Could Grass Roots Save us From Climate Change?18 September 2013
GLOBAL – A tropical grass could hold the key to reducing greenhouse gas emissions from livestock.
Scientists are saying that a chemical mechanism exists in the roots of Brachiaria species, called ‘biological nitrification inhibition’ (BNI).
It works by reducing the conversion of nitrogen into nitrous oxide when put on nitrogen is put on soil, according to research soon to be unveiled at the 22nd International Grassland Congress.
Studies have found that a maize crop grown after Brachiara humidicola pastures yielded well after nitrogen inputs were halved, due to more nitrogen being retained in the soil.
Project leader, Michael Peters of the International Centre for Tropical Agriculture (CIAT) described BNI as agriculture’s ‘best bet’ for keeping climate change ‘within manageable limits’.
“Nitrous oxide counts for around 38 per cent of greenhouse gas emissions in agriculture, which accounts for almost a third of total emissions worldwide,” said Mr Peters.
"Livestock production provides livelihoods for a billion people, but it also contributes about half of agriculture's greenhouse gas emissions," Mr Peters explained. "BNI is a rare triple-win technology that's good for rural livelihoods as well as the global environment and climate. It defies the widespread notion that livestock are necessarily in the minus column of any food security and environmental calculation."
To reduce nitrogen waste, improvements can be made but farming systems need to change, according to Indupulapati Rao, CIAT scientist.
He says that modern grassland and arable farming is ‘very leaky’ with about 70 per cent of all nitrogen applied lost though leaching and nitrous oxide emissions.
This loss has a value of US$90 billion.
Covering 3.2 billion hectares, grassland is the biggest use of agricultural land out of a total 4.9 billion hectares.
“In Brazil alone, 11 million hectares of grassland have been converted to maize and soybean production, and another 35-40 million could be shifted to crop production in the near future,” said Mr Rao.
“Instead of more monocropping, developing countries need to integrate Brachiaria grasses into mixed crop-livestock systems on a massive scale to make them more sustainable."
Brachiaria grasses were originally from sub-Saharan Africa although found their way to South America.
Today they are gown on pasturelands in Brazil, Colombia and other countries and have recently been taken back to Africa to relieve forage shortage pressures.
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