Grazing Management of Herbal Leys Over Winter

Herbal leys are great for providing increased forage availability through late spring, summer and autumn when simple grass leys may drop off; their inclusion of deeper rooting species provides drought resistance, and seasonal growth helping to keep consistent production through the season.

However, most herb and legume species grow from a crown just above the ground so it is imperative that they are not damaged from overgrazing. Overgrazing also reduces the green area which is vital for improved photosynthesis and maximum regrowth. Some kind of managed grazing (strip or mob grazing) helps reduce cherry picking and damage and ensures the plants have enough reserves to grow strongly as soils warm up in the spring. During the grazing season, aim to leave 6-8 cm residual and back fence recently grazed areas to allow recovery. 

As temperatures drop going into winter, the rate of photosynthesis and regrowth drops. Unlike grasses (which are actively growing in soil temperatures as low as 5℃), legumes and herbs are more sensitive to the cold. They require soil temperatures of around 7℃ to actively grow. Once the soil temperatures drop below this, they sit dormant as buds in the crown, getting energy from stored carbohydrates, preparing them for regrowth in the spring. 

Lightly graze the ley in the Autumn, then take stock off by November to allow ample rest and recovery. Where we are having milder winters, grass growth may continue longer through the autumn but grazing beyond November should still be avoided as you risk losing diversity in the sward from damaging the crowns if stock are left in situ for too long.

It is as important to monitor soil temperature going into spring as it is going into winter. Generally, the ideal soil temperatures to promote spring growth occur around April (keep in mind clay soils take longer to warm up!). However, where herbal leys have been grazed later in the winter, there is a cascading effect on the following season; you may need to wait later into spring before reintroducing stock or taking the first cut. If the ley has been damaged, it may need overseeding with more legumes/herbs to rejuvenate the area and avoid grasses becoming dominant. 

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Date Posted: 5th November 2024