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Year II Kick-Off

Welcome to year two of our SARE-funded research project to evaluate the effectiveness of Integrated Weed Management practices to control the invasive spread of chicory. The fact that this post didn’t come out earlier this spring doesn’t mean nothing has been happening. On the contrary, a lot has been going on. The emphasis this year has changed a bit from last year. In 2019, many initial steps of the research project were taking place. This year, we are monitoring and continuing to study and evaluate the results of efforts taken last year. Now that the growing season is in full swing, the next steps in the project can begin in earnest.

Before we provide a quick recap of 2019, here is a brief review of the five principles of Integrated Weed Management (IWM). IWM is a process that applies the following techniques: mechanical (mowing, cultivation, tillage, hand-pulling), chemical (herbicides), cultural (cover crops, crop rotation), biological (grazing animals, beneficial insects), and preventative (curtailing the spread of undesirable seeds), combined to control and/or eradicate problematic weeds over the course of a growing season. The key to IWM is not relying too heavily on one method. Sequentially applying as many of the IWM principles as possible often assures greater success.
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Often downplayed but vitally important in a successful weed management program, and critical before implementing IWM actions, is the necessity of looking for and selecting specific weed species to target. Once that is done, it’s also a good idea to research the physiology of the targeted plant to learn what makes it tick. This makes it possible to adjust the timing of control methods and resources to match when the plant is most vulnerable, which increases the chances for success. Applying control or eradication actions at the wrong time can lead to less than desirable results. 

2019 Recap

We had some successes and failures during the 2019 research period. Some results, as is true with any research, will take more time to evaluate. For a detailed summary of 2019’s results, refer to the “End of Year 1 Review” report from November of last year. That post also outlines possible directions we were, at the time, planning for 2020. While some slight modifications will be made to those ideas, the objectives outlined at the end of 2019 are still valid.  

Among the goals of the chemical (herbicide) trials was the goal to identify which chemical(s), if any, effectively controlled chicory but were safe to use on alfalfa and legumes in our farm’s pastures and hay fields. At end of 2019, we had no conclusive results to indicate potential chemical options. However, a couple of chemical plots showed some early, promising signs. As reported below, our 2020 observations are making it clear that the one sure-fire method to control and eradicate chicory is through the use of herbicides. However, we still want to ensure that legumes, and the overall quality of forage, won’t suffer, so our 2020 efforts are going to be critical.

One hurdle that needs to be crossed with any weed-control program, whether it be conventional or organic, is whether the practice is possible of a long-period of time—is it sustainable?    Unfortunately, not many organic methods developed in 2019 seemed promising. This is especially true of organic methods related to our semi-arid pasture lands and hay fields. The topic of sustainability was covered in the September 2019 post “The Question of Sustainability.”  In short, a “sustainable” agriculture operation must be economically viable over the long-term, the operator must practice ecologically responsible stewardship of their resources, and the operation must provide a desirable quality of life for its operator and supporting community. One aspect without the others may result in short-term survivability. But without all three sustainable characteristics, a long-lasting operation will undoubtedly fail. 
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If the farm/ranch operator is a “hobbyist,” losing money isn’t so damaging and labor-intensive practices may be tolerable for a short time. But when a farm/ranch owner must consider the needs of the operation year after year, the vision is dramatically different. 

From the organic approach, large scale use of organic chemical methods (vinegar or alcohol) were simply not practical. Those options may work in a small garden but not on a 20-40-160-acre field. Repeated mowing of the chicory (and the associated desirable plant community) may keep the weed from flowering and producing seed, but yield and forage quality will ultimately suffer. Many successful organic producers are able to use mechanical, tillage methods—often repeated several times throughout the growing season—to keep the weeds at bay in their crops. But tillage simply isn’t an option in pastures or in areas where it isn’t realistic to replant hay fields every year. 

In our conversations last year with one particular organic producer from outside of our area, he emphasized the need of the organic farmer to get weeds under control before moving to organic production. He explained that it may be necessary to start out with chemicals and, once the weeds are manageable, convert to organic practices. This particular producer uses conventional tillage (plowing and other methods), but, again, this is not possible on pastures. He also emphasized that if a producer finds themselves in a situation where the weeds are taking over, it may be necessary to step away from being organic on a particular field, use conventional methods (chemicals) to regain control of the weeds, and then reapply for organic status. 
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As a result of last year’s observations, our project in 2020, while continuing to conduct trials using IWM that certainly apply to organic operations (mechanical, biological, cultural, and preventive), will not be focusing any further on finding a strictly organic solution to control chicory in our pastures and hay fields. 

Early 2020 Observations

In the first week of February, while there was still snow on the ground, we noted that the chicory had already began sprouting from existing plants. We noted a similar situation last year. This proves that even if the old plants appear to be “dead” above ground, problems lurk below the surface. This is why, for effective weed control, it’s advisable to use a chemical with a residual, pre-emergent element to kill young weeds as they sprout. This can be devastating, however, to other plants (such as legumes) that can also be killed by the pre-emergent chemical. Another technique often used to control weeds at their early growth stage while minimizing damage to desirable plants is to spray early-sprouting weeds with a herbicide (preferably, glyphosate because it does NOT have a residual component). This process kills the early weeds before the other plants that are also susceptible to the chemical grow enough to be affected. But this is risky and, generally, with snow on the ground, even the chicory isn’t actively growing to the extent that any herbicide will be completely effective.

