Apr 30, 2015 11:27 AM EDT
Organic Farming Could Reverse Global Warming
New research suggests that human reverse global warming by sequestering through regenerative, organic farming, ranching and land use.
Approximately 35 percent of global greenhouse gases come from agriculture. Researchers believe that increasing the soil's organic content will not only fix carbon and reduce several hundred billion tons of excess CO2, it will also improve the soil's ability to retain water and nutrients and resist pests and droughts.
Organic agriculture seems like an optimal choice to mitigate greenhouse gas emissions and retain soil fertility. This method could decrease the intensive use of synthetic fertilizers, protecting environments, and further improving crop yields.
Recent research showed that replacing chemical fertilizer with organic manure significantly decreased the emission of greenhouse gases. Organic farming can reverse the agriculture ecosystem from a carbon source to a carbon sink.
For the study, Jiang Gaoming, a professor at the Chinese Academy of Sciences' Institute of Botany, conducted an experiment on a temperate eco-farm in eastern rural China to explore the potential of farmlands acting as a carbon sink without yield losses. Crop residues were applied to cattle feed and the composted cattle manure was returned to cropland with a winter wheat and maize rotation. Crop yield and greenhouse gas (GHG) emissions were carefully calculated according to the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories 2006.
They found that replacing chemical fertilizer with organic manure significantly decreased the emission of greenhouse gases. Yields of wheat and corn also increased as the soil fertility was improved by the application of cattle manure. Totally replacing chemical fertilizer with organic manure decreased greenhouse gases emissions, which reversed the agriculture ecosystem from a carbon source (+ 2.7 t CO2-eq. hm-2 yr-1) to a carbon sink (- 8.8 t CO2-eq. hm-2 yr-1).
Making full use of crop residues as forage for cattle, collecting and composting cattle manure, and replacing part of the chemical fertilizer input with organic manure have been successfully shown to be ideal choices to reduce energy waste and cut greenhouse gases emissions without crop yield losses.
A combination of organic manure and chemical fertilizer demonstrated the best result in improving soil quality and crop yields, while decreasing greenhouse gases emissions. Solely utilizing chemical fertilizer on the farmland not only led to increased greenhouse gases emissions, but also deteriorated the quality of the soil.
The findings are detailed in the journal Science Bulletin.
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