Soil review Complexity of soils Intensity and capacity concepts Weathering Florida soils Collected from over a dozen books

Major Florida soil types Ultisols Spodosols Entisols Histosols 7 out of 12 orders, 4 major in Florida 1 organic and 11 mineral soils Histosols: muck or peat, accumulation of OC in wet environment Ultisols: high in clay, has a clay layer in subsurface Major Florida soil types

Properties of Florida surface soils CEC Clay Silt Sand OC pH Soil Cmol kg-1 % Entisols (no coating) 1.59 0.40 0.50 99.0 0.41 5.30 Entisols (s coating) 4.79 1.80 1.30 97.0 0.77 5.03 Entisols (coating) 4.98 2.10 4.00 94.0 0.98 5.36 Spodosols 12.2 1.29 3.93 94.8 2.30 4.54 Ultisols 7.41 3.80 6.92 89.3 1.11 5.05 Weathering, losing Na, K, Ca and Mg hard Lewis bases Ma, L.Q., F. Tan and W.G. Harris.  1997.  Concentrations and distributions of 11 elements in Florida soils.     J. Environ. Qual.  26:769-775. http://lqma.ifas.ufl.edu/publication/ma-97c.pdf.

D. Hardison

Kabata-Pendias and Pendias (1992) Three phases: not concrete solid Concern: Liquid > air > solid Solid phase: organic and inorganic Inorganic-minerals: present as sand, silt and clay Organic: Living phase. Heavier than water? Soil moisture content: volume basis, what about mass basis Density of minerals. Kabata-Pendias and Pendias (1992)

Trace metals review Elemental classification Lewis acid/base Pearson’s hard/soft metals Ionic and covalent index Ionic potentials Electron negativity Earth Scientist's Periodic Table of the Elements and Their Ions Common minerals and aqueous species in soils Familiar with equilibrium reactions Use log activity-pH graphs

Elemental classification Atomic configurations (Lewis, 1923): Lewis acid/base Lewis acid e-acceptor cations/metals Lewis base e-donor anions/oxyanions Acidity of PbCl2: and Na3PO4 acid due to hydrolysis of Pb and basic due to Gilbert Lewis/Ralph Pearson Class A and B metals Polarity/formation of stable compounds (Pearson, 1968) Hard/Soft acceptor Hard acceptor/donor non-polarizable and small Soft acceptor/donor more polarizable and larger JCB lecture

low En, large size, high polarization, easily oxidized /metal /metal low En, large size, high polarization, easily oxidized Atomic configurations (Lewis, 1923) Polarity/formation of stable compounds (Pearson, 1968) Common anions in soils Hard to hard, soft to soft Adriano (2001) HSAB-the 13th most cited paper in JACS

/metal /metal /metal Ross (1994)

Softness Hardness JCB lecture

Ionic potential and solubility IP = ionic charge (Z)/ionic radius (r) Low IP  high solubility IP and metal solubility IP  money for a given family, large family less $ per person Pressure: Nail sharp Two forces: attraction of metals for O2-, and repulsion of metals for H+ Sequence is H2O  OH  O Kid grows up, elementary middle school  high school JCB lecture

Ionic potential and solubility H+ O2- H+ O2- H+ M+ O2- H+ M+ IP <2.5 (low): H+-O > O-M+ Ba, Li, Rb, & Sr

Ionic potential and solubility H+ O2- O2- O2- M+ H+ H+ O2- H+ M+ 2.5 < IP < 9.5 (medium): H+-O ~ O-M+ Cu, Ni, Pb, U, Zn, Cr, & Co

Ionic potential and solubility M+ O2- >9.5 (high): H+-O < O-M+ As, B, Mo, and Se M+

Ionic potential and solubility IP = ionic charge (Z)/ionic radius (r) Low IP  high solubility IP and metal solubility IP <2.5 (low): H-O > O-M Ba, Li, Rb, & Sr 2.5 < IP < 9.5 (medium): H-O ~ O-M Cu, Ni, Pb, U, Zn, Cr, & Co >9.5 (high): H-O < O-M As, B, Mo, and Se IP  money for a given family, large family less $ per person Pressure: Nail sharp Two forces: attraction of metals for O2-, and repulsion of metals for H+ Sequence is H2O  OH  O Kid grows up, elementary middle school  high school JCB lecture