Soil cover methods are probably the most widely used methods for measuring
the nitrous oxide emission rate from the soil surface. The methodology invo
lves estimation of the emission rate from repeated measurements of the nitr
ous oxide concentration beneath a soil cover. Based on a deterministic mode
l proposed by Hutchinson & Mosier (1981) we propose to use a diffusion proc
ess as a stochastic model for the evolution of the nitrous oxide concentrat
ions beneath a soil cover. From this model we derive methods for statistica
l inference about the emission rate that significantly extend the method pr
oposed by Hutchinson & Mosier (1981). In particular, the derived methods pr
ovide solutions to important problems with the method proposed by Hutchinso
n & Mosier (1981).