The New Agriculture Network's on-line newsletter with seasonal advice for field crop and vegetable growers interested in organic agriculture.

Vol. 2, No. 3 - May 26, 2005

In this issue

	Managing Canada thistle in organic cropping systems
	Some helpful tips on flaming weeds in corn and soybeans
	Community food profiles as a local engagement tool
	Reports from organic growers.

Next issue will be posted June 9. Read previous issues through our calendar of issues.

Managing Canada thistle in organic cropping systems
John Masiunas, Department of Natural Resources and Environmental Sciences, University of Illinois

Why is Canada thistle such a problem in organic cropping systems?
Canada thistle (also called creeping thistle, California thistle, field thistle), Cirsium arvense (L.) Scop. (family: Asteraceae (Compositae), is a vigorous, competitive perennial weed that is difficult to control because it can establish from seed or wide-ranging, deep creeping roots. An individual plant may produce over 40,000 seeds a year. Canada thistle produces chemicals that inhibit growth of neighboring plants. Canada thistle is adapted to a wide range of habitats and soil types. (View photos of flowering plant and mature seed.)

A small portion of seeds (0.2%) can disperse 0.5 mile or more from the parent plant, thus Canada thistle is difficult to prevent even if you are using best management practices. Canada thistle seeds float and are easily spread by flooding or in irrigation water. The seeds can also be dispersed in manure. Canada thistle seed germinate best in the top half-inch of soil at temperatures between 68 and 86^oF. Approximately 90% of seed germinate within one year but some seed remain dormant for 20 years.

What impact does Canada thistle have on crops?
Canada thistle causes extensive crop yield losses through competition and, perhaps, release of inhibitory chemicals. The prickly mature foliage reduces productivity by increasing harvest difficulty and deterring livestock from grazing. A density of two Canada thistle shoots per ft² caused estimated yield losses of 34% in barley, 26% in canola, 36% in winter wheat, and 48% in alfalfa for seed. Densities of Canada thistle in field infestations can reach 17 shoots per ft².

What can be done to manage Canada thistle in organic cropping systems?
The plant is very difficult to control once established, so any management strategy must prevent Canada thistle introduction and spread. Canada thistle spreads as a contaminant in crop seed, hay, and packing material. Additionally, it can be spread in mud attached to vehicles and farm equipment. Thus, using clean seed and cleaning equipment are important for preventing Canada thistle from being introduced or from spreading once on a farm.

There are a few key places in the Canada thistle life cycle that are most susceptible to management. The seedling to rosette and the rosette to flowering transitions, when root food reserves are at a minimum, are particularly important for reducing populations. The time of year when control measures are applied matters greatly. This is nice, because it allows organic farmers to focus on early spring rosette and seedling mortality. Reducing seed production and the survival of newly shed seeds is also important; in contrast, persistence of seeds that are already in the soil has little effect on Canada thistle populations.

It is believed that a major reason for Canada thistle's success in the northern U.S. is lack of natural enemies. Because of this and because Canada thistle is an introduced, noxious weed, it was among the first weeds targeted for biological control by the USDA and the literature contains much information on insects associated with Canada thistle. A number of European insects and pathogens attacking Canada thistle have been accidentally introduced into North America, and some of these have been studied as potential biological control agents. For example, the leaf-feeding tortoise beetle Cassida rubiginosa Müller (Coleoptera: Chrysomelidae) and the Larinus planus (F.) (Coleoptera: Curculionidae) occur widely in the eastern United States. Recently, it was found that seed predators might greatly reduce populations of invasive thistles.

But historically, biological control efforts have had limited success in controlling Canada thistle in crops and problems have occurred. In early introductions, host specificity testing for agents attacking Canada thistle was focused on assessing potential risks to economic related species, of which the two most important are safflower and globe artichoke. Effects of biological control agents on native, non-target thistle species were not adequately determined. Some native thistle species are endangered in our region and are being attacked by Canada thistle biological control agents. Also the limited success was due to potential biocontrol organisms not adequately synchronized with Canada thistle's life cycle in North America. Thus, biological control from organisms occurring in our region needs to be encouraged and may reduce the severity and competitiveness of Canada thistle infestations but it will not be a sole management strategy for Canada thistle on organic farms.

Once Canada thistle has established, a combination of mechanical, cultural, and other methods will be more effective than any single method used alone. One approach is tillage. Any form of cultivation should be applied in early spring, when reserves are at a low. Farmers need to use a repeated form of disturbance to force the plants to use reserves to send up new shoots, which must be promptly killed. If adventitious roots are sliced later in the season, after they've had a chance to build up new reserves, this approach will just spread vigorous roots throughout the rest of the field thereby increasing the number of new upright shoots borne by the horizontal roots.

