Developing drought tolerant grasses
WITH the Met Office and Defra warning this year could be year another of low rainfall and dry conditions across the UK, research into the water-use efficiency of grasses has gained even more importance to livestock farmers in particular.
Encouragingly, a programme at IBERS Aberystwyth University as part of The Sustainable Livestock Production (SLP) LINK Programme is reporting significant progress in producing stress-resistant festuloliums, which are fescue cross ryegrass hybrids.
According to Dr Mike Humphreys of Ibers, results from their simulated drought trials under controlled conditions have already been very promising.
“We have recorded an improvement in water use efficiency, which is the forage yield per unit of water consumed, in some festuloliums of 88 per cent,” he says.
“Drought resistant lines from the LINK Programme are now being field tested for their suitability for entry into National List trials this year.”
Earlier breeding work at IBERS resulted in the first festulolium coming onto the England and Wales Recommended Lists for 2012.
AberNiche, an Italian-type ryegrass cross meadow fescue, is now available in drought-tolerant seeds mixtures.
AdaptedDr Humphreys says this heralds the beginning of a range of new grasses more adapted to a range of stress conditions that may become more common as a result of climate change.
“AberNiche has been bred through natural hybridisation as part of a programme designed to increase stress resistance, including winter hardiness and drought tolerance,” he says.
“Improved root systems are bringing environmental benefits, such as more efficient water and nutrient use and carbon sequestration.
“This variety shows the transfer of more stress resistant fescue genes into ryegrasses can be achieved without negatively affecting the yield or quality characteristics of the grass.
Improved root systems are bringing environmental benefits, such as more efficient water and nutrient use and carbon sequestration“In addition to the development of drought-tolerant Italian ryegrass cross fescue hybrids, we are also working towards introducing the beneficial fescue genes into perennial ryegrasses. This will expand the scope for utilisation by livestock farmers quite significantly.”
For now, the approved and available festulolium AberNiche can be combined in short-term mixtures with Italian or hybrid ryegrasses, whilst those seeking a long-term grass-based mixture can consider the inclusion of cocksfoot alongside perennial or hybrid ryegrasses, plus white clover.
As Paul Billings of British Seed Houses points out, there are alternative forage crops that also provide a solution to dry conditions with breeding progress again offering livestock farmers better options than in the relatively recent past.
“Perennial chicory has become increasingly popular in recent years, mainly used within grazing mixtures alongside perennial ryegrasses and often white clover,” he says.
“Bred and used extensively in New Zealand, new varieties such as Puna II perennial chicory are performing well in UK conditions. This produces high yields of quality grazing suitable for cattle and sheep and – due to its deep tap root – is much more resilient in dry conditions than ryegrasses.
Interest“Lucerne is another forage crop attracting increased interest amongst UK livestock farmers and is more typically grown as a monoculture to provide three or four silage cuts in a season.
“Like perennial chicory, lucerne has a deep tap root, which gives it the ability to perform in dry conditions. Being a legume, lucerne also generates its own supply of nitrogen through fixation and helps reduce the reliance on bought-in fertiliser.”
In addition to alternative forage crop options, increased productivity in dry conditions will be achieved by maintaining good soil structure, avoiding compaction and including more traditional companion species, such as white clover or red clover, in rotations.
“Ryegrass swards containing white clover will tend to perform better in dry conditions,” says Mr Billings.
“White clover roots will tend to help improve overall soil structure, which means all plant roots are better able to locate water. Red clover is similar to perennial chicory and lucerne in that it has a deep tap root that can penetrate further into the soil profile.”