Why deeper rooting grass varieties may be more productive

• Drought summers are now more frequent

• Consider more resilient grass seed varieties

• Fescues are better for deeper root systems

Over-reliance on fast-growing ryegrass varieties that head quickly and then deteriorate rapidly could be contributing to forage shortages on many farms.

Grass mixes based on shallow rooting varieties have long been popular with livestock farmers seeking high silage yields.

But drier summers mean root systems must reach deeper to access moisture – and shallow rooting grasses may not perform so well, explains Jim Juby, of forage specialists Horizon Seeds.

“Apart from the odd difficult year, ironically largely because of high rainfall in spring and early summer, ryegrass-based grazing and silage mixes have been the backbone of grass production over the last 20-30 years.”

Much of the conventional approach to maximising grass production has been based on mixes that are geared towards multi-cut silage systems. But Mr Juby says these mixes might not be best suited to the changing climate.

“The last five years have signalled the start of very different growing conditions for grassland in the UK,” he says.

“Climatologists largely agreeing conditions typified by earlier summer droughts will be more common in the future.

“With that in mind, producers in the worst hit parts of the country would be well advised to consider whether their choice of grass varieties is now contributing to their problems. If they think it is, they could adjust this to add greater protection against climate risks in the future.

“For many years we have been encouraging the more livestock-focused farmers to consider fescues in their mix as they are a lot more accommodating if your management is not always spot on.

“But now with other factors in play such as drier conditions, fescues, festuloliums and other more persistent grasses have valuable properties for all producers wanting to build greater resilience into their production systems.

Big advantages

Deeper roots, extended heading periods and a longer time after heading before plants deteriorate significantly are just a few significant advantages, according to Stuart Eglington of Horizon Seeds.

“The roots of ryegrass typically don’t extend much beyond the first six inches of soil and without regular rainfall they are unable to reach the vital ground water further down the soil profile.

Fescues and festuloliums on the other hand put deep roots down, says Mr Eglington. While they might be slower to establish, they keep growing unchecked in extended periods of low rainfall and are ultimately a lot more tolerant of drought.

“We’ve seen fescue roots going down to a one-metre depth and more – and this is invaluable when you consider the types of year we have had recently.

You can easily get two to three cuts of fescue-based swards even in fairly droughty years – in stark contrast to last year when many producers took a first cut and that was it until they were able to take a couple of cuts in the autumn, which ended up saving many.”

Fescues and festuloliums head over a longer period and take longer to deteriorate than ryegrasess, says Mr Eglington. They are easier to manage, particularly if bad weathermeans grass can’t be cut at the optimum moment.

“A high yielding ryegrass can be almost like straw within a week of heading whereas as a good fescue will probably take up to four weeks to reach the same stage. In good grass growing area a fescue-based mix should produce 60-70% of a ryegrass based one.

“But the gamble is whether you are better off being able to rely on this every year than losing everything in the years when more variable conditions – which are becoming more common – really take hold.”