White Paper
On the Ergonica Weed Twister and Other Alternatives to Precise Hand Weeding in Agricultural Applications

Special crops require the use of special tools to protect them against weeds left behind by cultivation, chemical treatment, hand weeding, hand rogueing, hot capping or flaming, and other, less effective, applications and hand weeding tools.  The Ergonica Weed Twister was designed to more efficiently penetrate the soil with a minimum of soil disturbance and extract both new seedlings and deep roots of various shapes and sizes more precisely and efficiently than other hand tools and weeders, including various hoes, weed pullers, weed poppers and other weed twisters.  As California, along with other states, is embarking on a new era in agriculture when traditional methods of hand weeding are being reexamined and new alternatives for precision weeding and the short hoe are being explored, a greater emphasis on creative tool design is mandated.   A tool, such as the Weed Twister, which promises to provide powerful deep root extraction as well as efficient precise hoeing and tilling, is causing much excitement in the agricultural community. 

Much of this excitement is the result of a legacy of conflicts between the health of farm workers and the growers' demands for efficient and precise weeding.  After the short hoe was banned in 1978, farm workers were forced to remove weeds by hand for many hours a day.  Some would argue that this was more damaging to the health of farm workers than the use of the short hoe.   Recent litigation between the UFW, represented by CRLAF, and California growers has climaxed in Cal OSHA regulations that not only prohibit the use of the short hoe but also severely restrict the use of hand weeding. 

Machines are working, but people are broken!

Enforcement of safety regulations in California agriculture has recently (2008) led to 28 inspections on January 23 and 24 and the issuance of 26 violations totaling $12,750 in penalties, as reported by the California Department of Industrial Relations.  Employers were cited for not paying minimum wage, failing to provide sufficient meal and rest periods, inappropriate operation of driverless tractors and operating tractors with defective seat belts. Citations were also issued for failure to provide adequate tools for hand weeding, not providing adequate toilets on site and having drinking water too far away from work areas.  These citations were issued by the Economic and Employment Enforcement Coalition (EEEC) in Imperial and Riverside counties.  The EEEC, now established as the Labor Enforcement Task Force (LETF), is a multi-agency task force designed to root out California’s underground economy by enforcing California labor laws, and educating business owners and workers about those laws and regulations in workshops held regularly statewide.

The Coachella Valley Farmworkers Survey (www.iurd.org) interviewed 525 farm workers in 2006, reporting that 54 percent were legal immigrants, 37 percent unauthorized, and nine percent US citizens. About 71 percent do not speak English, and 72 percent live in the area year round, although 58 percent reported going to Mexico for medical care.

Sustainable agriculture should also mean sustaining the health, prosperity and human dignity of every hand that touches our food.  The tools employers choose or don't choose can either empower or enslave our human resources.  A number of other weeding machines images are presented by the European Weed Research Society including the rotary hoe, flexible chain harrow, spring tine harrow, Lilliston rotary weeder, horizontal-axis brush hoe, vertical-axis brush hoe, compressed air and brushes, finger weeder and torsion weeders.  None of these machines is based on human sacrifice.

Three new cultivation tools were recently compared (year 2007) with a traditional between-row cultivator, an herbicide control, and the conventional herbicide-plus-cultivator weed management program used in a first-year strawberry (Fragaria xananassa) planting. The new implements were (1) a Rabe Werk flex-tine harrow, (2) a Buddingh finger weeder, and (3) a Bärtschi brush hoe.   This study showed an improvement in productivity when using certain cultivators for situations in which labor is scarce.  Organic growers, and growers who plant in nontraditional annual systems, may benefit from their use as well.  An abstract of this study was published in HortTechnology 17: 9-141 (2007) under the title Cultivation Tools to Reduce Hand Hoeing in Matted-Row Strawberries, with authors Mary Jo Kelly, Marvin P. Pritts and Robin R. Bellinder, Department of Horticulture, Cornell University, Ithaca, NY 14853.   This study, unfortunately, did not endeavor to compare the efficiency of various hand hoeing tools for this application.  Such a comparison in scientific measures would be most useful to farmers of various vegetable crops as well as to the organic farming industry in general.

Can classical music help to control weeds and pests?  The green revolution may have outlived its initial impetus but the music revolution may be the next big thing in agricultural innovation.  For two brothers in Punjab playing music to their crops has produced a bumper harvest and with fertilizers and pesticides wrecking havoc on the soil this might be a viable and entertaining alternative.  These two brothers of Sangrur district in Punjab, for the last 2 years have not used any pesticide for their crop grown on a 6-acre land.  Instead, they decided to treat their crop to a dose of music. They claim the yield has gone up by 5 per cent but more importantly the quality has been phenomenally well.  This remarkable innovation was reported by NDTV.COM in January, 2008.  Unfortunately, the article doesn't tell us whether Mozart, Chopin or Bach was more effective?

