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Home  > Question of the Week

Question of the Week



Permalink How can I manage Fusarium on tomatoes?

T.S.
Nevada

Answer: There are different forms of Fusarium disease in tomatoes: Fusarium wilt and Fusarium crown and root rot.

Fusarium wilt, caused by the fungus F. oxysporum f. sp. lycopersici (FOL), produces less extensive discoloration in the plant's water-conducting tissue than Fusarium crown and root rot; the brown streaks extend less than 20 to 30 cm. (8 to 12 in.) above the soil line. Fusarium crown and root rot is caused by the fungus Fusarium oxysporum f. sp. radicis-lycopersici (FORL). Crown and root rot is more likely with cool temperatures (10°C to 20°C/50°F to 68°F), low soil pH (acidic), ammoniacal nitrogen, and water-logged conditions. Since your soils are likely on the alkaline side and generally not waterlogged, it is likely that you have Fusarium wilt (FOL).

Crop rotation for 4 to 6 years is a possible control measure for both diseases, but success is not assured. Practice sanitation in the garden by destroying any infected plant debris. The best method of control is to plant resistant varieties. Some Verticillium wilt and Fusarium wilt (VF) resistant tomato varieties are listed below.

Better Boy
Heinz 1350
Beefsteak
Roma VF
Big Girl
Rutgers
Campbell
Springset
Floramerica
Supersonic

Research has shown that non-pathogenic strains of Fusarium oxysporum—particularly Isolate CS-20—can protect against low pathogen innoculum densities (Larkin et al., 1997). CS-20 apparently triggers development of systemic acquired resistance in the infected tomato plant, thereby making the plant more resistant to subsequent infections of pathogenic forms of F. oxysporum. Unfortunately, there are no commercial products available that use the non-pathogenic forms of this fungus at present. Some (but by no means all) commercially available formulations of bacteria or fungi that have shown effectiveness against Fusarium are listed below. Make sure you check with your certifier to learn which products are allowed for use in organic systems.

Product Name/trade name

Active ingredient

Effective Against

Comments on use

Manufacturer

T-22 HC (OMRI* listed), Rootshield, Plantshield, TopShield

Trichoderma harzianum (Rifai strain KRL-AG2)

Fusarium, Rhizoctonia, Sclerotium,  Sclerotinia and Botrytis species.

For preventative control of root diseases. Apply to seed, roots or soil, and can also be applied to foliage for control of fungal diseases.

BioWorks, Inc.
122 North Genesee St.
Geneva, NY 14456
315-781-1703
315-781-1793 Fax
Toll free: 800-877-9443
chayes@bioworksbiocontrol.com
www.bioworksbiocontrol.com</a>

Bio-Trek

Trichoderma harzianum (Rifai strain KRL-AG2)

Fusarium, Rhizoctonia, Sclerotium,  Sclerotinia and Botrytis

For preventative control of root diseases. Apply to seed, roots or soil, and can also be applied to foliage for control of fungal diseases.

Wilbur-Ellis
1801 Oakland Blvd., Suite 210
Walnut Creek, CA 94596
415-772-4000
415-722-4005 Fax
Toll Free: 800-500-1698
www.wilburellis.com

Mycostop (OMRI listed)

Streptomyces griseoviridis (S train K61)

Fusarium spp., Alternaria brassicola, Phomopsis spp., Botrytis spp., Pythium spp., and Phytophthora spp.

For preventative control of root diseases. Apply to seed, roots or soil. Particularly effective against Fusarium.

U.S. Distributor:
AgBio Development Inc.
9915 Raleigh St.
Westminster, CO 80031
877-268-2020, 303-469-9221; 303-469-9598 Fax
www.agbio-inc.com</a>

Kodiak ™ (Gufstasen)

Seranade (Agraquest)

Subtilex (Becker Underwood)

Bacillus subtilis

Wide range of foliar and root diseases

Used as seed treatment, biofungicide, inoculant and protectant.

Gustafson, Inc.
1400 Preston Road, Suite 400
Plano, TX 75093-5160
972-985-8877
972-985-1696 Fax
www.gustafson.com

AgraQuest, Inc.
1530 Drew Avenue
Davis, CA 95616
530-750-0150
530-750-0153 Fax
www.agraquest.com
E-mail: info@agraquest.com

Becker Underwood, Inc
P.O. Box 667
801 Dayton Ave.
Ames, IA 50010
515-232-5907
515-232-5961 Fax
Toll free: 800-232-5907
request@beckerunderwood.com
www.beckerunderwood.com</a>

s Review Institute is a 501 (c)(3) nonprofit. Its mission is to provide professional, independent, and transparent review of materials allowed to produce, process and handle organic food and fiber.

