Term
| about 75-80% of N in soil is found in... |
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Definition
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Term
| 2 common valence states for soil N |
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Definition
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Term
| behavior of ammonia (NH3) in solution |
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Definition
| strong base that's hydrolyzed to produce hydroxide and the the ammonium ion |
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Term
| what happens to ammonium (NH4+) in aerated systems? |
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Definition
| gets oxidized to nitrate (NO3-), which is a microbially mediated process |
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Term
| how NH4+ and NO3- are relatively conservative in soils |
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Definition
-they don't form mineral precipitates
-they don't participate in aqueous complexation rxns |
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Term
| where ammonium fixation can occur |
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Definition
| in soils containing vermiculite |
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Term
| valence state of P in soils |
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Definition
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Term
| amount of P in soil that's organic P |
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Definition
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Term
| the basic inorganic P species |
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Definition
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Term
| when orthophosphate (PO43-) occurs as H2PO4- |
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Definition
| when the soil solution pH is < 7.2 |
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Term
| how orthophosphate (PO4-3) is affected by pH |
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Definition
| releases protons as the pH increases |
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Term
| the orthophosphate (PO4-3) species that form stable aqueous complexes with numerous mono- and divalent metal cations |
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Definition
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Term
| the phosphate species that can become strongly, if not irreversibly, adsorbed by Al and Fe oxyhydroxides and clay minerals and how this happens |
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Definition
| -H2PO4-
-HPO42-
-this happens via ligand exchange mechanisms |
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Term
| the commonly occurring oxidation states of As and Sb |
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Definition
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Term
| why As and Sb may be able to isomorphically substitute in primary and secondary minerals |
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Definition
| similarities in ionic radii |
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Term
| how AsIII exists in soil solution |
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Definition
| as arsenite, a hydroxyanion (As(OH)3) |
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Term
| where the AsV oxidation state is stable |
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Definition
| in oxic and suboxic environments |
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Term
| when neither AsIII nor SbIII are stable |
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Definition
| when in the presence of FeIII or MnIV oxyhydroxides
thus, they are readily oxidized |
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Term
| will As or Sb form stable secondary minerals in soil? |
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Definition
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Term
| why As and Sb won't form stable secondary minerals in soil |
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Definition
| because of their innately low soil concentrations |
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Term
| the primary retention mechanism for As and Sb |
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Definition
| adsorption by Fe oxyhydroxides |
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