Perhaps you should try some spelling variations:
"support grant irrigation schemes." » "support grant irrigation scheme.", "support grant irrigation systems.", "support grain irrigation schemes.", "support gray irrigation schemes.", "support gravity irrigation schemes."
"support depth interaction series." » "support depth interactions series.", "support depth interaction studies.", "support depth interaction terms.", "support data interaction series.", "support dem interaction series.", "support earth interaction series.", "support despite interaction series.", "support de interaction series."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("support grant irrigation schemes.") or ("support depth interaction series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support grant irrigation schemes.") OR ("support depth interaction series.")).
• Removing quotes may allow a broader search: (( support grant irrigation schemes. ) or ( support depth interaction series. )).
• Adding a wildcard symbol may retrieve word variants: (("support grant irrigation schemes.") or ("support depth interaction series."))*.