DairyCo

Opportunities for new forage species

Published 7 March 11

A brief overview of the project outcomes

The Importance of Grasslands

Grasslands are one of the most important ecosystems and forms of land use in the world. They are crucial for food production and have ecosystem benefits. However, particularly when used for livestock production, they are also a significant source of pollution including the greenhouse gases methane and nitrous oxide. Energy inputs into grassland agriculture, particularly fertilisers, also contribute to greenhouse gas emissions.

It is very difficult to predict all impacts on traditional grassland due to climate change.

Likely responses include: increased herbage growth, increased use of forage legumes particularly white and red clover and alfalfa (lucerne), reduced opportunities for grazing and harvesting on wetter soils, greater incidence of summer drought and increased leaching from more winter rainfall.

Rainfall

There may be a reduction in grass yield (up to 2tDM/ha) due to the reduced summer rainfall in all but the North East and Scotland.

Flooding may become more common resulting in more water logged soils, increasing risk of poaching and damage to pasture and soil this could lead to fewer opportunities to over-winter animals outside or undertake extended grazing. This along with drier summers resulting in soil shrinkage can lead to compaction. If this is not corrected this will result in lower yields, increased risk of flooding and loss of soil and p

Environmental stress for example extreme rain closely followed by drought could make forage crops more difficult to manage and retain, with poorer germination and more weed ingress.

Carbon dioxide

Climate change means that there will be more CO₂ in the atmosphere.  As plants use the carbon from CO₂ acts as a source of carbon for plant growth, there could be a 15% increase in herbage dry matter yields per ha over the year as long as other factors do not limit growth.  As clovers respond more to higher atmospheric CO₂ than grass, it is likely that clovers will contribute most of this yield increase. This may result in higher red and white clover proportions in mixed swards.

Temperatures

Higher temperatures in spring lead to earlier heading in grass and heading dates have already advanced by 7.5 days every decade since 1978.

Earlier heading may allow for earlier cutting and grazing if management is changed, which may help in terms of getting maximum milk and meat production from grass.  However if management is not changed earlier heading can result in reduced forage quality - as grass matures fibre content increases and this can lead to reduced digestibility and energy content.

Ozone

Increasing ozone levels may reduce yields of forage crops in particular white clover and this may more cancel out the effect of yield increases due to increasing CO₂ concentrations.

Forages and grasses for the future

New mixtures of grasses and legumes may need to be developed as the climate changes.

For forage crops some adaptations for climate change will be common to all species whilst others will vary depending on whether the forage is part of a short term rotation or a long term ley

Selection and breeding of varieties better able to tolerate prolonged periods of drought are one area to focus on, along with using deep rooting forage mixes that can draw water from further down.

The key species of improved grasslands in substantial parts of Europe, Australasia and to a lesser extent North and South America are forage grasses in the families Lolium (ryegrasses) and Festuca (fescues) and forage legumes in the families Trifolium (clovers) and Medicago (particularly Medicago sativa, alfalfa (or lucerne)). These species are the major source of grazed and conserved feed for dairy, beef and sheep production.

Additional challenges for the Dairy Industry

The Milk RoadMap details a number of the key factors influencing the dairy industry to 2020. An important one is further reform of the CAP leading to competitive pressures and possibly greater intensification and larger herd size.  However, this could be accompanied by higher feed prices: an incentive towards greater reliance on home grown produce. A key component of this is sources of protein and therefore the importance of legumes whether grown on farm or imported. Within Europe, the need to increase home grown sources of high quality protein for reasons of traceability, environmental protection and self sufficiency has been recognised for a number of years (European Parliament, 2002).

 To download the report click here