Cover crops have also been used to suppress Canada thistle. Buckwheat (Fagopyrum sagittatum) suppressed Canada thistle through a combination of rapid growth and possible release of inhibitory compounds. Alfalfa plants and residues along with some other legumes can suppress Canada thistle. The suppression is likely due to the legume's ability to grow at low nitrogen levels, their dense growth, and possible allelopathy.  Summer annual grasses, such as sudangrass, which grow when Canada thistle growth is reduced, may suppress the weed.

Other management methods may kill the shoots, preventing seed production and eventually "starving" the root systems. Mowing if initiated early and repeated multiple times before flower bud opening can prevent seed production and require the root systems to expend food reserves regrowing shoots. Recently, vinegar has been evaluated to kill Canada thistle shoots. Work at the USDA-ARS in Beltsville reported Canada thistle control, but they were using 20% acetic acid. We found that a single rescue treatment killed Canada thistle shoots with 3 to 5% organic vinegar. The USDA IR-4 Program is currently evaluating vinegar for its weed control efficiency. Vinegar alone will not eliminate Canada thistle but it could be a valuable tool when combined with other management strategies and used over a number of seasons.

Thus, Canada thistle due to its spread from an extensive root system and prolific seed production will continue to be a problem in organic cropping systems. The best approach is to prevent Canada thistle from establishing on your farm by transitioning thistle-free fields, using clean crop seed, and cleaning equipment. If Canada thistle is introduced, it will first occur as a small patch that should be immediately eliminated. Once Canada thistle infests an organic farm an integrated approach should be used including tillage, mowing, competitive crops, cover crops and green manures, and spot removal of thistle.

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Some helpful tips on flaming weeds in corn and soybeans

Dale Mutch, John Simmons, Jim Monroe and Gene Vogel

The best time to flame weeds is when the temperature outside is hot and humidity is low, as lower gas pressures and higher groundspeeds can be used.  Higher humidity and lower temperatures need more/longer heat.  Best results from flaming are achieved after dew is off the weeds and before dew starts forming at night.  However, base your timing decision on vulnerable weed stage more than perfect, hot/dry conditions.  If the weed is dry, you can kill it. 

For best results, control weeds when they are less than one-inch tall for broadleaf and newly emerged for grasses.  When grass weeds are taller, the flaming operation may need a supplemental cultivation.  Flamers can adequately kill lambsquarter up to three inches tall or at the two-leaf stage without supplemental tillage.  Taller weeds may require higher gas pressures or slower groundspeed.  Since the weeds are only being controlled in a narrow band, and only weeds emerged at the time of flaming, supplemental cultivation will be needed for season-long control.

When corn plants are small and weeds are small, flamers should be placed directly over the row for best control.  This also saves money by using about half as much gas.  When corn plants are taller, the flame needs to be directed on each side of the plant, increasing gas costs.  John Simmons figures about 5 to 6 gallons of LP gas per acre with the over-the-row application.

Soybeans are much more sensitive to flaming.  Farmers need to use caution when flaming soybeans.  Some organic farmers in Michigan have perfected this system, but many are avoiding flaming soybeans.  The best stage to flame soybeans is in the emergence stage when the cotyledons are closed around the growing point, but above ground.  Since the growing point of soybean is exposed after cotyledons are open, soybeans are much more susceptible to damage than corn.  The growing point of corn is below the ground up to vegetative stage 4, and, therefore, burning the leaves of corn will not kill the corn plant.

Simmons flames his corn at a ground speed of 5 mph and with a system pressure of about 20 psi.  Groundspeed and pressure will likely vary from flamer to flamer.  Pressure especially will be influenced by where in the line the gauge is mounted.  Simmons determines the success of flaming by placing a burned weed leaf between his thumb and index finger and moves the thumb up.  If the leaf tears, he has been successful.  He compares the burned leaf to a non-flamed control leaf.  Carry a fire extinguisher!  Prevent hydraulic system leaks, as high pressure hydraulic systems atomize leaking oil and the flamer is a huge and effective pilot light.