Beyond the legal, moral and health issues, the ongoing needs for better efficiency and sustainable agriculture energize the movement for technical advances.  Because of its power and precision, as well as an ergonomic, light-weight design, the unique Ergonica Weed Twister is being regarded by many experts as an essential tool for every farm and garden where exceptional care is a must.  Although hand weeding has long been considered the most precise manner of protecting crops, Ergonica presents a challenge to a higher level of surgical precision by using a tool that more effectively removes weeds that are often left behind by hand weeding methods.  Whether weeding strawberries or other cash crops, removing volunteer potatoes or stubborn mallow weeds, or harvesting truffles worth over $100 per pound or $300 per ounce at some consumer markets, surgical precision in an efficient and ergonomic framework is an ideal standard that the farming industry should ultimately expect. 

Weeding and propagating are essentially the two principal arts of agriculture:

Unless you grow crops in the desert or in artificial platforms, before you plant or germinate your crop, you must clear the existing vegetation, whether it is native or introduced. Thus, agriculture may be seen as the art of nurturing and separating preferred plants in a selected area from the undesired plants that thereby become identified as 'weeds'. The designated weeds may be relatively useless plants or sometimes, unfortunately, native flora and forests of value to other parties and species as well as to the regional ecology. Effective separation and selective nurturing become critical due to the economies of space, time and resources.

According to a study by P. W. Owston and L. P. Abrahamson hand weeding has been the mainstay of forest -nursery weed-control programs.  Amounts reported vary from 1 to 80 person-hours per acre over an entire season, the variation resulting from differences in weed populations, management philosophies, and other practices.

The need for precise weeding in agriculture is as old as the history of agriculture itself.  What is new in California, is the greater interest in this society for the protection of the health and safety of farm workers.  The trend of increasing organic farming also demands alternatives to harmful chemicals often resulting in hand-weeding and the use of precise hand tools.

The Weed Twister and other hand tools of its class that we will examine and compare in this paper, are all fairly simple in design, have few, if any, moving parts, and, for the most part, are not motorized, except for the new drill-ready Turbo Weed Twister.  With all the technology available in California, often housed in the same valleys which nurture our bountiful crops, we are not yet at the point where we are discussing more sophisticated tools.  A classification and comparison of other hand tools used primarily in home gardens is presented on the Weeder Features page.

Perhaps the new regulations may spur the imagination of California's technology leaders to invent the laser weeder, for example.  Imagine a light weight laser wand that can exterminate any weed of any size and shape with a lightning-quick zap?  Could the next evolution be the robo weeder?  Visualize the robotic rover automatically weaving through the fields and deftly taking out each enemy by intelligently making the identity and status of every growing thing in its path.  Recent advances in online graphic object recognition, such as the work being done by Microsoft, may eventually lead to uploading images of plants by cell phone and receiving a species identification search response. 

Robotic Cultivator System

Sometime within the next few years, though, there may be a new mechanized weeding system available to growers, which will save them hundreds of dollars per acre. Over the past three years, David Slaughter, a researcher at the University of California-Davis, has been working on perfecting a precision weed control robotic cultivator system that can tell the difference between weed seedlings and tomato seedlings in the field.  On the back of the mechanism, there would be several mounted miniature hooded sprayers that would go in between the rows and spot spray the weeds, leaving the tomato plants and everything else in the field untouched.  Machine vision based detection of volunteer potatoes in cropped fields is also being studied by the Wageningen University, a Dutch university in Europe, which claims to be the leading European university in the Life Sciences.  The Hortibot is another design in development in by Rasmus Jørgensen in Denmark that may use mechanical means to remove weeds as well as chemical sprays. 

No Chemicals Needed!

More recently (2015) the same UC Davis team has devloped a faster way to identify weeds in beds mixed with crop seedlings that can be singled out and removed deftly with knives. No chemicals needed! Slaughter?s team is designing a robotic cultivator that can remove weeds in commercial fields as carefully as gardeners pull weeds in their own backyard, without the time-consuming labor and cost. They?re developing a ?smart? cultivator with small knives that reach out to uproot weeds and retract to keep crops intact. This will be especially useful in wide beds of densely seeded crops like spinach and baby lettuce, which can turn green almost overnight with weeds and leafy crops.

The key technology to facilitate this is to make the crop seedlings glow with a faint, fluorescent color. Glowing plants are protected by the robotic identification system. The fluorescent glow is accomplished by a simple seed coating. Seeds are commonly coated with various materials (like fertilizers, fungicides or herbicides) for different reasons. No biotechnology or any genetic engineering is involved. The USDA is investing $2.7 million in the new cultivator design, which will take shape over the next five years. More information.

