Next issue will be posted August 29. Read previous issues through our calendar of issues.

Transition strategies and disease suppressive soils
Darin Eastburn and Shin-Yi Lee Marzano
Crops and Soil Sciences
University of Illinois

One of the goals of the process of transitioning to an organic agricultural production system is to improve soil health. The term soil health means different things to different people, and it can be difficult to define and measure. To a plant pathologist, one aspect of soil health is the level of disease suppressiveness exhibited by the soil.

The phenomenon of disease suppressive soils is well documented. A disease suppressive soil is one in which the incidence or severity of a disease on plants growing in that soil is less than what one would see on a plant growing in a conducive soil with a similar pathogen population. However, disease suppression is not a qualitative trait, meaning that soils are either suppressive or not. Rather disease suppression is a quantitative characteristic, with all soils falling along a gradient of levels from highly conducive to highly suppressive.

Most natural field soils have some degree of natural disease suppression. In many cases the suppression is the result of the activities of microorganisms in the soil. This can be demonstrated by comparing the level of disease that develops on plants growing in natural field soil with the disease level that develops in that same soil after it has been sterilized. In most cases the level of disease developing on plants growing in the sterilized soil will be significantly higher than the level seen on plants growing in the natural, non-sterilized soil.

There are many mechanisms that may contribute to the soil suppression of plant diseases, including non-pathogenic microorganisms competing with pathogens for nutrients or infection sites, direct parasitism of plant pathogens by antagonistic organisms and stimulation of a plants ability to resist disease—a phenomenon known as systemic induced resistance. And it has been shown that the level of disease suppression of a soil can be altered by changing environmental conditions, which in turn alter the structure and activity of the microbial community in the soil. For instance, studies have found that the disease suppressiveness of a soil can be altered by the additions of certain types of organic matter, or by growing certain crop species. The addition of organic matter or the presence of some crops can enhance the number and activities of certain antagonistic organisms, such as bacteria found in the root zone of the plants.

The development of suppressiveness is thought to be the result of a complex web of interactions among the microorganisms, the plants, the pathogens and the soil environment. The enhancement of disease suppressive soil may be one benefit of transitioning from a conventional to an organic production system.

In a collaborative study, researchers at the Illinois Natural History Survey and the University of Illinois have been evaluating the biological implications of using different systems of transitioning from conventional to organic production. This study has involved the establishment of three cropping intensity systems (a three-year pasture [grass/legume] system, a cash grain [corn, soybeans, wheat] system and a vegetable [tomato, crucifer, squash] system. In addition, three organic amendment treatments (cover crop only, animal manure and compost) were applied to each of the three cropping systems over the three-year transition period. In 2006, tomatoes and peppers were planted in all the plots as assay crops, and in 2007 all plots were planted to soybeans as an assay crop. The assay crops allowed us to directly compare the effects of the various cropping system and organic amendment treatments.

As plant pathologists, our part of the study has focused on evaluating the effects that these treatments have on the levels of plant diseases that occur. We have been doing this in two ways. First, we have monitored the types and levels of diseases that have developed on the various crops in each of the systems, and on the assay crops in 2006 and 2007 following the transition period. We did find some effects of the organic matter treatments on some of the diseases that occurred during transition, namely increase in levels of rust on grasses in the pasture system and corn in the cash grain system on those plots receiving manure applications. We also found differences in the levels of diseases that developed on tomatoes in 2006 (the first year after transition) associated with both the transition cropping system and amendment treatments. We generally found the lowest levels of disease on tomatoes that were grown in the former pasture system plots receiving the manure amendments and the highest levels in the former cash grain system plots with no amendments other than cover crops. It is interesting that changes in the soil conditions resulting from the transition treatments had measurable effects on these foliar diseases in a crop grown the following year, especially as the pathogens involved have little or no contact with the soil environment. This means that the soil conditions played a role in determining the plant's ability to resist disease.

