GrassCheckGB is a grass monitoring project involving 50 dairy, beef and sheep farms.

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Final results from GrassCheckGB show how farmers met the challenges

As final results from the season’s GrassCheckGB farms are recorded, lessons are shared from the most prolific performers.


The final figures from a season of grass growth have now been recorded which confirm what every grassland farmer knows – that it’s been a challenging year. However, many producers – farming either dairy, beef or sheep – have excelled in the face of difficult conditions, some producing average yields across the farm as high as 12 tonnes of dry matter (DM) per hectare, despite constraints on growth. And although the peak in growth was higher than in the previous two years, the average was lower, at 9.2t DM/ha across the monitored group (figure 1).

Figure 1:  Average annual grass yields across GrassCheckGB farms, March to mid-October 2021
Figure 1: Average annual grass yields across GrassCheckGB farms, March to mid-October 2021


Who has excelled?

The hallmarks of the most prolific grass growers have been noted by GrassCheckGB (GCGB), an industry, academic and levy board collaboration which has monitored this year’s grassland performance and helps British farmers improve their grassland management. 

“Over the three years of the project, not one of the grass growth seasons could be considered typical,” says Dr Kathryn Huson, a research scientist with the Agri-Food and Bioscience Institute (AFBI), which has a central role in the project.

“But one of the keys to dealing with atypical conditions is adaptability,” she says. “It’s about building resilience into your system and being prepared to make use of grass when it’s available, while having the capability to deal with shortages, even when they come at unexpected times.”

2021 has clearly demonstrated this need, according to Dr Huson.  

“It’s definitely been a challenging year in which we’ve seen some extreme growing conditions and grass growth patterns shift,” she says.

In fact, peak growth was very high (see figure 2), particularly in Wales, the north of England and Scotland, but came a week later than expected.

Figure 2: Regional average daily grass growth rates recorded across GrassCheckGB farms, 2019/2020 2021.
Figure 2: Regional average daily grass growth rates recorded across GrassCheckGB farms, 2019/2020 2021.


“Spring was colder than average, with regular frosts, and April was the driest since 1980, with 28 per cent of average rainfall for the UK, combining to delay the initiation of growth,” she says. “By contrast, May was very wet, especially in Wales and the south west, with 171 per cent of average rainfall overall.”

The upshot was that peak growth, which would normally be at the end of May, shifted to early June. After this point, many growers continued to face challenges as frequent periods of soil moisture deficit continued through to October, holding back growth. 

“Many people certainly struggled with covers in early spring, to be faced with abundance in early June,” she says, emphasising the need for measures such as cutting big bale silage at times of surplus, or opening bales in times of need.

“The key to doing this is having a measurement and management culture, as GCGB farmers have demonstrated,” she says. “It’s a case of knowing what grass is in front of you and being able to react to the upcoming surplus or deficit.”

Dairy, sheep or beef?

Figure three shows that as usual, dairy farmers’ average grass production was the highest, peaking in the week leading up to 7 June, with an average across the GCGB group of over 90kg DM/ha/day, while the peak for beef and sheep producers averaged just over 70kg DM/ha/day across the group.

Figure 3: Average daily grass growth on GrassCheckGB dairy, beef and sheep farms, 2021.
Figure 3: Average daily grass growth on GrassCheckGB dairy, beef and sheep farms, 2021.

“This does not mean that dairy farmers are doing a better job than those with beef cattle or sheep,” she insists. “It’s about different systems and farms.

“There are farmers who have averaged yields of 12-15t DM/ha in both groups over the past three years, but typically total yields are lower from the group of beef and sheep farms in the project, averaging 7-9t.

“However, a larger number of beef and sheep producers will be farming in a more challenging environment, such as on poorer soils or in more upland areas, and with lower average nitrogen inputs,” she says. “But in many instances there is no reason why they can’t achieve the same grass yields as dairy producers, and often they do.” 

Performance with lower nitrogen is more pertinent than ever this year as fertiliser prices rise to their highest ever levels.

“For many farms, lowering artificial nitrogen is already a key target,” she says. “This is reflected in the higher use of swards containing legumes, particularly red and white clover.”

