Treatment

Initial log concentration (T=0) (a)

Decay rate (-b) in days

Decay rate (-b) in years

Adjusted r2

Predicted time to decline below detection limit

Lysimeters 1, 2, and 4; YEPG plate counts

6.6430

-0.0001

-0.0366

0.6849
(P < 0.0001)

16,630 days
(45.6 years)

Lysimeters 1, 2, and 4; YEPSS plate counts

5.2432

-0.0008

-0.2801

0.9013
(P < 0.0001)

1,782 days
(4.9 years)

Lysimeters 3 and 5; YEPG plate counts

5.4976

-0.0001

-0.0438

0.5677
(P = 0.0003)

14,740 days
(40.4 years)

Lysimeters 3 and 5; YEPSS plate counts

5.4616

-0.0008

-0.2973

0.9056
(P < 0.0001)

1,843 days
(5.0 years)
Table 2: Decay rate data for a 2 parameter exponential decay curve for log cfu/g soil versus log time (days) or time (years) using the equation y = ae-bx.