One knows about soil damaging to organism (10)
I believe the answer is:
agronomist
'one knows about soil' is the definition.
(agronomy is the science of soil management)
'damaging to organism' is the wordplay.
'damaging' is an anagram indicator.
'to'+'organism'='toorganism'
'toorganism' is an anagram of 'AGRONOMIST'.
(Other definitions for agronomist that I've seen before include "Farming expert" , "Crop specialist" , "occupation for expert on land" , "Crop expert" .)