In combination with applied materials, cultural controls are important components of any sustainable agriculture system. Cultural controls include:
+ Use disease-free transplants and seed
+ Use planting stock resistant to Fusarium.
+ A 5-7 year rotation away from hosts.
+ Use nitrate nitrogen rather than ammonium nitrogen.
+ Use localized fertilizer placement to feed the plants rather than the fungus.
+ Do not flood irrigate or use pond or ditch water to irrigate. Well water may be preferable, as it’s less likely to contain Fusarium propagules.

An effective strategy to help destroy Fusarium innoculum is to solarize your soil. The basic technique entails laying clear plastic over tilled, moistened soil for approximately six to eight weeks. Solar heat is trapped by the plastic, raising the soil temperature and destroying the innoculum. The incorporation of poultry litter prior to solarization, or use of a second layer of clear plastic, can reduce effective solarization time to 30 days. (Brown et al., 1989; Stevens et al., 1990) Brassica residues are also known to increase the solarization effect, in a process known as biofumigation. The plastic holds in the gaseous breakdown products of the brassica crop (or food processing wastes), thereby increasing the fumigation-like effect. (High microbial activity has been reported to suppress Fusarium wilt, so maintaining healthy soils with sufficient organic matter to support high microbial populations is another form of cultural control. A University of California Cooperative Extension leaflet (No. 21377), "Soil Solarization: A Nonchemical Method for Controlling Diseases and Pests," details the technique:
ANR Publications, University of California.
6701 San Pablo Ave.
Oakland, CA 94608-1239
510-642-2431; 800-994-8849
www.anrcatalog.ucdavis.edu</a>

site www.uckac.edu/iwgss</a> provides links to current research and publications on solarization.


References:
Borrero, C., M.J. Infantes, E. Gonzáles, M. Avilés, J.C. Tello. Relation Between Suppressiveness to Tomato Fusarium Wilt and Microbial Populations in Different Growth Media

Brown, J.E. , M.G. Patterson, and M.C. Osborn. 1989. Effects of clear plastic solarization and chicken manure on weed control. p. 76–79. In: Proceedings ofthe 21st National Agricultural Plastics Congress. Nat. Ag. Plastics Assoc., Peoria, IL.

Gamliel, A., and J.J. Stapleton. 1993. Characterization of antifungal volatile compounds evolved from solarized soil amended with cabbage residues. Phytopathology. Sept. p. 899–905.

Larkin, R. P. and D. R. Fravel. 1997. Biological Control of Fusarium Wilt of Tomato Under Varying Environmental Conditions.
www.epa.gov/ozone/mbr/airc/1997/036larkin.pdf</a>

P. D., McGovern, R. J., and L.E. Datnoff. 2001. Fusarium Crown and Root Rot of Tomato in Florida. Plant Pathology Department, Florida Cooperative Extension Service. Publication PP-52. http://edis.ifas.ufl.edu/PG082

Stevens, C., V.A. Khan, and A.Y. Tang. 1990. Solar heating of soil with double plastic layers: a potential method of pest control. p. 163–68. In: Proceedings of the 22nd National Agricultural Plastics Con gress. Nat. Ag. Plastics Assoc., Peoria, IL.

 Permalink

 

Permalink How can I control bahia grass on my hay farm?

M.S.
Texas

Answer: Controlling bahiagrass in any scenario is extremely difficult. Bahiagrass reproduces by rhizomes (primarily) and seeds, is very tolerant of grazing, and tolerates droughty conditions. It isn't very cold tolerant, which makes it an ideal pasture species for the Gulf Coast region. Some grasses you can "mismanage" in order to reduce their incidence in the field, but bahiagrass usually thrives on rough treatment. Several chemical means are available that purport to control bahiagrass, but this treatment is extreme, questionable in its efficacy, and results in upsetting the ecology of the field by reducing biodiversity and subsequent long term viability.

Bahiagrass can certainly play a part in a diversified pasture or hayfield system. Being different from bermudagrass, it can express itself at times when the conditions for bermudagrass growth are compromised. This principle of agricultural biodiversity is extremely important for low input systems that rely on nutrient cycling, natural pest immunity, and plant species diversity to maintain ecological balance and productivity in perpetuity.

Monocultures of any crop are problematic from an ecological and often economic standpoint. That being said, market constraints or yield differences often dictate the species of grass grown in an area. Hybrid bermudagrass can yield greater than 10,000 pounds per acre per year, and bahiagrass encroachment can reduce yields and affect per-acre profitability. If a monoculture bermudagrass hayfield is your goal, then setting up a management regime that favors bermudagrass proliferation at the expense of other species is the best bet. Hybrid bermudagrass has been genetically selected for nitrogen use efficiency and rapid, voluminous growth. Careful attention to soil fertility and timely watering would be the first line of defense in selecting against bahiagrass proliferation in bermudagrass. Granted, bahiagrass uses nitrogen and water much the same as bermudagrass does, but hybrid bermudagrass can out-compete bahiagrass given high levels of fertility.

