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Home  > Question of the Week

Question of the Week

Permalink What are some options for controlling thorny locust?


Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service. I am pleased to provide you with information on controlling thorny locust.

Brush Control Practices

Mature, single-stemmed trees provide shade for livestock and can increase the aesthetics of a landscape if they are not too numerous. They are also much more difficult to remove. For this reason it is advisable to concentrate on new seedlings and young bushes and trees. If the infestation is small, use a grubber or root plow to remove these plants individually. If the infestation is wide-spread, encompassing small and medium-size trees and bushes, consider root plowing, chaining, or roller chopping followed by a controlled burn to remove most of the biomass. It will most likely be necessary to grub out re-sprouts for several years after to obtain optimal control.

Mechanical methods of brush control have varying levels of success. Methods such as chaining or mowing, are more expensive than other practices such as grazing and herbicide use because of high inputs for energy, labor, and equipment. For some species, like locust, even chemical control may not be completely successful without repeated applications and constant attention to new growth. Having brush on your land can be exasperating, but if kept in check can actually become a beneficial contribution to a farm, such as providing cover and food for wildlife and serving as riparian buffers.

Mowing is discouraged as a control method for many brush species, because this activity trains the tree to become a bush. Repeated mowings often encourage crown development, and in general make future control more difficult. Some species, like eastern red cedar, however, can be controlled by cutting them below the first branch, as they will not regrow after cut in this manner.

Grubbing is effective if you are able to remove the basal bud zone. This is an enlarged portion of the root just below the soil line on species like juniper, mesquite, and locust. It is the principle carbohydrate storage structure and the source of future sproutings. Basal bud removal remains the best way to effectively reduce re-sprouting of most brush species.

Grubbing can be accomplished manually for small infestations with the use of a hand grubbing hoe to remove single seedlings and small plants. For larger infestations, a mechanical root plow attached to a tractor is more appropriate.

If you are able, you can conduct a burn after you have grubbed up the stumps and basal bud crowns. Grubbing exposes sensitive plant tissue and builds up fuel necessary for an intensely hot burn. If the fire is not hot enough, it will not kill the plant but merely defoliate it and encourage it to re-sprout. Make sure you contact your local USDA-NRCS office or county Extension agent if you plan on conducting a burn. They will be able to advise you on the legality of this activity, and may be able to offer practical assistance.

Chemical Brush Control: Organic Alternatives

Synthetic herbicides for brush control are usually systemic herbicides that translocate throughout the plant and kill living tissue by disrupting life processes. Organic herbicides do not have the same mode of action, nor the efficacy, of synthetic herbicides. Organic and natural herbicides usually consist of plant oils, vinegar, soap solutions. The oils and acids in natural herbicides work to desiccate the leaves, and the soap acts as a sticking agent. Natural herbicides are only a "burn down" chemical, and will not kill the whole plant. Repeated treatments will be necessary to use up the energy reserves in the roots as they resprout. Organic and natural herbicides work best on annual plants, including grasses and forbs, especially while in the succulent vegetative stage. They are less effective on perennial plants and even less effective on woody species. For continued long-term control, I recommend using a multi-faceted approach to include grazing and mechanical removal.

Grazing is a cultural control method you can use. Pigs or goats will effectively suppress seedlings, and will repeatedly defoliate older shrubs, thereby using up all the plants energy reserves as they try to regrow. Several seasons of grazing has proven effective on many tree and shrub species, including locust, mesquite, wild rose, and Chinese tallow.

Grazing Pigs for Weed Control

Pigs are very destructive to sod, and this can be of use in pastures with high concentrations of weeds or brush. Pigs root up plants and turn over the soil, all the while manuring it while they graze. It is only necessary to provide shelter, water, and temporary fence such as electric netting to confine them to the area while they graze. The ATTRA publication Hooped Shelters for Hogs ( discusses the use of easy-to-build hooped structures for hogs. Pigs can be thought of as a pasture renovation tool… and after they leave the pasture, grasses and clovers can be overseeded and harrowed. In addition, the pigs can be marketed locally for added income.

