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
vi technical » ii technical, die technical, iii technical
i technical » ii technical, 2 technical, 3 technical

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "rich fertilizer usage assessment ((vi technical) OR (i technical)) experts.~".
• Adding a wildcard symbol may retrieve word variants: rich fertilizer usage assessment ((vi technical) OR (i technical)) experts.*.