Sustainable farming practices key to combating climate change | Global Ideas | DW | 01.03.2011
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Global Ideas

Sustainable farming practices key to combating climate change

What do insects, trees and agricultural crops have in common? They can all play a role in making farming more sustainable and environmentally-friendly and contribute towards ensuring food security.

A farmer harvesting sorghum seeds in Sudan

Grain sorghum is the fifth most important cereal crop grown in the world

The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has an outpost in Mali where researchers study sustainable farming - investigating new varieties of sorghum, for example. Along with rice, wheat and corn, sorghum is one of the world's most important food crops.

The researchers involve local communities in their efforts to grow different crop varieties, with men helping out on the fields and women cooking with what they harvest. Local farmers continue growing the most promising new crops.

The scientists' aim is not just to develop more resilient crops but also to help secure small farmers' livelihoods. According to a recent study by the United Nations Conference on Trade and Development, smallholder farms could be the key to reducing climate change and securing food supply.

The report concluded that innovations and major improvements in cultivation methods used by smallholder farmers are needed to restore food security, and urged a "green revolution" built on technology and innovation aimed at the needs and capabilities of millions of smallholder farmers and at coping with varying climate conditions.

In search of perfect rice

Farmers in rice paddies

Rice is usually cultivated in flood-prone regions where few other crops would survive

In both Africa and Asia, populations are growing rapidly. Their diet consists primarily of rice. But rice farmers are hard hit by climate change, with the rainy season less predictable than ever before.

The result is that farmers are unable to plan their planting and harvesting and are therefore seeing lower yields. At the International Rice Institute, IRRI, in the Philippines, experts are conducting research to improve rice for better grain quality and higher yield, resistance to pests and diseases and tolerance of environmental stresses. This involves genetically modifying the rice in laboratories.

Using less water in the rice fields is a first step to making rice farming greener. The warm, waterlogged soil of rice paddies provides ideal conditions for methanogenesis. Studies show that methane is up to 30 times more harmful for the environment than CO2. Much of the methane produced by human activity (300 to 400 million tons a year) originates in rice fields, 90 per cent of which are in Asia.

One way to tackle this problem is to flood the rice paddies every few days – rather than having them permanently flooded. This way, the fields dry out and the soil-dwelling microbes die. The microbes absorb carbon released by the plants' roots and use it to make methane, which is then released into the soil and emitted from there into the atmosphere.

This method saves water and reduced methane emmissions. But its success is a matter of debate.

"Rice is farmed in regions that get flooded by monsoons and where there is therefore no alternative to rice," agroecologist Folkard Asch from the University of Hohenheim in Germany said.

Methane would be released even in the absence of rice paddies, since all waterlogged fields inevitably contain the microbes. Asch has conducted research to find out how rice reacts to altered climatic conditions and established that rice farming that uses less water only yields satisfactory harvests in peak seasons. But if the climate changes, yield is immediately affected.

Antagonists as aids

Insects feeding on small planthoppers

Antagonists are used in the management of diseases in fields

Josef Settele from the Helmholtz Center for Environmental Research takes a different approach, and proposes a more natural method of making rice farming more sustainable:

"The use of antagonist insects means we don't have to resort to genetically-modified plants which are more resistant to pests," he points out. Antagonists are the natural enemies of pests and not only useful to farmers but also to the environment, since they mean farmers can use less pesticides. In order to encourage them to breed, the rice paddies should be surrounded by natural and diverse vegetation.

This method would protect against erosion, stabilize the water supply and help secure stable yields. According to Stefan Sieber from the Leibniz Center for Agricultural Landscape Research (ZALF), agriculture in general is seeing a shift away from monocultures to intercropping – with farmers growing trees, for example, in between rows of sorghum.

It is increasingly obvious that sustainable farming is slowly becoming the only option, stresses Marita Wiggerthale from Oxfam. "It reduces poverty, boosts the food supply and reduces the effects of climate change," she says.

But flawed farming practices are not the only reason for world hunger. According to one US study, 25 percent of food in the US is thrown out. Improved distribution of the world's resources is therefore key to food security. Sustainable agriculture is just one part of the solution.

Author: Michaela Fuehrer (jp)
Editor: Sonia Phalnikar

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