General Stocking Rate Recommendation

According to University of Missouri animal scientists, stocking rates will depend upon soil fertility, quality of pasture, and time of year. Recommended pasture stocking rates are:

Sows with litters 6-8 per acre
Pigs from weaning to 100 pounds 15-30 per acre
Pigs from 100 pounds to market 10-20 per acre
Gestating sows 8-12 per acre

These recommendations assume the use of good quality legume pasture under conditions of adequate moisture. Stocking rates in your area (where soil moisture and precipitation may be more limited than Missouri) should be more conservative at the outset, unless you have a good source of irrigation or good sub-irrigated meadows. These stocking rates can be adjusted up and the pigs can be intensively grazed in areas where weeds need to be controlled. For more info see Joel Salatin’s Experience with Pastured Pigs below.

Source: Wheaton, Howell, and John Rea. No date. Forages for swine. University of Missouri Extension.

Joel Salatin’s Experience with Pastured Pigs (in Virginia)

Joel’s pastures are two acres in size, and he uses electric fence to subdivide them into eight, 1/4 acre paddocks. The two acres are stocked with 30 to 50 feeder pigs with a one-ton, self-feeder. The two acre pastures are rested for 12 weeks between each group of feeder pigs grazed. Joel uses crabgrass as the major forage, which has the ability to produce 4 to 6 tons per acre during the growing season in Virginia. Likewise, you would need to use a forage with similar yield potential and grazing resilience in your area to approach the stocking rates and productivity that Joel realizes in Virginia.

Sources: Crabgrass a favorite of pastured pigs, by Allan Nation, and Warm-Season Grass Production Responses to Site and Defoliation Frequency.

Concerns for grazing land degradation

Pigs have a natural rooting behavior that can quickly degrade the pasture if not managed. In some instances this behavior can be good, for instance in situations where a farmer wants to clear a parcel of land from noxious weeds or brush. For grass pastures, especially in semi-arid regions where regrowth is generally slower, increased management to prevent pasture destruction is warranted. A pig tractor is one method for controlling how much land is destroyed through pig behavior. I recommend the following articles which address integrating pig tractors into pasture in detail.

Raising Organic Hogs by the Tractor Method, by Alice Percy

Animal Tractor Systems, by Andy Lee

Resources for more information on pastured swine production

Anon. no date. What is pasture based swine management?
Pasture-Based Swine Management (PBSM) is an alternative approach for raising swine outdoors using pasture as a major source of nutrients, particularly for gestating sows. Compared with confinement or indoor systems for raising hogs, the PBSM approach can offer the producer lower initial costs, lower production costs, and a sustainable method for producing pork. Typical designs of pasture-based systems use low-cost portable housing and electric fencing. Because these systems require no expensive buildings and waste handling equipment, farmers can feasibly down-size or expand their operation depending on prevailing market conditions. In addition, the portability of pasture systems should allow farmers to utilize rented land. These systems should be especially appealing to limited-resource and/or beginning farmers.

Wheaton, Howell, and John Rea. No date. Forages for swine. University of Missouri Extension.
Use of good pasture containing alfalfa, ladino clover, and grass can lower sow feed costs, help maintain high level reproductive capacity of boars, and in many cases increase litter size as compared to confinement raising of hogs.

Karma Glos. 2004. Organic Pork Production. Kingbird Farm

Profitable Pork: Strategies for Hog Producers. Hog Production Systems, Raising Pigs on Pasture

The Basics of Raising Pigs, by Diane Schivera. Maine Organic Farmers and Gardeners Association.

Brush Control with Goats

Fire and low density wildlife grazing historically maintained grasslands. However, now brush has encroached and is very difficult and expensive to remove. Goats can be a good tool to help maintain grasslands if you have the necessary fencing and time to manage them.