Another method of bahiagrass control would be limited tillage in spots where bahiagrass is dominant. Rhizomes can be tilled, raked up, and removed from the field, and if the spot isn't too large, the bermudagrass should be able to spread into the bare spots. Careful attention should be paid to other invasive species like sand bur, ragweed, carpetgrass, crabgrass, and nightshade. Spot sprigging with bermudagrass sprigs or tops might be appropriate in some areas.

Again, controlling a persistent perennial grass in a warm-season hayfield is very challenging. Short of wiping the field out with glyphosate and starting over, which I do not recommend, you'll need to resign yourself to the slow process of changing the environment so the bermudagrass proliferates at the expense of the bahiagrass.

If you would like more information on sustainable pasture, hayfield, and meadow management, you can see ATTRA's publications on Grass Farming, or Ask a Sustainable Agriculture Expert.

 Permalink

 

Permalink What organic controls are there for Septoria Leaf Spot in tomatoes?

P.D.
Virginia

Answer: First, make sure that you have identified Septoria Leaf spot as indeed the culprit of your tomato woes. Following are some ways of identifying Septoria leaf spot, which is a fungus, compared to many of the bacterial diseases that affect tomatoes.

Symptoms
Numerous, small, water-soaked spots, which are the first noticeable characteristic of Septoria leaf spot, appear on the lower leaves after fruit set. Spots enlarge to a uniform size of approximately 1/16 to 1/4 inch in diameter. They have dark brown borders and tan or light colored centers. Yellow haloes often surround the spots. Severely infected leaves die and drop off. Septoria leaf spot is sometimes confused with bacterial spot of tomato. Septoria leaf spot is easily distinguished from early blight/ bacterial spot, another foliar disease of tomato, by the uniform, small size of the spots (which if you look closely are spore receptacles) and the lack of concentric rings in the spots. The presence of fruiting bodies (the spores) of the fungus, visible as tiny black specks in the centers of the spots, confirms Septoria leaf spot.

Favorable weather permits infection to move up the stem, causing a progressive loss of foliage from the bottom of the plant upward. Plants appear to wither from the bottom up. Loss of foliage causes a decrease in the size of the fruits and exposes fruit to sunscald. Spotting of the stem and blossoms may also occur.

Once you have identified the disease it is helpful to know its life cycle in order to develop a pest management strategy.

Disease Cycle
Septoria lycopersici overwinters in old tomato debris and on wild solanaceous plants, such as ground cherry, nightshade, and jimsonweed. Seeds and transplants may also carry the fungus. The disease is favored by moderate temperatures and abundant rainfall. Spore production is abundant when temperatures are 60°-80°F (15.5°-28°C). Spores are easily spread by wind and rain. Infection occurs on lower leaves after the plants begin to set fruit.

Control Measures
Cultural control is one of the only ways to control/ prevent Septoria Leaf Spot.

Cultural Control
• Dispose of crop refuse by plowing under deep or composting.
• Control weeds (particularly those in the Solanum genera) in and around the edge of the garden.
• Rotate tomatoes with cereals, corn, or legumes. A 4-year rotation is recommended where disease has been severe.
• Mulch acts as a barrier between soil and plant to prevent splashing spores onto plant.
• Prune lower leaves that are infected at first sign—will also improve air circulation.
• Stay out of growing areas when the foliage is wet.
• Water early in the day and, if possible, avoid wetting the foliage, through using drip irrigation or soaker hoses.
• Stake plants.
• Be sure plants have adequate nutrition.

Control via biorational, compost tea, etc.
Fungicides, organic or not, have shown limited results with Septoria leaf spot:
• Copper and sulfur are fungicides approved by the National Organic Program (NOP) Standards. Application of copper is a routine disease control practice in organic tomato production in the eastern United States. Copper functions both as a fungicide and bactericide and is labeled (under the NOP) for anthracnose, bacterial speck, bacterial spot, early and late blight, gray leaf mold, and septoria leaf spot.

Commercial products like Kocide 101™ are used in both conventional and organic tomato production for the control of Septoria leaf spot, bacterial spot, bacterial speck, anthracnose, and early blight. Applications are made on a 7-10 day schedule and the result may be 8-12 sprays per growing season. See the resource Eggplant, Pepper, and Tomato XXIV; Septoria Leaf Spot by Howard Schwartz and David H. Gent of High Plains IPM for information on applying specific copper fungicidal controls. Note that the pesticides listed in this publication are not all organic. Only some of the copper fungicides are permissible.

