Nitrous oxide emissions and soil mineral nitrogen status following application of hog slurry and inorganic fertilisers to acidic soils under forage grass

• Published in: Canadian journal of soil science Vol. 88; no. 2; pp. 145 - 151
• Main Authors: Mkhabela, M.S, Gordon, R, Burton, D, Madani, A, Hart, W
• Format: Journal Article
• Language: English
• Published: 01.04.2008
• Subjects: acid soils; ammonium sulfate; fertilizer application; forage grasses; gas emissions; mineral fertilizers; nitrate availability; nitrates; nitrogen; nitrous oxide; pig manure; potassium nitrate; soil fertility; Nova Scotia
• ISSN: 0008-4271; 1918-1841
• DOI: 10.4141/CJSS06024

Field application of livestock slurry often results in higher nitrous oxide (N 2 O) emissions than inorganic fertiliser, because slurry contains large amounts of available N and C, and when applied it increases soil water content, thus enhancing denitrification. This study evaluated the impact of hog (Sus scrofa) slurry and inorganic fertilisers on N 2 O emissions and soil inorganic N. Three short-term (3 wk) field experiments were conducted during summer 2005 on two contrasting acidic soils seeded to forage grass. Treatments included hog slurry (Slurry) at 126 kg N ha -1 , potassium nitrate (Nitrate) at 120 kg N ha -1 , ammonium sulphate (Ammonium) at 120 kg N ha -1 , Carbon (Dextrose) at 500 kg ha -1 and an unamended control (Control). Potassium nitrate increased (P< 0.05) cumulative N 2 O losses compared with the other treatments. Emissions of N 2 O from Slurry and Ammonium were similar, but higher than from Dextrose and Control, which were similar. Soil NH 4 + -N contents for Slurry and Ammonium treatments were generally similar but higher than for the other treatments, particularly during the first and second sampling dates. Soil NO 3 − -N contents, meanwhile, were higher with the Nitrate treatment compared with the other treatments, especially at the first sampling date. These results imply that N 2 O production in these acid soils was limited by NO 3 -availability. Therefore, N 2 O emissions from these soils can be minimised by using ammonium-based fertilisers including hog slurry rather than nitrate-based fertilisers. Key words: Acidic soils, hog slurry, mineral fertiliser, soil nitrogen, N 2 O emissions