Switchgrass varieties currently on trial at four locations in California

Coalinga, Calif. rancher Anthony Amaro has been a frequent visitor to the University of California’s Westside Research and Extension Center at Five Points, Calif. over the past year.

“I want to be the first farmer in California to grow switchgrass,” said the fifth-generation SJV producer. And the only place he can find how switchgrass grows is from a small test plot at the field station.

“He comes by here just about every week,” said Bob Hutmacher, station research director and UC Extension agronomist.

Amaro raises cattle and alfalfa crops in Los Gatos Canyon nestled in the Coast Range on the West Side of the San Joaquin Valley. He wants to try switchgrass because he has read it is drought-tolerant and does well on marginal ground. Amaro is dependent on rainfall for pasture grass.

He was among a handful of farmers, pest control advisors and seed company representatives gathered at a WREC field day recently to look at the switchgrass variety and management trial on the station, and hear Dan Putnam, UC alfalfa and forage specialist, and others talk about what researchers have learned so far about switchgrass growing in the irrigated West.

However, knowledge gained is limited because the trial is young. Yet, there was an air of guarded optimism about the crop that has never been grown commercially in California.

The WREC switchgrass trial is one of four that the University of California currently has underway in conjunction with a Southern California Company, Ceres Inc. — which is evaluating a variety of crops for biofuel. The other three switchgrass trials are in Imperial Valley, on the UC Davis campus and at Tulelake in Northern California.

Switchgrass is a summer perennial grass that is native to North America. It was part of the mix in the tall grass prairies that covered most of the Great Plains.

It is identified often as an efficient bio-energy crop.

However, corn has been the major feedstock for U.S. biofuel production so far.

That is now coming under intense political scrutiny with the growing worldwide shortage of food. American farmers’ ability to produce billions of pounds of corn en route to making America energy independent was once very popular with the politicians and media. About 20 percent of U.S. corn production now goes for ethanol production.

However, with world hunger reaching the front pages, U.S. corn producers and ethanol plants are now the bad guys, even though the issue of world hunger is impacted by far more factors than corn for ethanol. Droughts and growing world populations are bigger factors than corn for ethanol.

Corn has been the No. 1 biofuel feedstock because starch is easier to convert into fuel. However, government officials and others claim cellulosic biofuel is much more efficient than starch-based ethanol production. Unfortunately, the technology to convert things like wood waste, corn stover, paper, straws, and other cellulosic products into biofuel has been lacking.

Putnam says there are “three or four” government-subsidized cellulosic biofuel plants now starting up in the U.S. to see if the technology can be economically developed.

Switchgrass can be co-fired with coal to produce electricity in existing power plants. Pelletized switchgrass has been tested in pellet stoves for general home heating in some rural areas.

Putnam said corn takes considerable nitrogen to produce. The energy return can be much higher using switchgrass for biofuels.

“The payback can be four to seven times making biofuels from cellulosic products — than the 20 percent to 50 percent with corn,” noted Putnam at the field day.

California’s high value, high economic input agriculture has not jumped on the biofuel bandwagon. California increased its corn production strictly as a response to ethanol-driven corn prices, but much of the grain and corn silage produced in the state goes to animal feed.

Alfalfa, the state’s No. 1 field crop with more than one million acres, has been identified as a potential feedstock for biofuel. However, the economic return as a forage crop for milk and beef production is far greater than for biofuel.

Putnam has doubts about California forages becoming feed stock for fuel production. “Forages produced in California equate to food production ... milk, cheese, meat, and a good question to answer is whether the No. 1 food producer in the nation will grow crops for biofuels,” he said.

It is a question that does not beg for an answer now because there are only corn-fed biofuel plants in California and the feedstock for them is coming from the Midwest.

Nevertheless, Putnam, along with other UC researchers and Ceres, wants to find out as much as he can about switchgrass. It may become a biofuel feedstock at some point, but in the meantime it could become an alternative forage crop. It may be an alternative crop for marginal ground that will not economically support other crops.

Putnam called it “fairly efficient” at photosynthesis, as well as being drought and high temperature tolerant. It requires little fertilizer to survive, but UC researchers are pushing hard at WREC to maximize production.

In a recent on-farm study in the Midwest, switchgrass produced 2.3 to 5.9 tons per acre. That is about the same yield range generated in California variety trials last season, the first year of the trial. By comparison, winter cereal forage yields in the central valley are typically 20 tons per acre.

However, it likely will yield more than that in the second and third year. Putnam estimates it will maintain a stand for at least three years.

Hutmacher says by late April it was already taller than it was at the end of last season after it was planted in the summer. It was about 42 inches tall at harvest last fall. It goes totally dormant in the winter.

“It was incredibly responsive to irrigation in mid-March this year,” said Hutmacher.

“It looks quite good in all trials across California,” added Putnam.

It was summer seeded and harvested only once. Putnam said research elsewhere noted it can be harvested two or three times a season when stands mature. Putnam believes it will be harvested more often with typical, intense irrigation and fertility management in California.

“The yields off a first year stand of a perennial grass were very respectable,” he added.

It does not establish as quickly as alfalfa. “You need patience in getting a stand of switchgrass. It is definitely a warm season grass. I would not plant it too early to avoid the flushes of summer weeds,” he said. Putnam and UC Tulare County Farm Advisor Steve Wright said pre-irrigating to generate spring weed flushes to control weeds with herbicides or disking before planting switchgrass would ensure a stronger stand.

Wright applied Prowl H20 and did some hand weeding last winter to control weeds before the switchgrass began growing this spring.

The WREC trial received 65 pounds of nitrogen per acre last year and 100 pounds this spring.

Putnam surmised switchgrass could be swathed and windrowed for baling, cut for silage, or grazed.

“It must be cut no shorter than 4 to 6 inches to ensure good regrowth,” Putnam warned.

UC researchers are evaluating about 10 different varieties under a wide range of California growing conditions.

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