Herbal leys: their contribution to beef output from grazed forages
Results from a five-year trial carried out by scientists at Reading University are confirming that dry matter output from diversified swards will out-perform that achieved by a perennial ryegrass (PRG) ley - receiving 250 kilos of nitrogen per annum - three years after all the swards were established.
Significantly, the diversified leys did not receive bagged nitrogen at any time.
This was one of the key findings delivered to delegates participating in the third EIT Food ‘Focus on Farmers’ webinar series - a collaboration by ABP, Queen’s University, the University of Reading and John Deere.
Reading University’s Dr David Humphreys also confirmed that cattle on a grazing trial performed as well on the herbal leys as they did on the PRG sward. The research trial, entitled the ‘Diverse Forages Project’, is centred on a number of sites across the south of England. Four different swards types are being compared: one containing 17 different species of grass, clover and herbs, one containing 12 different forage species and another comprising six different forage types.
“The PRG sward was the control,” Dr Humphreys continued.
“The work, which addressed a wide range of sward-related issues, was extremely complex in nature.
“Analysis of the results obtained will be carried out over the coming months, the aim of which is to identify which species’ mixes can deliver the best return to beef farmers in a grazing context.
“But it is already evident that the use of diverse leys has a key role to play in helping to deliver a sustainable future for livestock producers.”
The ‘multi species grassland’ webinar was chaired by ABP UK’s Senior Agricultural Manager, James Draper (PICTURED) , using AgriSearch’s knowledge exchange IT platform.
Reading University soil scientist Professor Martin Lukac also addressed the event. He said that soil structure was a key driver of soil productivity, adding:
“All our grassland soils have evolved from a forest environment over many thousands of years.
“In the past, biomass falling from the forest canopy would have provided the energy required to allow the soil below to function correctly.
“Within a pasture scenario, it is the forage plants that provide the energy to allow the soil function effectively while also generating the capacity for the soil to support agricultural output on a sustainable basis.”
Lukac stressed the importance of understanding soil biology. He said: “Soil health is also inextricably linked to soil structure and productivity. We know that employing a mix of herbs and grasses will help to optimise sward output. The wide range of root depths, which this approach will deliver, ensures that soils can adapt to the changing climatic and other related conditions which so characterise the growing conditions in this part of the world.
“Research trials have also confirmed that certain forms of silvo pasture will act to improve soil health further still.”
Beef farmer, Sam Chesney, who supplies ABP, also addressed the webinar.
He confirmed that his switch to the establishment herbal leys across a number of his grazing paddocks two years ago is now paying a dividend, adding: “The grazing mix comprises a combination of tetraploid rye grass, red clover, white clover, plantain and chicory.
“Output from these swards is now averaging 8.6t per hectare per annum. The plan is to further increase the number of grazing paddocks sown out in herbal leys. We are finding that plants such as plantain and chicory are extremely deep rooting. This helps to improve soil structure.
“Farm yard manure and a little chemical P are the only fertilisers spread on these diversified pastures. It is also evident that taking this approach has helped to vastly improve the number of earthworms in the soil.”
Sam is also a firm advocate of regular soil testing. In his opinion, getting an accurate insight into soil pH values alone makes this an investment worth making. He further commented: “At a pH of seven, soil nutrient availability is maximised. This figure falls to 50% if the soil pH value drops to 6.0 or below.”
Organic suckler beef producer James Evans, who also supplies ABP, is the second ambassador for the project. He farms close to Bishop’s Castle in Shropshire. Courtesy of his presentation to the webinar, James explained that the switch to organic forced him to put the issues of soil health and fertility as key priorities for the businesses. He added: “Gone are the days when a sales rep would be given the results of a soil test and then ask to come up with a suitable fertiliser policy.
“Over the past three years, we have found that increasing the organic matter content of our soils has delivered a significant number of benefits. In the first instance, it has increased their water holding capacity. As a result, we have been able to extend the grazing, season both in the spring and autumn periods.”
James also pointed out that grazing policies can beneficially impact on soil structure. He concluded: “Mob grazing entails putting large numbers of stock onto mature swards for a very short period of time and then moved on. The practice results in one third of the available forage being eaten; onethird being tramped into the ground and the remaining one-third left to produce seed. The grazed area is given up to 40 days to recover.
“This approach improves soil organic matter levels. It also provides herb species in the sward with an opportunity to shed their seed, which will germinate the following year.”
‘Focus on Farmers’ is part of EIT Food, an EU innovation project to deliver a sustainable, healthy and trusted food system. All six ‘Focus on Farmers’ webinars can be viewed on the AgriSearch website.