EN
Ontologies recently have important role especially in knowledge management systems dedicated for agriculture. In the paper, issues related to indexing documents against the ontology, are presented and discussed. Problems with indexing documents in Polish language which has an extensive inflection are described. There are presented and discussed examples of ontologies and thesauri in the field of life sciences, in particular possible to use to describe aspects of plant production. We have tested Agrotagger the existing tool for indexing agricultural texts with publication in Polish. Original software developed for indexing web pages in Polish against potato ontology is described. In the final part some conclusions and plans for further research are formulated.