Perhaps you should try some spelling variations:
"agriculturalist" » "agriculturalists", "agricultural", "agriculturists"
"horticulturist" » "horticulturists", "horticulturalists", "horticulturae"
"agriculturist" » "agriculturists", "agriculturalists", "agricultural"
"horticultural" » "agricultural", "multicultural"

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: ((("agriculturalist" OR ("horticulturist" OR "agriculturist")) OR "agriculturalist") OR ("horticultural" OR ("horticulture" OR "agriculture"))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((\"agriculturalist\" or (\"horticulturist\" OR \"agriculturist\")) or \"agriculturalist\") or (\"horticultural\" or (\"horticulture\" or \"agriculture\")))".
• Removing quotes may allow a broader search: ((( agriculturalist or ( horticulturist OR agriculturist )) or agriculturalist ) or ( horticultural or ( horticulture or agriculture ))).
• Adding a wildcard symbol may retrieve word variants: ((("agriculturalist" or ("horticulturist" OR "agriculturist")) or "agriculturalist") or ("horticultural" or ("horticulture" or "agriculture")))*.