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
vvi technical » i technical, ii technical, iii technical
vi technical » i technical, ii technical, die 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 ((vvi technical) OR (vi technical)) experts.~.
• Adding a wildcard symbol may retrieve word variants: rich fertilizer usage assessment ((vvi technical) or (vi technical)) experts.*.