Controlling Rushes
In this article, That’s Farming looks at controlling rushes through chemical and non-chemical practices, applications, and cross-compliance regulations to ensure water quality while spraying.
Rushes grow exclusively in wetland habitats. They are upright, perennial herbs and are always round in cross-section. Soft rush (Juncus effuses) is a perennial plant which you will often find in the wettest areas of fields or alongside watercourses.
Rushes infest grassland habitats across the country and can take over grass and clover swards. The presence of rushes deteriorates the productivity of the land, influencing the profit margins.
A single rush seed head has the potential to produce 8,500 seeds each year, which can be dispersed in the wind.
Hereafter, there are a number of ways to control rushes within your fields, which you can do both with and without chemicals.
Preventing rushes
Rushes prefer acidic and wetland soils. However, there are some steps you can take to reduce the population of rushes on your farm, such as:
- Maintaining a soil pH of 6.5, including adequate levels of Nitrogen, Phosphorus, and Potassium;
- Sowing grassland mixes which are persistent and have a high tillering ability, which provides competition to rush seedlings;
- Ensuring optimal field drainage;
- Prevention of damage to grassland through avoidance of overgrazing. Poaching leads to bare patches where rushes have the ability to develop.
Furthermore, the encouragement of grass growth, leading to a dense, leafy grass sward, which is the key to reduce the prevalence of rushes.
Non-chemical
According to expert sources, a 10% infestation can reduce grassland productivity by 10%, You can eliminate the population of rushes in your field by cutting rushes through either mowing or topping.
However, carry out cutting alongside grassland management essentials of drainage, soil structure and fertility, and pH. These actions are all required to reduce the prevalence of rushes in the long-term on your farm.
Controlling rushes through cutting will prevent the plant from setting and spreading seeds. In addition to this, the cutting process will allow light into the sward, allowing for a higher level of productivity in the sward.
Topping and mowing
You can cut rushes by using machinery such as a topper or a mower. Machinery you use for cutting depends on accessibility and how level or rough a field is.
Moreover, where rushes are not in abundance on flat ground, disc mowers are a much more successful tool. Comparatively, on rougher land, flail mowers and rotary blade toppers are most effective.
Grazing and mulching
In a study conducted by The Soil Association, it found that tight grazing, before and after cutting, was successful in controlling young rush plants emerging.
Furthermore, cattle appear to be more successful in controlling rushes in comparison to sheep due to their less selective grazing habits.
They found that trampling by grazing cattle helped to break up rush root clumps, helping grass and clover in the sward obtain light. This practice works best in dry conditions, as heavier stocking during wet periods could accelerate the rush infestation.
Mulching is referred as the addition of decomposed plant materials, such as rushes to the soil under the plants.
Mulching of rushes is an opportunity to assist with grass growth, as well as avoiding the application of chemicals, allowing for an opportunity to ensure cross-compliance.
Chemical control
These perennial plants flower in June. Before flowering, rushes should receive a herbicide application in June.
Control soft rushes using chemical control such as MCPA or 2,4-D. Apply in June or July, should the soil conditions allow.
Before introducing a chemical herbicide, topping of rushes three weeks before spraying is recommended by Teagasc to promote the re-growth of rushes which are capable of absorbing the herbicide.
Wetting agents improve the capacity of the spray sticking to the slender rush, which is being targeted. In addition to reducing the rush population, these herbicides also reduce grass growth and white clover.
Following spraying, the rush turns a sandy brown colour. Cutting using a topper or mower to remove dead material, allowing grass to regenerate, will follow.
Ensuring water quality standards
Should you decide chemically control rushes on your farm, you must keep in mind the guidelines set by the Department of Agriculture, Food and the Marine in relation to water quality.
If spraying in fields with water courses present, keep boom sprayers at least 5 meters from the point of water. Low drift nozzle introduction can prevent chemicals drifting into surrounding water courses.
You must look at the application rate as advised by the chemical manufacturer and do not exceed this maximum application rate. In addition to this, always follow label guidelines.
If you expect rain within the day, do not conduct spraying. This could lead to surrounding water pollution. Moreover, if fields are currently waterlogged, then avoid spraying until dry conditions arise.
When you have completed spraying, do not wash out the sprayer near drains or on concrete surfaces where chemicals have the potential to run into drains.
A certified individual holding a certificate in the Safe Use of Pesticides should conduct chemical spraying applications.
Extra precautions
Spraying at a particular time of the day is important; in the later evening when temperatures drop or in the early morning before temperatures rise. This is to avoid the burning of grass.
Once you have completed a chemical spray application, Teagasc recommends to avoid grazing the area for a period of 10 days.
In addition to this, triple rinse the empty chemical spray container, and put the washing into the sprayer and in turn, spray this onto grassland.