For best results, match goat grazing to the brush stage of growth, presence of secondary chemicals, and nutrient density. For instance, in winter woody plants have high palatability and low toxicity from secondary chemicals. In addition, protein supplementation increases browsing by goats. For best results use high density grazing for short periods of time to target brush grazing and allow ample time for grass regrowth.

A good resource for using goats as brush control agents can be found in the Targeted Grazing Handbook available online at

Copper as an alternative?

Some practitioners have suggested the use of copper nails driven into trunks to kill trees. For this to be effective, the copper nail must be able to oxidize and absorb into plant tissue. This chemical reaction takes time and might not release enough copper to cause death. Copper sulfate in appropriate concentration is toxic to trees, and is used as a root killer to prevent root build-up in sewer pipes and drain fields. It is questionable, however, how effective copper nails are in causing tree mortality. A tree wound allows entry for pathogens including fungi, bacteria, viruses, and insects. I am not aware of a method to determine if indeed a tree died of copper toxicity, a disease, or some other condition.

Send feedback » Permalink


Permalink What information can you give me on multispecies grazing with horses?

J. S.

Answer: Horses can be grazed successfully with other livestock species. There are really no behavioral reasons why they should not, but the main consideration when grazing animals of different species on the same pasture is uniform utilization of the pasture. Having two or more livestock species grazing a pasture makes management a bit more difficult but with knowledge of grazing principles and animal behavior, multispecies grazing with horses can be very successful.

My rationale for this letter is to offer some models of successful multispecies horse grazing operations and introduce the concepts of forage requirements for livestock and forage yield on pasture, and try to bring them together to help estimate how many animals and how much land is needed to sustainably graze livestock. The examples I use should be adjusted for your own situation. I will also provide some online resources I have found helpful for managing pasture and developing a grazing system.

I understand you are particularly interested in models and working ranches that utilize horses in a multispecies grazing scenario. I have contacted Kathy Voth of Livestock for Landscapes who is doing some project work on multispecies grazing throughout the country. Kathy responded to me that she will place this question in her next newsletter so practitioners that graze horses with other species can contact me with relevant information.

I mentioned that I will also offer the concepts of forage management for successful multispecies grazing with horses. I think, and this is the reason I go into such detail on grazing, that this is fundamental to being successful in this kind of grazing operation.

Pasture Implications of Multispecies Grazing with Horses
Multispecies grazing can be accomplished by maintaining animal diversity on pasture in time or space. For example, horses can be grazed in the same pasture with goats or cattle, or can follow other species in a pasture rotation.

Managing grazing with different species of livestock requires knowledge of (1) daily forage demand of the livestock in question, (2) forage yield expected from the pasture, (3) and the differences in forage selection of the various livestock species involved.

Forage Demand
Forage demand is relatively easy to estimate. A good way to estimate daily demand is to calculate intake based on the animal's weight and a utilization value. Daily utilization rates are expressed as a percentage of body weight. The utilization rate may take into consideration actual forage intake, loss of forage through trampling or plant death, and wildlife use.

The formula used to calculate daily forage intake or demand is:
(# of animals) x (average animal weight) x (daily utilization rate) = daily forage requirement

The chart below can help determine the utilization factor to use for calculating forage intake on a daily basis. Some practitioners add an extra 0.5% to account for loss of forage through trampling or plant death, and wildlife use.

Animal group % body weight

(forage demand = % x animal body weight)
Beef cattle, lactating 2.0 – 2.5
Beef cattle, growing and finishing slaughter stock 2.25 – 3.35
Goats, weaned, slaughter or replacement stock 2.25
Goats, brood or lactating 4.0
Horses, mature 1.5 - 2.0
Horses, lactating 2.0 - 3.0
Horses, working 1.5-3.0
Horses, young 2.0 - .0
Sheep, weaned, slaughter or replacement stock 3.3
Sheep, brood or lactating stock 3.65

Note: horses that are lactating or growing have higher nutrient requirements than mature, idle horses.

