Changes in the structural stability of soil when is treated with an un
composted municipal solid waste (MSW) have been studied in a calcareou
s soil from South East of Spain. The structural improvement was relate
d to carbohydrate content of the soil and the correlation coefficient
was calculated. The equation corresponds to a second grade curve. Maxi
mum of the curve is explained by simultaneous presence of molecules wi
th different capacity to create or stabilize aggregates in the pool of
soil carbohydrates.