Robocrop InRow - The Revolutionary Robotic Weeder! Using similar image analysis techniques to those used on the Robocrop 2 high speed hoes, Robocrop InRow analyses images of the crop immediately in front of the weeder. Applying a predetermined grid and best fit logical deduction techniques individual plants are pinpointed and tracked through the image. The weeding rotors are then synchronised to work around each individual plant, the rotor speed being continually adjusted to take into account plant spacing variations. The InRow rotors are then followed up by a set of inter-row cultivation units to complete the all round cultivation process. Performance is 2 plants per second per row.

BoniRob robotic platform Another promising non-chemical robotic development is a tractor that punches seedling weeds with a series of rods. Developed by Deepfield Robotics, this device uses a series of sensors that distinguish weeds from crops and enable efficient mechanical destruction of weeds with the "punching" action. Known as the BoniRob robotic platform, this invention features four independently steerable drive wheels with an adjustable trackwidth making the machine highly maneuverable within the field. Through a series of highly advanced programs, the robot can differentiate what is a weed seedling and what is the desirable crop. More information about agricultural automation can be seen here.

We acknowledge that new technology is often a double edged sword.  New jobs are created and old jobs are eliminated.  More efficiency usually means lower cost and less people on the payroll.  Politics and legal conflict have brought us to the historical point where we are today examining new and old methods of precisely removing weeds.  The grower will benefit by better tools and methods of precise weed removal regardless of the political context of the day.  More efficient and ergonomic tools will be of value to both growers and laborers whether or not traditional methods are restricted by society.

ERGONICA WEED TWISTER

Although we're not talking about the robo weeder or the laser weeder here, the patented double helix design of the Ergonica Weed Twister is an advanced state of the art of probing and pulling out weeds by the roots in a precise and efficient manner.   Its pointed double coils are designed to efficiently penetrate the soil and can be used to screw deeply into the root structure of the weed.  The coils can also be applied as a circle-shaped hoe, gliding along a shallow path beneath the surface of the soil to unearth new weeds and seedlings with very short root structures.  Both the deep root extracting and the shallow depth hoeing applications of the Weed Twister are of special importance to precise weeding in the agricultural setting.  We will examine these and other features more analytically in comparison to competing designs below.

Organic Growers may Use this tool as an alternative to hand weeding when crops are closely spaced and extra precision and care is required. Works great for both new seedlings and deep-rooted weeds in various situations including around the edges of plastic mulch. View this new lineup of Weed Twister models as an alternative to short-handled tools and knives that often injure workers and increase labor costs.

Several Weed Twister features have ergonomic value.  The name of the manufacturer, Ergonica, was derived from "Ergonomic America."  The standard model is 36 inches in length and weighs about one pound.  This design has been in production and distribution through internet marketing in the United States for several years.  Although it has never been distributed through normal retail channels, the Weed Twister has thousands of happy customers who often come back and buy extra Weed Twisters as gifts for their friends.  A few nursery stores in southern California also carry the original 36-inch Weed Twister model.

In the agricultural setting, a longer handle prototype has been designed for testing and development and is now available for online purchase.  We have recently tested a 42-inch and 48-inch Weed Twister model in several farms in Oxnard and Davis, California, where we successfully removed such weeds as little mallow, goosefoot, yellow nutsedge, purslane, nightshades and lambsquarters.  These were preliminary tests aided by the UC Cooperative Extension and limited in scope with the intent of evaluating the general applicability of this tool in agriculture and to compare the ergonomics of the various Weed Twister models.  These initial agricultural tests have also led to refinements in the design of the tool including the sharpening of the thicker coiled tines, the optional 8-inch T-handle expansion kit, and the addition of the bar grip in the 54-inch model for increased torque strength and speed when twisting into deep roots in clay soil.  

While fully automated robotic weeding machines are still in the development and testing phases, it appears that a semi-automated solution, such as a drill-powered device may provide relief to weed pressure without excessive labor costs.  Perhaps a robotic device may be hooked up with a Turbo Weed Twister instead of a jet of chemicals?  What it takes is possibly looking outside the box of chemicals, as productive as they have been in the recent decades, and looking for quicker and more efficient plant removing mechanical tools controlled by robotic weed detection and guidance systems.

CLASSIFICATION STANDARDS

To meaningfully compare competitive tools and technologies we need to determine the definitions of the applicable classes.  We offer the definitions of the classes we have used as examples to use for reference only.  If needed, we expect the industries involved as well as the appropriate regulating bodies will more formally establish appropriate standards.

