Managing dominance in multispecies swards

To keep your multispecies sward balanced, diverse and productive, it is important to prevent any one species from becoming too dominant. By regularly monitoring the sward, adapting management and selecting species carefully, you can grow resilient, diverse leys that support livestock and long-term farm sustainability.

When a single species takes over, biodiversity drops, sward performance can suffer and risks from pests and diseases increase. Managing balance in multispecies swards is an ongoing task. Here we discuss how to manage species dominance effectively.

Regularly check your sward or carry out botanical surveys to spot early signs of dominance. Photographing and recording sward composition over time can track trends and guide future decisions.

Use rotational grazing and move stock regularly to avoid overgrazing vulnerable species and give them time to recover.

Match stocking rates to sward resilience. Overgrazing can boost robust species like perennial ryegrass, while undergrazing leads to selective grazing and dominance by favoured species.

Use heavier grazing in areas where dominant species are overrepresented to reduce their advantage.

Adjust the cutting height as lower cuts can check tall dominant species and support lower-growing plants like clovers.

Cut every 4–6 weeks during the growing season to prevent dominant grasses from setting seed. Target cuts just before flowering to reduce vigour in dominant species and give slower growers a chance to compete.

Keep nitrogen rates low (50–100 kg/ha/year max). Too much nitrogen encourages grasses and suppresses legumes and herbs.

Test soils every 4–5 years to maintain good levels of phosphorus, potassium and trace elements. Balanced fertility supports weaker species.

Overseed by reintroducing underrepresented species, such as clover or herbs, after hard grazing, harrowing or cutting. Typical overseeding rates are 5–8 kg/ha, focusing on specific species (e.g. chicory, plantain, red/white clover).

Be selective with reseeding. When sward balance or performance drops, reseed with a more diverse mix.

Full reseed rate for herbal leys (30–35 kg/ha total):

• Grasses: 12–18 kg/ha
• Legumes: 8–12 kg/ha 
• Herbs: 3–6 kg/ha

Use tailored seed blends for goals like drought tolerance, pollinator support or productivity.

Control pests that favour dominant species to maintain balance through Integrated Pest Management (IPM).

Monitor for diseases:

• Clover is prone to rot and red clover sickness
• Chicory can suffer from root rot and mildew
• Lucerne is vulnerable to fungal infections like Phytophthora

Spotting and managing issues early can protect sward diversity.

Use well-calibrated equipment for even sowing and good seed-to-soil contact.

Keep sowing depths to the following:

• Small seeds (clover, herbs): 0.5–1 cm
• For larger seeds of 1–2 cm, sowing too deep reduces germination, especially for small-seeded species
• Aim for a soil pH of 6.5–7. Imbalanced pH can suppress certain species and encourage others to dominate

Ensure optimum selection by picking species that suit your soil, climate and goals – mixing growth habits, rooting depths and nutrient needs.

Avoid dominance risks by limiting use of aggressive grasses or legumes and balancing with companion species.