Cooperative Extension San Joaquin County
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Cooperative Extension San Joaquin County

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The body of CT research knowledge continues to grow

UC scientists presented recent additions to the growing body of research on conservation tillage in California at the second annual Twilight Conservation Tillage and Cropping Systems field day last month, demonstrating progress in agricultural systems that will help farmers cut production costs, reduce soil disturbance and save water.

UC scientists and their partner farmers are conducting research that addresses the current needs of the San Joaquin Valley agricultural industry and research that is looking to the future by anticipating changes that may need to be negotiated in coming decades.

During the field day at UC's West Side Research and Extension Center in Five Points, Calif., participants visited two primary research areas. The first is the longest-standing conservation ag system study in California, where a cotton/tomato rotation has been farmed for 12 years running. The plots include standard tillage with and without cover crops and conservation tillage with and without cover crops.

“This might be the most-visited research field in California,” said Jeff Mitchell, UC Cooperative Extension vegetable crops specialist and chair of the CT workgroup. “Many students and scientists have conducted research here.”

For example, scientists have been able to quantify significant improvements in soil quality with the use of cover crops and conservation tillage. UC Davis soil biochemist Will Horwath reported that conservation tillage combined with an off-season cover crop has increased the soil carbon content close to five tons per hectare.

“Is that significant?” Horwath asks. “Yes. In 10 years, we have almost doubled the soil carbon content.”

Because of the valley’s dry, hot climate, the native soils are typically very low in carbon, which is a characteristic of low soil quality. Carbon in the soil acts as a glue, helping reduce wind erosion.


Jeff Mitchell presents research updates on a broccoli field with overhead irrigation.

At the second research field, conservation tillage research is being combined with overhead and subsurface drip irrigation. Coupling overhead irrigation with conservation tillage is common in other regions of the U.S., but is just beginning to get attention in California.

“There are more than 17,000 center pivots in the state of Nebraska, and it is estimated that there are somewhere between 300 and 500 pivots currently in use in California, the No. 1 ag state in the nation,” Mitchell said. “This situation is changing rapidly.”

Overhead irrigation is efficient, automated, allows for diverse cropping and, with soil residues from conservation tillage, permits uniform infiltration.

Four users of overhead irrigation shared their experiences with the irrigation system at the field day. West side farmer John Deiner said mechanized irrigation has significantly reduced labor input in his agronomic crops while boosting crop yields.

“Our corn grew two to three feet taller under the pivot,” he said.

Will Taylor of King City grows potatoes for In and Out Burger under center pivots. He said his yields are 20 percent higher when using the overhead irrigation system.

“Once you overcome challenges,” Taylor said, “they’re awesome.”

He demonstrated their ease of use by bringing along his 9-year-old son Liam, whom he said can already manage the machine.

Darryl Cordova of Denair uses overhead irrigation in a hilly area on the east side of the valley.

“What used to take three guys six hours of moving pipe is now done with a push of a button on my cell phone,” Cordova said.

Scott Schmidt, who farms across the street from the West Side Research and Extension Center, said he has learned how to successfully use overhead irrigation and conservation tillage from the “school of hard knocks.”

“Most of the problems have been self-inflicted wounds,” Schmidt said. But now, he calls the system “flawless.” “We have seven pivots that I operate remotely from my phone.”

Left to right, Scott Schmidt, Darryl Cordova, Liam Taylor, Will Taylor and John Deiner.

Posted on Wednesday, October 19, 2011 at 8:24 AM

Can GE and non-GE alfalfas co-exist?

Those of us who work with alfalfa have seen our much-loved Queen of Forages relegated to poster child of all things evil about genetic engineering (GE) and the supposed damage it may wreak. While hay growers have always felt alfalfa has received insufficient attention – this was probably not what they had in mind!

I’m referring, of course, to the release of Roundup Ready alfalfa (RRA) in 2005 and the subsequent lawsuit that stopped its planting from 2007 until 2011 – a case that went all the way to the Supreme Court!

The drama continues today with newly minted lawsuits, as farmers once again plant RRA and conventional alfalfa throughout the U.S. But what does this ballyhoo mean for those who actually grow alfalfa?

