Table 2. Regression analysis of corn silage production against soil temperature at planting or growing degree days at harvest

Silage corn maturity		Parameter	Coefficient of regression	p-value	R2
STP
Early		Constant	−1,385.34	0.20	0.50
		Linear	26.52	0.92
		Quadratic	−126.76	0.04
Medium		Constant	−1,178.38	0.04	0.74
		Linear	−15.50	0.89
		Quadratic	−135.51	< 0.01
Late		Constant	−348.35	0.74	0.63
		Linear	46.87	0.83
		Quadratic	−267.89	< 0.01
GDD
Early		Constant	−22.52	0.94	0.89
		Linear	-0.40	0.78
		Quadratic	-0.02	< 0.01
Medium		Constant	−1,214.11	0.01	0.85
		Linear	2.33	0.17
		Quadratic	−0.01	< 0.01
Late		Constant	−300.09	0.22	0.49
		Linear	1.38	0.44
		Quadratic	−0.03	0.04

STP, soil temperature at planting; GDD, growing degree day.