The daily forage requirement for horses is (# of animals) x (average weight) x (daily utilization rate) = daily forage requirement:

→ Example: 1 horse x 817 lb average weight x 0.035 = 28.6 pounds per day

The daily forage requirement for goats is (# of animals) x (average weight) x (daily utilization rate) = daily forage requirement:

→ Example: 1 goat at 45 lb average weight x 0.055 = 2.5 pounds per day

Forage Yield
(1) Clip and Weigh Forage Yield Measurement. This method is rather time consuming but provides the most accurate assessment of forage productivity.

To determine forage yield, clip all the forage from a 1.92 square foot quadrat and weighs the sample in grams. The quadrat is constructed from PVC pipe and measures 11.5 inches by 22 inches. The quadrat is thrown randomly on the ground and all the forage inside the quadrat is harvested with shears or scissors. This sampling procedure is repeated at least ten times to get a representative sample of the area.

The weights of the samples in grams are summed and multiplied by the percent dry matter of the forage that was harvested. Fresh, succulent vegetative forage in most improved pastures has a moisture content of 75 to 85%. Below is a table that shows the % dry matter for various forages at different stages of maturity. Generally, the more mature a forage is, the less the moisture content. The dry matter forage weight is then multiplied by a conversion factor – in this case the conversion factor is 50 for a 1.92 sq ft quadrat. Multiplying the dry weights of the forage in grams by 50 results in lb/ac yield, which is the forage dry matter yield for the site sampled.

Percent Dry Matter for Various Forages

Plants Before heading Headed out Seed ripe Leaves dry Dormant
Cool season grasses 35 45 60 85 95
Warm season grasses
Tall grasses
Mid grasses

Short grasses













Calculating annual forage yield (lb/ac)

  Forage Samples, grams        
Forage 1 2 3 4 5 6 7 8 9 10 Sum Conv.

%DM lb/ac

Grama 2 1 0 0 2 2 1 0 3 2 13 50 55% 357
Bluestem 10 12 12 10 14 15 13 13 11 15 125 50 45% 2812

(2) Estimating forage yield per acre-inch. This method works well especially for dense, vegetative, productive pastures. The tables below can be used to estimate the amount of forage in your pastures. This method is easy to use, and involves measuring forage height with a ruler and multiplying the height in inches by the appropriate yield per acre-inch from one of the tables. For instance, if your forage height is 7 inches, and the percent cover (density of the stand as a percent of plants covering the soil surface) is between 75 and 90%, the pounds per acre yield would be around 1400 to 2100 pounds per acre. Also included below is a table that depicts average and ranges of yields per acre inch for various forage grasses.

<75% forage cover 75 to 90% forage cover > 90% forage cover

100-200 lb/ac/in

0 lb/ac/in

300-400 lb/ac/in

Forage species Dry matter pounds/acre/inch
Average Range
Alfalfa and grass mixes 225 75-400
Arrowleaf clover 200 100-300
Bermudagrass 260 150-500
Caucasian bluestem 180 75-350
Crimson clover 200 100-300
Kentucky bluegrass 160 100-175
Native warm season grasses 100 50-250
Orchardgrass 180 75-300
Orchardgrass + clover 200 100-300
Red clover 220 100-300
Annual ryegrass 250 75-400
Oats, wheat, rye 150 75-250
Tall fescue 210 100-350
Tall fescue + clover 190 80-325

Estimating Carrying Capacity
To more accurately divide grazing resources among different species of livestock, the concept of animal unit equivalence is used. An animal unit (AU) is roughly equated to the amount of forage consumed by a 1000 pound cow. All other species are relative to 1 AU. Typical animal unit equivalence values (AUEs) for different livestock species and classes are:

Cow and calf = 1 AU
Weaned calf = 0.75 AU
Bull = 1.5 to 2 AU
Sheep and goats = 0.20 AU
Horses = 1.5 AU

This concept will come in handy below when we estimate carrying capacity of a pasture.