Jim Monroe's approach to flaming weeds is a little different than Simmons.  Monroe plows or chisels the ground, fits it and plants his crop.  He waits until weeds are very small and just emerged.  He then burns a 20-inch zone over the row at about 3.5 mph at 30 psi.  He prefers to do this when the corn is spiking and/or soybeans are just cracking through the soil.  He cautions everyone that most fields do not have perfectly uniform emergence and flaming can cause damage when soybeans are at the first true leaf stage.  Another caution mentioned by Monroe was wind speed and direction, as wind can reduce flaming effectiveness.  Jim uses about 7.5 gal./A of gas at a cost of about $1.12/gal.

Gene Vogel farms in Michigan's Thumb area and is recognized as an expert flamer for soybeans.  Gene's first choice for flaming soybeans is at the cotyledon stage where the cotyledons protect the growing point of the soybean.  The cotyledons are tied together or in the praying position.  Vogel runs his flamer at 5 mph and at 35 psi.  The second and more risky time to flame soybeans is just before the first tri-foliate opens up.  The leaves are tight around the growing point at this time.  He increases his speed to 5.5 mph for this treatment to reduce injury.  Please remember that some of the plants will be more mature and can be injured with this treatment.

The hardest weeds to control by flaming for Vogel are mustards and common ragweed.  Lambsquarters and pigweed are much easier to control.  Grass can be set back, but not controlled with the flamer.  Corn can be flamed up to the fourth leaf stage without killing the corn.  Gene uses the flamer as another tool in the toolbox.  It allows him to manage his 600-acre farm by himself.  Depending on the weather conditions, he decides between rotary hoeing or flaming.

The MSUE/KBS cover crop program has access to a flamer for weed control this year, and we are excited to implement this weed control strategy.  We would like to hear from farmers about their successes and failures using a flamer.  Please share your experiences with us.

Contact information:
Dale R. Mutch
MSU Kellogg Biological Station
mutch@msu.edu
800-521-2619, ext. 224 (phone)
269-671-4485 (fax)

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Community food profiles as a local engagement tool

Marty Heller,
C. S. Mott Group for Sustainable Food Systems,
Michigan State University

Everyone-regardless of economic status, ethnicity or political bent; whether economic development professional, farmer, grocery retailer, public health advocate or eater-has a stake in the food system.  It is indeed reasonable for citizens to ask, "What type of food system do I want for my community?"  The C.S. Mott Group for Sustainable Food Systems at Michigan State University is developing a tool to assist communities in considering this question.  The Community Food Profile, a 24-page booklet of local facts and stories, is intended to give readers a better sense of how producing, processing, distributing, retailing, preparing and eating food influence and interconnect a community's economic, ecological and social well-being. 

Usually, we think of food as following a linear path from farm to table-produced on farms, processed in factories, distributed in trucks, purchased by consumers at grocery stores or restaurants.  In contrast, when we consider food from a community-based systems perspective, we can see the food system as a dynamic, interconnected circle.  By paying attention to the connections and, when possible, making them within our community, we begin to see that a host of outcomes are possible. 

In the Community Food Profile, these interconnections are represented as a "circle of connections."  The inner ring of the circle shows the basic components of the food system-growing, processing, preparing, eating, retailing and distributing.

The outer ring of the "circle of connections" suggests a number of issues or outcomes that can be influenced by a community-based food system.  They include small- and medium-scale farm viability, environmental stewardship, jobs, healthy individuals, economic development, farmland preservation, and community and social vitality.  Descriptions of these outcomes follow, with specific examples for Michigan's Capital Area community (Clinton, Eaton and Ingham counties around Lansing, Michigan).

Small- and medium-scale farm viability
If current trends continue, Michigan will loose 71 percent of farms that are between 50 and 500 acres by 2040, representing nearly 50 percent of the total farms statewide.  In the Capital Area, this would translate to 1,120 farms-one-third of the area's total.  This loss is not just farms, but also farmland, farmers, skills and infrastructure necessary for long-term food production capability.  Many studies have demonstrated the importance of small- and medium-scale farms in maintaining the social, economic and environmental health of rural communities.

Environmental stewardship
Food production is inextricably linked to the environment.  However, the intensification and industrialization of agriculture over the past 50 years have resulted in practices that are detrimental to environmental health.  A community-based food system highlights the connection between food and environment, creating opportunities for consumers to recognize and value the environmental services provided by local farms, such as water filtration and wildlife habitat.

Jobs
In a time when job outsourcing is a painful reality for many communities, local food production and processing can create significant numbers of stable jobs.  Like "Buy American" campaigns, "Buy Local Food" campaigns can foster an understanding that purchasing choices affect the economic well-being of people in our community. 