We also collected soil samples from each of the treatment plots throughout the course of the study, and evaluated the levels of disease suppressiveness of the soil samples in greenhouse bio-assays. These bio-assays involved infesting the soil samples with one of two soybean pathogens, Rhizoctonia solani, causal agent of damping-off and Rhizoctonia root rot, or Fusarium solani f. sp. glycines, causal agent of sudden death syndrome. Both sterilized and non-sterilized soil samples were infested with the pathogens for comparison. The infested soils were planted with a susceptible variety of soybeans, and the disease severity and root system characteristics (root length and volume) were measured after several weeks. While we consistently observed a difference between the levels of disease that developed in the sterilized and non-sterilized soil samples, we did not observe differences in the levels of disease suppressiveness resulting from either the cropping system or organic matter treatments. So at least in the systems that we were evaluating, there were no observable benefits of using one system or another in terms of enhancing disease suppressiveness levels to these two pathogens.

Other studies have shown effects of cropping systems and organic matter amendments on severity of soilborne diseases, and additions of organic matter should result in increased microbial activity and shifts in microbial community structures. The fact that we did not see differences in suppressiveness to the two pathogens in our study may be the result of the relatively low amounts of organic matter added, or other factors. However, we did observe differences in some foliar diseases, indicating that the choice of transition strategy can have an effect on plant diseases both during the transition period and for a short time thereafter.

Publication: Managing cover crops profitably
Andy Clark, Coordinator
Sustainable Agriculture Network (SAN)

Editor’s note: The following article is the forward of the new SAN publication, Managing cover crops profitably, which describes the book for your reference. Cover crops slow erosion improve soil, smother weeds, enhance nutrient and moisture availability, help control many pests and bring a host of other benefits to your farm. At the same time, they can reduce costs, increase profits and even create new sources of income. You’ll reap dividends on your cover crop investments for years, because their benefits accumulate over the long term.

Order the publication at: http://sare.org/webstore.htm

Increasing energy costs will have a profound effect on farm economics in coming years. As we go to press, it is impossible to predict how fast energy costs will increase, but since cover crop economics are connected to nitrogen dynamics (how much N you save or produce with cover crops), fuel costs (the cost of N and trips across the field) and commodity prices, energy prices will certainly impact the economics of cover crop use.

Economic comparisons in the second edition were based on the old economy of two-dollar corn, twenty-cent nitrogen and cheap gas. Some studies showed that cover crops become more profitable as the price of nitrogen increases. We retained some of these excellent studies because data from new studies is not yet available. What we do know is that cover crops can help you to increase yields, save on nitrogen costs, reduce trips across the field and also reap many additional agronomic benefits.

There is a cover crop to fit just about every farming situation. The purpose of this book is to help you find which ones are right for you.

Farmers around the country are increasingly looking at the long-term contributions of cover crops to their whole farm system. Some of the most successful are those who have seen the benefits and are committed to making cover crops work for them. They are re-tooling their cropping systems to better fit cover crop growth patterns, rather than squeezing cover crops into their existing system, time permitting.

This third edition of Managing Cover Crops Profitably aims to capture farmer and other research results from the past 10 years. We verified the information from the second edition, added new results and updated farmer profiles and research data throughout. We also added two new chapters.

Brassicas and Mustards (p. 81) lays out the current theory and management of cover crops in the BRASSICACEAE family. Brassica cover crops are thought to play a role in management of nematodes, weeds and disease by releasing chemical compounds from decomposing residue. Results are promising but inconsistent. Try brassicas on small plots and consult local expertise for additional information.

Managing Cover Crops in Conservation Tillage Systems (p. 44) addresses the management complexities of reduced tillage systems. If you are already using cover crops, the chapter will help you reduce tillage. If you are already using conservation tillage, it shows you how to add or better manage cover crops. Cover crops and conservation tillage team up to reduce energy use on your farm and that means more profits.

We have tried to include enough information for you to select and use cover crops appropriate to your operation. We recommend that you define your reasons for growing a cover crop—the sec­tion, Selecting the Best Cover Crops for Your Farm (p. 12) can help with this—and take as much care in selecting and managing cover crops as you would a cash crop.

Regional and site-specific factors can compli­cate cover crop management. No book can ade­quately address all the variables that make up a crop production system. Before planting a cover crop, learn as much as you can from this book and talk to others who are experienced with that cover crop.

We hope that this updated and expand­ed edition of Managing Cover Crops Profitably will lead to the successful use of cover crops on a wider scale as we continue to increase the sustainability of our farming systems.

