  The work which we present takes place within the framework of mission SMOS of
the ESA which will consist to send a radiometer (1.4 GHz) in space. The goal of
the research which we propose is the improvement of the comprehension of the
effects of structures composed of soil and litter. The effects of the litter
and heterogeneities of the ground are probably important but still ignored. The
objective of this work was to study the dielectric properties of a type of
litter and ground in order to integrate these values into an analytical multi
layers model of soil. The objective is to characterize the effects of this
layer on the total multi layer system. This will make possible to lead to a
simple analytical formulation of a model of litter which can be integrated into
the calculation algorithm of SMOS in order to collect information on moisture
starting from measurements of emissivity
