Regression coefficients

Variable

Biochar source

Rate

Rate²

Intercept

Overall model

R²

P

a coefficient

Poultry litter

78.2^*

−7.16^*

244^*

0.037

0.42

Woodchip

4.05

−0.34

479^*

0.998

0.00

b coefficient

Poultry litter

−0.075

0.0086

−2.40^*

0.100

0.32

Woodchip

0.0057

0.00052

−2.70^*

0.790

0.04