Under the NOP, The National List of Allowed and Prohibited Substances §205.600 are:
1) Coppers, fixed—copper hydroxide, copper oxide, copper oxychloride, includes products exempted from EPA tolerance, Provided, That, copper-based materials must be used in a manner that minimizes accumulation in the soil and shall not be used as herbicides.
(2) Copper sulfate—Substance must be used in a manner that minimizes accumulation of copper in the soil.
• The use of copper fungicides in organic production is somewhat controversial. It is directly toxic at applied rates to some beneficial organisms, particularly earthworms and some soil microbes such as blue-green algae—an important nitrogen-fixer in many soils. Excessive use can also result in the buildup to phytotoxic (crop damaging) levels of copper in the soil. Thus, organic growers often monitor soil copper levels through regular soil testing.

Compost Teas
Research has shown that compost teas seem to work more for phytopthera (root rot) and Pythium (damping off) diseases in tomatoes. It might be beneficial to try spraying (fully cured) compost tea on just a few plants to see if it is effective for you. ATTRA offers a publication titled Notes on Compost Teas.

Biological Controls
Unfortunately, there has not shown to be any effective biological control agent for Septoria Leaf Spot. Biological fungicides are a new and emerging field. F-Stop™, registered as a seed treatment for tomatoes, contains a biocontrol agent called Trichoderma viride sensu and may be effective for treating seed infected with Septoria leaf spot. There is no conclusive evidence on its efficacy with Septoria Leaf spot specifically, however.

The ATTRA publication titled Organic Tomato Production can help with general tomato disease control strategies as well as some specific information on other tomato diseases.

References
Hansen, Mary Ann, Extension Plant Pathologist, Department of Plant Pathology, Physiology and Weed Science, Virginia Tech. Adapted from a previous publication by R.C. Lambe. Septoria Leaf Spot of Tomato. Virginia State University Cooperative Extension. Publication Number: 450-711, Posted December 2000.
www.ext.vt.edu/pubs/plantdiseasefs/450-711/450-711.html

Delahaut, Karen and Walt Stevenson. Tomato Disorders: Early Leaf Blight and Septoria Leaf Spot. University of Wisconsin Extension. 2004. http://s142412519.onlinehome.us/uw/pdfs/A2606.PDF

Schwartz, Howard F. and David H. Gent. Eggplant, Pepper, and Tomato XXIV; Septoria Leaf Spot. High Plains IPM.
http://highplainsipm.org/HpIPMSearch/Docs/SeptoriaLeafSpot-EggplantPepperTomato.doc

 Permalink

 

Permalink Where can I find information about the mechanical roller-crimper used in no-till production?

J.H.
Minnesota

Answer: The mechanical roller-crimper equipment used in no-till production, including equipment designs and technical specifications. This roll-down equipment is also known as a "knife roller" and a "crimper/roller."

Mechanical suppression of cover crops for no-till production can be accomplished through various kinds of mow-down and rolling/slicing/crimping techniques. These non-chemical methods of killing cover crops are appealing as an alternative to chemical-kill methods using synthetic herbicides.

There are three notable journal articles dealing with mechanical suppression of cover crops in no-till production that are relevant to this topic because they summarize promising non-chemical methods of killing cover crops for no-till production in organic farming. The paper by Nancy Creamer et al in the 1995 issue of American Journal of Alternative Agriculture (AJAA) highlights the undercutter/roller basket equipment, developed at Ohio State University and North Carolina State University. The paper by Nancy Creamer and Seth Dabney in the 2002 issue of AJAA discusses various mow-down, roller-slicer, and undercutter methods. Finally, the paper by Ashford and Reaves in the 2003 issue of AJAA addresses the use of the mechanical roller-crimper.

Creamer, N., et al. 1995. A method for mechanically killing cover crops to optimize weed suppression. American Journal of Alternative Agriculture. Vol. 10, No. 4. p. 157–162.

Creamer, Nancy G. and Seth M. Dabney. 2002. Killing cover crops mechanically: Review of recent literature and assessment of new research results. American Journal of Alternative Agriculture. Vol. 17, No. 1. p. 32–40.

Ashford, D.L. and D.W. Reeves. 2003. Use of a mechanical roller-crimper as an alternative kill method for cover crops. American Journal of Alternative Agriculture. Vol. 18, No. 1. p. 37–45.

The roller-crimper is a water-filled heavy round drum with protruding blunt metal blades arranged in horizontal, angled, or spiral patterns. These roller-crimpers are most commonly rear-mounted and pulled behind a tractor or draft animals, but they can also be front-mounted on a tractor. When the roller-crimper is pulled through a high biomass cover crop—such as wheat, rye, oats or oilseed radish—the cover crop is flattened and “crimped” by the heavy drum with metal strips. The purpose of the metal strips is to crimp or crush the stems of the cover crop rather than cutting or chopping the stems; this silmultaneously prevents re-sprouting and slows down decomposition of the no-till mulch. No-till crops are seeded or transplanted in the same direction as the flattened and crimped cover crop, which slowly senesces and dies out over the course of several weeks, leaving a high-residue no-till mulch.

