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IWM Underway

The research project is officially underway! The past few weeks have been busy—measuring and flagging test plots, collecting forage samples, making modifications to equipment, coordinating research plans, and actually getting things started. Many local producers agree that the growing season is about three weeks behind normal. But recently, the plants have come to life. Most days have been on the cooler (albeit seasonable), damper side but warm enough for grasses, plants and, yes, weeds, to grow—a lot!

Our project tasks thus far have been focusing on four of the five Integrated Weed Management (IWM) techniques: mechanical (mowing), cultural (monitoring ground cover), chemical (herbicides), and biological (using goats for grazing). 

Preventive measures, the fifth component of IWM, hasn’t been necessary at this point since the chicory isn’t flowering and no seed is being produced. Our goal is to keep it that way! 

Let's get into what we’re working on so far...

 Mechanical IWM

​Mowing is obviously one of the more visible aspects of our research, especially in these early stages of the project. The mowing will be monitored to determine which, if any, mowing procedures adversely affect the vitality of the chicory plant. 

It’s too early to say what effect the mowing is going to have on the chicory plants. One of the basic elements of IWM is to use mechanical methods (mowing) to control weed growth. Thus, our immediate, short-range goal is to control the spread of chicory by removing the flower. We have measures planned for later in the growing season during which a cover crop of various plant species will be broadcast seeded into a weed-infested area that will have chemical applied to it prior to remove as much plant competition as possible. 

Several sources have agreed that mowing alone may actually stimulate the chicory plant, as it can spur shoots to grow from the existing root structure. This data causes us some consternation about whether mowing will have the desired result. Then again, common weed management rationale infers that if the plant can be prevented from reaching the mature seed stage (a process called “bolting”) by eliminating the flowering stem, fewer seeds should be produced, resulting in fewer new seedlings. 

The trick is to keep the plant from going to seed. To get a sense of the challenge we face, imagine controlling dandelions on your lawn. You mow your grass and, in a period of 24 hours, the dandelions have grown, bolted, and produced a new seed head almost overnight. Remember, chicory is a relative of the dandelion and they share some characteristics. In fact, in the early growth stages, a person has to look closely to distinguish between the two plants. 
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While chicory doesn’t flower nearly as quickly as a dandelion, the seed stem reappears in amazing time. We have seen this quick recovery in areas of our farm we’ve cut with a lawn mower, typically at heights of less than four inches. With repeated mowing, we have still seen the plant bolt, but the flowers develop closer to the ground, just below the height of the mower blade. Without lowering the mower, the blade can’t reach the stem to cut it off and the plant flowers and reseeds. Below are some photos showing just how persistent chicory is to reproduce. The first photo was taken on June 19th and shows the chicory just before being mowed. The second photo was taken after the mowing was completed a few hours later. The third photo was taken on June 27th.  The grass is still short (four inches) but the chicory has grown and bolted, and the stem is already 24” tall. Left in this condition, it would flower in a short time. 

​So, what’s the difference between what is happening on the lawn and the mowing we are doing in our fields? Not much! Will the varied mowing heights make a difference? That’s to be seen. The critical task is to monitor the chicory’s condition and make adjustments as necessary to meet the control goal. 

Cultural IWM

​At this point, only one IWM cultural procedure is in progress—monitoring the ground cover to assure adequate residue and plant material are present to shade and protect the ground. Rather than demonstrating practices that could be duplicated in a garden (techniques such as mulching or hand weeding, for instance), our project will demonstrate practices that the typical ag producer would be doing on acres and acres of land. Even though most producers are cognizant of the effects of harvesting hay, we chose to add this component to our research so we can readily show how removing the forage and plant material affects the soil and plant health.  

 Chemical IWM

The herbicide trials will undoubtedly be getting a lot of attention from people, both through our blog posts and our farm visits. When we mention to producers what we are doing for research on our farm, we typically get asked what herbicide works best to control chicory. We very much appreciate the help of Paul Johnson (SDSU Cooperative Extension Weed Science Coordinator) and his staff for helping us perform verifiable, university-driven tests using various chemicals. Each herbicide we’re using is readily available to producers.

After scouting out various locations on our farm, we decided on a portion of a hay field that has become infested with chicory. The field’s forage is a mixture of grass, clover, and alfalfa. If weather conditions would have allowed, we would have harvested a portion of the forage from the plots to determine how much the use of herbicides will affect the alfalfa. Because timing didn’t work with this round of applications, we have a high degree of certainty that the alfalfa and clover will take a hit. Even so, our sense is that the alfalfa may still recover; the result will all be part of the research. Later in the year, we plan to harvest a portion of a weed-infested hay field and then apply an herbicide within a day or so, giving the chicory time to recover but not waiting too long so the alfalfa has time to regrow. 
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The chemical trials were conducted on 34 plots measuring 10’ x 30’ each. Two plots are “control plots” and received no chemical treatment at all. On the other 32 plots, 15 different chemical combinations were applied, some of which were applied at varying rates to ascertain the lowest effective amount that can be applied to the plants and that will still get a satisfactory result.  

