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40 Cards in this Set
- Front
- Back
- 3rd side (hint)
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fates of mineralized nutrients |
leaching immobilization adsorption |
3 of them |
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compenents of OM |
•living biomass •dead roots and unrecognizable material •humus |
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organic carbon vs organic matter |
OM = 50% OC |
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humification |
humus becomes co2 + h2o + plant nutrients through oxidation decomposition and mineralization |
becomes 3 things through 3 processes |
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fates of OM |
•mineralization •oxidation •decompisition |
3 |
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how carbon is used respired/incorporated |
2/3 of g respired 1/3 of g incorporated in tissues |
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C:N ratios |
>25:1: •immobilization of soil microorganisms •more competition for N means mobile microorganisms uptake all N and plants suffer N deficiency •decay is slowed <25:1: •no immobilization |
remediate excess C with more N |
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components of OM |
•lignins •polyphenols •fats and waxes •cellulose •hemicellulose •crude/simple proteins •starches and sugars |
slow decomp to fast decomp |
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factors that increase OM and how? |
•more precipitation ●more plant growth •lower temperatures ●slower decompisition •less tillage ●less oxidation •less drainage ●less o2 =less decomp •high clay/silt % |
5 |
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losses of OM |
•erosion •tillage •fire •increased Nitrogen •plant removal •over grazing |
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Importance of N % dry weight |
part of amino & nucleic acids in charge of chlorophyll root growth growth & overall productivity 2.5-4% dry weight 1-6% in legumes |
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plant available forms of N |
NH4+ •ammonium NO3- •nitrate |
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effects of N deficiency |
•chlerosis yellowing of leaves in older leaves bc N is mobile •necrotic spots brown dead parts of leaves |
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effects N toxicity |
•ammonium toxicity light brown scorching •nitrate toxicity tan colored toxicity |
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N fixation |
•lightening •N fixing bacteria |
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fates of N |
immobilization and mineralization |
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volatilization of N |
•high pH •low OM% •low clay% •higher temps •sandy soils |
5 |
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nitrification increases with.. |
•good aeration •warm soils •dry soils •after rain •after spring thaw •after tillage |
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ph and H+ concentration |
10^-pH = h+ concentration -log (h+ concentration) = pH |
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precipitation effects on pH |
makes soils more acidic because it adds H+ |
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N in Humboldt |
•mineralization of OM into ammonium •august annuals dead perennials dormant=low demand for N means increase of leaching •spring soil still too cold for mineralization but plants grow •late spring active mineralization •summer bc lack of moisture mineralization and plant growth slowed |
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phosphorus uses in plants |
needed for atp part of DNA RNA phospholipid bilayer 0.2-0.4% plant matter mobile in plants immobile in soils |
what % of plants |
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phosphorus deficiencies |
stunted growth weak stems poor flowering delayed maturity older leaves first |
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fates of phosphorus |
•adsorption and desolation •immobilization and mineralization •plant root uptake (enhanced by myccorhizae) |
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problems with phosphorus |
•susceptible to leaching •most compounds unavailable to plants •low concentration in upper layer •10-15% used •only available between 6-7 pH |
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p fixation |
made unavailable to plants least->most 2:1, 1:1, fe or al oxide |
which clays fix the most |
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available forms of Phophorus |
•H2PO4 pH: 4-5.5 •HPO4 pH:>7 |
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chelation |
creation of shell around iron and aluminum |
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Potassium plant uses |
over 80 different enzymes require K |
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potassium (K) deficiency |
begins on tips as chlerosis then becomes necrosis as guard cells suffer |
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K+ cycle |
minerals weather to be obtained by plants most K ->least K biotite feldspar muscovite |
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slowly available K |
1-10% of K •secondary minerals •fixed in 2:1 |
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readily available K+ |
0.1-0.2% 90% exchangeable |
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grass tetony |
too much K in plant matter causes animals that eat it to get Mg deficiency |
excess K |
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serpentine soils |
high Mg means less K+ intake |
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calcareous soils |
high in K means less Mg uptake |
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nutrient management required when: |
imbalance of minerals •removed •leakage •simplification •high productivity needed |
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goals of nutrient management |
production of high quality plants maintain/enhance soil quality protect the environment |
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liebigs law of minimum |
must attend to the least abundant element before seeing a change |
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Argillic horizon |
Ultisols |
what soil tax? |
