Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
situ conservation » bird conservation, nature conservation, land conservation
grain irrigation » gray irrigation, gravity irrigation, drip irrigation
supply grain » supply chain, supply main, supply ukraine
supply situ » supply side, supply shifts, supply sides

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply situ conservation efforts. ) or ( supply grain irrigation schemes. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply situ conservation efforts. ) OR ( supply grain irrigation schemes. )).
• Adding a wildcard symbol may retrieve word variants: (( supply situ conservation efforts. ) or ( supply grain irrigation schemes. ))*.