The timing of the roller-crimper field operation is critical to gain effective kill of the cover crop. Cereal-based cover crops should rolled at the “anthesis” (flowering) stage of growth or later—in the milk or soft dough stages of growth, a period which corresponds to the mid-spring planting season shortly after the last frost-free day. Growers can refer to charts published by the Extension Service on the Feekes or Zadoks scale of crop growth to gain a clear understanding when anthesis, milk, and soft dough stages occurs (1–2).

Dana Ashford and Wayne Reeves, researchers with the USDA-ARS National Soil Dynamics Laboratory in Alabama, have thoroughly documented the ability of a roller-crimper to kill a cereal cover crop at the flowering to soft dough stage of growth (3). Several field trials have demonstrated that a mechanical roller-crimper can kill a cover crop just as effectively as herbicides.

On the other hand, weeds that emerge in the no-till mulch can be a problem. In conventional no-till production herbicides can be used as a post-emerge treatment so weed control is fairly straightforward. In organic farming special attention needs to be paid to a clean field, excellent establishment of a winter annual cover crop, and high biomass cover crop production. Spot treatment of weeds is feasible with a hand-held flame weeder or with the use of organically approved natural herbicides on small acreages, but these labor-intensive treatments aren’t practical in broadscale crop production.

The mechanical roller-crimper has revolutionized no-till production methods in Latin America where over 40 million hectares (98 million acres) are managed by no-till production systems.

The books and web sites from Carlos Crovetto Lamarca, Rolf Derpsch, and Roland Bunch are critically important resources on the benefits of conservation tillage systems, green manure mulches, and no-till methods on soil health in Latin America (4–6).

In the United States, the roller-crimper method is being promoted by the Rodale Research Institute in Pennsylvania as well as by several university and USDA-ARS research stations.

Jeff Moyer, the farm manager at the Rodale Institute, is spearheading the Rodale research project on knife roller equipment designs and on-farm trials using roll-down, no-till production systems. Moyer explained that machine shop specifications for a build-your-own knife roller are an expected outcome of the Rodale project. These plans will be available when they can convert the Auto-CAD drawn designs to Adobe PDF for posting on the NewFarm.org Web site. Some of the Rodale equipment designs are unique by placing the knife roller on the front end of the tractor while a no-till seeder is simultaneously located on the back of the tractor. This enables a “one pass” roll-down/no-till planting system.

The NewFarm.org Web site, hosted by the Rodale Research Institute, has published several noteworthy articles and updates on this project, including very helpful photos of equipment mounted on tractors. Please see the following articles and features from NewFarm.org. The slide show titled The Long Road to No-Till and the photo gallery titled The Roller/Crimper Gallery are excellent online sources to view equipment designs with close-up photos.

The No-Till + Page
www.newfarm.org/depts/notill/index.shtml

The Roller/Crimper Gallery
NewFarm.org | May 24, 2005
www.newfarm.org/depts/notill/roller_gallery/index.shtml

The Long Road to No-Till Slide Show
www.newfarm.org/depts/NFfield_trials/1103/slideshow/notillroller1.shtml

New Tools for Organic No-Till—Introducing a Cover Crop Roller Without All the Drawbacks of a Stalk Chopper
By Laura Sayre
www.newfarm.org/depts/NFfield_trials/1103/notillroller.shtml

Perfecting Organic No-Till Systems Nationwide
By Laura Sayre | September 28, 2004
www.newfarm.org/depts/RI_ops/0904/grant.shtml

Farmers Gear up Cover-Killing Rollers for Spring No-Till Planting Season
By Laura Sayre and Greg Bowman | February 16, 2006
www.newfarm.org/features/2006/0206/springnotill/bowman.shtml

Choosing Cover Crops for No-Till Organic Soybeans
By Dave Wilson | October 13, 2005
www.newfarm.org/depts/weeds/features/1005/weeds_dw.shtml

The Resources, References and Web Resources sections below contain several important documents you may find helpful for further background reading. Several papers and technical notes from agronomists conducting research on the mechanical roller-crimper and its use for suppression of cover crops are listed.

Thus far I am aware of only two equipment manufacturers in the United States that supply bonafide roller-crimpers: Kelley Mfg. Co. in Georgia and and Bigham Brothers Mfg. Co. in Texas (7–8). These roller-crimpers can be custom-made according to any width a farmer might need, based on tractor size and field layout.

In addition, various brands of stalk choppers, roller harrows, cultipackers, bed rollers, and land rollers are being used by farmers, either factory-made or modified, to accomplish the same function of rolling and crimping of cover crops for no-till production.

Farmers who want to “build their own” roller-crimpers can review the slide shows and photo galleries on the NewFarm.org Web site and read the accompanying papers from land-grant university and USDA researchers. Farmers who want to duplicate the Rodale Institute’s roller-crimper can obtain a front-mounting 3-point hitch from Buckeye Tractor Co. in Ohio (9).