At the heart of the controversy is co-existence: whether cross-pollination from GE alfalfa would completely prevent organic or other growers who didn’t want GE alfalfa from practicing agriculture as they see fit. Or, alternatively, whether farmers can adopt methods to avoid undue neighbor influence or contamination.

Successful coexistence can be defined as the ability of diverse production systems (organic, GE-adopting, conventional) to thrive without excessive neighbor influence, or resorting to extraordinary protection measures.

Is co-existence possible? The answer is a definitive “yes” based on both history and principle.  Agriculture is replete with examples of farmers adjusting and cooperating to make diverse systems work. In principle, there is no technical reason that diverse farming practices cannot co-exist.

So if you produce alfalfa for organic, export or other markets that don’t want GE crops, what is required? The answer is very different for those who grow alfalfa for hay vs. those who produce seed. Seed requires considerable isolation distances to prevent contamination – and always has.

For hay, a series of steps can reduce this risk to very low levels.

The first, and most important step is to plant seed tested and determined as non-GE. Plenty of conventional seed is available, as are inexpensive testing methods to assure that the seed is non-GE. Seed companies have committed to produce conventional seed in the future, including seed destined for GE-sensitive markets.

The next step is to assure that contamination doesn’t happen during harvest – through partial bales moving in balers from field to field or accidental misidentification of hay lots. This is likely the second-highest risk of contamination.

The lowest – but not zero – risk of contamination in hay: inadvertent gene flow from hayfield to hayfield.

Neighbors can reduce this risk further by: 1) Controlling unharvested plants on field edges and feral alfalfa along roadsides to prevent seed production; 2) Routinely harvesting hay to prevent excessive flowering; and 3) Completely removing crop before excessive flowering or seed production. Crop removal prevents permanent contamination, since seed must fall to the ground and grow into new plants to contaminate hayfields.

Lastly, it is important to understand thresholds or market tolerance.

Does a single RRA stem, accidently baled in a 200-ton lot of conventional hay (containing billions of stems), constitute contamination? This will be market-determined. Commercially available test strips will likely satisfy most if not all sensitive markets of a hay product’s non-GE status.  All markets have thresholds for contaminants, and there is no reason to believe this to be an exception.

In short, methods are readily available to assure an alfalfa crop’s non-GE status, even as neighbors start growing GE alfalfa. These require a higher awareness of gene flow and other avenues of contamination, but do not appear to be onerous or difficult.

We also should not underestimate the importance of mutual respect and willingness to cooperate among parties as keys to a co-existence strategy. It is axiomatic that coexistence is impossible if parties are unwilling to listen to each other, allow a diversity of viewpoints or develop a way to resolve disputes.

The alfalfa industry has largely stepped forward to support diverse systems within the agricultural landscape and needs to continue to do so. This has been the case with National Alfalfa & Forage Alliance efforts to promote coexistence over the past 5 years, which continue today (see their website).  Seed companies and growers continue to negotiate isolation distances for production of GE and non-GE seed. Likewise, hay farmers have demonstrated co-existence by growing RRA and organic alfalfa successfully on the same farms.

This year in California’s Imperial Valley, seed, hay and organic growers, exporters and seed companies have met extensively and decided to prohibit RRA in their region due to the close proximity of seed, hay, biological factors and the importance of seed and hay exports.

These are examples of “bottom-up” co-existence approaches led largely by farmers and companies – in contrast to regulations decided in Washington or through the courts.

The concept of right-to-farm and co-existence between neighbors and diverse industries is not new to agriculture. Yet the introduction of GE alfalfa and its potential influence on neighboring farmers requires improved co-existence strategies for alfalfa.

(This article was first printed in Hay and Forage Grower magazine.)

Posted on Tuesday, October 11, 2011 at 12:55 PM

Hummingbirds are noisy romancers

Forget bird watching; next time you spot a hummingbird, listen.

Most of us pause to gaze at the tiny birds’ impressive mid-air hovering, part of their hunting behavior, but males of some hummingbird species generate loud sounds with their tail feathers while courting females.

Now, for the first time, the cause of these sounds has been identified: a paper published in the Sept. 9, 2011, issue of Science reveals that air flowing past the tail feathers of a male hummingbird makes his tail feathers flutter and thereby generate fluttering sounds.

Watch a video of hummingbird tail feathers in an wind tunnel.