At the end of March, we checked the plots in which, in 2019, we had tested mowing chicory at variable rates (4”, 6”, 8”, and 10” heights) to determine if there was any difference in the degree of control due to more or less residual matter being left on the ground. Observations indicated the mowing height made no difference and, as was observed in February, the young plants were actively growing in all plots. The only difference to mowing at higher heights (8”and 10”) is some forage was available for livestock.

​We checked these mowed test plots again in mid-May with more obvious results showing that the chicory was even more actively recovering from the mowing.

Therefore, in these plots, mowing alone may have reduced the seed population of the chicory, but it certainly did nothing to eradicate the plant. As a reminder, during research to put our project’s proposal together, we learned that chicory is theoretically an annual/biannual plant, meaning that a plant should live for two years. However, research also found that chicory may live for five to seven years if the conditions are good. Our experience has been that mowing repeatedly over several years has had no apparent reduction in the chicory population and, in fact, stimulates its growth. The research from the test plots so far only bolsters our previous observations, thus leading us to conclude that mowing alone is not an effective control (and certainly not an eradication measure), regardless of the height the plants are being cut. For more details on what we learned early on about mowing chicory in our 2019 research, check out the “Mechanical IWM” section of our June 2019 post “IWM Underway.” The studies we found dealt with cultivated chicory, and at the time, we wondered if wild chicory would react the same as its tame cousin. Our observations lead us to believe the wild plant does respond the same.

In May, we also studied the herbicide test plots to ascertain whether any early conclusions, differing from 2019 observations, could be made. In 2019, most of the herbicides were effective in removing the chicory, but many or most also appeared to have eradicated the alfalfa and clover. The one exception, as noted in our September 2019 post “Recording Results,” was the chemical Plateau, which we learned is designed to be ineffective in controlling chicory. As for any clearer indications of chemical results, it was still too early in May to make conclusions.
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In June, we surmised even more that mechanical measures to control chicory (i.e. mowing) are, at best, stopgap control measures to keep the plants from seeding out. These efforts are totally ineffective in achieving total, long-term control and certainly will not lead to eradication of the chicory plants.

​With regard to our biological practices, grazing by our goats shows evidence that animals are nipping tops of stems as the plants bolt (form the flowering stem). As in 2019, however, we see no indication that they are reducing the plant’s nutrition sources. We had previously learned that the leaves taste bitter so we are not surprised. The grazing behavior we are seeing is indicative of goats’ preference to eat plants at shoulder height and not ground level. As with the mowing, their grazing will control flowering but we are not seeing any sign that the population of the chicory is being reduced.

​As we’ve re-examined the herbicide plots in June, we see that, in many of the test plots, the alfalfa is recovering and the chicory appears to have been eliminated. This could potentially be a result that the alfalfa in these plots is “old” alfalfa, several years old with deep roots. Because of the root structure, the plants may have “staying power.” This fact could be used to our advantage. However, we would caution applying our results from this project to fields containing young alfalfa and clover plants, as the roots will likely not be as deep. Because the herbicide trials are being officially conducted by the South Dakota State University (SDSU) Weed Science Department, we are not releasing any conclusions until their research is finalized. We will, however, continue to provide updates as to whether any chemicals reveal any candidates that may meet our goal of eradicating the chicory plants but retaining the legumes in our hay fields. 

2020 Plans Preview

Now that we know the strengths and weaknesses of each IWM method, when used individually, our actions this year will reflect a more non-research, day-to-day practical application of IWM to develop options for producers. 

First, we will be applying herbicide to the variable-height mowing areas to prevent chicory from spreading further in the pasture containing the test plots. Because repeated mowing alone has little negative impact on the chicory, we currently have cattle grazing that pasture. They have not consumed the chicory, but we are noticing some impact on the plants. Depending on the condition of the plants once the cattle are moved, we anticipate mechanically mowing the area to further damage the chicory. We will then apply herbicide while the chicory is actively recovering to determine its eradication rate. 

Second, we may repeat some chemical trials on new plots within the pasture being grazed by our goats. These pastures contain clover and alfalfa, so we plan to test those chemicals that show potential of eliminating the chicory but not completely removing the legumes. We would like to test whether or not grazing will weaken the chicory plants enough so that we may be able to use a lower rate of chemical. 

Third, we would like to improve a certain hay field that has historically been a poor producer due to a high water table stunting the grass varieties present. We have been applying chemical to the field because of chicory infestations, thereby removing all legumes, and we are going to attempt to change the plant population and diversity of the field (an IWM cultural approach). The field is not a good candidate for conventional tillage due to the water table. We also do not have a no-till drill and, while we could rent one, we are trying to find other ways to plant grass seed using livestock. We will be studying the effect of using cattle to graze the area concurrently with introducing grasses that are more moisture-loving to determine whether the hoof action of the cattle duplicates the action of a no-till drill. This process will be weather-dependent. We may try it yet in July if the moisture conditions are favorable. If conditions are not satisfactory, we will perform this experiment in the fall when we typically get autumn moisture.   

Finally, we have been conducting other routine IWM practices on our farm as part of our normal operation. Through these efforts, we have noted a “new” plant that appears to be taking hold in one particular hay field. Through reading and research, we have identified the plant as Deptford Pink (scientific name Dianthus Armeria). This plant is relatively unknown in South Dakota. Many other areas of the country have noted its presence but little is published about the plant or its possible impact on fields and pastures. It is not a noxious weed at this time, although some have noted that it can be invasive. Because we are already cooperatively working with the SDSU Weed Science Department on the chicory plots, we will be conferring with them on treatment options. 

​That is all for now! 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!