Healthy individuals
Michigan is the midst of an obesity epidemic.  Sixty-two percent of Michigan's adults and 12 percent of high school students are overweight.  In 2003, obesity-related medical costs in the state totaled $2.9 billion.  Most people become overweight from inadequate physical activity and poor diet.  Community-based food systems encourage healthy lifestyles by making fresh, delicious fruits, vegetables and other foods more accessible.  Healthier citizens mean reduced healthcare premiums, making Michigan communities more business friendly.

Economic development
People in the Lansing Tri-county Area spend $1.1 billion annually on food and beverages in stores, restaurants and other eating establishments.  The vast majority of these food dollars are spent on products originating from outside the area.  Community-based food systems capitalize on opportunities for entrepreneurial farmers and small businesses to add value to local agricultural products and keep a larger portion of each food dollar within the local economy.

Farmland preservation
Community and state efforts are under way to preserve farmland from the growing threat of urban sprawl.  Preserving farmland, however, must go hand-in-hand with assuring farm viability.  Re-localizing the food system-relying more on local and regional sources for our food needs-forms valuable markets that help keep farmers farming on farmland and increases awareness of the importance of preserving local farmland.

Community and social vitality
At the heart of a community-based food system are relationships that build social capital, strengthen social networks and form the basis of community identity.  Food is a deep-rooted aspect of our social interactions.  In fact, the Latin root of the words companion and company means "with bread."  Food is an inclusive focal point for rebuilding community, in urban as well as rural settings, and especially between the two.

To demonstrate the value of a Community Food Profile as a community and economic development tool, the Mott group has created "Food Connections:  Capital Area Community Food Profile" (available at http://www.mottgroup.msu.edu/downloads/CACfoodprofile.pdf).  This 24-page booklet uses a collection of local stories representing the breadth of food system components-farmers, farmers' markets, grocery stores, restaurants, food processors, community supported agriculture, farm-to-school, community gardens-to expose community and economic development opportunities in the local food system.  The Community Food Profile points to multi-sector partnerships and networks around community food system development that can result in mutually beneficial programs and projects.  It challenges each of us to consider our relationship to food and how our food purchases affect our community.

The Community Food Profile is an exploration into how we navigate and communicate the change in perspective needed to create community-based food systems.  It's an ongoing exploration, continuing with observation of how the Capital Area Community Profile is used within the local community.  The exploration continues further as other groups and communities take these ideas and place their own "spin" and values on them.  The Mott Group will be assisting interested communities across the state in developing Community Food Profiles unique to their area.  For more information on Community Food Profiles, contact Marty Heller at the C.S. Mott Group for Sustainable Food Systems at 517-353-3542 or email hellerm@msu.edu. (View pdf of poster with additional information.)

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Central Indiana - George Mears
Corn and soybeans are up and have been rotary hoed. Horseweeds (giant ragweeds) survived the hoeing and the next step is to use a flamer to try to kill them or set them back.

South Central Indiana - Dale Rhoads
We have experienced the full range of spring possibilities here. We saw high temperatures in the 90s with very dry conditions at the beginning, next gentle rains, and then torrential rainstorms-one that delivered four inches of rain in less than one hour. Now we have very mild, spring-like conditions with nighttime lows in the 40s and highs in the 60s.

Although most of our growing areas are on hillsides, the land did not wash bad, only in vole runs that collapsed and formed gullies. But the rain compacted all recently tilled fields that were awaiting germination of weeds to be killed with organic herbicides for planting. So all of these fields have to be re-tilled and leveled for weekly succession planting of greens. The areas where we plan to finish the transplanting can, for the most part, still be used without a new tilling.

Sweet corn for home use was planted three weeks ago and is just barely up. Cool weather is slowing its germination. Later plantings have not yet emerged.

With the cool, dry spring, the major fruit pest, plum curculio, was just taking a breather. Two weeks ago with hot weather followed by three days of rain, the plum curculio came alive. We entered that time period with no stings on fruit, and three days later, the rains exited with an estimated 50 to 60 percent stung fruit. This is our third year of organic fruit production, and after a successful first year, plum curculio has gotten worse each year. We are thinking after further investigation that there are a number of additional cultural practices to try. There is a mating scent attractor/trap available which should help. Surprisingly, trees that had never fruited before-pears and some Asian pears-all got hit. Later setting apples and cherries are still 90 percent sting free.

I'm beginning to suspect we have some particularly virulent forms of fruit tree fireblight in this area. Several varieties of my disease resistant apple trees got hit with blight again this year, right at the end of blight season, and it makes me want to cuss and resolve to protect them better next year.

