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A recent study at Oregon State University has shown that native bumble bee species have consistently high pollination and seed production levels in red clover.

The bumble bee pollination findings offer promise for the use of bumble bee crop pollinators as an alternative to European honey bees, whose populations have recently declined in many areas of the United States.

Red clover, which is grown for forage and as a rotation crop to improve soil, is raised for seed in western Oregon's Willamette Valley. It will not produce seed without pollination, so growers typically place two to five European honey bee hives on each hectare. 

Search for Alternative Pollinators

Bee diseases, mites, and colony collapse disorder have recently limited availability and resulted in higher costs for hive rentals. Given these changes, an alternative pollinator for red clover seed crops is needed.

Worldwide there are over 200 species of bumble bees; some of whom are known to pollinate red clover. While commercially reared bumble bee species are available to growers elsewhere, they are considered exotic species in Oregon and cannot be introduced into the state. This leaves Oregon growers dependent on naturally occurring populations of bumble bees as pollinators. However, there is currently no information on the pollination efficiency of native bumble bee species.

Scientific Evaluation of Blooms and Seed Set

Through funding from the Clover Commission, scientists at Oregon State University investigated native bumble bees in commercial fields of red clover seed crops in the Polk County region of the Willamette Valley. Prior to bloom, researchers covered plants with mesh-screened cages. European honey bee hives were placed in some cages and nests of B. vosnesenskii, a native Oregon bumble bee,in others. Some cages were also left vacant. After bloom, seed yield and seed set were compared amongst the different cages. Seed set was also evaluated in four different fields without cages to assess the efficiency of existing bee pollinators. In addition to analyzing seed set, researchers assessed the diversity and abundance of native bumble bees through visual observations of foragers on red clover flowers and through trapping bumble bees in blue vane traps. 

Pollination Differences between Bumble Bees and Honey Bees

While there were no differences in seed yield or average seed set in cages with bumble bees compared to honey bees, the study revealed:

• Variability across cages was lower with bumble bees indicating that bumble bee pollination is more uniform than pollination by European honey bees.
  
• The abundance of bumble bee peaked during mid-to-late bloom.
  
• They recorded six species of bumble bees gathering pollen from red clover flowers. Of these, more than 92% consisted of B. vosnesenskii, indicating that it is the key pollinator in Oregon.
  
• 25 more species of native solitary bees, belonging to 12 genera and five families, were collected in the bee traps.

Research Findings

The study has not only documented a great diversity of native bees in synchrony with red clover bloom, but it has also found that seed set was uniform and high across four fields. Under current pollinator regimes, researchers believe red clover seed production is close to its maximum in Oregon.

Solutions for Pollination

"To sustain these high yields in Oregon, we must

• Conserve the habitat of bees,
  
• Use pesticides judiciously and
  
• Provide floral resources prior to red clover bloom

Oregon State University entomologist Sujaya Rao, one of the researchers on the study, concluded,  "Globally, where red clover seed is produced, similar studies are needed. If seed set is found to be well below the maximum, appropriate alternative options such as augmentation with commercial bumble bees could be considered."

Research is ongoing at Oregon State University to determine whether high yields can be achieved by native pollinators alone. If so, European honey bee hive rentals would not be required, and this could lead to more economic red clover seed production in Oregon.

The Crop Science Society of America (CSSA), founded in 1955, is an international scientific society comprised of 6,000+ members with its headquarters in Madison, WI. Members advance the discipline of crop science by acquiring and disseminating information about crop breeding and genetics; crop physiology; crop ecology, management, and quality; seed physiology, production, and technology; turfgrass science; forage and grazinglands; genomics, molecular genetics, and biotechnology; and biomedical and enhanced plants.

SOURCE:  ©2009 Newswise, Inc

Young Farmers and Ranchers Leadership Conference brought topics of CHANGE to California's farmers.

National Young Farmers and Ranchers conference in Baltimore. During the opening session, an economist from Washington, D.C., said, "I never thought I would say this, but agriculture is a shining star in our slowing economy."

