The livestock sector’s reliance on soya, maize and wheat leaves it vulnerable to the effects of a changing climate, according to Dr David Styles, a lecturer on carbon footprinting at Bangor University in the UK.

Speaking at a climate change conference in London last week, Dr Styles said that many dairy and beef farming systems around the world had moved cattle on to high-concentrate diets in the belief that this would intensify the animal’s production and lower carbon emissions per unit of milk or beef.

However, Dr Styles said this was a very “narrow” way of thinking about production efficiency in the overall climate change debate.

“Intensifying production in this system may look efficient from a climate change perspective by using a very narrow metric of kg of CO2/litre of milk or beef produced. However, it actually becomes very inefficient when you think about the global food system and interactions between cropping systems and livestock that arises as a consequence of the transition to higher concentrate diets,” said Styles.

According to Styles, this focus on animal level efficiency has made global agriculture more reliant on crops such as maize, soya and wheat, which are vulnerable to climate change.

“We’ve become heavily dependent on these short crop rotations which are contributing to soil organic matter depletion, as well as a lack of resilience and biodiversity in crop systems,” said Styles.

“In the US and Brazil, it’s typical for farmers to use a maize-soya rotation, while in Europe we’ve got wheat-barley-oilseed rotations.

“Those short rotations are linked with a number of challenges that are becoming increasingly apparent,” he said.

Crops reach a yield plateau

Styles added that he could see many of these crops were reaching a yield plateau.

“We’re starting to see yield plateaus globally for wheat and other important staples such as rice and maize. Yet we’re relying on these crops more than ever to feed our livestock, which is a vulnerability. These yield plateaus in crops might be climate related but it’s also partly down to soil degradation. We’ve been mining the soils for the same nutrients for decades for these same crops,” said Styles.

In 2019, there was heavy flooding across the US Midwest, which will see a big drop off in US soya bean production this year.

At the same time, wheat yields are back in Russia and France, while maize yields are also down in China, Brazil and France. Soya is particularly important to feed the global livestock sector.

“Soya requires quite a lot of water to grow. Growing 1kg of soya beans requires over 2,100 litres of water. And almost one-fifth (19%) of the world’s soya beans are produced in areas of water stress, while 8% of global soya is produced under irrigation,” said Styles.

“The EU’s livestock sector relies on importing 17m tonnes of crude protein every year. About 13m tonnes of this is soya.

“And a lot of that soya comes from Brazil, which accounts for 30% of the world’s soya bean needs,” he added.

Brazil is particularly vulnerable to the impacts of climate change with the average length of the yearly dry season increasing over recent years.

In the last decade, Brazil has experienced a number of droughts (2005, 2010 and 2015) and flood (2009 and 2012) events, which will only be exacerbated by climate change, said Styles.

To reduce this reliance on imported soya and maize, Styles believes Europe needs to dramatically increase its production of protein crops and legumes. At present, less than 2% of the arable land in the EU is used to grow legumes compared with 20% in other countries.

Pea gin

Styles gave the example of using peas as a feedstock to produce gin.

“We carried out a recent study where we used peas instead of wheat to produce gin. This is not a new technology but by changing the feedstock from wheat to peas you drive up the demand for peas. This means farmers can diversify their crop rotations and move away from those short rotations. Peas will also fix nitrogen for the next crop reducing the need for fertiliser,” said Styles.

On top of this, using peas to make alcohol leaves behind a much higher protein by-product from the distillation process. Many Irish farmers use distiller’s grains from the whiskey industry as cattle feed. This product is made from spent wheat or barley grains and has a typical protein level of 13% to 18%.

Using peas in the distillation process would leave behind a far more protein rich by-product to use as animal feed – roughly double that of wheat or barley distiller’s grains.