Quackgrass has, for a long time, devastated farmers in North America. For one, it is tough to eliminate this species, more so in uncultivated fields.
Also, it calls for a lot of patience on the part of the farmer as control methods take time. Thirdly, prevailing weather conditions influence the success of the controls in place.
This guide will delve into how you can identify and deal with this species using integrated methods.
What is quackgrass?
Couch grass, or quackgrass, goes by the scientific name Elytrigia repens. However, in the past, people referred to it as Agropyron repens.
It is native to Europe and got introduced to North America by settlers towards the 17th century. To date, it is present in many agricultural lands in the region.
Most affected areas by quackgrass in the US
How to identify quackgrass
This species, which falls under the Graminaceae family, propagates by way of seeds and rhizomes. It is thus able to spread over a large area at a fast rate. These rhizomes, which have a yellow or white hue, measure between one and a half to four millimeters wide.
On their tips, they are hard and pointed. These parts serve as sources of food for the plant, and as long as they are in ideal conditions, the grass will thrive.
It is important to note that the buds on rhizomes can develop new stems if they are in the required conditions. However, in most cases, the buds remain dormant. Phew!
In most cases, people will advise that you dig up the plant and have a look at the rhizomes. While this may work, there is an easier way to do this.
You can observe the base of the leaf stems, and if tiny hooks are clinging to the stem, you could be dealing with this grass. You can dig the plant up and check if the stem originates from a rhizome.
The leaves are another feature that can help in the identification. At first, the leaves are hairy and coiled. As they continue developing, the hairiness reduces.
Leaves will measure about 4 to 8 inches in length, and a half to one inch in width. Towards the tip, they will have a flute-like appearance.
Quackgrass can be as high as 15 to 40 inches when fully grown. From this, it can have a spike of at least 2 inch.
However, where the conditions are ideal, it could be as long as 10 inches. Adult grass produces seeds that measure about half an inch.
Look-Alikes
There is often confusion regarding smooth brome and quackgrass, as these plants are similar in appearance.
However, you can distinguish the two by looking at the hue and the size of the plants. The brome should be short and dark with a distinctive ‘W’ on its leaf.
Growth characteristics of quackgrass
This grass mainly spreads by way of rhizomes. However, the means of propagation will depend on the prevailing soil conditions. Take an example of cropland where there is adequate light and a lot of nitrogen.
In this case, the grass would produce a lot of rhizomes and spread by this means. However, in grassland, the species would rely on seed production for propagation. Let us take a look at both methods.
Rhizomes
Did you know that quackgrass can produce rhizomes devoid of flowering? Yes, that’s true. The plant doesn’t need to be mature for rhizome production to commence. All that is necessary is an ideal temperature ranging from 2 degrees Celsius through to thirty.
Also, the grass does not have to produce rhizomes if there is enough nitrogen. It can rely on the development of stems above the ground. But where the grass competes for light with nearby vegetation, the production of rhizomes is necessary for survival.
As quackgrass grows, its rhizomes spread in different directions. Where the soil conditions are ideal, the rhizomes can spread to one and a half meters away from the parent plant.
And this can take place in one season. Imagine how far the rhizomes would cover if they had a few more seasons. As they spread, the number of buds also increases, often by thirty times their current population.
Soil cultivation plays a vital role in the behavior of rhizomes. Take an example of a section measuring a few centimeters in length left in the ground. No matter how small it is, it is likely to lead to the growth of a new plant.
However, that is not to say that all nodes lead to stem development. The fact is that only ten percent of buds are viable, while the rest remain dormant. But this dormancy depends on soil cultivation. Where the soil gets tilled, the buds get activated.
If you cut off one section of the rhizome, one node will develop into a stem while the others will remain dormant. But this will depend on the depth of the section and the prevailing conditions.
Where the section is far underneath the surface, its chances of reaching the surface are dim. But if it a long section, it could be strong enough to germinate to the top.
However, where the soil is uncultivated such as in a grassland, its chances of surviving will not be high. Sections in the ground to a depth of ten centimeters or less will have the upper hand.
Seeds
Propagation by seeds is not common, but it happens. A mature plant will produce an average of 25 seeds, which can remain viable for up to four years.
If the seeds are at a depth of 2 or less inches in the ground, they can germinate. However, if they are four inches or more in the ground, their chances of growth reduce significantly.
Interestingly, this does not hold for seeds in manure piles as they can still germinate, even at great depths. But if the seeds get exposed to high temperatures, they could die.
Given that seeds remain viable for four years, it is essential to monitor fields after using control methods. If they get close to the surface, they could germinate.
How does it grow?
Quackgrass follows a cycle. It starts with a rhizome in most cases, where one bud develops a stem. The stem will be visible when the conditions are ideal. In some places, this may take longer owing to unfavorable conditions.
