rushes decomposing after spraying with MCPA on a grass field

How Long Do Rushes Take To Decompose?


Rushes, those grass-like plants often found near water bodies, serve a dual role in the environment. They provide valuable habitat to wildlife and contribute positively to various ecosystems. However, on farmland, they may become a nuisance, reducing productivity and hindering agricultural processes. The challenge of managing rushes presents farmers with a complex task that requires understanding their decomposition.

This article is focused on how long their removal takes through various methods and strategies, such as seasonal variations, moisture levels, and different agricultural practices.

Decomposition of Rushes Through Different Seasons


Spring’s warmer temperatures and increased rainfall foster a rapid decomposition rate in rushes. The thawing ground and frequent showers promote microbial activity, typically leading to faster decomposition compared to other seasons.


Summer presents a contrasting environment. While heat can accelerate decomposition, extended dry periods may slow the process. Decomposition during summer often depends on localized weather conditions and moisture levels.

rotavating dry rushes
Dry conditions are not good for decomposing rushes – Also mulching is better than rotavating as shown above as it chops the rushes into smaller pieces which makes ploughing and cultivating much easier.


In autumn, cooler temperatures and more stable moisture conditions provide a balanced environment for decomposition. Rushes tend to break down at a moderate rate during this season, but the onset of frost can slow the process.


Winter usually sees the slowest decomposition rates, with cold temperatures inhibiting microbial activity. Snow and frost can further suppress the process, leading to a substantial reduction in decomposition during this season.

The Influence of Moisture on Decomposition

Moisture levels profoundly impact the decomposition of rushes. In wet environments, decomposition may be expedited due to enhanced microbial action. Conversely, dry conditions often retard the process, leading to a prolonged decomposition timeframe. Thus, moisture plays a pivotal role in determining how quickly rushes will break down.

Decomposition After Spraying with MCPA

MCPA can have varied effects on the decomposition of rushes, potentially accelerating or slowing down the process. Here’s a simplified breakdown for practical implementation:

mcpa herbicide
MCPA herbicide
  • Accelerated Decomposition: MCPA might speed up decomposition if it weakens the plant structure, possibly reducing the time to 1 to 4 months. This is more likely in optimal weather conditions and with specific MCPA concentrations.
  • Slowed Decomposition: Conversely, certain concentrations of MCPA might inhibit the microbial activity necessary for decomposition, extending the process to 5 to 8 months.
  • Consideration of Other Factors: Soil type, moisture levels, temperature, and MCPA concentration must all be carefully considered, as they can interact to produce varying outcomes.
  • Strategic Planning: Understanding how MCPA will affect decomposition in your specific context can guide the best application methods and timing. Conducting a site-specific assessment and consulting with a local expert or extension service may provide the most accurate guidance.
  • Environmental Caution: Be aware of potential broader environmental impacts and comply with guidelines and regulations associated with MCPA use.

Decomposition When Cut and Left on the Ground vs. Ploughed Under the Soil

Cutting Rushes and Leaving on the Ground

When rushes are cut and left on the surface, the decomposition process can vary widely. Exposure to sun, rain, and ambient air can lead to inconsistent rates of breakdown. Generally, cut rushes left on the ground may take anywhere from 3 to 9 months to decompose.

In warm and moist conditions, the process can be on the quicker end of this range, with microbial activity and other environmental factors facilitating rapid decomposition. In contrast, during dry or cold periods, the lack of moisture and reduced microbial action can slow the process considerably, pushing decomposition towards the longer end of the estimate.

This method of leaving cut rushes on the ground is often used as a management strategy for controlling their growth or as part of a mulching process to enhance soil health. Understanding the timeframe for decomposition is crucial for farmers and land managers to plan accordingly and achieve desired outcomes.

Ploughing Rushes Under the Soil

Ploughing rushes under the soil creates a different decomposition dynamic. Buried rushes are subjected to different microbial communities and less exposure to weather variations, leading to more controlled decomposition rates. Generally, ploughing rushes under the soil may lead to decomposition within 2 to 6 months.

The soil’s moisture content, temperature, and microbial composition are key factors influencing this process. In conditions where the soil is moist and warm, decomposition can occur more rapidly, often within the shorter end of the estimated range. Conversely, if the soil is dry or cold, decomposition may take longer, approaching the upper end of the estimate.

Ploughing rushes into the soil is a common agricultural practice, particularly when seeking to improve soil structure and fertility. By integrating the organic material into the soil, it not only aids in decomposition but also enhances soil nutrients and moisture retention.

However, careful planning and consideration of local conditions are necessary to optimize the decomposition process and achieve the desired benefits for the soil and subsequent crops.

Benefits of Mulching Rushes Before Ploughing vs. Ploughing Full-Length Rushes

Mulching Rushes

Mulching rushes before ploughing has numerous benefits. It can enhance decomposition by creating smaller, more easily digestible pieces for microorganisms. Additionally, mulching helps in soil moisture retention and prevents erosion, promoting overall soil health.

Ploughing Full-Length Rushes

Ploughing full-length rushes can present several challenges to farmers, which might impact soil management and cultivation practices. Here are some difficulties related to handling long rushes:

Full-length rushes are challenging to cultivate if not fully decayed. They have wrapped around the tines of this power harrow reducing its ability to cultivate the soil.
  1. Difficulty in Ploughing: Full-length rushes are tough and fibrous, making them resistant to breaking down. Ploughing these long rushes into the soil may result in uneven decomposition, making it challenging to achieve a consistent soil texture. The unbroken rushes can form a dense mat, hindering proper soil aeration and making the ploughing process itself more strenuous and time-consuming.
  2. Cultivation Challenges: The presence of long, undecomposed rushes in the soil can obstruct the proper development of new plants. These rushes may interfere with the planting equipment and can cause uneven seed placement during drilling. The difficulty in cultivating soil with full-length rushes may lead to decreased planting efficiency and, subsequently, reduced crop yield.
  3. Drilling Issues: Drilling seeds in soil with full-length rushes can lead to inconsistent seed depth and spacing. The obstructive nature of the long rushes can cause the drilling equipment to become entangled, leading to potential damage and requiring frequent maintenance. This can slow down the planting process and affect the overall productivity of the farmland.
  4. Long Decomposition Time: Ploughing full-length rushes might result in a slower decomposition process, potentially taking anywhere from 6 to 12 months, depending on the soil conditions and the type of rushes. The slow breakdown hinders nutrient cycling, possibly affecting the growth of subsequent crops.
  5. Potential Soil Management Challenges: The incorporation of full-length rushes into the soil may lead to an imbalance in soil moisture levels, as the dense mat of rushes might prevent water from penetrating deeper soil layers. This can lead to waterlogging in some areas and dryness in others, creating an unfavourable growing environment.


The decomposition of rushes is a multifaceted process influenced by various factors such as season, moisture, MCPA treatment, cutting practices, and mulching. If you have long rushes the best strategy is still to spray with MCPA, mulch the long rushes into tiny fragments and then plough in, fully inverting the rush roots. The affected rush area will most likely take extra cultivating and/or a full season of growing a break crop or for the rush roots to decompose completely.