Perhaps you should try some spelling variations:
"supply chain irrigation schemes." » "supply chain irrigation scheme.", "supply chain irrigation systems.", "supply grain irrigation schemes.", "supply change irrigation schemes.", "supply basin irrigation schemes."
"supply annual irrigation system." » "supply canal irrigation system.", "supply annual variation system.", "supply annual inflation system.", "supply annual irrigation systems.", "supply annual irrigation water.", "supply annual irrigation scheme.", "supplies annual irrigation system.", "supply ann irrigation system."

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: (("supply chain irrigation schemes.") OR ("supply annual irrigation system."))~.
• Removing quotes may allow a broader search: (( supply chain irrigation schemes. ) or ( supply annual irrigation system. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply chain irrigation schemes.") or ("supply annual irrigation system."))*.