Ergonomic - Long Handle

The Ergonomic handle has a length of at least 30 inches.  This is also known as the Long Handle and the Back-Saving Handle.  The standard model of the Weed Twister, with a length of 36 inches, fits into this standard.   A number of other weeders listed on this website also comply with this standard.  A sub-class of this with a length of at least 45 inches is the Extra Long Handle or Industrial Length Handle.  The 48-inch and 54-inch Industrial Weed Twister models fit into this class.  The Full Length Handle has a length of at least 60 inches. 

It should be noted that current Cal OSHSB regulations define long-handled tools as those with handles at least 48 inches in length.  The latest regulations restrict the use of either long-handled or short-handled weeding tools from a stooped, kneeling or squatting position.  The 48-inch Weed Twister model and the 54-inch Dual Grip Weed Twister model would both be acceptable for agricultural use in California.  Hand weeding may be acceptable under the new regulations in situations where it is proven to be the only practical way to effectively remove weeds without damaging crops.

Light Weight

We define a Light Weight hand weeder as a tool with a weight of 2 pounds or less.  A sub-class of this standard would be the Very Light Weight standard with a weight of one pound or less.  The standard Weed Twister, with a weight of one pound, falls into the Very Light Weight classification.  The 48-inch Weed Twister weighs less than two pounds and the 54-inch model with the added bar grip weights 3 pounds.  These standards are appropriate only for the Long Handle tools as defined above.

Precision Weed Removal Tool

The measure of precision is inversely related to the dimensions of the action point of the weed removal tool.  In other words, a 3-inch hoe blade is more precise than a 5-inch hoe blade.  We have used a maximum of 3 inches in width to determine the classification of a tool as Precise.  Most of the hand weeders that are claimed by their manufacturers to be "precise" on the market today fit within the 3-inch standard.  We have extended this class to smaller dimensions by defining the Very Precise class as a tool with an action point width of 2 inches or less.  The Extremely Precise tool has a dimension of one inch or less.  The Weed Twister standard model has a width of 2 inches in diameter and is thereby classified as Very Precise.

Because of the forceful manner by which a hoe is normally applied to the target area, that is with a hammering or hacking motion, the effective precision of this tool may be compromised.  The hacking motion exposes to possible damage anything in the path of the tool and handle as it is applied. With the swift motion, it also requires great accuracy to hit the target precisely and effectively. Every hack increases the possibility of damage to nearby plants.   This increases the effective precision area for a 3-inch hoe blade to possibly 6 inches or more.  Even the short hoe requires a relatively violent motion compared with the Weed Twister and other precision tools on the market today.  Thus, a 3-inch hoe may effectively be not precise since its normal use required by its design exposes to damage an area greater than 3 inches.

STANDARD CLASSIFICATIONS AND ECONOMIC / ERGONOMIC TRADE-OFFS

The standard Weed Twister is a Long Handle, Very Light Weight, Very Precise hand weeder.  When comparing it to other tools, the comparisons should be made against other tools in the same class.  The agricultural models with 48 and 54 inch handles are in a different class.  These models are Extra Long Handle, Light Weight, Very Precise hand weeders. The newest 60-inch model is designed especially for wheelchair gardeners.  If we expand the diameter of the coils of the Weed Twister, we may change it from the Very Precise class to the Precise class.

The trade-offs are fairly straightforward.  The longer handle appears to have more ergonomic value since it requires less bending of the back or stooping.  The 48-inch length also makes it legally acceptable for Cal OSHA standards for long-handled tools.  The 54-inch Dual Grip model weighs a pound more than the 48-inch model.  In other words, the trade-off is more weight for less back stress and compliance with Cal OSHA regulations. 

We propose more tests in agricultural settings with perhaps several lengths to determine the optimum trade-off.   There are actually two advantages to shorter Weed Twister lengths: 1) less weight, and 2) more efficient motion depending on the distance between the worker's hands and the target weeds.  We may also find that the optimum length may depend somewhat on the height of the worker.  In this case, we may offer the grower the option to purchase a number of tools at different lengths, and allow each worker to pick the tool he or she finds to be most comfortable and efficient for himself or herself.

There may also be trade-offs in efficiency when modifying a tool to be more precise.  For example, a 3-inch hoe blade may be less efficient than a 5-inch hoe blade because it takes more work to cover a larger area.  However, it may be less effective when 3-inch precision is necessary to protect the crops. The need for precision is the justification for using relatively inefficient tools.  Depending on how much precision is needed, relatively less efficient tools may be appropriately selected.  We would not be looking at hand tools at all, if the required precision and care for all of our crops could be accomplished with tractor-driven solutions or chemicals.  

The grower needs to evaluate not only if precise methods and hand tools are needed, but also what degree of precision is needed and what cost is affordable to accomplish such precision?

More ... See Page 2 of 2 >  (Weeding Tools Specifications and Comparisons)

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