I just found out about greenhouse gases on my dairy farm

Well, that was an interesting exercise. Gillian Hayman took all our farm data and produced some colourful charts with the Dairy Greenhouse Gas Abatement Strategy calculator. Like most animal-centred farms, the vast majority of our emissions come from the methane burped up by the cows.

Source of farm greenhouse gas emissions

Where our greenhouse gases come from

In total, our farm produced 13.3T CO2e per tonne of milk solids in 2010/11 – quite a bit above the average 10.2T CO2e per tonnes of milk solids recorded by the DPI Farm Monitor Project of 2009/10. Why is it so? Ironically, it could well be because our cows eat so much grass rather than grain.

So, what should a dairy farmer do?
According to the authorities:

“Production improvement options and best management practices are most often linked to greenhouse gas emissions reduction. At present, well managed farms have few options to reduce emissions without significant changes to their farming or feeding system…A great deal of research is underway within the Australian dairy industry to decrease the release of methane and nitrous oxide from farming systems.”

In the meantime, we will keep planting trees and be judicious with our fertiliser use.

Farming and the carbon tax

Cow wearing a monitor to detect methane gas production

Cow wearing a monitor to detect methane gas production - pic by DPI Victoria

Donald Rumsfeld could have been talking about the impact of the carbon tax on farming and agriculture when he infamously said:

“Reports that say that something hasn’t happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns — the ones we don’t know we don’t know.”

The politics of carbon are still in full swing and it’s too early to say for sure how we will be affected but there are some things we do know:

1. Agriculture is the second biggest source of Australia’s greenhouse gas emissions – just ahead of transport

2. Much of current best-practice farming minimises emissions

In a recent study (see link at point 2 above), Department of Primary Industry researchers say:

“We calculate, therefore, that in 1980 an Australian dairy cow emitted approximately 33 gm of methane for each litre of milk produced. But, in 2010, because of better feeding practices, genetic improvements, higher per cow milk production, and efficiency improvements adopted by the Australian dairy industry, this number has fallen to approximately 24 gm of methane per litre of milk produced.”

Great news! We are doing well, you say? The only problem is that until science provides us with some more tools, we cannot achieve a lot more. As the researchers go on to say:

“As a greenhouse gas, methane is about 25 times more powerful than carbon dioxide and methane emissions from cows constitute about 65 per cent of the total dairy farm greenhouse gas emissions.”

Meanwhile, as Neil Lane of the Carbon Ready Dairy Demonstration Project notes:

“Highly digestible feed and cereal supplements, along with products like Rumensin, are the best way to minimise emissions at the moment. Many dairy farmers are already doing this.”

This may be why agriculture has been excluded from the carbon tax, although our inputs, like fertiliser and fuel will not be exempt. On the other hand, the much-touted Carbon Farming Inititiative seems equally as impotent to this dairy farmer.

Reforestation and revegetation isn’t really an option because each planting needs to be at least 2ha and 10 metres wide. Soil sequestration sounds wonderful but the fact is that the rich fertile soils of dairy farms are generally already high in carbon content. The other options of reduced fertiliser emissions and effluent management are already being practised on our farm and, as I understand it, would therefore be ineligible under the CFI.

Will be interesting to see how it all pans out and I would love to hear from anyone who sees lots of emerging opportunities for dairy farmers to actively participate in the carbon economy.