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59 Cards in this Set
- Front
- Back
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proportionof different sized particles in soil
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textures |
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three categories of soil texture |
sand, silt, clay Sand:2mm > .063 mm Silt:.063mm > .002 mm Clay:<.002 |
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textures that are due to weathering; can be physical or chemical |
sand and silt |
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texture that is only produced chemically |
clay |
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name for all of the soils together; the best top soils (most fertile) |
loam |
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composition of the soil solution |
minerals, water - soil solution and organic material - humus (together called topsoil) |
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little layer is called... |
o layer |
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top soil; has inorganic nutrients |
a layer |
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subsoil is called... |
b layer |
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parent material layer is called... |
c layer |
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generate carbon dioxide |
root hairs |
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thetotal capacity of a soil to hold exchangeable cations;aninherent soil characteristic and is difficult to alter significantly.It influences the soil's ability to hold onto essential nutrients andprovides a buffer against soil acidification.
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cation exchange |
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removeswater from the particles and reach them down at the same time
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acid rain |
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stimulates decomposition |
water and temperature |
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madeup of dead organisms, leaves, wood, feces
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humus |
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bacteria,fungi (affect soils physical and chemical characteristics), protists,insects, worms, plant roots
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living organics |
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affect soils physical and chemical characteristics
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fungi |
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H2O80-90% water96%of dry mass is organic molecules (CO2 + H2O)
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essential elements |
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tendto congregate around roots; Plant-growthpromoting RhB; produces growth hormones, antibiotics, absorbs toxic metals, makes nutrients more available
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Rhizobacteria
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forms topsoil |
the mineral particles released by weathering mixed with living organisms and humus |
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top soil and other distinct soil layers |
soil horizons |
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the topsoil; a mixture of broken down rock of various textures living organisms, and decaying organic matter |
the A horizon |
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contains much less organic matter and is less weathered than the A horizon |
B horizon |
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composed mainly of partially broken down rock - some serves as "parent" material for minerals |
C horizon |
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neutralize the negative charge of soil particles |
H+ ions |
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reacts with H2O to form H2CO3 |
CO2 |
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releases hydrogen upon disassociation |
H2CO3 |
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acidify the soil solution by releasing co2 and pumping H+ into the soil; also absorb the released cations |
roots |
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the addition of mineral nutrients to the soil |
fertilization |
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a chemical element is considered this only if it is required for a plant to complete its life cycle and produce another generation |
essential element |
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nine of the essential elements are called this because plants require them in relatively large amounts |
macronutrients |
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the remaining eight essential elements are known as this because plants need them in only tiny quantities |
micronutrients |
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how many essential elements are there? |
17 |
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the soil layer that surrounds the plants roots |
rhizosphere |
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describes transformations of nitrogen and nitrogenous compounds in nature |
nitrogen cycle |
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reduces N2 to NH3 |
nitrogen fixation |
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swellings along a legumes root |
nodules |
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contained within vesicles formed in the root cells |
bacteroids |
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explain crop rotation |
An approach to decide which crop to plant where from one year to the next. This helps manage soil fertility. |
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mutualistic associations of roots and fungi |
mycorrhizae (fungus roots) |
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the major mutualistic symbioses of fungi and plants are classified as either.... or... |
ectomycorrhizae or arbuscular mycorrhizae |
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compare ectomycorrhizae and arbuscular mycorrhizae |
ectomycorrhizae forms a dense sheath over the surface of the root; arbuscular mycorrhizae do not have a dense mantle ensheathing the root |
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major components of plants organic compounds |
carbon, oxygen, and hydrogen |
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plants are grown in mineral solutions instead of soil to determine which chemical elements are essential |
hydroponic culture |
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six major components of macronutrients of organic compounds forming a plants structure |
carbon, oxygen, nitrogen, hydrogen, phosphorus and sulfur |
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name the 9 macronutrients |
carbon, oxygen, nitrogen, hydrogen, phosphorus, sulfur, potassium, calcium and magnesium |
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contributes the most to plant growth and crop yields |
nitrogen |
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affects the availability of water, oxygen, and minerals in the soil |
soil particle size |
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what does a soils composition refer to? |
its inorganic and organic components |
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a complex ecosystem teeming with bacteria, fungi, protists, animals, and the roots of plants |
topsoil |
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deficiency of mobile nutrients affects older or younger organs more? |
older organs |
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Nutrients that are less mobile within a plant affects older or younger organs more? |
younger organs |
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support the energy needs of the rhizosphere |
plant secretions |
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most of the mass of organic material of a plant comes from... |
carbon dioxide |
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micronutrients are needed in very small amounts because... |
most serve mainly as cofactors of enzymes |
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mycorrhizae enhance plant nutrition mainly by... |
absorbing water and minerals through the fungal hyphae |
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plants that grow on other plants |
epiphytes |
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problems associated with intense irrigation |
mineral runoff, land subsidence, aquifer depletion, and soil salinization |
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A mineral deficiency is likely to affect older leaves more than younger leaves if... |
the mineral is very mobile within the plant |