Michigan workshop focuses on building healthy soils
Laura Probyn
ANR Communications
Michigan State University

Farmers will have an opportunity to get some hands-on experience while they learn from scientists and other farmers during a late August workshop on the importance of maintaining healthy, productive soils.

Paul Hepperly, a plant pathologist with The Rodale Research Institute, will kick off both days of the conference (Aug. 29-30) with discussions on the importance of composting in sustainable food systems during “Building Healthy Soils in Vegetable and Grain Systems.” 

“It will be very exciting to hear about The Rodale Research Institute’s long-term research project and how various farming systems affect soil health,” says Vicki Morrone, Michigan State University (MSU) Extension outreach specialist for organic vegetables and field crops. “Dr. Hepperly’s research spans the breadth of sustainable farming systems, including the connection between soil health and plant and animal nutrition.”

In his 27 years as a plant pathologist, Hepperly has received numerous awards for his research, including the 2004 Rachel Carson Sense of Science Award and the 2005 DaVinci Scientists Award.

The two-day workshop, sponsored by MSU Extension, the C.S. Mott Chair for Sustainable Agriculture—Sustainable Agriculture Research and Education, Morgan Composting and the MSU departments of Crop and Soil Sciences and Horticulture, will take place at Morgan Composting in Sears, Mich., and will cover multiple methods of improving soil and crop quality. Aug. 29 the focus will be on field crops; Aug. 30, on vegetable production.

Sessions include discussions about soil-building techniques, managing cover crops, seeding with a slurry air seeder and building compost using your own inputs. Participants will also have an opportunity to tour Morgan Composting.

The cost of the workshop is $30 for one day and $45 for both days. Registration materials must be postmarked by Aug. 25. Early birds who register before Aug. 15 will receive a $5 discount. Tradeshow space is available for $50.

For a detailed program and registration and lodging information, contact Morrone at 517-353-3542 or sorrone@msu.edu or www.michiganorganic.msu.edu

Michigan growers invited to organic blueberry discussion meeting
Annemiek Schilder
Plant Pathology
Michigan State University
 
The MSU blueberry team has received funding from Project GREEEN and the North Central SARE (Sustainable Agriculture Research and Education) Program to develop an organic blueberry research project. Before we establish the research planting at the MSU Horticulture Farm and get too far into the project, we would like to have a meeting to gather input from blueberry growers (organic growers and those interested in transitioning to organic production) and others with experience in this industry. We will present the project outline and objectives and will then start a discussion of possible treatments to evaluate and approaches to management of organic blueberry plantings. We would also like to invite growers who are growing blueberries organically or are transitioning to organic production to participate in the project.

Publications help with beetle identification
Liz Maynard
Horticulture and Landscape Architecture
Purdue University

During the New Ag Network organizational call on August 14, we discussed several beetles. The following publications and newsletter article from Purdue include descriptions and photos of striped cucumber beetle, western corn rootworm beetle, squash beetle, Mexican bean beetle and bean leaf beetle.

 E-65-W Vegetable Insects Identification
http://www.entm.purdue.edu/entomology/ext/targets/e-series/EseriesPDF/E-65.pdf

E-100-W Squash Beetle on Cucurbits
http://www.entm.purdue.edu/entomology/ext/targets/e-series/EseriesPDF/E-100.pdf 

Vegetable Crops Hotline Issue 438, July 23, 2004. Striped Cucumber Beetle And Western Corn Rootworm Beetle On Pumpkins http://www.entm.purdue.edu/Entomology/ext/targets/vegcrop/VCH2004/VCH438.pdf 

Reports from organic growers

Indiana
West Central Indiana, Tippecanoe County – Kevin Cooley
The weather has been dry and hot; I can't believe that most crops are still hanging in there. It has been more than two weeks since the last measurable amount of rain on our farm. The heat and excessive dryness has taken its toll on a late planting of snap peas and shelling peas. The peas are developed and ready, however, the shells are soft and lifeless. The heat has also been stressful on the tomato crop. A large percentage of fruits have been ripening too early in addition to ripening unevenly. I fear that our tomato season will end a month earlier than it should.

