No-till agriculture in heavy clay soil may increase nitrous oxide emissions

EurekAlert: …Soils under no-till usually host a more abundant and diverse biota and are less prone to erosion, water loss, and structural breakdown than tilled soils. Their organic matter content is also often increased. In addition, no-till is proposed as a measure to mitigate the increase in atmospheric carbon dioxide concentration. To assess the net effect of no-till on greenhouse gas emissions, other gases also have to be examined.

Researchers at Agriculture and Agri-Food Canada (Québec City) investigated the short-term impacts of no-till on soil nitrous oxide emissions. They compared emissions of nitrous oxide as well as nitrogen contents and physical properties between moldboard plowed (early fall) and no-till soils near Québec City, Canada. Measurements were made during three growing seasons in a poorly drained clay and a well-drained loamy soil cropped to barley. The results of the study were reported in the 2008 September-October issue of the Soil Science Society of America Journal.

The authors concluded that their investigation indicates "that no-till can result in incremental nitrous oxide emissions that can more than offset the soil carbon dioxide sink during the first 5 yr after adoption of this soil conservation practice in a heavy clay soil…. Consequently, the potential of no-till for decreasing net greenhouse gas emissions may be limited in fine-textured soils that are prone to high water content and reduced aeration"….

Spare the plow? An afalfa field shown here