Perhaps you should try some spelling variations:
"supply grain irrigation schemes." » "supply grain irrigation scheme.", "supply gray irrigation schemes.", "supply gravity irrigation schemes.", "supply drip irrigation schemes.", "supply chain irrigation schemes.", "supply main irrigation schemes.", "supply ukraine irrigation schemes."
supply canal » supply canada, supply annual, supply china
supply case » supply cost, supply chain, supply curve
systems." » system."

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

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