Perhaps you should try some spelling variations:
irrigation system » irrigation systems, irrigation water, irrigation scheme
ann conservation » land conservation, aid conservation, plant conservation
cost irrigation » crop irrigation, cost mitigation, et irrigation
supply cost » supply costs
supply ann » supply a, supply annual, supply chain

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

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