Currently we are tying up tomatoes in the greenhouse; mulching tomatoes and basil in the greenhouse; weeding and mulching with rotted sawdust kale, chard and dandelion; tilling and re-tilling planting areas; transplanting some parsley; and weeding-always weeding! We are harvesting twice weekly our salad greens, kales, cilantro, chard and arugula. It is nice to have some money coming in again.

In the next two weeks we will be tilling and re-tilling areas for weed germination to kill and then plant salad greens. We will also do a final hoeing on head lettuce that is starting to head up nicely. If weather warms up, we'll begin planting basil outside. We are busy trying to keep up on tying up tomatoes that are growing fast in the greenhouse and setting fruit. We are also keeping up with fruit sprays; and keeping up with regular rotation of salad greens planting.

Questions
Every year we have problems with Swiss chard developing disease spots on the leaves. Adding boron in a foliar spray has not helped. We suspect either disease or insect holes that developed into disease spots on the leaves. There is also some russeting on the stems. We have considered covering it with a floating row cover to protect from insects. Does anyone have any suggestions?

Also does anyone know anything about brands of good small tractors. We are looking in the 20-24 horsepower range. We want to do tilling, light front-end loader work and some grading of drive. Any with recommendations?

Illinois
Northeastern Illinois - Dave Campbell
There have been no major weather conditions that have affected my cropping system.  We have been very dry this spring and the month of May has been cool.  Even though we have been very dry, there is still plenty of moisture once you get just below the soil surface.  My clay soils are still very wet. Corn has just recently been planted.  Oats and clover seeding look very good at this time.  Presently, I've been doing some tillage on my ground that will be planted to soybeans.  Rotary hoeing of corn has also been done this past week and will continue for about another week.  I have just finished shipping last year's corn crop.  Four loads of corn were sold in the month of May.  Today (May 25) I plan to spread some gypsum on my soybean fields.  Planting of soybeans will hopefully start to take place early next week.  Rotary hoeing of soybeans will take place three to five days after my last tillage pass (directly before planting) and will hopefully take place a second time three to five days after the first hoeing, assuming the soils are not too wet.  I am planning to have the 2004 soybean crop sold sometime the first half of June.

East Central Illinois - Jon Cherniss
Cool, dry and windy has been the norm here. We did get one inch of needed rain last Thursday (May 19), but it looks like it will be at least another 10 days to two weeks before another chance of rain. With the dry weather we are able to work non-stop. Mowing perennial covers began this week and a lot of mechanical and hand cultivation.  We also prepared ground for the next wave of summer plantings, which will begin the first week of June. At present we are harvesting salad greens, spinach, radishes, turnips, kohlrabi, green onions and basil (in the greenhouse). It looks like we are about two weeks behind last year's harvest pace.  Summer plantings of tomatoes, peppers, eggplant and winter squash are planned for next week.  We also will plant summer covers of sudangrass and cowpea in an attempt to control Canadian thistle, which is having a great year.  If we don't figure out a reasonable control method soon, we will have to start putting it in our salad mix.  We also plan for the weekly plantings of salad greens and cultivation of weeds whenever possible.

Southern Illinois - Stan Schutte
Still very dry, we only had 0.3 inches of rain this past week. Things are starting to show some stress. No sign of any bugs yet. We planted regular soybeans, more sweet corn, finished potatoes, more tomatoes and peppers. We are harvesting lettuce, asparagus and onions. We are also bailing the first cutting of hay. We've rotary-hoed regular corn, cultivated early sweet corn as well as processed our second group of chickens. Farmer's markets started last week. In the next two weeks, I will work early tomatoes, mow weeds around wheat fields and plant more produce.

Michigan
Southwest Michigan - Dale Mutch
Over the past two weeks we've had cool and wet conditions, which have helped our cropping situation. Matt Wiley is planning to plant soybeans on May 25-26. Cover crops of rye and hairy vetch at the Kellogg Biological Station are both flowering. Rye is about 5.5 to 6 feet tall and vetch is about 3 feet tall. The corn and soybeans in Southwest Michigan will be in the ground by the end of the month.

Southeast Michigan - Dale Mutch
For the first time in two weeks Rob Malcomnson was able to work his soil. He had 22 acres of corn planted and was expecting to finish planting corn on May 25. Wet conditions over the past two weeks have kept most organic farmers in this area out of the field. Early planted corn had to be replanted due to rotting of the seed. Soybeans tolerated the high moisture conditions much better than the corn. Early planted soybeans look very good.

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