was applied for correcting the infrared reflectance for 
soil background (equation 9). This assumption holds for 
many soil types. 
3. For a green vegetation, the inverse of a special 
case of the Mitscherlich function, namely the one 
passing the origin (equation 15), was used for descri 
bing the regression function of LAI on the infrared 
reflectance corrected for background. In this semi- 
empirical model two parameters of a physical nature 
have to be estimated empirically. 
4. Model simulations with the SAIL model indicated 
that the accuracy of results obtained with the model 
for correcting for soil background corresponds to the 
accuracy of results obtained if soil reflectances are 
known. 
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