Impact of Planting BMR-6 Forage Sorghum with Corn On Silage Yield in the Mid-Atlantic Region of the United States.

Corn silage is grown on more than 76,000 ha in Virginia and North Carolina and is the primary component of dairy rations throughout the mid-Atlantic region.  Although the yield potential of corn grown for silage is high, it is also sensitive to environmental stress.  Dry conditions during any stage of corn growth can significantly reduce corn silage yields.  In contrast to corn, forage sorghum possesses a much higher level of drought tolerance and water use efficiency.  Planting mixtures of corn and forage sorghum may reduce the risk of low yields during years with below average rainfall and above average temperatures.  The objective of this study was to evaluate the impact of planting corn alone or in mixtures with four rates of forage sorghum (2.25 to 9 kg ha^-1) on the yield and nutritive value of late planted corn silage.   Plots were established at Virginia Tech’s Southern Piedmont Research Station located outside of Blackstone, VA in late May 2010 and 2011, approximately a month after the optimal planting date.  Adding as little as 4.5 kg ha^-1 of forage sorghum to late planted corn doubled (11.0 to 26.0 Mg ha^-1) and tripled (12.1 to 32.0 Mg ha^-1) the adjusted silage yield in 2010 and 2011, respectively.  These data indicate that forage sorghum grown either in mixtures with corn or alone could help to mitigate the effects of drought and high temperatures in silage production systems in the mid-Atlantic region of the United States.