Why do some fields have problems with moss?

Moss growth in fields is annoying, its presence impacts crop productivity and soil health. For me, addressing this issue requires a thorough understanding of the reasons why moss is an issue and then I can begin to work on the best solution to the problem

Improving drainage

Good land drainage is essential for preventing waterlogging, which creates favourable conditions for moss growth. I look at the following:

• Look at the natural lay of the field to identify areas prone to water accumulation.
• Install subsurface drainage systems, in areas where pooling water is a constant problem. Often there is an existing drain which may have become blocked with roots or muck.
• Open new ditches or clean out existing ditches to help to redirect excess surface water away from fields.
• Consider land regrading to ensure proper slope for efficient water runoff, this can especially be a problem where ditches are cleaned and the excess soil builds up before the ditch holding back water.

Soil nutrition

Moss thrives in acidic soils, adding iron sulphate, either by sprayer or using a fertiliser sower will kill the moss in a matter of days. Although this removes the moss it does not address the problem of low soil pH. Adding lime to fields (2 tonnes to the acre) is one of the most basic starting points to combat acidic soil.

Balancing soil nutrition refers to the practice of ensuring that essential nutrients in the soil are present in the right quantities and proportions to support healthy plant growth. This process involves assessing the nutrient levels in the soil, correcting any deficiencies or imbalances, and maintaining optimal nutrient levels over time.

• Conduct soil tests to identify nutrient deficiencies and pH levels.
• Apply fertilisers containing nitrogen, phosphorus, and potassium to support crop growth.
• Consider soil amendments like lime to correct acidic pH conditions, creating an environment less favourable to moss.

Improving soil health

Improving soil health by adding more manure or other physical amendments improves the soil structure, reduces compaction and promotes vigorous crop growth, which suppresses moss establishment.

• Incorporate organic matter inputs such as compost, manure, or green manure crops.
• Employ conservation tillage methods to minimise soil disturbance and maintain soil organic matter levels.
• Implement soil health-building practices like crop rotation and cover cropping to improve soil structure and biological activity.

Soil compaction

Preventing soil compaction improves soil structure and improves crop growth, reducing moss establishment.

• Use soil aeration techniques such as subsoiling, deep tilling or mechanical aerators.
• Adopt rotational grazing strategies to keep animals off wet fields, this will reduce animal impact and minimise soil compaction.
• Grow cover crops with deep root systems to break up compacted soil layers and enhance soil structure.

Monitor irrigation

Here in Northern Ireland, there is not much irrigation needed or used, but if you do use irrigation, it should be closely monitored to maintain optimal soil moisture levels. This prevents excess moisture accumulation, which promotes moss growth.

• Monitor soil moisture levels using sensors or visual inspection.
• Adjust irrigation practices to match crop water requirements and prevent overwatering.
• Implement precision irrigation systems to deliver water directly to the root zone and minimise surface runoff.

Manage grazing

If you have livestock, sometimes they can be the main cause of the moss. Effective grazing management promotes grass health and resilience against moss invasion. Overgrazing, especially with sheep can cause moss to take hold in grassland which receives very little fertiliser and is constantly grazed tight to the ground.

• Develop grazing plans that rotate livestock to different paddocks, allowing for rest and recovery periods for grass.
• Monitor grass height and density to prevent overgrazing, which can lead to soil erosion and moss establishment.
• Integrate multi-species grazing systems to maximise pasture utilisation and promote diverse plant communities.

Selecting plant varieties

Choosing grass species and crop varieties adapted to local conditions enhances crop vigour and competitiveness against moss.

• Research and select grass species and crop varieties suited to the local climate and soil types.
• Consider cultivars known for their vigorous growth, deep root systems, and natural resistance to pests and diseases.
• Incorporate legumes into pasture mixes to improve soil fertility and support grass growth.

Maximising sunlight

Moss has a tendency to grow well in shaded areas. Increasing sunlight in shaded areas helps to prevent moss growth by creating less favourable conditions for its development. Although this will have a limited effect, it can be substantial if large leafy tree limbs come out into the field along both sides or more.

• Assess the positioning of shading elements such as trees and hedges.
• Cut massive overhanging branches to allow more sunlight penetration.

If moss is a problem in a field, the first thing I check is the drainage, if that is ok, it is usually because the soil hasn’t received enough nutrition, this can be fertiliser, pH or the application of organic material such as farmyard manure. In most instances the field is overgrazed, under fertilised, overstocked has a broken drain and has compacted soil. Rarely does a productive field have any issues with moss – get drains fixed, the plough hooked on and get some nutrition back into the soil.