The paper from NRCS Soil Quality Institute, The Knife Roller (Crimper): An Alternative Kill Method for Cover Crops, and the paper from American Society of Agricultural Engineers, Cover Crop Rollers: A New Component of Conservation Tillage Systems, provide descriptions and design ideas. As noted above, the Rodale Institute will eventually provide Auto-CAD drawings and design specifications for roller-crimpers on the NewFarm.org Web page.

References:

1.Wheat Growth Stages and Associated Management (e.g., Feekes scale)
Ohio State University Extension
http://ohioline.osu.edu/agf-fact/0126.html

2. Growth and Development Guide for Spring Wheat (e.g., Zadoks scale)
Universty of Minnesota Extension
www.extension.umn.edu/distribution/cropsystems/DC2547.html

3. Ashford, D.L. and D.W. Reeves. 2003. Use of a mechanical roller-crimper as an alternative kill method for cover crops. American Journal of Alternative Agriculture. Vol. 18, No. 1. p. 37–45.

4. Lamarca, Carlos Crovetto. 1996. Stubble Over the Soil: The Vital Role of Plant Residue in Soil Management to Improve Soil Quality. American Society of Agronomy, Madison, WI. 245 p.

Stubble Over the Soil by Carlos Crovetto Lamarca was a landmark book heralding the value and importance of conservation tillage on soil health. Lamarca focuses on soil improvements, soil organic matter, and soil quality that result from plant residues and reduced soil disturbance inherent to conservation tillage systems. His 245-page book is filled with color photos and educational illustrations of no-till agriculture, agricultural implements, cover crops, mulches, crop residues, and soil quality improvements. Larmarca is an agronomist with Chequen farm in Chile, a famous site of no-till agriculture in South America. He has played an instrumental role in no-till agriculture in Venezuela, Columbia, Argentina, Brazil, Uruguay, Bolivia, Mexico, the United Kingdom, and the U.S.


5.No-Tillage—Rolf Derpsch
www.rolf-derpsch.com/notill.htm

Rolf Derpsch, No-Till Agronomist
www.rolf-derpsch.com

The Knife Roller—A New Development for Permanent Cover Cropping Systems
by Rolf Derpsch
www.rolf-derpsch.com/kniferoller.html

The Importance of Green Manure Cover Crops
by Rolf Derpsch
www.rolf-derpsch.com/covercrops.html

The Importance of Green Manure Cover Crops and Crop Rotation in the No-tillage System: Experiences from Latin America
by Rolf Derpsch
Paper for South Australian No-Till Farmers Association—SANTFA
www.santfa.com.au/downloads/RolfDerpschpaper.pdf

Rolf Derpsch is a leading research agronomist based in Paraguay who provides worldwide technical support and education on no-till production systems. The Web sites listed above provide access to his articles, publications, and resources. Also see the following excerpt on knife rollers from a paper by Rolf Derpsch.

Crop Rotations and Green Manure Cover Crops in Latin America
by Rolf Derpsch
Crop Updates 2001: Farming Systems
Department of Agriculture, Western Australia
http://agspsrv34.agric.wa.gov.au/cropupdates/2001/Farm_systems/Derpsch.htm

“GMCC's (green manure/cover crops) and crop rotation are the key factors for the unprecedented growth of no-tillage especially in Brazil and Paraguay. Linked to the spread of cover crops is the use of a 'knife roller' to put the cover crops down to the ground. This implement is not terribly expensive and in many cases can be made locally or by the farmer himself. The implement can be pulled by medium sized tractors or by animal traction and has contributed a lot in reducing herbicide rates in the no-tillage system. The knife roller has become an essential tool for managing GMCC's in many countries of South America. Alternatively steel bars can be welded on top of the discs of disc harrows and the implement used for the same purpose.”

6. Nutrient Quantity or Nutrient Access?: A New Understanding of How to Maintain Soil Fertility in he Tropics
By Roland Bunch, October 2001
http://ppathw3.cals.cornell.edu/mba_project/moist/RolandB.html

Roland Bunch is the author of Two Ears of Corn: A Guide to People-Centered Agricultural Development. He has worked as an agronomist for non-profit organizations in Central American for several decades. The above paper by Bunch highlights the work of the famous Brazilian soil ecologist, Dr. Ana Primavesi, as well as Bunch’s Five Principles of Soil Management for the Humid Tropics: 1. maximize organic matter production; 2. keep the soil covered with green manures and cover crop mulches; 3. zero tillage; 4. maximize biodiversity; and 4. feed crops largely through mulches.