Calculating Carrying Capacity with Animal Days per Acre (ADA)
Animal days per acre (ADA) is a subjective measure of how long a pasture or paddock will supply forage to a given number of animals. It is an estimate of how many days an acre will support one animal or, how many days a given number of acres will support a herd of a given size. The ADA method is useful if a producer has a good idea of how much land area an animal unit (AU) will need for grazing for one day. In fact, it can be a very good method once the producer, through observation and monitoring, becomes more accurate at estimating the amount of area needed for one animal unit (AU) for one day. The ADA method can be used to estimate carrying capacity for pastures during the growing season or for grazing winter stockpiled forage.

The ADA method is useful in planning grazing but, as was stated above, is only as good as the initial estimate of animal daily forage needs. The examples above on estimating daily forage demand and forage yield can be helpful here in determining the area needed for one animal unit (AU).
Producers need to also take into consideration (1) yield estimates for the forage and (2) forage stubble height after grazing when determining the area needed for one animal for one day. The ADA method is especially useful for estimating the number of days grazing for stockpiled forage or for strip-grazed systems where the animals graze along a front and do not return to previously grazed pasture until plants have recovered fully.

To calculate animal days per acre, an area is first paced off that represents the amount of land an animal needs for one day. For example, suppose a producer knows that an animal unit (AU) needs an area of 12.25 yards by 12.25 yards (150 square yards) of forage to provide enough dry matter intake for one day. 12.25 yards X 12.25 yards = 150 square yards.

Next, divide 4840 (number of square yards in an acre) by 150 square yards to get 32 stock days per acre (SDA). This means that one acre will support one animal unit for 32 days. SDA is multiplied by the total number of acres in the pasture to arrive at the number of stock days in the pasture (SD). To continue the example, 32 SDA X 200 acres = 6400 stock days for the pasture.

To get an estimate of the number of days a herd can graze the pasture, divide SD by the number of animal units in the herd. In the example, assuming 50 AUs, 6400 SD ÷ 50 AUs = 128. So, in this example a producer could graze 50 animal units (AUs) on 200 acres for 128 days.

In the preceding example, 50 animal units are assumed on 200 acres. These 50 animal units can be split up between horses, goats, cattle, etc. If you had 30 horses to graze, you would multiply 30 by 1.5 AU to arrive at the number of AUs representing the horses. 30 x 1.5 = 45 AU for the horses. 50 – 45 = 5 AUs left for other livestock species or classes. If grazing sheep, these 5 AUs represent 25 sheep (one sheep is 0.20 AU, so 5 ÷ 0.20 = 25).

Forage Selection
Grazing livestock consume varying amounts of the different forages that are available in a pasture, which makes pasture plant species diversity and grazing management very important in multispecies grazing. Horses are primarily grass eaters, but will consume some amount of forbs (broadleaf plants) and browse (brush or tree species). Their mouthparts and grazing behavior allow for very close cropping of forage plants, so particular attention should be given to ensure horses do not overgraze a pasture. Goats are more nimble in their mouthparts and primarily consume browse, but will also eat forbs and some grasses. Sheep consume forbs and grasses, and cattle prefer grasses and legumes (clover, alfalfa) but will also consume many other forbs and even some browse when the plants are succulent. If different species are grazed the same pasture at the same time, careful attention to utilization should be considered. Pay close attention to which plants each are eating and move them when the plants have been grazed to a pre-determined height. Having two or more livestock species in a pasture at the same time makes it a little more difficult to achieve uniform grazing unless animal density is high. There are also fencing considerations. Fencing is no problem if a sheep fence is used, but if using a barbed wire or single electric polywire, you might have a hard time keeping sheep and goats contained.

Grazing Management
A grazing system rations out forage according to animal requirements, allowing full plant recovery while minimizing forage waste. A sustainable grazing-management system has a number of elements:

• Proper timing of grazing to correspond to plant physiological stages
• Proper intensity of grazing (duration on the pasture)
• Residue or plant height after grazing
• Plant recovery time after grazing
• Adaptive management of grazing time depending on pasture recovery rates (For example, grazing time on a pasture may increase during less productive times of the year to allow for more plant-recovery time after grazing.)