As the stem grows, it produces leaves, and when they get to three, other stems start developing from the nodes near the surface. As this happens, nodes produce more rhizomes.
Where the stem resulted from a seed, the production of other stems will start when the leaves get to six or more.
Where does it grow?
This grass prefers neutral soils but can do well in slightly basic or acidic soils. In most cases, it will thrive in heavy soils, but that does not mean that it will not survive in light soils. It is hard to pinpoint its best-growing conditions, owing to its ability to adapt to varying conditions.
What are the benefits of quackgrass?
Studies show that quackgrass contains harmful compounds that affect other plants. However, this weed has a wide range of uses:
Prevention of erosion
People living in sloping areas often need a means to control the rate of erosion, and this grass comes in handy for this. It stabilizes the soil and makes growing of other plants possible.
The downside to this grass is that it is invasive and will spread at a faster rate than intended. Conservationists now argue that people should use less invasive plants, among them smooth brome.
Pasture
Animals can feed on this grass as it has high nutritional value, more so sheep. However, it is essential to note that the harvesting of this grass should take place before it starts heading. Failure to do this will decrease its digestibility.
The downside to this, other than invasion, is that most of the plant lies beneath the ground surface. Harvesting of the same is, therefore, not easy.
Natural Medicine
This grass is rich in minerals such as silica and potassium, and it plays a significant role in diuretics. Additionally, it can treat symptoms associated with gout, urinary problems, and rheumatism. Animals, too, benefit from ingesting this grass, more so as they facilitate digestion.
NB
Did you know that quackgrass was once used to make bread? Yes, this happened in southern Germany as a bid to fight food shortage during the First World War.
Threats: Why is quackgrass a noxious weed?
Quackgrass has creeping rhizomes that grow at a fast rate. If left uncontrolled, the rhizomes can spread at a rate of ten feet a year, making this weed highly invasive.
Perfect example of why quackgrass is so difficult to control. pic.twitter.com/bzT24aWhil
— Kevin W. Frank (@MSUTurf) May 4, 2013
And that is not all. As it spreads, it weeds out native species in the land. Suppose it establishes in agricultural land, it can reduce the yield from the field as well as contaminate the crops. The farmer would suffer devastating losses accruing from this.
As the grass takes hold, it becomes more competitive. Where it is in high numbers, it can wipe out up to 80% of the crop yield, where potatoes are in play.
For corn yields, a farmer can expect losses amounting to 35% of the total yield. Depending on the crop’s ability to resist the invasion, the effects vary.
Take potatoes as an example. Studies show that rhizomes are not only capable of penetrating the hard soils that are characteristic of this crop- but they also grow into the tubers. How much damage would that cause?
And the spread of this grass is quite easy as it takes place during harvesting and cultivation. A fragment on machinery is enough to wreak havoc on crop fields. That is why this grass ranks as a noxious weed in tons of states.
Management of quackgrass
In this aspect, we will cover two areas- prevention and control. The former applies to situations where the weed is yet to spread over a large area, while the latter is best for invaded fields.
Propagation of quackgrass takes place either by seeds or by rhizomes, and it is best to ensure that this does not take place. Here is what you can do:
For Rhizomes
Keep equipment clean
If you use implements in an area with quackgrass, ensure that you clean it before using it on a clean patch. Rhizomes have an easy time sticking to farm implements, and this eases their spread over an area.
Isolation
Suppose only one part of the field has quackgrass, you should deal with it separately. That means that you should till and cultivate it by itself while handling the un-infested area differently.
Till Actively
People often leave their fields to rest for some time before they commence planting. While this helps farmers to get healthy crops, it also encourages the growth of quackgrass.
Where you do not plan on using the land soon, ensure that you do not leave it as grassland for more than two to three years. It works better to have annual crops on the field to prevent invasion.
Monitor Manure
A lot goes into manure, and you may find that your batch has contamination, more so if it was near quackgrass infestations. You should plant rye around the pile, as this will prevent infestation. Where you are unsure about the quality of the manure, it is best not to use it as it could be a source of rhizomes.
For Seeds
While seed propagation is not the most common means of quackgrass growth, it could also lead to invasion. Here is what you can do:
Screen Seeds
Quackgrass seeds bear a striking resemblance to oat seeds, and for this reason, people often confuse them. The same goes for smooth brome seeds. Thus, before you plant seeds, ensure that you screen them to ensure they are not contaminated.
Harvesting Practices
With combine harvesters in place, work on the farm has become easier. However, this machine has the downside of spreading weeds across a wide area. It is thus best that farmers conduct post-harvest screening to ensure that they eliminate all traces of quackgrass.
Also, hay harvesting should take place as soon as it is ready. Allowing time and conducting late harvesting leads increases the viability of quackgrass seeds. Animals then consume these seeds and pass them out as manure, which gets used on crop fields.
