Submitted to: Soil and Erosion and Global Change
Publication Type: Government Publication
Publication Acceptance Date: 5/5/1996
Publication Date: N/A
Interpretive Summary: Methane and nitrous oxide are two important gases contributing to global warming. Nitrous oxide emissions occur naturally from all soils, but the use of green manure or commercial fertilizer has been shown to increase the amount of nitrous oxide emitted from agricultural lands. Most soils consume methane reducing the amount of methane in the atmosphere. However, the use eof ammonia based fertilizer has been shown to reduce the amount of methane consumed at some locations. This study found no evidence of ammonia based fertilizer reducing the amount of methane consumed. Water stress during the summer was found to decrease methane consumption and tillage and crop residue management practices that conserved water increased consumption at several locations in interior Alaska.
Technical Abstract: Nitrous oxide and methane flux from or into soil was measured at Fairbanks, Alaska in fields, which had been in grass for many years. One field had been fertilized with urea for the last 10 or more years, and the other had no known history of ever receiving commercial fertilizer. There was no evidence of urea fertilizer reducing methane consumption, but urea did increase nitrous oxide emissions. Nitrous oxide and methane measured in field plots near delta junction, Alaska indicated that green manure and ure fertilizer both contributed to increased nitrous oxide emissions, with the greatest amount coming from urea fertilizer. Tillage and residue managemen studies showed that treatments with the least water stress (no-till) had th highest consumption of methane indicating that water stress can be a major caused of decreased methane consumption in agricultural field.