NITROUS OXIDE EMISSION FROM AGRICULTURAL SOILS

A review of the salient features of N2O emissions from agricultural soils was done to assess our current understanding and associated problems. Nitrous oxide is an important globe warming gas and a destructive agent of ozone in the stratosphere. A major concern is the increasing contribution of chemical fertilizers to atmospheric N2O buildup. There is only a limited understanding of the contributions from manures, biological N2 fixation and crop residues. A recent estimate suggests that agriculture's share of N2O emissions is 80% although such estimates are highly uncertain because of imprecise data and the physical and biological complexities of the production process. As a product of the nitrification and denitrification process in soils, a major problem is our understanding of the proportion of N2O produced, i.e. the product ratios, although there is a good general understanding of the processes involved. Measurements of N2O emissions from the soil surface fail to take into account N2O flux from the bo...