Winter 2007-2008

Roll Out the Rye
Socking It to Strawberry Root Rot
Garlic’s Goodness Best Released With a Crush
Vitamin K for Bone Health
Disinfectants for Fruits and Vegetables
Planting Wheat Blends Means Higher Yields

Roll Out the Rye

Ecologist Adam Davis, with the USDA Agricultural Research Service in Urbana, Illinois, is experimenting with a no-till system in which 7-foot-tall cereal rye is flattened into dense vegetative mats that secure soil and curtail weeds. A multi-bladed roller, designed by The Rodale Institute, attached to a tractor’s front or back end, crimps rye stems and flattens plants into a two-inch-thick matted mulch. A planter accompanying the roller then deposits soybean seeds into the soil beneath, eliminating the need for tillage.

Agricultural Research Service News Service, July 27, 2007,

Socking It to Strawberry Root Rot

Perennial strawberries planted in compost-filled mesh socks are less susceptible to black root rot and produce more marketable fruit than those planted in unfumigated, unamended soils, says researcher Patricia Millner, a USDA-ARS microbiologist at the Sustainable Agricultural Systems Laboratory in Beltsville, Maryland. “Commercially available compost socks – sold under various trade names such as BioLogs, SiltSoxx, FilterCell, EdgeSaver and EcoBlanket—are simply mesh tube bags,” says Millner. “When filled with compost, they usually range in diameter from 8 to 24 inches, and can be as long as needed to fit the application or planting row.”

The socks can be made of cotton, burlap, other textiles or plastic, including biodegradable. Their uses include replacing fabric silt fences to reduce erosion at construction sites, stabilizing roadsides and stream banks, flood control and horticultural production.

“Black root rot is a severe threat to strawberry growers,” says Millner. “Infected plants establish poorly and produce few runners, resulting in plant beds that tend to have more bare spots and smaller yields.”

Using a scale of 1 to 5 – with 5 being totally free of root rot – Millner rated the root health of strawberries grown in the compost socks. All but one scored 4 or 5. “The root health of strawberries grown without the compost ranged from 1 to 3, except for one rating of 4,” she says. “The bagged compost keeps strawberry roots away from contact with soil pathogens.”

The compost used on the private Maryland farms in the study was a commercial Leafgro mixture, made from leaves and yard trimmings and stuffed into cotton mesh socks. At Beltsville, Millner and colleagues used their own compost made from leaves, grass and poultry manure placed in polyethylene-mesh socks. All socks were 8 inches in diameter.

“Socking It to Strawberry Root Rot,” Sept. 2007, Agricultural Research,


Garlic’s Goodness Best Released With a Crush

Garlic – like its close relative, the onion – is rich in heart-protective compounds called thiosulfinates. These sulfur compounds, best known for causing eyes to water, may lower blood pressure and break up potentially harmful clusters of platelets in the bloodstream. Until now, most researchers and nutritionists assumed that the best way to obtain garlic’s cardiovascular benefits was to eat the raw cloves.

Not so, discovered ARS plant geneticist Philipp Simon, based in Madison, Wis., and colleagues in Argentina.  After boiling, baking and microwaving crushed and uncrushed garlic and evaluating antiplatelet activity, the scientists learned that lightly cooked, crushed garlic provides most of the health benefits found in raw garlic. The only exception was microwaving, which stripped garlic almost entirely of its blood-thinning effects. The researchers say that crushing enables the beneficial compounds to be freed.

Agricultural Research Service News Service, Sept. 18, 2007,


Vitamin K for Bone Health

Volunteers with the highest blood levels of the main form of vitamin K – phylloquinone – had the lowest risk of having osteoarthritis in the hands and knees according to a study by USDA Agricultural Research Service (ARS)-funded scientists. Low dietary intake of vitamin K is associated with relatively higher amounts of bone loss in the elderly. The researchers also  determined the amount of several major types of vitamin K in hundreds of foods, which are posted at (At left, choose “Products and Services” then “Reports by Single Nutrients.”)

Agricultural Research Service News Service, Aug. 2007 Agricultural Research,


Disinfectants for Fruits and Vegetables

In the produce industry, chlorine is commonly used to remove microbes such as bacteria and mold from produce. In the home, a water wash, with or without the help of a produce brush, is typically used to clean fruits and vegetables. Recently, fresh produce has been treated with ozone as well.

Ozone, a gas with three oxygen atoms, has been used in European water treatment facilities for nearly 100 years and offers many advantages over traditional disinfectants. It has stronger oxidizing and antimicrobial activity than chlorine, and it disinfects without producing toxic or cancer-causing compounds like those produced by chlorine treatments.