These have the unique ability to take nitrogen from the air and store it in the soil, for subsequent use by the sward or following crop.

“There is definitely scope for their even greater use and many farmers are moving to more diverse species in their leys, including a range of legumes,” she says. “It’s worth remembering that a sward containing 10-20 per cent clover is estimated to fix as much as 50-200kg nitrogen per hectare in a year, so potentially displacing this amount of bagged fertiliser.” 

Grass quality

Despite the season’s slightly lower yields, the quality of grass has been consistently high, and better than both the previous two seasons. The average metabolisable energy (ME) for each period never dropped below 11MJ/kg DM, and levelled over the season at 11.7 MJ/kg DM (see table 1).



“This demonstrates a combination of good and perhaps improving management and attention to grazing residuals, but was also helped by periods of sunny weather,” says Dr Huson. 

In the spring this also helped to achieve an average ME of 12.1-12.4 MJ/kg DM across a six-week period (5 April to 17 May) across all GCGB farms.

Management of grass covers

Specifically, management which promotes high ME is that which turns stock on to the right cover and removes it at the right stage.

“This is likely to mean going on at no more than 3,000-3,200kg DM/ha, or approximately 12 cm,” says Dr Huson. 

“It should also mean turning stock on to the cover when grass is at or just below the three leaf stage,” she adds. “Once a fourth leaf starts appearing, the first leaf will die off, and if swards are allowed to grow on and mature this produces more fibrous grass with a lower ME.”

The residual left after grazing should also be around 1,500kg DM/ha (4-5cm) and certainly not below, according to Dr Huson.

Although the ideal pre-and post-grazing residuals will vary with the system, she says leaving enough post-grazing is important to support regrowth, while ensuring consistency across the residual sward will help maintain quality.

“Another important factor is to balance supply and demand,” she adds. “If you can match the biomass available with the stock then they will eat what’s in front of them to leave a more consistent residual, but there must be enough to avoid any check in performance.”

Future challenges and opportunities

Challenges for the future are to continue increasing grass yields and quality by following good practice and building adaptability into the system.

“With grass and grazing land accounting for over 70 per cent of the UK’s farmed area, how our farmers make the most of grass growth increasingly matters, as it impacts productivity, profitability and environmental footprint in our livestock sectors,” says Dr Huson.

“To help improve efficiency, we have been collecting weather as well as grass growth data from all GCGB farms over the three years of the project, along with data from two grass plot sites managed by project partners Rothamsted Research and Germinal,” she continues. 

This has been used to develop grass growth predictions for the British regions. These rely on using weather forecast data to provide seven and 14-day estimates of grass growth rates – something which could prove invaluable to any grassland manager.

“Although the models have not been finalised, they are looking very promising, and we are hopeful that we can use them in future seasons, when better forecasting of growth rates will support continued improvements in grassland planning and management.  

“However, none of these industry-focussed research collaborations would have been possible without the hard work of GCGB farmers, and the support of all the project partners and sponsors, so I want to say ‘thank you’ to all involved,” she says.

GrassCheckGB is a collaborative grass monitoring project run by CIEL (Centre for Innovation in Livestock), the Agri-Food and Biosciences Institute (AFBI) and Rothamsted Research, and supported by AHDB Beef & Lamb, QMS, HCC, Germinal GB, Handley Enterprises, Sciantec Analytical, Waitrose & Partners and Datamars Livestock. 


Management Notes

  • With some farms now set-stocked for tupping and others starting to house stock, this will be the last weekly GCGB bulletin for 2021.
  • However, there remain plenty of opportunities to utilise grass and extend this grazing season – particularly given the unseasonably good conditions! Every extra day at grass equates to savings in forage and housing costs, and part-time/ ‘on/off’ grazing strategies are an excellent tool to use grass in the shoulders of the season.
  • Whilst periods of 2021 were very challenging for grass growth, GCGB data shows grazed grass yields averaging 9.2 t DM/ha to date – highlighting the productivity that is achievable with attention to grassland management, even in trickier conditions.
  • Huge thanks go out to all the GCGB farmers, sponsors and supporters for their hard work and support over the last 3 years