June 18, 2012. By: adminThe International Potato Centre (CIP) urges global leaders at the the United Nations Conference on Sustainable Development (Rio+20) to highlight the critical role of soil management for sustainable agriculture and climate change, an area where Brazilian researchers are leading the way.
The Brazilian Agricultural Research Corporation (Embrapa) and CIP are spearheading research into carbon stocks to mitigate climate change. Soil contains more carbon than the Earth’s plants and atmosphere combined. When undisturbed, carbon retained in the soil enhances soil quality and productivity, but when land is cultivated carbon is released into the atmosphere in the form of greenhouse gases.
“Not many people realise that agriculture contributes close to 15 per cent of greenhouse gas emissions globally,” says CIP’s Roberto Quiroz. “It’s not talked about in climate change policy discussions and global accords because until recently it was difficult to measure carbon levels in the soil,” he adds.
“But now, using new spectroscopic techniques developed by Embrapa, we can accurately quantify soil carbon and measure its stability, so we can work with farmers to reduce carbon emissions.”
CIP and Embrapa’s research into soil carbon levels in five major agricultural regions in Peru has shown that wet grasslands and peat lands in the highlands have the highest concentration of carbon stocks – between 200 and 300 tonnes per hectare. These stocks are also at highest risk of being released into the atmosphere as farmers are increasingly moving their crops into these higher areas to avoid issues related to climate change found at lower altitude, such as drought, pests, and diseases.
To combat this problem, CIP is working with farmers in the Andes region to develop a number of potato varieties with drought-, pest-, and heat-resistant characteristics that can be grown in the existing lower-lying areas, leaving the vulnerable highland areas unaffected. Embrapa is taking this one step further by trialling methods to increase the amount of carbon stored in degraded pastures, thereby increasing soil fertility and slowing the pace of global warming through carbon sequestration.
“By replacing native vegetation with grasses such as Brachiaria decumbens, soil organic matter increased by 1.71 tonnes per hectare annually,” says Embrapa’s Aline Segnini, noting, “carbon accumulated at over two to three times this rate with the addition of fertilizer”.
“We believe that over time this will create greater carbon stocks, making tropical pasture lands suitable as long-term carbon sinks,” she said. No-till farming practices, which produce good yields without the need to turn the soil and release greenhouse gases, also represent an opportunity to increase soil carbon stocks. “There is real potential to mitigate the effects of climate change, while at the same time helping poor farmers to increase their crop yields and improve their incomes in a socially and environmentally responsible manner,” notes Quiroz .
“Simple steps towards sustainable development such as teaching farmers crop management techniques and water management processes that reduce carbon emissions could make a real difference, as could incentive schemes that encourage carbon neutral farming systems.
“These methods are applicable all over the world, especially in other regions that are already experiencing the effects of climate change, but until we can bring these discussions to the fore, agriculture will continue to add to the problem, instead of being a big part of the solution.”