Best Agricultural Practice for the Protection of Air

Keywords: Best agricultural practice, Carbon dioxide, Ammonia, Nitrogen oxides, Methane.

Various gases are taken up or emitted as a result of agriculture: carbon dioxide, ammonia, noxious odours, nitric oxide, nitrous oxide and methane. They all impact on the environment. Good agricultural practices can keep such emissions to a minimum:

– Appropriate fertilisation and waste management ensure high yields and reduce the need for clearing new land with associated carbon dioxide emissions.

– Emissions of ammonia and odours originate mainly from farm animals and their waste. Cleanliness in animal housing, covered waste storage and rapid incorporation of manures after spreading ensure low emission levels.

– Inputs of nitrogen (N) (especially as NH₃/NH₄⁺) diminish the capacity of soils for the removal of atmospheric methane by oxidation. Hence diminished ammonia emissions and depositions are also desirable for this reason.

– Emissions of nitrogen oxides originate with microbial transformation of N compounds in the soil. Measures designed to counteract nitrate leaching curtail N availability for such transformation outside the growing season and also serve to diminish nitrous oxide emission.

Oluf Chr. Bøckman, Norsk Hydro Research, Porsgrunn, Norway.

20 pages, 2 tables, 32 refs.