Analysis of Crop Water Productivity of Forage Sorghum and Corn.

In recent years hyper-extraction from the Ogallala Aquifer in Kansas has reduced the ability for irrigators to supply the necessary water for optimum yields.   A portion of corn grown in western Kansas is used as silage for confined animal feeding operations.  Research suggests that forage sorghum may be a possible replacement for corn in limited water situations.  A study was conducted to evaluate the yield and water use differences in both irrigated and dryland corn and forage sorghum.  In 2011 a study was planted at the Southwest Research and Extension Center at Tribune that contained irrigated corn, irrigated forage sorghum, dryland corn and dryland sorghum.  Neutron probes were installed in each plot to measure water volume to a depth of 2.4 meters.  Biomass was collected at each tube reading.  Biomass yields increased throughout the growing season with irrigated forage sorghum with the highest yield of 19349 kg ha^-1 producing 508 kg of biomass per cm of water.  Irrigated corn produced 17792 kg ha^-1  of biomass at 480 kg cm^-1.  Dryland corn produced 9668 kg ha^-1 at 522 kg cm^-1.  Dryland sorghum produced 13245 kg ha^-1 at 620 kg cm^-1.  Forage sorghum appears to be a good alternative to corn for silage in a limited water environment.