A new industry collaboration is seeking to get practical scientific research out to farmers and policymakers to help improve grassland management and livestock production. Jane Brown reports.
Healthy soils are key to healthy animals and, ultimately, humans, but our understanding of their complex functions is surprisingly limited.
Fortunately, a farm-scale research facility in Devon is carrying out a number of trials into the impact of different management options on soil, the environment and the livestock produced.
The North Wyke Research Centre, near Okehampton, established the Farm Platform in 2010. It comprises three 21-hectare (52-acre) farmlets, with each field bounded with French drains to collect all the water running off or through the land.
All external parameters are measured, including rain, temperature, soil pH and nutrient levels, gaseous CO2 and N2O emissions and water nutrient content.
According to Prof Adie Collins, farmers typically lose between 0.2-1.4 tonnes/ha (0.08-0.56t/acre) of soil a year through erosion, costing them £6-£42/ha (£2.40-£17/acre).
However, the knock-on effect of this erosion – through pollution and water treatment, for example – equates to an estimated £696 million a year.
Although soil loss from grassland is significantly lower than on arable land, it is still a risk, particularly in areas of high rainfall on sloping fields, says Prof Collins.
He says: “There are three key considerations, which are cover, compaction and connectivity with water courses.”
Maintaining crop cover is absolutely critical, so poached land or reseeded leys are particularly at risk.
Prof Collins says: “If the weather takes a turn for the worse, reseeding can increase soil losses by five or 10 times.”
Farmers should carry out their own assessment of individual fields and potential mitigation of risk factors.
He says: “Compaction is one of the most serious issues facing grassland. It is almost ubiquitous as a problem, causing sheetwash and flooding.”
Loosening compaction will improve soil health and reduce risk of erosion, but farmers should also consider resiting gateways, reducing stocking rates in wet weather and moving ring feeders regularly, says Prof Collins. Other mitigation measures include laying a concrete base under feeders, improving farm tracks and fencing off water courses.
He says: “Soil loss is a natural process. Pre-World War Two there was an intrinsic background annual loss of 0.05t/ha. But modern grassland farming has increased this soil loss by five to 14 times.”
Environmental bodies are increasingly focusing on agricultural pollution, alongside other sources, to comply with the Water Framework Directive. However, they are keen to work with farmers to help them mitigate losses, so having scientific understanding of the efficacy of different measures is vital, says Prof Collins.
“If farmers’ uptake of the low cost, least intrusive measures increased dramatically, the environmental benefits would be very significant.”
Initial results from the North Wyke Farm Platform show permanent pasture to be the most environmentally friendly form of grassland management, with huge spikes in CO2 and N2O emissions in the year following a reseed, says Mr Orr.
However, if farmers do reseed, they should consider using deep-rooted grasses such as festuloliums alongside legumes for nitrogen fixing. They should also focus on the quality of their pasture, not just the quantity of grass produced.
Hugh Frost, product and technical manager at Mole Valley Farmers’ Forage Services, says: “Maintaining and improving grass swards needs due consideration, planning and attention to detail. We are carrying out a number of independent trials to look at what is happening with grass and soil and the cost benefits of different approaches.
Applying this research to real farm management will help farmers maximise their forage quality and quantity with minimal environmental impact. Examples include adding a soil conditioner at establishment to increase yields and quality of the ley, and tailoring fertiliser applications to boost production and reduce costs.
Mr Frost says: “As an industry, we have not paid enough attention to biological fertility of soil. It is important to analyse your soil and get the pH right. A pH of 6.5 is optimum for microbial activity and the availability of nutrients varies according to pH, so it really is critical.”
Analysing forage and pasture is just as important as analysing farmyard manure if farmers are to maximise efficiencies. The Farm Crap App, created by Duchy College, helps farmers make the most of manure by recording applications and calculating nutrients available to the crop.
Chris Hogson from Duchy College says: “Farm waste is not a waste, it is a resource. It is important to look at the nutrient and financial value of manures.”
According to dairy farmer and cheese producer Mary Quicke, closer attention to detail has enabled her to increase forage production at Home Farm, Newton St Cyres, Devon.
She says: “Moving from floppy set-stocking to highly measured, fenced and tracked paddock grazing has doubled or even trebled our production from that grassland.”
The 500 cows graze for up to 11 months of the year, with the 580-hectare (1,433-acre) farm comprising a mixture of long-term, low-input grassland, silage leys and arable crops.
“We look at the field history and yields to identify soil structure issues and are aiming to build organic matter, reduce mechanical damage and grow deep-rooted swards.
“We have trialled different types of soil aeration and the sward-lifted ground drains a lot quicker after heavy rain. I really welcome this conversation between farmers and research scientists, as we really do need to work on evidence.”
James Small has also dramatically increased his grassland production at Warren Farm, Cheddar, Somerset, which has enabled him to slash the area set aside for silage.
He says: “We have 120 suckler cows and 1,400 ewes on mainly thin, limestone soils. Track maintenance is important to us to avoid compaction and we compost our manure so it incorporates quickly.”
Mr Small lets 20 hectares (50 acres) of land to a neighbour for 400 outdoor pigs – an area which is rotated around every two years.
He says: “They trash the fields, but there are real nutrient benefits. The field is returned to us ready to reseed, which requires dragging soil back up the hill, levelling it, subsoiling, ploughing, power harrowing and rolling.”
Having reseeded with deep rooting legume and herb rich grasses in early autumn, Mr Small takes two cuts of silage before grazing the aftermath.
He says: “Yields are so good we now only need to take 28ha of first cut silage, compared to 69ha before. This frees up more land to do other things.”