Perhaps you should try some spelling variations:
fertilizer usage » fertilizer use, fertiliser use, fertilizer type
usage assessment » stage assessment, image assessment, use assessment
rich fertilizer » rice fertiliser, africa fertilizer, bio fertilizer
vii technical » iii technical, vi technical, die technical
ii technical » iii technical, i technical, vi technical

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: rich fertilizer usage assessment ((vii technical) OR (ii technical)) experts.~.
• Adding a wildcard symbol may retrieve word variants: rich fertilizer usage assessment ((vii technical) or (ii technical)) experts.*.