Our field activities have included harvesting crops for farmer’s markets as well as for our subscription families. Crops being harvested include tomatoes (slicing, heirloom and cherry), wax and green beans, beets, carrots, cucumbers, summer squash, herbs, potatoes, turnips, broccoli, cabbage, melons and onions. We have also been getting beds ready for fall plantings as well as fall transplants. Tillage has been kept at a minimum to preserve what moisture we have, however, we did till the shorter season pumpkins. While tilling the pumpkins we stayed a few inches further from the plants and then followed up a day later by pushing the loose dry soil into the row, smothering the weeds and keeping moisture in the row.

In the upcoming weeks we plan to transplant lettuce, cabbage, cucumber and squash. We will try to prepare plots for fall cover crops. We will be working to get the last planting of bulb onions out of the field and onto the drying racks. Other tasks will include preparing high tunnels for fall salad greens and salad crops. We will continue to put down more drip line on crops that need it.

South Central Indiana, Brown County – Dale Rhoads
We have had very hot weather with no rain. Salad green production has held up well until this week, when plots that had 50 percent plant loss due to disease from hot and humid weather caused a 50 percent production loss. The fact that temperatures are still in the lower 70s and upper 60s at night has keep growth and soil temperatures within good growing ranges.

I have been watering since June with only a couple of weeks of intense watering not needed. This has used more water from our pond than ever before. About a month ago I started to get pressure loss, which cut down on the number of watering devices I could run at one time and slowed down the watering process, which makes for more time spent watering. At the same time I began hearing the pressure tank in the house click on and off at odd times. This lead to a lot of time spent trying to figure out whether it was a leaking check value, a worn pump or a leak. After a month, I finally found the leak. Of course, the year I need water is the year there is a leak that I cannot find. I can’t determine how many thousands of gallons of much-needed water I lost.

We should have been transplanting fall basil and kale to bolster the spring plantings that lose some quality or vigor later in the year, but we missed the window. It was too hot and dry to transplant and now the plants are too large to transplant and have any kind of survival rate worth putting time into. Tomatoes are ripening too quickly, making for a short, intense season rather than one that is more spread out. We are still setting fruit, but in smaller quantities.

We are supposed to cool down and get some rain. I have about two more feet of water in the pond that I can use before it will run to the bottom of my pond well and have to jury rig a new pump situation to get more, which I prefer not having to do, but can if I need to.

Currently, we are in the heaviest harvest season. Tomatoes are pouring off the vines. Last harvest, salad greens were at half, but coming on crops that are doing well and with a cool down, harvest should jump back up. I have been preparing our fall salad greens planting plots for when we plant everything we can that will grow and hold for cutting into November with some slower growth in October.

I just finished fixing the water system and if we do not get rain in next day or so, I will have to begin using significant amounts of water as we are very dry.

In the next two weeks we will get fall salad plantings setup and planted, put in some cover crops, take out squash plantings and put to cover crop, do significant corn harvest and keep up with regular planting schedules.

Illinois
Northern Illinois, Kane County – David Campbell of Lily Lake Organic Farm
We received 5.1 inches of rain on July 26 and 27. Since then, we’ve also had generous amounts of rain with warmer temperatures and high humidity. Great weather for corn-growing, but it’s been very difficult trying to harvest hay.

Presently, I’m trying to harvest hay and I’m mowing grass and weeds along fencerows and field borders. I decided to spray for rootworm beetles in my corn recently. Spray dates were July 27 and August 3. Two applications were flown on. Cedar oil alone was used; in the past I’ve used Cedar-Gard. This time I used a new product called Cedar-Act. Approximate cost was $6.50/acre for the cedar oil and $7/acre application cost. A total of $13.50/acre for each application for two applications equals a total cost of around $27/acre. 

In the next two weeks I’ll be harvesting hay, weather permitting.

Question
I’m interested in any information on organic oat yields in northern Illinois. My father’s oats yielded approximately 80 bushels/acre with a 38-pound test weight. These oats were planted on April 11, the day before it snowed at his location, which is west of Rockford, Illinois. In my specific area (Kane/DeKalb counties), most organic oats yielded only 50 to 60 bushels/acre. The very low yields appear to be attributed to poor germination along with much hot, dry, windy weather back in May, especially the last half of May. Given the wet weather we’ve had from mid-July on, it’s been very challenging to get the oats harvested. A very disappointing year for oats, to say the least. There was virtually no winter wheat planted in my area last fall due to the excessively wet weather we experienced in October and early November.

