April 4, 2008 

Many western Nebraska farmers would like to share in the higher commodity prices driven by demand for bio-fuels, but not all of them can grow irrigated corn. So what options are available in dryland areas or where irrigation is limited?

Some answers might develop from research being conducted by UNL specialists in the Panhandle. One project is exploring the agronomic and energy-producing potential of sweet sorghum, a potential new crop for western Nebraska. Another project is intended to provide more localized data about growing canola and camelina with limited water.

Canola and camelina are oil-seed crops that can be used for biodiesel production. Learning more about how they will respond to dryland or limited irrigation settings is one of the objectives of a three-year research project led by Dr. Gary Hergert, Extension soils specialist at the Panhandle Center, with an $885,000 grant from the U.S. Department of Agriculture.

The grant is being used to refine and expand the Water Optimizer, UNL software that helps producers with limited water evaluate what crops to grow, how many acres to irrigate and how much water to apply. USDA's Risk Management Agency is funding the project.

The first version of Water Optimizer, released in 2005, is useful but doesn't address all of the critical risk-management issues surrounding limited water, said Hergert. He and a multi-disciplinary team from UNL's Institute of Agriculture and Natural Resources plan several product improvements:

• Expanding and enhancing the program to include oil-seed and pulse crops and cover a larger geographic area. Additions will include western Nebraska counties and irrigated areas in Colorado and Kansas.

   

• Developing a management tool within the Water Optimizer framework that can be used to make whole-farm, as well as field-by-field, cropping decisions.

   

• Developing the capability to determine the best strategies for managing multi-year water allocations.

This information will be useful to farmers in semi-arid regions like the High Plains. The improvements also are intended to make Water Optimizer useful to USDA's Risk Management Agency (RMA), which manages the federal crop insurance program by providing information to offer insurance coverage for deficit irrigation.

In 2008, researchers will conduct the second year of field research on oil-seed crops. They hope to develop information to predict how canola and camelina yields vary with different levels of irrigation, including dryland, 4 inches, 8 inches, and 12 inches.

The sweet sorghum research is being conducted on dryland plots at UNL's High Plains Ag Lab near Sidney and at other Nebraska locations. UNL is looking at some alternative ethanol-producing crops for farmers who rely on dryland or limited-irrigation production, according to Drew Lyon, extension dryland crops specialist at the Panhandle Center. Growing dryland corn is risky in the Nebraska Panhandle. Sweet sorghum may be a crop that dryland farmers can grow more consistently and profitably.

In 2007, field studies were conducted at Sidney, North Platte, and Clay Center to determine theoretical ethanol yield from sweet sorghum, corn, and grain sorghum. This work was done by Lyon, in cooperation with other UNL experts, Ismail Dweikat of Lincoln, Charles Wortmann, extension, from Lincoln, and Bob Klein, extension cropping systems specialist at the West Central REC in North Platte.

Preliminary findings indicate that, compared to corn and grain sorghum, sweet sorghum does not produce more ethanol yield per acre, but does produce greater net energy. This results in a net reduction in CO₂ emission compared to corn or grain sorghum, and much more energy produced per energy invested. Approximately 250% more energy is produced than invested for sweet sorghum, compared to 50% more produced than invested for corn or grain sorghum.

Sweet sorghum produces more net energy because it produces sugar, rather than starch. According to Lyon, less energy is needed to make ethanol from sugar than from starch. Sweet sorghum may require less nitrogen fertilizer input than corn, and may be more water-use efficient than corn.

Some potential problems with sweet sorghum include harvest challenges - for example, what to do with all the biomass and where and how to extract the sugar. The plants are very tall, and seed production is low. Questions also remain about how to feed sugar into a corn ethanol stream.

The UNL group plans to repeat this study in 2008.

David Ostdiek
Communications Specialist
Panhandle Research and Extension Center