This is a subscriber-only article
The potential for herbal leys to benefit both soil structure and livestock performance was the subject of a third EIT Food “Focus on Farmers” webinar on Monday.
Outlining results from a five-year study on diverse forages, David Humphries from Reading University said dairy-bred steers grazed on herbal leys achieved 0.9 to 1kg per day of weight gain, which was similar to animals on ryegrass swards.
One of the main benefits of these mixed species swards is that legumes and herbs contain compounds with potential anthelmintic properties, and in the study, Humphries maintained that cattle grazing herbal leys had lower worm burdens compared to the control group.
Ryegrass swards performed well, but dry summers in 2018 and 2019 saw growth hit hard
In terms of overall growth, sward yields were similar at 8t/ DM/ha, despite ryegrass swards being dressed with 250kg N/ha/year, while the herbal leys received no fertiliser.
“Ryegrass swards performed well, but dry summers in 2018 and 2019 saw growth hit hard. The herbal mixes came into their own, as they are deeper rooting and tolerate dry conditions better. But herbal mixes are slower growing in spring compared to ryegrass. So there is a role for including both in grassland mixes,” said Humphries.
However, he also outlined some drawbacks of herbal mixes.
But on drier soils, well-managed leys should last for six to eight years
“Site location and soil type are key to persistency. On heavier soils, the herbal leys were harder to establish and less persistent.
“But on drier soils, well-managed leys should last for six to eight years,” he suggested.
Experience also indicates that herbal leys are mainly suited to grazing rather than silage, as they are slow to dry, requiring wilting periods of three to four days.
Plant diversity
Also speaking at the event, Reading University Professor Martin Lukac said multi species swards improve soil fertility and structure, as well as building up organic matter.
He maintained that a range of plants in the grazing pasture means there are roots at different depths tapping into nutrient reserves.
“With some herbal varieties developing roots as deep as three metres, they open up soils, improving aeration and drainage. These factors combined improve soil health, which results in more productive pasture,” said Lukac.
SHARING OPTIONS: