THE FLORIDA STATE UNIVERSITY ARTS AND SCIENCES ...

Once again the equations developed based on the restricted variables are better at
predicting the denitrification rate. The improvement is however not sufficient enough for
it to be used with any confidence.
4.2.10. Texture 10 (Silty Clay Loam)
Texture ten is divided into two groups, the first group comprises of 55 records and is used
for the development of the equations and the second contains 16 records and is used as an
assessment
Equations for silty clay loam are developed based on the information below, the
coefficient of determination for both equations is 0.28.
R
R
dn
dn
=
=
- 0.17
+ 9.74 ∗ pH + 0.03 Nitrate
- 0.08
- 0.14
∗
∗Temperature
( ° C) + 0..03 ∗ WFP (%) - 1.75 ∗
Concentration
Soil Depth (cm) + 8.53 ∗ Bulk density (gm cm
∗Temperature
( ° C) + 0.03∗
WFP (%) - 2.5 ∗
+ 0.02*
Nitrate Concentration
( μg
N g
-1
soil) - 51.5
(
OC (%)
136
OC (%)
-1
μ g N g soil) ----- Equation 4.16
+ 9.5 ∗
-3
pH
) −
63.
45
Table 4.24 Texture 10, Linear multi-regression using all variables.
----- Equation 4.17
Coefficients Estimate Std.Error t-value Significance
Intercept -63.45 60.63 -1.05
Bulk Density (g cm -3 ) 8.53 41.27 0.21
NO3 - Conc ( µg N g -1 soil) 0.03 0.01 0.89
OC (%) -1.75 4.25 -0.41
pH 9.74 2.89 3.37 **
Soil Depth (cm) -0.09 0.41 -0.21
Temp (ºC) -0.17 0.29 -0.58
WFP (%) 0.03 0.12 0.25
Signif.Codes Signif.Codes Signif.Codes
0.00 '***' 0.00 '**' 0.01
0.01 '*' 0.05 '.' 0.10
0.10 1.00