Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme
chains irrigation » change irrigation, grain irrigation, canal irrigation
annual irrigation » canal irrigation, annual variation, annual inflation
supply chains » supply chain
supply annual » supplies annual, supply ann
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 chains irrigation schemes. ) or ( supply annual irrigation systems. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply chains irrigation schemes. ) OR ( supply annual irrigation systems. )).
• Adding a wildcard symbol may retrieve word variants: (( supply chains irrigation schemes. ) or ( supply annual irrigation systems. ))*.