An example of a good grazing system is one that employs a rotation in which animals are placed on a paddock (pasture subdivision) at a high density and moved to another paddock at the appropriate time. High animal density is necessary for uniform grazing. Most rotational grazing systems utilize 10 or more paddocks to best achieve the benefits of the system. This type of rotational grazing has been called planned grazing, cell grazing, controlled grazing, management-intensive grazing, high-density grazing, and intensive rotational grazing. Whatever the name, the main point of this system is that it allows for more effective forage use through increased forage quality and through decreased grazing selectivity due to highly dense numbers of animals.

Intensive rotational grazing is a management system designed to maintain forages in their growing stage throughout the grazing season. Forage grasses are grazed prior to the reproductive (seed) stage of development and allowed adequate rest for regrowth prior to being grazed again. This is done to maintain the competitive nature of grasses in a forage system by preventing them from getting too mature. Grazing grasses before they go to seed also encourages tillering. Tillering occurs when new grass shoots grow from the base of the plant, resulting in more leaf area and a more dense forage sward. So a strategy of grazing grasses before their reproductive stage and leaving adequate leaf area for regrowth is an important way to manage pastures for quality, quantity, and weed resistance.

A word on overgrazing…Many times we are tempted to assume that overgrazing occurs when too many animals are on the pasture. However, overgrazing is the result of how much time animals are on pasture, not the number of animals. In other words, overgrazing is caused by allowing animals, whether many or few, to remain on a pasture for too long.

Livestock select the most nutritious plants in a pasture while they are grazing. Once a grass plant is grazed, it begins to regrow from growing points close to the base of the plant. If animals are left on a pasture for more than a few days, livestock are likely to graze off the new growth, causing stress to the plant. As plants are grazed successively in this manner, the grass's root system will begin to decline, and the plant will eventually die. Grazing management is a matter of keeping an animal from grazing new regrowth until it has had a chance to grow several inches and renew the root system's energy stores.

A grazing system allows adequate time for forage leaf and root regrowth. If not, an overgrazed pasture is the result. There are a great many well-prepared resources available to assist producers in designing and implementing a controlled grazing system. ATTRA offers the following publications:

• Paddock Design, Fencing, and Water Systems for Controlled Grazing
• Rotational Grazing
• Nutrient Cycling in Pastures
• Assessing the Pasture Soil Resource
• Pastures: Sustainable Management
• Managed Grazing in Riparian Areas
• Pasture, Rangeland, and Grazing Management

Smith, Ray and Mike Panciera. 2007. Using a Grazing Stick for Pasture Management. Kentucky Cooperative Extension.

Horse Forage and Forage Management, The Samuel Roberts Noble Foundation

OSU Extension. Getting Started Grazing. Henry M. Bartholomew, editor. Ohio State University.

Pasture & Range Information, The Samuel Roberts Noble Foundation

USDA. 2008. Pasture Management Guide for Horse Owners. Missouri NRCS.

Rangeland Health and Planned Grazing Field Guide
An introduction to planned grazing on arid and semi-arid rangelands.

NRCS National Range and Pasture Handbook

How to Measure Forage Production For the Astute Producer, Texas NRCS

Send feedback » Permalink


Permalink How can I get a fertilizer product certified organic?


Answer: Thank you for contacting ATTRA for information about achieving recognition of your fertilizer products as allowed for use in organic production. I state it that way, because input materials are not actually “certified”, but rather may be recognized as being allowed for use in organic production. Often that recognition takes the form of being included on a list of allowed products that is recognized by the USDA accredited certifiers that have responsibility for verifying compliance of organic producers’ practices with National Organic Program (NOP) regulations.

Two commonly used lists are the Organic Materials Review Institute (OMRI) see and Washington State Department of Agriculture (WSDA).
Application forms are available on line, and both have frequently asked questions sections.

