Why dairy farmers are looking to the sea to reduce methane emissions

From theguardian.com

Many Australian dairy farmers are actively taking steps to reduce their environmental impact. A native sea plant could be the next big thing.

In the picturesque Tasmanian Midlands, Richard Gardner has been farming dairy for seven years. His 1,250 cows roam 336 hectares of irrigated land, producing and supplying milk to Fonterra. He calls his farm a “non-traditional dairy” - he’s not in a typical dairy region, and shifted to dairy from sheep and cropping.

Like many dairy farmers, Gardner is conscious of his impact on the environment. Like all cattle, his herd contributes greenhouse gases to the atmosphere, but Gardner has been proactive on climate change for two decades. (Agriculture accounts for approximately 13% of Australia’s total emissions, while greenhouse gas emissions from the dairy industry as a whole represent 12.5% of this total).

“Climate change is the greatest risk to humanity,” he says. “It’s something we all need to concern ourselves with.”

Finding a way to offset his impact is a priority for Gardner, and he has trialled a variety of ways to reduce his greenhouse gas emissions.

“One challenge is that we use a lot of nitrogen fertiliser,” he says. “You can reduce the amount of mineral fertiliser by encouraging legume plants. But it’s not as simple as it sounds, and takes significant time and management.”

While there are many tech options that have been useful to explore, Gardner says it’s a more unlikely source that’s got him really excited: red algae, or Asparagopsis, growing in the waters of our southernmost state.

“I’m excited to be part of the early development of this - there’s a huge amount of excitement from all sides,” Gardner says.

In these pristine waters, red fronds shift with the water, feeding off natural resources and returning oxygen to the atmosphere. Seaweed has been known to reduce emissions for some time, but Australia is using it to take significant strides towards a greener future.

The Australian dairy industry accounts for 2% of total national greenhouse gas emissions, and methane from enteric fermentation makes up the majority of on-farm emissions (57%).

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