The University of Reading has released a study which shows climate change is damaging yields of hay crops, according to a report published in the Journal of the Royal Society Interface.
The long-term study analysed more than 100 years of data showing that hay yields have already been reduced by more than a third as a result of climate change.
Warmer, drier autumn and winter seasons, have seen reduced yields, with warmer springs also causing a similar effect.The report notes that optimum spring weather for crop growth is colder and wetter, and springs are also generally expected to become warmer and drier too.
As a result, the study predicts that between 2020 and 2080, hay yields will decline by a further 20 to 50%.
As part of a partnership between the University of Reading and Rothamstead Research, data from between 1902 and 2016 were collected in the Park Grass long-term experiment at Rothamsted’s main site in Harpenden, Hertfordshire.
A new statistical modelling approach was used to analyse the data, taking into account unusual patterns of yield variability.
Dr John Addy, a statistician at Rothamsted Research and the study’s lead author said, “The precise response of spring hay yield to temperature and rainfall varied during the year but there is an optimum “Goldilocks” spring rainfall and temperature associated with the maximum level of yield.
“Changes in autumn and winter temperature had more of an effect on yield than autumn and winter rainfall.”
“Managed grassland (rough grazing and pasture) is the UK’s largest crop by area at over 12 million hectares; it underpins a livestock sector worth over 13 billion GBP each year.
“Spring hay and silage is fed to livestock throughout the winter and in also in times of summer drought, as is the case this year.”
Professor Richard Ellis of the school of agriculture, policy and development at the University of Reading added “The 115 years of results from the Park Grass experiment allow us to analyse the consequences of the previous year’s weather on yield.
“There is a substantial legacy effect in this perennial crop: if the weather in one year is poor for hay yield, then yield in the following year is also reduced to some extent and vice versa. This is highly relevant to the resilience of farming businesses.”
While the projections are specific to the Park Grass site, experiment has been designed so that “a range of grassland systems” are studied, varied by levels of fertilizer.
The relative effect of climate change on yield was “remarkably” similar across all of the controls.
Professor Ellis explains: “Many livestock farmers in the region have already responded to change,” says the increase in the area of forage maize over the past half century being but one example, but future investments in milk production from grass are more likely to favour the wetter and cooler regions of the UK.”
Hay can make up as much as 100% of the diet of grazing animals, especially during drought or during winter, and is an essential fodder for keeping livestock.
The research is published in the Journal of the Royal Society Interface on Wednesday, August 24.