I understand that the Environmental Protection Agency (EPA) also has a process (see for evaluating and labeling EPA-registered pesticides, but I believe this program applies only to pesticide materials that have an EPA registration number, and not to fertilizer materials, which do not.

It is important for you to know that a material need not be listed on either the OMRI or WSDA lists to be recognized by a certifier as allowed for use in organic production. Producers wishing to use products as inputs must list them in their Organic System Plan (OSP) that is submitted to their certifier, and the certifier must approve it for the intended use. As the manufacturer, you can offer clear information to producers who wish to use your product, and to their certifiers. If they have adequate documentation about the material, they can make a determination about whether the material is allowable.

With that said, both the OMRI and WSDA lists are widely used by producers and accepted by many USDA accredited organic certifiers. Producers often learn about products from these lists, and can have confidence in listing a product on their OSP when it appears on one of these lists. As an organic inspector, I rely on these lists every time I do an inspection, and consider them invaluable to the certification process. You may consider whether this visibility and level of confidence is worthwhile to you.

Both organizations charge for their services, and both must do a careful review of the material before they list it as allowed. As I understand it, that process involves several steps. After receiving an application, they review it for completeness and potential for eligibility with organic standards. In most if not all cases, they arrange for an on-site inspection, then review the report and any sample results from that visit. All these things require time. They have to get it right, because many organic producers and certifiers rely on the veracity of this information. If a material is not listed on one of these two lists, then a certifier must do its own due diligence to verify allowability.

What you can do to make sure that this process of evaluation proceeds as quickly and efficiently as possible is to fill out the application and accompanying documentation carefully and completely. You will want to be familiar with the National Organic Program regulations on materials. See the Electronic Code of Federal Regulations (eCFR) (Standards) to open the electronic copy of the federal code of regulations.

If the reviewer comes back to you with any requests for further information, you can respond promptly with any clarification or additional information. If timing is critical, or you wish to have your materials listed by some certain date, you will want to ask about the timing of their review process, and inquire whether either organization offers expedited processing for an additional fee.

Send feedback » Permalink


Permalink What information can you give me on building and using a roller-crimper for cover crops?


Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service. I am pleased to provide you with information and plans for no-till roller-crimpers for cover crops.

The mechanical roller-crimper is a tool that “rolls down” and “crimps” the stalks of cover crops for no-till weed suppression. 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 which rely on the use of synthetic herbicides.

The roller-crimper is a water-filled heavy round drum with protruding blunt metal blades arranged in horizontal, angled, or spiral patterns. Roller-crimpers are most commonly rear-mounted and pulled behind a tractor or team of draft animals, but they can also be front-mounted on a tractor. When the roller-crimper is pulled or pushed 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 simultaneously prevents re-sprouting and slows down decomposition of the no-till mulch. No-till crops are seeded or transplanted in the same direction of the flattened and crimped cover crop, which slowly senesces and dies out over the course of several weeks, leaving high residue no-till mulch.

The drums are designed to be filled with water for added weight. The amount of water added varies depending on the size of the roller as well as the field conditions it will be used on. In other words, different field conditions will require different amounts of added weight.

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).

The Rodale Institute, Kutztown, PA, is spearheading research on roller-crimper equipment designs and on-farm trials using roll-down, no-till organic production systems. Research at the Rodale Institute finds that the best results are achieved by placing the 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. They have found that in an organic no-till system, they do actually have to till once every 5-6 years to reduce weed populations.

The Rodale Research Institute has published several noteworthy articles and updates on their roller-crimper research project, including photos which are all located on their web site: This site also contains AutoCAD drawings of their design. Below you will also find the contact information for Buckeye Tractor Company, located in Ohio. Buckeye Tractor Company manufactured the 3-point hitch for front-mounting the roller-crimper for the Rodale Institute.

