Perhaps you should try some spelling variations:
irrigation schemes » irrigation systems
irrigation scheme » irrigation systems
spate irrigation » scale irrigation, water irrigation, surface irrigation
grid irrigation » drip irrigation, syria irrigation, crop irrigation
support grid » support agri, support grant, support group
supply spate » supply system, supply side, supply water

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: (( support grid irrigation schemes. ) OR ( supply spate irrigation scheme. ))~.
• Adding a wildcard symbol may retrieve word variants: (( support grid irrigation schemes. ) or ( supply spate irrigation scheme. ))*.