Also see:

An Odyssey of Discovery: Principles of Agriculture for the Humid Tropics
By Roland Bunch
Leisa Magazine, Vol. 11, No. 3 (October 1995). p. 18-19.
www.metafro.be/leisa/1995/11-3-18.pdf

Achieving Sustainability in the Use of Green Manures
by Roland Bunch
ILEIA Newsletter, Vol. 13, No. 3. (October 1997). p. 12-13.
www.metafro.be/leisa/1997/13-3-12.pdf

Adoption of Green Manure and Cover Crops
By Roland Bunch
LEISA Magazine, Vol. 19, No. 4. ( December 2003). p. 16-18.
www.metafro.be/leisa/2003/194-16_18.pdf

Soil Fertility Management Under Pressure
By Roland Bunch
Leisa Magazine, Vol. 13, No. 3 (October 1997). p. 4-5.
www.metafro.be/leisa/1997/13-3-4.pdf

7. Kelley Manufacturing Co.
P. O. Box 1467
Tifton, GA 31793
229-382-9393
800-444-5449 Toll-Free
229-382-5259 Fax
info@kelleymfg.com
www.kelleymfg.com


8. Bigham Brothers, Inc.
[Tech Support: Mike Wisian]
P.O. Box 3338
Lubbock, Texas 79452
806-745-0384
800-692-4449 Toll-Free
806/745-1082 Fax
www.bighambrothers.com

9. Buckeye Tractor Co.
P.O. Box 97, 11313 Slabtown Road
Columbus Grove, Ohio 45830
419-659-2162
800-526-6791Toll-Free
419-659-2082 Fax
buctraco@bright.net
www.buctraco.com

Resources:

The Knife Roller (Crimper): An Alternative Kill Method for Cover Crops
Soil Quality - Agronomy Technical Note No. 13
http://soils.usda.gov/sqi/files/13.pdf

This 4-page PDF, an NRCS Technical Note, is of particular interest because it has a technical description of the roller equipment.

“Knife rollers are hollow steel drums, generally 2 to 3 feet in diameter and no wider than 6½ feet, that adjust to soil surface irregularities. More than one can be pulled side-by-side to achieve greater operating width. Approximately 10 blunt knives are along the length of the drum. These knives are 3 to 4 inches tall and are spaced 7 to 8 inches apart (Derpsch et al., 1991; Grooms, 2002). The blunt knives do not cut or chop the stems of the cover crops but crimp or crush them. The drums generally weigh over 800 pounds when empty and can weigh in excess of 1,700 pounds when filled with water. The water is helpful as the height and amount of biomass increase.”

Rolling and Crimping: Scientists Study Alternative Cover Crop Kill Method
Dana Ashford and Wayne Reeves
Online Highlights, Alabama Agricultural Experiment Station of Auburn University
Volume 48, No. 3 (Fall 2001)
www.ag.auburn.edu/aaes/communications/highlightsonline/fall01/fall-ashford.html

Use of a mechanical roller-crimper as an alternative kill method for cover crops. 2003. By D.L. Ashford and D.W. Reeves. American Journal of Alternative Agriculture. Vol. 18, No. 1. p. 37–45.
www.spcru.ars.usda.gov/Pubs/ashfordreeves03.pdf

Modified Abstract: This study was conducted to determine the effectiveness of using a mechanical roller-crimper as an alternative method for killing cover crops. Rye, wheat and black oat were evaluated in terms of ease of kill and optimum time of kill using a roller-crimper, (note: compared to herbicide treatments). Four Feekes' scale growth stages were used to determine optimum time of kill; 8.0 (flag leaf), 10.51 (anthesis), 10.54 (early milk) and 11.2 (soft dough). Plant growth stage was the main determining factor for effectiveness of the roller-crimper for killing the cover crops. At the flag leaf stage, the roller-crimper provided only 19% kill across all covers over the 3 site-years. After plants reached anthesis, the roller-crimper with half-rate herbicide combinations equaled the effectiveness of herbicides alone at their label rate, averaging 94% kill. By the soft dough growth stage, all kill methods were equally effective due to accelerating plant senescence (95% mean kill across kill methods). Use of the roller-crimper alone after anthesis can decrease costs by as much as $26.28 per ha, while providing a kill rate equivalent to that of herbicide treatment alone.

Effectiveness in Terminating Cover Crops Using Different Roller Implements
Ted S. Kornecki, Randy L. Raper, and Andrew J. Price
USDA-ARS, Auburn, Alabama
26th Southern Tillage Conservation Conference
www.ag.auburn.edu/aux/nsdl/sctcsa/Proceedings/2004/Kornecki.pdf

This 10-page PDF is an article from the 26th Southern Tillage Conservation Conference.

