Table 2-1. List of regression (R2) coefficients used to determine which isotherm equation,
linear, Freundlich or Langmuir, best fit the P-sorption data.
Linear,R2 Freundlich,R2 Langmuir,R2
RC1 0.930 0.990 0.880
RC2 0.900 0.980 0.830
RC3 0.980 0.990 0.980
RC4 0.920 0.980 0.840
Table 2-2. P-sorption parameter results for the linear, Freundlich and Langmuir equations for
equilibrium phosphorus concentration (EPC), Kf- a constant in the Freundlich
equation, Cn measure of P concentration in solution after 24 hours, Smax the P
sorption maximum and b a constant in the Langmuir equation.
Linear Freundlich Langmuir
EPC, [tgL-1 Kf Cn Smax u 1 b
RC1 94.5 0.469 0.858 397.7 0.0007
RC2 18.8 1.49 0.853 268.4 0.0041
RC3 73.6 0.506 0.78 206.4 0.0009
RC4 93.2 0.201 0.848 189.5 0.0006
concentration measurement data used to calculate each isotherm equation and associated plot
data is listed in Appendix 2-1.
Results of oxalate-extractable Al (Figure 2-3) and oxalate-extractable Fe (Figure 2-4)
were variable with no apparent spatial trends, therefore results are combined. The isotherm
soils were composite samples collected from the field and not replicates. Due to the single
measurement per site, statistical differences between sites could not be established, and are
used to characterize soil chemistry. Concentrations of Fe and Al were high compared to
other Everglades marsh areas. The average Fe content for the RC transect in RWMA is 4950
275 mg/kg compared to Fe content in WCA2A at 344 37 mg/kg (SFWMD, Everglades
Threshold data) and Loxahatchee National Wildlife Refuge (LNWR) of 339 57 mg/kg
(SFWMD, Everglades Threshold data). Average Al content is 2450 + 515 mg/kg for the RC
transect in RWMA, 248 13 mg/kg in WCA2A (SFWMD, Everglades Threshold data) and