Thus far I am aware of two equipment manufacturers in the United States that supply roller-crimpers: I & J Mfg. in Pennsylvania, and Bigham Brothers Mfg. Co. in Texas (3-5). These roller-crimpers can be custom-made according to any width a farmer might need, based on tractor or draft animal team size, and field layout. In addition, farmers are using various brands of stalk choppers, roller harrows, cultipackers, bed rollers, and land rollers, either factory-made or custom modified, to accomplish the same function of rolling down cover crops for no-till production.

Below is a list of resources on the mechanical roller-crimper equipment used in no-till production, including equipment designs and technical specifications.


1. Wheat Growth Stages and Associated Management (e.g., Feekes scale)
Ohio State University Extension

2. Growth and Development Guide for Spring Wheat (e.g., Zadoks scale)
University of Minnesota Extension

3. Buckeye Tractor Co.
P.O. Box 97, 11313 Slabtown Road
Columbus Grove, Ohio 45830
419-659-2082 Fax

4. I & J Manufacturing
5302 Amish Road
Gap, PA 17527
717-442-8305 Fax

5. Bigham Brothers, Inc.
P.O. Box 3338
Lubbock, Texas 79452
800-692-4449 Toll-Free
806-745-1082 Fax

Further Resources:

1. Bowman, Greg. Date Unknown. Plans for No-Till Roller. Kutztown, PA: The Rodale Institute. Retrieved April 30, 2010.

This site contains blueprints for building the roller-crimper that was designed at the Rodale Institute.

2. Michigan State University Roller /Crimper Research website

The Kellogg Biological Station (KBS) roller/crimper was crafted by station technicians with metal from a salvage yard. It is a 10-foot long, hollow cylinder designed with a small plug on the surface to allow the addition of water for higher or lower weight operations depending on field conditions. The R/C weighs 1500 pounds empty and roughly 2300 pounds when full. Like the Rodale model, the KBS R/C has fins extending down the length of its surface designed to crimp the covers as they are rolled. Site contains schematic illustrations.

3. The Knife Roller (Crimper): An Alternative Kill Method for Cover Crops
Soil Quality - Agronomy Technical Note No. 13

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.”

4. New Roller Crimper Concepts for Mechanical Termination of Cover Crops in Conservation Agriculture. 2009. By T.S. Kornecki, A.J. Price, R.L. Raper and F.J. Arriaga. Renewable Agriculture and Food Systems: 24(3); 165-173.

Modified Abstract: Rollers crimpers have been used in conservation agriculture to terminate cover crops; however, excessive vibration generated by the original straight-bar roller design has delayed adoption of this technology in the United States. To avoid excessive vibration, producers generally reduce operating speeds that increase the time needed to perform the field operation. The objectives of this research were to identify roller crimper designs that terminated rye cover crops consistently, resulted in soil moisture conservation after use, and minimized vibrations when operated in the field. New roller designs generate less vibration than the original design and can be used safely at higher operating speeds.

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Permalink What are some resources for energy self-audits for my farm?


Answer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service regarding energy self-audits for your farm.

Understanding the energy required and consumed by your farm is the first step to planning how to reduce energy consumption, invest in more energy efficient equipment, and select renewable energy equipment. There are a number of energy analysis tools which will help you audit your own farm and buildings.

The Farm Assessment Toolkit will help you assess your farm’s energy efficiency as well as identify areas for improvement and suggestions for energy-efficient equipment. Each assessment will take about 10 to 20 minutes to complete. The assessments collect general information about your operation to help determine if you may be able to save energy. At the end of each assessment, you will get a report with your responses and any appropriate energy tips. After completing an assessment, you can print out the report and use it to guide decisions you make to improve the energy efficiency of your operation.

You may also wish to use the Energy Tools available from NRCS These tools allow you to assess improvements that can be made to things like lighting, a greenhouse, and ventilation. They also explain the basics of things like solar water pumping.

The Alliant Energy Energy Efficiency Calculators page provides a list of energy efficiency calculators for residential, small business, commercial and industrial equipment that includes air conditioning and lighting.

More energy calculators are available on the ATTRA website at

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