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THE FLORIDA STATE UNIVERSITY ARTS AND SCIENCES ...

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groundwater reflects the average year round temperature, 25ºC is used, this is the average<br />

yearly temperature for Jacksonville. In addition as much of the aquifer is made up of sand<br />

and gravel all predictions are based on texture 5 (Sand). Where required an assumed bulk<br />

density of 1.25 gm cm -3 is used. The pH and organic carbon values are obtained from the<br />

soil survey database from the Natural Resources Conservation Service (NRCS), soil<br />

Survey Geographic (SSURGO) database. The information from the NRCS data is<br />

averaged for the area and additional sources such as literature data were then used to<br />

gather input information for the Study area in Jacksonville.<br />

The following information is used to calculate the denitrification rates for the Lake Shore<br />

region, Texture 5 (Sand), Temperature 20ºC, WFP (100%) as we are concerned with the<br />

saturated zone, pH 5.2 (average pH of soils in the region), bulk density 1.5 gm cm -3 ,<br />

saturated thickness of 1000 cm, Organic carbon percentage of 2.1% and an average<br />

concentration of 10.3 μg N gm-1soil. All of the values were derived based on averages.<br />

7.1. Linear Regression and Monte Carlo analysis<br />

The closest equation that can be used is the linear regression developed from 5-15-100-6<br />

(Texture 5, Temperature 15, WFP 100, Nitrate Concentration 6). Based on Figure 2.60<br />

the denitrification rate can be estimated using the following equation<br />

R dn<br />

= 1.984 ∗ organic carbon - 0.3768<br />

----<br />

165<br />

Equation 7.1<br />

Based on an organic carbon value of 2.1 percent, the denitrification rate is estimated to be<br />

3.7896 Kg N ha<br />

-1<br />

d<br />

−1<br />

. As reaction rates are assumed to double for every 10 ºC the<br />

denitrification rate at 25 ºC is 7.5792 Kg N ha<br />

-1<br />

d<br />

−1<br />

. In addition to using the equation<br />

above the Monte Carlo simulation is run for an organic carbon value of 2.1 percent. The<br />

simulation results in a predicted mean of 8.4628<br />

1.0025<br />

Kg N ha<br />

-1<br />

d<br />

−1<br />

Kg N ha<br />

and a maximum value of 11.7355 Kg N ha<br />

-1<br />

d<br />

−1<br />

with a minimum value of<br />

-1<br />

d<br />

−1<br />

.

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