In a nod to the fact that cotton is no longer king in the San Joaquin Valley, the cotton field day also provided extensive information about potential alternative crops on traditional cotton ground in the West Side, including small grains, switchgrass and alfalfa.
UC Cooperative Extension Forage Specialist Dan Putnam discussed the production of switchgrass for feed and biofuels, as a potential alternative crop on cotton ground.
Putnam said the UC is looking toward the future to help introduce crops that might be economical for growers to produce while providing a commercial source of alternative fuels.
“Biofuels are a big question all over the U.S. Corn of course is the nation's No. 1 biofuel, but there are other concepts including using oil seeds and cellulose to produce biofuels as well,” Putnam said.
Unlike grains, which are fermented into ethanol, cellulose from crops such as switchgrass is converted to fuel through a chemical process.
Switchgrass is a highly productive, drought-tolerant native forage and groundcover that was identified nearly 25 years ago by the U.S. Department of Energy as one of the most promising crops for cellulosic biofuels, Putnam said. Little research and investment has been done since, however, on the conversion of these types of cellulose crops to fuel.
“The conversion of cellulose into ethanol is behind current technology for starch based ethanol, but we want to look at this now and potentially be ahead of the game.”
Putnam said UC Cooperative Extension is looking at how well switchgrass grows in different regions of the state and its economic potential as a multi-use crop in the San Joaquin Valley and other areas.
“We have a deficit of forage in the state so we have a significant demand for forage crops in California. The question is, can we grow this crop profitably to meet demands for biofuels and forage at the same time,” he said.
The UC trial is looking at 10 different varieties, including seed company and public selections, to not only compare different varieties but also various fertility programs, water requirements, and cutting schedules. In general, switchgrass yields on the West Side trial were the best in the state, averaging 8 to 12 tons per acre on the first cutting.
Despite promise, one of the biggest challenges to growing switchgrass in California is that it is listed as an invasive species, though Putnam said it is much more difficult to establish than Johnsongrass, and expects that designation could one day change.
Putnam also provided an update on UC alfalfa variety trials. Variety selection is extremely important in alfalfa production, he noted, and thanks to breeding efforts by seed companies, growers have a number of varieties to choose from. He noted that choosing the right variety can make a difference of between 5 percent and 25 percent in yield in some situations.
UC Davis Small Grains Specialist Lee Jackson also presented a talk on the production of small grains in the San Joaquin Valley, including wheat, triticale, barley and oats, as a rotational crop to cotton.
Small grains provide for rapid and relatively low-cost production as a winter rotation or cover crop. Their deep root system improves soil structure and the crops can be produced with relatively little applied water. Small grains and winter forages also fit well in double cropping systems with corn silage for year-round feed for dairies and are less vulnerable to drought than summer forages, Jackson said.
However, he noted that there are some crop production issues with small grains in the Central Valley, particularly on the West Side, that must be addressed. These winter grains are prone to diseases, such as damping off or wilt, and nematodes can also be a problem.
“But for the most part, standard integrated pest management allows us to adequately control the problems facing small grains in the Central Valley.”