26) Can Agriculture Be an Ally against Global Warming? (23 April 2001)

Long-Term Experiments by ICRISAT Reveal that Improved Soil Management Practices Help to Increase Carbon Sequestration

Global warming is likely to induce devastating cyclones, floods, and droughts worldwide over the coming decades, according to the recent U.N. report on Climate Change. These events will especially hurt the poor of the developing world, who will have little means to cope.

Fossil fuel combustion, generating massive carbon dioxide emissions into the atmosphere, is thought to be a major cause of global warming. Many suggest that polluting industries should pay the cost of cleaning the carbon back out of the atmosphere again.

Plants can help clean the atmosphere by 'sequestering' carbon as plant tissue through photosynthesis. A new agricultural enterprise can be envisioned in which farmers accept payments from urban industries to scrub their pollutants back out of the atmosphere - so-called 'carbon markets' that balance industrial needs against environmental concerns.
But would these gains be real? The only way to confirm net carbon sequestration is to track soil carbon patterns over long periods of time in particular agro-ecosystems.

Experiments ongoing since 1976 on Vertisols (heavy black clay soils) at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), based at Patancheru, Andhra Pradesh – recently revealed that improved management practices have indeed sequestered an average of 335 extra kilograms of carbon per hectare per year over the 24-year period, compared to traditional practices.

“Over a 10-year period, it may be possible to sequester about 0.5 gigatons of atmospheric carbon from 1.49 million km2 Vertisols in the semi-arid tropics," said ICRISAT Soil Scientist Dr. S. P. Wani. “In an eventual carbon market, this might have a value somewhere between US$ 10-15 billion - funds that could be used to address food security and environmental quality.”

The management practices that helped increase carbon sequestration included multiple cropping, fertilizer application, and the addition of legume crops to complement the traditional cereals. These practices also increased farm productivity and farmer income, creating a win-win situation for both the environment, and for the poor farmer.

Excited by these findings, the Government of India is now funding a 3-year project on 'Identifying systems for carbon sequestration and increased productivity in semi-arid tropical environments', engaging ICRISAT and three member institutions of the Indian Council on Agricultural Research - the Central Research Institute for Dryland Agriculture (CRIDA), the Indian Institute of Soil Science (IISS), and the National Bureau of Soil Survey and Land Use Planning (NBSS&LUP). The project will study carbon stocks in soil profiles at 26 selected locations across the semi-arid tropics of India, seeking a better understanding of why some systems sequester more carbon than others.
For more information, contact: s(dot)wani(at)cgiar(dot)org.

by ICRISAT. All rights reserved.