“Rollers may provide a valuable alternative to herbicides for terminating cover crops, however, research has shown that excessive vibration that is caused by the roller passing over the cover crop. To avoid excessive vibration, users must limit their operational speed which reduces the number of producers willing to use this technology. To improve the roller’s performance, three different rollers designs were compared: (1) a roller with long blunt ¼ inch steel angle bars equally spaced), (2) a roller with elliptical blunt bars, and (3) a smooth roller with an oscillating crimping bar behind the roller. Preliminary data have shown that the smooth roller with crimping arm produced the highest kill rate of the cover crop (rye, Cecale cereale L.). Data indicate that operating rollers at higher speed (5 MPH) produced significantly higher kill rate of the cover crop compared to low speed (1 MPH). Also, the kill rate evaluated at the end of second week from rolling/crimping was 2 times higher as compared to the kill rate at the end of the first week. The minimum vibration levels measured on tractor’s frame were produced by smooth roller with oscillating crimping arm. This study provides valuable information to further improve mechanical rollers’ effectiveness to terminate cover crops and to give design guidance to researchers who are in the process of developing a mechanical roller widely acceptable to producers in conservation systems.”

Cover Crop Rollers: A New Component of Conservation Tillage Systems
R.L. Raper, P.A. Simionescu, T.S. Kornecki, A.J. Price, D.W. Reeves
ASAE Paper Number: 031020
American Society of Agricultural Engineers (ASAE)
2003 ASAE Annual International Meeting
Las Vegas, Nevada, Held 27- 30 July 2003
www.spcrcu.ars.usda.gov/Pubs/raperreeves03.pdf

This 10-page PDF is a professional paper from American Society of Agricultural Engineers.

Abstract: Rollers may provide a valuable alternative to chemicals for terminating a cover crop. Several producers are now using versions that they have made or have purchased. Most of these producers, however, complain about excessive vibration that is caused by the roller passing over the cover crop. To avoid this excessive vibration, they must limit their operational speed. Experiments were performed to determine if two alternative designs for the blades of the rollers would decrease vibration while maintaining the ability to kill a cover crop. Results showed that a curved blade system or a short-staggered straight blade system significantly reduced vibration as compared to the standard long-straight blade system typically found on rollers. These two alternative blade systems were also found to kill the cover crop as effectively as the long-straight blade system.

Web Resources:

SoilSaver - A Black Oat Winter Cover Crop for the Lower Southeastern Coastal Plain
Conservation Systems Fact Sheet No. 1, National Soil Dynamics Laboratory, Auburn, AL
www.ars.usda.gov/SP2UserFiles/Place/64200500/csr/FactSheets/FS01.pdf

Roller-Crimper Direction and Various Row-Cleaning Attachments for Cotton Establishment
Research Project Description No. 30, National Soil Dynamics Laboratory, Auburn, AL
www.ars.usda.gov/SP2UserFiles/Place/64200500/csr/ProjectDescriptions/PD30.pdf

Improving Rollers for an Alternative Cover Crop Kill Method
Research Project Description No. 31, National Soil Dynamics Laboratory, Auburn, AL
www.ars.usda.gov/SP2UserFiles/Place/64200500/csr/ProjectDescriptions/PD31.pdf

Evaluation of a Mechanical Roller-Crimper and Reduced Glyphosate Rates on
Cover Crop Desiccation and Weed Dynamics in Corn and Cotton
Research Project Description No. 35, National Soil Dynamics Laboratory, Auburn, AL
www.ars.usda.gov/SP2UserFiles/Place/64200500/csr/ProjectDescriptions/PD35.pdf

Keys to Successful Production of Transplanted Crops in High-Residue, No-Till Farming systems. 1998. By Ronald Morse. p. 79-82. In: Meeting the Challenges — 21st Southern Conservation Tillage Conference for Sustainable Agriculture.
www.ag.auburn.edu/aux/nsdl/sctcsa/Proceedings/1998/Morse.pdf

Effects of Rolling/Crimping Rye Direction and Different Row-Cleaning Attachments for Cotton Emergence and Yield
T.S. Kornecki, R.L. Raper, F.J. Arriaga, K.S. Balkcom, and A.J. Price
Proceedings of the 27th Southern Conservation Tillage Systems Conference, Held 27–29 June, 2005, Florence, South Carolina
www.ag.auburn.edu/aux/nsdl/sctcsa/Proceedings/2005/Kornecki.pdf

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Permalink How much black oil sunflower can I use in poultry feed?

A.O.
Ohio

Answer: Black oil or other sunflowers should be avoided above 10% of the diet for younger and developing poultry, due to the high levels of fiber. Even for adult poultry the fiber levels may be excessive. However, sunflower seeds are used as a mid-level nutritional feed ingredient that would replace corn and full-fat soy products equally. In other words, if you were to use 100 pounds of sunflower you would replace 50 pounds of corn and 50 pounds of full-fat soy in the feed mix.

In the poultry feed recipe found in the publication Pastured Poultry Nutrition (available in hard copy from ATTRA at (800) 346-9140), this substitution of sunflower for corn and full-fat soy can be done with up to 200-250 pounds of sunflower per ton of feed.

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