Grassland conversion warning | The Scottish Farmer

Converting cattle farms to arable land would mean regular crop failures, some of the UK’s top agri-scientists have warned.

As society is increasingly urged – or pressured – to shift towards a more plant-based diet, it’s common to hear activists claim that the land currently dedicated to grazing could produce a lot more food if it were rather dedicated to cultures.

But a new study from Rothamsted Research, also involving SRUC, has challenged that easy assumption and pointed out that certain soil types and climates will not adapt easily to conventional arable farming.

The Rothamsted-led study focused on the South West of England and concluded that the chances of successfully growing winter wheat on fields once used to raise cattle could be as low as 28% in the future, as increased rainfall will make field access impossible for machinery.

While forecasts show that in the absence of climate change yields could be over 14 tonnes per hectare – but when the almost certain impact of increased future rainfall on sowing and harvest dates has been included in the simulation, it fell in some situations to less than three tonnes per hectare.

Lead author Dr Lianhai Wu said, “Adapting to climate change and changing consumer demand will require us to diversify land from its current uses. Cattle grazing is the main type of agriculture in the West of the British Isles and it has been suggested that the grasslands in the area could be converted to other land uses, such as growing cereals.

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“However, our simulations suggest that, for the South West of England and regions under a similar combination of soil types and climates, planting winter wheat between October and December would be impractical in some years due to constraints on the “workability” of the soil.”

The study, which also involved the SRUC, looked at three common soil types in the South West, under the current climate and three Met Office climate forecasts, which show the number of heavy rain days – those with more than 2cm of rain – will increase in the southwest by six, to 17 days a year, by the end of the century.

Delays in planting and crop failure in some years due to wet weather have made the idea of ​​converting to arable crops a “no go” for herders in the southwest, Dr Wu said. “But the question remains – if we are going to eat less meat and raise fewer livestock, what happens to those farmers and those agricultural areas? »

The study also looked at the implications for soil carbon storage and greenhouse gas emissions if grassland cut three times a year to provide silage was converted to winter wheat – and found that although the average greenhouse gas emissions from ryegrass grown in soil were higher than those from the same land converted to wheat, this was offset by the greater amounts of carbon stored in the ryegrass. fat.