Southwest Central Illinois, Montgomery County – Floyd Johnson of Shoal Creek Farm
We have been very, very dry; it does keep the weeds down, though. We seem to get enough rain to get the concrete wet once a month, whether we need it or not.

Currently I have been mowing weeds on idle ground, end rows, ditches, etc. After we get the weeds mowed, I will disk oat stubble to keep weeds down. If I get any time or find any employees, we will walk two fields of soybeans. They are clean enough that I think we could get through them.

North West Central Illinois, Fulton and Peoria counties – Anne Patterson of Living Earth Farm
Once again I have been blessed with rain just when things were looking very dry again. I went to crank up the irrigation system and it rained 1.4 inches last week. Now I have a bumper crop of summer crops. If I had not had the rains last week I shudder to think what things would look like with the past two weeks of very hot and humid weather.

It seems we are spending all of our time harvesting, with only minimal attention to transplanting some head lettuce and direct seeding arugula, spinach, fall beets and mesclun. We (the we includes me and my full-time employee) continue to seed flats of kale, kohlrabi and head lettuces for fall. I am also spending too much time trying to find adequate markets for tomatoes and eggplants. I called three restaurants today and have appointments with two places tomorrow. This is not how it’s supposed to go; I should not be chasing markets in August. However, it may be good after all, because I may line up more business for my future winter crops. With the heat, winter gardening is looking better every day (it’s 90 degrees plus). This report wouldn’t be adequate without mentioning that I’m still behind in weeding!

In the next two weeks we will research and order a new hoophouse for fall/winter crops; purchase and put in a new air conditioner and a cool-bot system into the new walk-in cooler; disk a section of garden to help eliminate summer weeds and get it ready for fall cover crop; continue on the long-term raised bed construction (if I have any spare time); prepare new bed area for heritage raspberries; keep our heads above the piles of tomatoes, beans, cucumbers and eggplant; and put up a deer deterrent fence at main garden at home—they have wiped out all the Swiss chard   

Question
How do you handle the emotional stress that always seems to hit this time of year along with hitting the wall with exhaustion? 

West Suburban Chicago, Will County – Steve Tiwald of Green Earth Institute
Over the past week we have had some relief from the drought, receiving 1.25 inches of rain.

Harvest for our CSA is taking the lion’s share of our time. Weekly we are harvesting lettuce; either Swiss chard or kale; root crops like carrots, beets or turnips; fruiting crops like tomatoes, eggplants, sweet peppers and hot peppers; and summer squash and zucchini. Yesterday we lifted potatoes, so they are now inside safely curing.

Besides our regular harvesting, we will bring in the onion crop within the next week. We will transplant out the fall crop of bok choi and continue seeding lettuce in the greenhouse and transplanting lettuce out to the field.

As strips get finished for the season, such as snap peas, broccoli, cauliflower and garlic, we will be doing light tillage and planting summer cover crops of either buckwheat or sorghum-sudan grass.

Iowa
Northwest Iowa – Paul Mugge
We have been very hot and very, very humid. I have gotten about 3.5 inches of rain, however, since the last report three weeks ago and it was sorely needed. The beans will be helped immeasurably and could yield very well with a couple of more showers. Aphids are a problem, however, and all of my conventional neighbors are spraying. We’ll see if the beneficials can keep up. The corn has been irreparably damaged. I am expecting the average ear length to be about five inches. There are a lot of corn earworms too.

I drilled the cover crops after the fall triticale—cowpeas, field peas and soybeans. The cowpeas emerged in four days. I tilled the field and waited for the rain and drilled as soon as it was dry enough. The red clover in the flax field looks beautiful as usual. I have spread some compost and have a lot of manure to haul to the compost windrow.

Over the next two weeks I plan to get some beef manure from a neighbor, but I have to haul it about three miles. It is quite time consuming. I have a field day here on August 25, so I need to clean the place up a bit and make handouts, etc.