Male hummingbirds only produce fluttering sounds during their elaborate courtship rituals. Typically, during such a display, a male hummingbird will climb into the air five to 40 meters, and then quickly dive-bomb down past a perched female; when the courting male bird reaches the lowest point of his dive, he rapidly spreads and then closes his tail feathers. This spreading exposes the tail feathers to air, which causes them to flutter and generate sound, according to Christopher Clark of Yale University, lead author of the study.

Clark's research, which he began as a graduate student at the University of California, Berkeley, shows that the males of each hummingbird species have their own signature sound — largely determined by whether and how the fluttering frequencies of its different tail feathers interact with one another and blend together.

Other factors, such as the size, shape, mass and stiffness of the hummingbird's feathers, also help determine the tone of each species' particular sound.

In addition to diving during courtship rituals, a male hummingbird may also brandish showy ornaments and produce sounds from other feathers besides his tail feathers.

All this, just to impress that special lady.

Clark analyzed the fluttering sounds of hummingbird feathers by measuring the fluttering feathers with a Scanning Laser Doppler Vibrometer — an instrument that is used to measure the vibrations of a surface — and by viewing high speed videos of the tail feathers of hummingbirds in a wind tunnel.

The study was co-authored by Damian Elias, also of UC Berkeley.

— Adapted from a story by the National Science Foundation.

Posted on Wednesday, October 5, 2011 at 9:41 AM
  • Author: Ann Brody Guy

U.S. Forest Service and UC study ways to reduce wildfire severity

The University of California Cooperative Extension (UCCE) recently co-hosted a field trip with the U.S. Forest Service to view the implementation of a forest fuels reduction project on the Tahoe National Forest.

Over 45 stakeholders, including representatives of state, federal, and local government, industry and environmental groups and local residents attended to see the project, known as the "Last Chance Project," which involves thinning the forest by removing small and medium-sized trees, masticating or mowing down brush, and burning dead material through prescribed fire. The work, being done by Sierra Pacific Industries, under contract to the U.S. Forest Service, should be completed by fall 2012.

University of California scientists and UCCE have teamed up with the U.S. Forest Service to provide independent third-party research on the project to determine its effects on forest health, fire behavior, wildlife, water quality and the public through the Sierra Nevada Adaptive Management Project (SNAMP).

The forest research team including Brandon M. Collins, now employed by the U.S. Forest Service Pacific Southwest Research Station as a research fire ecologist, collected data before the Last Chance project began to determine its likely effectiveness at improving the health of trees and reducing the potential for destructive high intensity wildfire. Collins led the effort to use computer models to determine how the Last Chance project, as proposed, will affect fire behavior across the surrounding landscape up to 30 years after completion. Additionally, other hypothetical treatments limiting the diameter of trees removed to different sizes were modeled to assess how effective the project will be at reducing fire severity.

The team sampled 199 forest plots and collected data, such as tree species, vigor, and diameter at breast height (dbh). Tree core samples were collected so the growth of tree rings can be determined to characterize tree productivity at each plot. Downed material, including branches, twigs, pine needles and decomposed organic material, were measured along with woody shrubs. Fuel loads were calculated using standard protocols.

This data was then entered into the Forest Vegetation Simulator (FVS) with the Fire and Fuels Extension to model the planned treatments and grow forest stands within the study area for several decades. Using a command line version of FlamMap, called Randig, and weather information from the Duncan Peak Remote Automated Weather Station, scientists simulated 5,000 randomly placed fire ignitions to model conditional burn probabilities, which are the chance occurrences of a pixel burning given an ignition within the study area under modeled weather conditions.

Simulated, conditional burn probabilities across the Last Chance landscape (By Brandon M. Collins)

Results from that modeling show that fuels treatments as planned for the Last Chance project will be effective at reducing fire behavior not only within treated areas, but also in adjacent areas. Differences in modeled fire behavior, when different limits on the diameter of trees removed were modeled, were slight. This suggests that the key to effective reductions in the probability of more hazardous fire occurrence at the landscape scale is treating surface fuels and thinning ladder fuels, and that the diameter of the trees removed is less important.

Changes in design of fuels treatments project often occur during implementation when unexpected conditions occur. Therefore, post-treatment forest plot data will be collected again beginning in Fall 2012 to better characterize the treatment as implemented, and to re-examine the effectiveness of the modeling results.

