Simulating the effectiveness of surface film on water evaporation and ammonia volatilisation

The application of surface films to flooded rice fields is one of the most effective measures of controlling ammonia volatilisation for improving nitrogen use efficiency. The feasibility of using a surface film is determined to some extent by the longevity of the effectiveness and this has never been estimated accurately in the field. The concept of half-life was introduced to estimate the effective life of a surface film by calculation from its effect on water evaporation. A simple laboratory experiment was carried out to validate the usefulness of the half-life concept. The results showed that effects on ammonia volatilisation could be quantified using a logistic equation based on the half-life concept. Keywords: half-life, logistic equation Australian Journal of Soil Research 40(7) 1243 - 1248 Full text doi:10.1071/SR01027 © CSIRO 2002