Commodity prices for a lot of products are up but that is not the only change on agriculture's horizon. Public perception and interest in the food supply is changing, too. Being a grower myself, I have noticed the variety of labels on food I see in the stores. There is organic, all natural, certified clean, free range, grass fed and carbon free. But I think the most important label of all is that it's California grown.

California farmers and ranchers grow, pack and ship some of the safest and best-quality products in the world. Many times we take this for granted because we can go to just about any store in California and have an abundance of beautiful produce to choose from. People living in other states or countries don't enjoy this same selection.

Consumers are becoming more educated on where their food comes from and how it is produced. They are concerned with food safety and as growers we need to be prepared to assure them that the product they are getting is the best in the world.

Consumers are not the only ones changing. Farmers and ranchers are changing, too. Many are beginning to understand the importance of telling their story and making sure their voice is heard on local and statewide issues affecting their farms and ranchers.

In a recent informal survey of young farmers and ranchers ages 18-35, conducted by the American Farm Bureau, 75 percent said state and local issues like property taxes concern them more than federal issues.

The same survey showed the vast majority--83 percent--of young farmers and ranchers are more optimistic about farming than they were five years ago. This is up from only 61 percent in 2003.

As consumers are showing more interest in the origin of their food, farmers and ranchers are doing even more to continue their role as stewards of the land. Fifty-five percent of those surveyed said they practice conservation tillage and 49 percent rotate three or more crops. Forty-percent said they use soil and tissue analysis and 36 percent use integrated pest management practices.

For more information on Young Farmers and Ranchers, call your county Farm Bureau office. For general information on the YF&R program, visit www.cfbf.com/programs/yfr or contact Danielle Rau at (916) 561-5598.

SOURCE:  California Farm Bureau

University of California researchers have studied the effects of irrigation on almonds for about 20 years. It has generally been thought that about 42 inches per acre per season is a reasonable estimate of water use by mature, productive almonds.

Seasonal water use follows a bell-shaped curve. Under this 42-inch model, water use starts out low after leafout at about 1.0 inch every 15 days, peaks at about 4.5 inches every 15 days in the first half of July, and declines back to about 1.0 inch every 15 days as the season ends.

In some situations, growers may have much less than 42 inches of water available from stored soil moisture and irrigation water. The challenge becomes managing crop stress over the course of the season.

One relatively effective approach that doesn't rely heavily on field monitoring is to attempt to sustain crop stress uniformly across all stages of tree growth and crop development by using estimates of crop water use. The limited water allocation is applied as a consistent percentage of the seasonal water use pattern. If 24 inches of irrigation water are available, representing about 60 percent of the potential water use, then the irrigation water would be allocated at about 60 percent of real-time or historic rates of crop water use over the course of the season.

UC water management specialist David Goldhamer of the Kearney Agricultural Center published results of a four-year study illustrating the effectiveness of the above approach.

Almonds were produced with 55, 70, 85 and 100 percent of a 42-inch water allocation.

Water was either cut back as a consistent percentage of estimated crop water use to try to sustain less pronounced crop stress across all stages of crop growth, or cutbacks targeted only pre-harvest, or post-harvest crop stages for higher crop stress.

The effect of limited water supply was minimized with uniform allocation of water across all crop stages. However, productivity was reduced particularly with 55 percent and 70 percent allocations.

• The uniform crop stress strategy gave both the highest four-year yields, and the largest average nut size within each water allocation.
  
• Sharp cut backs before harvest resulted in the second highest yields, but reduced nut size.
  
• Sharply withholding water after harvest affected bud development and reduced yield the next season.

UC Davis professor Ken Shackel was able to get by with a water allocation of about 85 percent of full supply with no short-term yield loss or effect on nut size by using a pressure chamber to actually track midday crop stress and keeping it within the -12 to -20 bar range in July during hull split.

For more information on on water management refer to UCManageDrought.ucdavis.edu.