Information for this article comes from: Collins, Brandon M., Scott L. Stephens, Gary B. Roller and John J. Battles. 2010. Simulating Fire and Forest Dynamics for a Landscape Fuel Treatment Project in the Sierra Nevada. Forest Science 57(2) 2011.

Photos by Shufei Lei, SNAMP

Photos by Shufei Lei, SNAMP
Photos by Shufei Lei, SNAMP

Posted on Wednesday, September 28, 2011 at 12:22 PM

The Good Soldier

If you see a black fly or its eggs and larvae while you're turning over your compost pile, don't be alarmed.

It's probably a "good soldier."

The black soldier fly (Hermetia illucens) is a beneficial insect. And a far-ranging one at that.

Martin Hauser, senior insect biosytemastist at the Plant Pest Diagnostics Branch,  California Department of Food and Agriculture, says this is the only Hermetia he can find in the Sacramento region. "If you go south and to Arizona and New Mexico, you'll find more species, which are more colorful."

This New World species, he says, is now worldwide. "I found it in Nepal, Borneo, Australia, Madagascar, Ghana, France and last year it was recorded for the first time in Germany."

The black soldier fly, about 15 to 20 mm long, is primarily black, as its name indicates.  The male has often a reddish abdomen while the female's abdomen is mainly black with dark black wings.

It's often mistaken for a wasp. "Hermetia illucens has that transparent white window on the first abdominal segments, which gives the optical illusion of a  [not only Sphecids, but also Eumenidae etc..] wasp with a petiolated abdomen," said Hauser, who received his doctorate in entomology from the University of Illinois at Urbana-Champaign.

The adults feed on floral nectar; in fact, we spotted one on sedum last week at the Häagen-Dazs Honey Bee Haven on Bee Biology Road, UC Davis. The females lay their eggs in compost, manure and the like. And they do like!

The eggs, pale yellow or cream colored, are in masses that contain as many as 500 eggs. Some folks, when they see them in a compost pile, wonder if they're cockroach eggs.

They're not!

The larvae, aka maggots, thrive on decaying organic matter or detritus. In doing so, they make short work of rotting organic waste. They're also used as a forensic entomology tool and as pet food.

Indeed, if you've never encountered a black soldier fly, you may have encountered the larvae. They're sold in pet stores under such names as Phoenix Worms, Reptiworms and Soldier Grubs to feed herptiles (amphibians and reptiles) and tropical species of fish. They're also used as composting grubs and for chicken feed.

Here’s a great video on the black soldier fly larvae.

When used in manure management, the black soldier fly larvae are known by the  acronym, BSFL.

"The larvae of this fly eat everything!" Hauser said. "They can get rid of all kinds of organic waste in no time, like mountains of orange peel from the juice industry, organic part of household garbage, and compost."

A video on YouTube shows how quickly these larvae consume dead fish.

"But the real cool thing is that you then can harvest the maggots, which are a prime source of protein," Hauser said. "...You can collect the mature maggots, and produce, for example, protein powder for the fish industry. Right now we catch a lot of small fish, grind them up and feed them to larger fish, which is a huge waste of resources, energy and protein--each trophic step loses 90 percent of the energy, which means you have to catch a lot of small fish to raise some big fish."

"But if you could feed the fish with orange peel and garbage, you would solve two problems at once - and this is where this amazing fly comes into play: it converts waste into protein. Saving the fish, getting rid of waste and being 100% organic."

So, if you think of insects as "the good, the bad and the bugly," think of the black soldier fly as "good."

The larvae are good for the compost pile, good for pet food,  good for manure management and good for biogradable waste.

And as an adult, it's a pollinator!

The black soldier fly is a beneficial insect. (Photo by Kathy Keatley Garvey)
The black soldier fly is a beneficial insect. (Photo by Kathy Keatley Garvey)

The black soldier fly is a beneficial insect. (Photo by Kathy Keatley Garvey)

Black soldier fly heading toward a compost pile. (Photo by Kathy Keatley Garvey)
Black soldier fly heading toward a compost pile. (Photo by Kathy Keatley Garvey)

Black soldier fly heading toward a compost pile. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, September 21, 2011 at 3:10 PM

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