An added component of the trials is the application of organically-friendly solutions on a separate group of plots. We decided to add this component after speaking with people who were interested in seeing what happens when some of the more common substances, typically used by organic gardeners, are applied to chicory-infested areas. Dave Heck, the Lawrence County Invasive Species Coordinator, specifically requested that we try vinegar and gin. After consulting with Paul Johnson, we decided to add seven additional plots, two of which will be for household cleaning vinegar (6% acetic acid strength) and one for horticulture vinegar (20% acetic acid strength or higher). The high percentage vinegar is rather difficult to acquire locally, and we will apply that vinegar once we have been able to find a provider. 
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The other four plots are somewhat more unique in what will be applied. Rather than using gin as the alcohol substance—gin contains up to 50% alcohol and is rather costly to apply in volume—we have decided to use 100% corn ethanol on two of the plots. On the remaining two plots, we have decided to try E85 Ethanol (yep, the same stuff used in fuel-flex vehicles) since that contains 85% ethyl alcohol. I’m not sure I’d recommend either just yet… this falls into the “don’t try this at home” category. Please let us see what happens first before attempting this yourself. These plots are smaller, measuring 10’ x 20’ each. The environmental impact, if any, will be minimal. 

The team from SDSU has a tremendous amount of experience in conducting these tests. All of the chemicals and substances were applied at a rate of 20 gallons of water/herbicide PER ACRE. Since the plots are small (0.0069 acres for the herbicide plots and 0.0046 acres for the organic trials), the amount of chemicals being applied to each plot was very minute (mere fractions of an ounce or pint). 
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The actual application process was a learning experience for me. Dave Vos (SDSU Weed Science Ag Research Manager/Specialist) and Jill Alms (SDSU Weed Science Ag Research Manager/Specialist) made short work of getting it done. While Dave walked the plots, applying the various herbicides, Jill methodically measured and mixed each substance. Dave used a backpack that was pressured by compressed carbon dioxide. He said that he has done this so many times that he doesn’t even have to think about how fast he walks to get the application rate correct. 

It should be mentioned that a part of the herbicide trial involves monitoring weather conditions. Jill documented wind speed and direction, temperature, and relative humidity. This data is necessary to assure the applications are done correctly and that the chemicals stay where they are intended to be placed. Thanks, guys, for all your work!!
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Just to give everyone an idea of the condition of the chicory in the plots being sprayed, the majority of the plant leaf matter ranges from 8” to 12” tall. However, some bolting is beginning to occur, meaning taller stems are forming. Jill located one very prolific plant that gives us an idea of what chicory is capable of. Jill is 5’ 4” tall. The photo speaks for itself.

 Biological IWM

Finally, the biological aspect (grazing with goats) has been ongoing. We have been monitoring the condition of the chicory in the goats’ pastures. Our experience over the years is that the goats (and other livestock on our farm) don’t really desire the chicory plant when it is in the rosette stage. That is the low-growing, leafy period that most of us are familiar with in the spring when dandelions are growing in our lawns. 

A quick internet search reveals a common characteristic of chicory. People who have eaten chicory leaves in salads have commented that the leaves have a somewhat bitter taste. Some folks prefer the taste while others avoid it. Many online sites mention that chicory leaves become bitterer the older they are and the more they are exposed to sunlight and air. They’re right—I’ve eaten chicory, and I’m not a fan. 

Do people and animals have similar selective tastes? Actually, yes, and there is a scientific explanation. According to Kim Cassida, author of “Chicory: Improved varieties are a pasture option” in Progressive Forage (August 29, 2014), “Chicory forage reduces worm burdens in small ruminants and farmed deer, offering an alternative to chemical dewormers. The primary bioactive components responsible for this effect are sesquiterpene lactones, which are also responsible for the characteristic bitter flavor of chicory… While chicory is usually highly palatable, occasionally animals are reluctant to eat it, which may be related to the bitterness of the sesquiterpene lactones.”

So, now we know why the goats, in fact, may not “eat everything,” as it is claimed. Cassida pointed out that sheep will commonly avoid chicory with high sesquiterpene lactone levels but goats don’t show a preference one way or another. Perhaps our critters are a little pickier.

All that being said, I know from working on another project in which we used sheep to eat dalmatian toadflax that animals can be trained to eat something that they initially don’t like. In that research project, the sheep initially wouldn’t touch any of the toadflax plant, leaves or stems. After a short time, and with a little encouragement in the form of being left in a toadflax-infested plot and having consumed nearly everything else, the sheep ate the toadflax. In fact, they even developed a preference for it to the point that they would eat the toadflax and leave grass standing. That’s called a “trained flock.”  
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In the chicory project, we’re a little ahead of the game. Even though the goats aren’t munching on the chicory leaves (they like to browse on plants about shoulder height or 12” off the ground), we’ve seen countless examples in the pastures where the goats have nipped the chicory stems all the way down to the rosette. The leaves are untouched (too bitter?) but the stem (and ensuing flowers and seeds) are gone. Now we just have to get them to target the leaf and really reduce the chicory plant matter, the next phase of what lies ahead for the weed-eating crew.

This post was long, but a lot happened this month! Please stay tuned for future news and research results at the end of July. If you haven’t already signed up for our newsletter on our website or Facebook page, we invite you to do so by following this link. See you next month!