Did you know that unused steppe and prairie areas emit much more of the dangerous GHG nitrous oxide than if they are used as pasture lands?

Long term studies in the Mongolian steppe proved that, especially after snow-melt, bacteria in the soil produce much nitrous oxide out of plant residues. However, if there are grazing animals like cattle to keep the grass short, fewer snow is able to linger and thus there is less melt water in the spring to wet the soil. The bacteria don’t like that, just as they don’t like the cold due to fewer snow on the ground in the winter, and produce much less nitrous oxide out of the lesser plant residues, even if adding the manure left by this grazing animals.

The scientists point out that this applies only to areas with a freezing season and refers only to the GHG nitrous oxide and not to the methane produced by the grazing cattle or other ruminants. Methane and nitrous oxide are both GHGs where methane has 25 times and nitrous oxide 298 times more global-warming potential than carbon dioxide. That’s why they recommend to mow the grass before winter to keep it short instead of using cattle to do it. But since the cattle are already existent (they do, but living in a stall and are fed with grain, corn or soy), and the pasture lands are already there and not easily to mow (like in the Alps or other mountains) – why not?

I know that dairy cattle nowadays are specially bred to give more milk and need therefore special feed – but do we really need that much diary products?

Especially since grain, corn or soy need more and more cropland (often formerly forests in South America) which leads to huge amounts of nitrous oxide due to fertilizer use and giant amounts of carbon dioxide, since the no-longer-forests cannot store it anymore. If the cattle stay on pasture and fed on grass, they don’t need that much corn or soy – more than a third of the worldwide grain harvest is fed to cattle, pork and co.

But there is more: Grazing secures humus in the soil, and every tonne humus is able to store more than 1.8 tonnes carbon dioxide.

Sources: Fewer nitrous oxide emission due to grazing cattle and cattle is no climate killer

Advertisements