What are your chances of success?
Some crop fields are more at risk of invasion than others. For example, where your land has heavy and poorly-drained soil, the chances of invasion are high. You would also have a hard time controlling the grass.
Also, where land cultivation is at a minimum, the grass will have an easier time establishing itself. It is unlike the case where the land is under heavy tillage as the disturbance would get in the way of growth.
Having many stones on the farm also affects the ease of eradicating this grass. It would be best to minimize the stones to have an easier time during the implementation of control measures.
How to control quackgrass?
Where quackgrass infestation is widespread, here is what you can do to eliminate this species:
Cultural Control
1. Introduce Competition
Quackgrass can adapt to a wide array of conditions, which most plants cannot do. You can weed out this grass by introducing vegetation that can fight its invasion as follows:
2. Provide Favorable Conditions
Most plants are unable to withstand wet zones as well as other conditions that prove unfavorable for their growth. This gap allows for quackgrass to take over.
An excellent way to deal with this would be to correct the prevailing conditions and introduce crops that can thrive in the same.
3. Use More Seeds
Research shows that if farmers use more seeds in an infested area, their crop yields will reduce by a much smaller margin. Let us suppose that one wishes to sow barley where quackgrass is in high numbers. The farmer can increase the seeding rate by four times to reduce the losses suffered.
4. Use Ground Cover
While these plants cannot eliminate the grass, they will slow its growth, and thus reduce its rate of invasion. An excellent example, in this case, would be the introduction of the dwarf red clover.
5. Use Edges
This weed starts invading a crop field from the edge, and if you can protect this area, you would have an easy time preventing an invasion. Good examples to use around the farm would be brome and orchard grass as they can compete with quackgrass.
Mechanical Control
There are two main ways of dealing with rhizomes. One is depletion while the other involves desiccation.
In the first method, you cut the rhizomes each time they grow. The more you do this, the fewer the food reserves the plant will have. This method works best in cool and wet weather conditions.
Fertilizing the soil before depletion aids in the success of this method. With high nutrients in the soil, the plant will produce more shoots, which will further use up the reserves. And as the cutting takes place continuously, the quackgrass will not stand a chance of survival.
In the second method, you bring the rhizomes above the ground surface, where they will be exposed to weather conditions. As such, they will dry out. This method is favorable as it does not involve a lot of repetition, as is the case with depletion.
For this to work, the weather should be hot and dry, and the soil should be well-draining. Note that if the rhizome gets access to water, from the ground or rainfall, it will not die and will continue to survive.
In some cases, you could use both methods where the weather is favorable for the same. Both ways call for perseverance and continuous monitoring of the situation.
Chemical Control
You can control quackgrass using herbicides in combination with other methods. For this to be successful, you should select the right herbicide for the job. In doing this, you should consider the soil moisture, the growth stage of the quackgrass, and the temperature and pH.
Any of these factors will affect the success or lack thereof of the application. Where you are in doubt, it helps to engage an extension agent on this.
Once you get a suitable herbicide, go through the label to figure out how to use it safely and dispose of the bottle. The application should take place as per the stipulated dosage and conditions.
You should calibrate the application equipment to ensure that you use what is enough. While you may think that using more than is necessary is not harmful, studies show that it is.
Overdosing plants leads to poor control of the grass, residues in soil, and injury to nearby vegetation. One last note- when applying the herbicide, be sure to dress as needed.
The application of the herbicide will also depend on the crops as follows:
Field Corn
The timing should fall between the end of spring and fall when the quackgrass is in active growth. If the application takes place during summer or the start of spring, the temperatures will lessen the effectiveness of the chemical. The chemicals have a better chance of working if preceded by tilling.
Soybean
As is the case with corn, it is best to start with tillage to suppress the grass before using chemicals. Controlling the grass using herbicides will not affect the rotation flexibility in soybean. But it does in corn.
Alfalfa
Where you wish to plant alfalfa, it is best to prepare the land a year before cultivation. Using tilling in combination with chemicals has been proven to work.
Small Grains
In this case, it is best to remove all the crop and treat the quackgrass with chemicals. Then you can start planting the grains.
Conclusion
Dealing with quackgrass calls for timing and patience as you integrate all the methods for the best results.
References
- Integrated pest management prescription – https://www.co.thurston.wa.us/health/ehipm/pdf/quackgrass.pdf
- Quackgrass (elytrigia repens) control methods in organic agriculture – https://www.maine.gov/dacf/php/gotpests/weeds/factsheets/Quackgrass-organic.pdf
- Elytrigia repens Management on Organic Farms – https://umaine.edu/weedecology/wp-content/uploads/sites/354/2018/02/quackgrass-management.pdf
- Quackgrass Management: An Integrated Approach – https://extension.psu.edu/quackgrass-management-an-integrated-approach