Michigan
South Central Michigan – Anthony Cinzori
We have had very dry weather. We got a little more than one-half inch of rain two times during the past two weeks. Currently we are harvesting green beans, peppers, onions, tomatoes, potatoes, greens, summer squash, cucumbers, pickles and eggplant. In the next two weeks we will plant fall greens, radishes, carrots and beets.

Southwest Michigan, Berrien County - Greg Vlaming
At Maple Grove Organic Farm in South Haven MI, in the last few weeks, we seem to have crossed a critical threshold between “summer” crops, and the time to start seeding/transplanting “fall” crops.  The hoophouse tomatoes have peaked, while the tom’s planted outdoors are coming into their own with solid production.  The hoophouse plants have endured a very sunny, hot summer-cooling and irrigation have been almost constant.  The Tomato hornworm has been our predominant pest, which we control by diligent scouting and hand picking them off.  The chickens love them.  Nonetheless, the hornworms have taken their toll on foliage and fruit.  We use the fruit that we cannot sell to make salsa, which is made fresh each Friday for sale at the South Haven Farmers Market on Saturday morning.  Same deal for the cucumbers.  Harvest of cucumbers has been more abundant than sales, so we ferment a croc of homemade dill chips each week for sale on Saturday.  We have customers ask each week for more, and at $5/pint, the value-added product helps the profit margin, with product unsuitable for fresh market (which usually means it otherwise is compost or chicken feed).

Other crops still in production include summer squash, potatoes (all of which have been dug), garlic (ditto), onions, scallions, carrots, lettuce, Swiss chard, red Russian kale and various cut flowers.  We have seeded our hairy vetch/rye cover crop in the garlic and potato areas, and will continue to seed areas taken out of production.

Question
We have 45 chickens, about 9 months old with 2 acres free range grass meadow, a secure coop with plentiful shading both in the coop and outside and (to me) a chicken utopia.  We supplement their feed with both scratch scattered in the pasture once a day (about a quart), and any culls and hand-picked insects from the garden.  We are getting 5-7 eggs a day presently, which is what we got when temperatures were in the 80-90’s.  Lately we have had clouds, intermittent rain and cooler daytime temperatures (upper 70’s to low 80’s), though nights do not dip below 60’s.  We have one rooster among the flock. This production seems low for happy hens – any ideas on what we are doing wrong? You can email me at vlaming@msu.edu

East Michigan, Lapeer County – John Simmons
The 2.5 inches of rain we received on August 7 has helped, but the following conditions still apply. Hot, dry conditions continue to dry soils. Spotty rains have some fields in good shape moisture-wise; others within two miles are hurting. Lots of “pineapple corn” on hot days. Tillage decisions on fields that were marginally dry or too wet are showing up in suffering crops. Organic fields seen to be taking the heat and dryness better. The hot, dry, windy weather has made it easy to “put the hurt” on quackgrass and Canada thistle. Hot, dry weather appears to be favoring seed set in clover seed fields. Corn has good color and most fields are in silk or farther. Sunflowers are blooming. Soybeans range from bloom to pod set. Hay re-growth is still limited/slow.

Currently we are working on soybean weed control. Buckwheat is planted, emerged, close to 12 inches tall and flower buds are formed.

In the next two weeks we will complete small grain harvest with oats, start harvest of clover seed and prepare fields for fall spelt/wheat planting.

Minnesota
Western Minnesota – Carmen Fernholz
I missed the last call, but in the past 10 days we have received nearly two inches of rain with heavier amounts in other parts of the state. In walking the soybeans during that time I have seen a remarkable improvement in the plants overall. This coupled with the lack of any aphid infestation make the soybean crop look a whole lot better. The corn crop shows impact from the dry conditions earlier. However, these rains should help to give test weight to what crop ends up being harvested.

Currently, I am getting ready to prepare seedbed for eventual winter wheat planting sometime within the next 10 days to two weeks. Soil and moisture conditions are better now, but may not be so in two weeks. I have just about completed walking the soybeans with the exception of a small acreage near home.

In the next two weeks I will begin to prepare for winter wheat planting. I have never done any winter grains before, so this will be a new endeavor for me. I have been asking around for good advice and most of the feedback has been very positive for this crop in the rotation.

Questions
If there is any good advice on winter wheat, I would welcome it. What have others been reporting on aphid infestation?