Table 4: Results from quadratic least squares regression when evaluating the effect of soil pH on grain sorghum relative yield (2009 and 2010).

DF Mean square Prob 2009 Lahoma 2 0.06 2.31 0.133 0.24 Perkins 2 0.04 0.35 0.7082 0.04 All locations 2 0.18 3.23 0.0542 0.18 2010 Lahoma 2 0.06 1.59 0.2371 0.17 Perkins 2 1.24 37.67 <0.0001 0.83 Haskell 2 0.25 15.65 0.0002 0.68 All locations 2 1.12 22.82 <0.0001 0.47