AGRIS searches differently than Agricola and CAB Abstracts.
The AGRIS software uses the tilde ~ character for 'fuzzy searches'-- to truncate words or indicate that the terms should be found within a certain range. For example, fertil~ would return fertile, fertilize, fertilizer, fertilizing, and also infertile and its variations.
A pair of terms with the ~ and a numeral yields the terms in a document with that range of number of words. + or - in front of words either require or exclude the term. For example, +pome gets documents with that word in them; -core excludes documents that include that word.