Changing farm management practices can provide real, if not modest, contributions to carbon sequestration in the Pacific Northwest.
That's the conclusion of two recently published studies by Washington State University researchers, according to a news release.
Carbon sequestration is the storage of carbon in soil.
Basically, the more productive the soil, the more carbon it can potentially store until it reaches saturation. Then it begins to release carbon.
Carbon, when combined with oxygen, creates carbon dioxide. Recently, the molecule has come under fire as a greenhouse gas that contributes to global warming or global climate change.
The exact amount of carbon that Pacific Northwest soils can store is difficult to assess, although a modest estimate is less than 1 percent of Washington's total greenhouse gas emissions, according to the release.
Nevertheless, the researchers say the promise of carbon sequesetrationo is real enough to warrant further study.
Among the practices that require further evaluation are:
• Using nitrogen fertilizer can increase nitrous oxide (a potent greenhouse gas) emissions and thus counteract the benefit of soil carbon sequestration.
• Including legumes in a cropping system requires less nitrogen fertilizer but produces less biomass and therefore stores less carbon than cereal-based crops.
• Organic farming systems tend to be more dependent on tillage to control weeds, and tilling soil requires fossil fuels and releases stored carbon.
The study studies were:
"Soil carbon sequestration in the dryland cropping region of the Pacific Northwest," available online at http://bit.ly/YtFHs4.
"Carbon storage and nitrous oxide emissions of cropping systems in eastern Washington: A simulation study," available online at http://bit.ly/UzmpUr.