but it can also hold toxic metals The lower the CEC of a soil, the faster the soil pH will decrease with time. |
Agriculture | Practice of raising crops and livestock for human use and consumption |
Cropland | the land used to raise plants for human use |
Rangeland / Pasture | land used for grazing livestock |
Soil | a complex plant-supporting system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms |
How does consumption and population effect/degrade soil? | feeding the world's rising human population requires changing our diet or increasing agricultural production mismanaged agriculture turns grasslands into deserts, removes forests, diminishes biodiversity, and pollutes soil, air, and water population dense regions have the highest rates of degraded soil ( due to deforestation, agriculture, overgrazing) |
Green Revolution | Intensive plan of the 1960s to add new technology, crop varieties and farming practices to increase crop yields in developing countries by introducing higher-yielding strains of plant and new fertilizers. created new problems, and worsened old ones (ex. The use of chemical fertilizers and synthetic herbicides and pesticides dramatically influenced the environment by increasing pollution and erosion) |
Solutions to soil degradation | - soil conservation - restoring plant cover - preventing salinization (the process of increasing the salt content) - better fertilization practices - better grazing practices |
Examples of how regional differences in soil traits affect agriculture | rain forests have high primary productivity (the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances), however, the nutrients are in the plants, not the soil. Temperate grasslands have lower rainfall and less nutrient leaching |
What causes erosion? | primary causes of erosion due to urban development. Habitat replacement often results in an increase in the amount of impervious surfaces. Normally, vegetation would slow surface water flow. Impervious surfaces increase water flow. Water can travel faster and in greater quantities. This action causes water to overflow stream banks, thus triggering erosion in vulnerable parts of the ecosystem. there is also natural causes to erosion, such as wind erosion & water erosion |
What are the impacts of erosion on ecosystems and agriculture? | Erosion removes the topsoil from the ground, often removing the seed bank that exists within soils. Further, this can introduce toxins from pesticide and fertilizer applications into waterways. |
What is Desertification? | A type of land degradation by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture. affects 1/3 of the planet's land area most prone areas are arid (area having little or no rain) and semiarid lands. |
What is the dust bowl and how did it happen? | an area of land where vegetation has been lost and soil reduced to dust and eroded, especially as a consequence of drought or unsuitable farming practice. Native prairie grasses originally held erosion-prone soils in place, this grass was removed due to cultivation of wheat and grazing, caused erosion |
crop rotation | growing a series of dissimilar or different types of crops in the same area in sequenced seasons. It is done so that the soil of farms is not used for only one set of nutrients |
Contour farming | growing crops across or perpendicular to a slope rather than up and down the slope in order to conserve rainwater and to reduce soil losses from surface erosion |
Intercropping and agroforestry | intercropping: to grow (a crop) among plants of a different kind, usually in the space between rows. Agroforestry: agriculture incorporating the cultivation and conservation of trees. |
Terracing | make or form (sloping land) into a number of level flat areas resembling a series of steps. |
Shelterbelts | a line of trees or shrubs planted to protect an area, especially a farm field, from strong winds and the erosion they cause. |
Reduced tillage | a practice of minimising soil disturbance and allowing crop residue or stubble to remain on the ground instead of being thrown away or incorporated into the soil. |
Irrigation | artificially providing water to support agriculture |
waterlogging | over-irrigated soils which suffocates roots |
What is Salinization, what does it cause, and how can it be prevented/corrected? | the buildup of salts in surface soil layers inhibits production of 20% of all irrigated cropland, costing more than $11 billion a year can be prevented by choosing crops appropriate for the area, irrigate with low-salt water |
What are fertilizers, and what are the pros/cons of them? | fertilizers are substances that contain essential nutrients inorganic fertilizers : mined or synthetically manufactured mineral supplements organic fertilizers : the remains/wastes of organisms Fertilizer affects plant growth by supplementing plant nutrients, which allows plants to grow faster and thicker. However, this applies only if the soil is deficient in nutrients. When the excess nutrients from all the fertilizer we use runs off into our waterways, they cause algae blooms |
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