As an alternative to chlorine for removing microbes such as bacteria and mold from fresh fruits and vegetables, ozone may offer promise to industrial food processing.  In fact, some wash treatments on the market contain ozone. Are they useful for cleaning produce at home?
Researchers in the Department of Food Science and Human Nutrition at the University of Maine tested three commercial wash treatments on blueberries:

    * Fit® (Proctor & Gamble, Cincinnati, Ohio)

    * Ozone Water Purifier XT-301 (Air-Zone Inc., Leesburg, Virginia)

    * J0-4 Multi-Functional Food Sterilizer (Indoor Purification Systems, Layton, Utah)

As a control, blueberries were soaked in distilled water for one to two minutes.

Fit® washes got rid of roughly the same amount of microbes as distilled water. Both Fit® and distilled water reduced the level of residual pesticides compared with unwashed samples.  Both ozone systems – the Ozone Water Purifier XT-301 and the J0-4 Multi-Functional Food Sterilizer – removed microbes from the blueberries, but the distilled water wash was more effective than either ozone wash. Overall, say the researchers, home-use ozone systems did not improve food safety quality appreciably in their study when used according to product directions.  They say that washing fresh fruits and vegetables with distilled water for one to two minutes is more efficient and economical.

According to Alfred Bushway, Extension food science specialist at the University of Maine, ozone technology (which is approved for certified organic products) at a commercial level can reduce the microbial load on fruits and vegetables destined for the fresh market or for minimal processing for use in ready-to-eat products. Either gaseous or aqueous ozone can be used. The cost to set up a plant could be significant; would require particular attention to worker safety; and would require a system to destroy excess ozone gas. Ozone is not stable, so there is no residual ozone on the produce; ozone released into the atmosphere will be destroyed rapidly.

The UMaine researchers make these recommendations for preparing fresh produce:

* Wash your hands before preparing food.

* Because some produce washes are costly, wash fresh produce with distilled water. Soak all produce for one to two minutes to reduce the risk of foodborne illness. (Distilled or bottled water has been filtered and purified to remove contaminants.)

* For produce with thick skin, use a vegetable brush to help wash away hard-to-remove microbes.

* Fragile produce should not be soaked in water; put it in a colander and spray it with distilled water.

* Clean counter tops, cutting boards and utensils after peeling produce and before further cutting. Bacteria from the outside of raw produce can be transferred to the inside when it is cut or peeled. Wash kitchen surfaces and utensils with hot, soapy water after preparing each food item.

* For eating on the run, fill a spray bottle with distilled water and use it to wash apples and other fruits.

* Homegrown fruits and vegetables should also be well washed.

Sources:  Email, Alfred Bushway, University of Maine, June 20, 2007.
[email protected]; University of Maine Cooperative Extension Bulletin #4336, “Best Ways to Wash Fruits and Vegetables,” by Kristi Crowe, Alfred Bushway, and Mahmoud El-Begearmi, University of Maine Department of Food Science and Human Nutrition, and Cooperative Extension.; University of Maine Cooperative Extension Bulletin #4338, “Do Food Sterilizers Work?” by Kristi Crowe and Alfred Bushway,


Planting Wheat Blends Means Higher Yields

A two-year study shows that blends of complementary wheat varieties out-yield single varieties, or nonblends, by a mean of 2.3 bushels per acre. The blends – mixtures of two or three varieties with carefully matched traits – showed a 3.2% yield advantage over single variety stands. The study was conducted by plant pathologist Christina Cowger with the USDA-Agricultural Research Service Plant Sciences Research Unit in  Raleigh, N.C.

Environmental stresses such as disease and drought are unpredictable, and wheat varieties have inherent weaknesses that cause fluctuations in yield under suboptimal conditions. For example, a variety may be resistant to some diseases, but susceptible to others; or a variety may yield well in the absence of disease, but fall short of its yield potential when an epidemic occurs.

From eight pure varieties, Cowger developed 13 blends, matching complementary features for best advantage. Each blend was made with equal numbers of seeds of each variety used. She planted the 13 wheat mixtures, and eight pure stands, in three North Carolina counties representative of the state’s sandy, organic and clay soils. All 21 entries were planted in a two-year, replicated experiment in each of three representative locations.

Cowger studied the blends’ response to powdery mildew, leaf rust, soilborne viruses and other diseases. She also evaluated yield, test weight and quality factors at all three test sites. For the analysis, Cowger averaged the 2005 and 2006 data.

Source: Agricultural Research Service News Service, USDA, May/June 2007 Agricultural Research,


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