Pasture: the secret to feeding the world?

20/04/2015

I recently had the pleasure of welcoming Dr John Meadley to Compassion’s Godalming headquarters to talk about the importance of pasture to producing decent food and higher animal welfare. John runs a new organisation of farmers passionate about keeping animals on grass called the Pasture-Fed Livestock Association. I am pleased to present this exclusive article by John on why the future is on pasture.

Ruminant livestock—particularly cattle—have been getting a pretty bad press recently. They are charged with causing global warming and consuming large amounts of grain that hungry people could eat. They destroy the rainforest in the process. Their manure pollutes the environment. Both red meat and butter take you to an early grave. Does this stand up to scrutiny? Or is it because ruminants are caught up in the emotive arguments around mega dairies and feedlots? In this three-part article, I will consider these issues and conclude with an explanation as to why the future is pasture.

Ruminants have the unique ability to convert grass and cellulose-rich foods into useable products such as milk, meat and leather. But in doing so they produce methane, one of the powerful greenhouse gases (GHGs). Feedlot cattle, raised on grain, grow more quickly than those raised on pasture. They produce less methane per pound of meat. Their lives are shorter. But this ignores the GHGs produced by the feed the animals eat (which has to be trucked in) and the manure they produce (which has to be disposed of).

There’s more to it than burps and farts. Grain crops are annual species. The land is cultivated for each crop, which dries out the soil, reduces the level of biological activity, and releases CO2. Manufacturing and applying the nitrogen fertiliser they need produces more than 3kg of CO2 per kg of nitrogen applied, which in turn consumes more than 1% of the world’s energy. According to the Centre for Ecology and Hydrology, on average, over 80% of nitrogen applied ends up lost to the environment, wasting the energy used to prepare it, and causing pollution through emissions into the atmosphere and compounds into the waterways. Planting, spraying, harvesting and transporting also uses a lot of energy. A typical feedlot steer in the US will consume the equivalent of around 275 gallons of oil in its lifetime.

In contrast, most of the world’s pasture is permanent. The leys that enrich an arable rotation are replanted only occasionally. Grazed pastures require little (if any) artificial fertiliser. The animals’ manures go back directly onto the land. Nitrogen is produced naturally by legumes (typically clovers), a process which takes CO2 out of the atmosphere. The UN Environmental Programme reports that pasture also removes carbon from the atmosphere into its roots and the surrounding soil at the rate of 200-500 kg/ha/year. This helps to explain why the world’s soils are the largest terrestrial reservoir of carbon, containing three times as much as the atmosphere, and five times that of the world’s forests. There is growing evidence that ruminants raised wholly on pasture can be carbon-neutral and in some cases carbon negative.

In the second of this three-part series, John Meadley takes a look at other issues which explain why the future is pasture.