Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
integration south » integration study, integration some, integration social
closed irrigation » led irrigation, flood irrigation, crop irrigation
supplies closed » supplies based
import trade » export trade, import price, import taxes

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: (( import trade integration south. ) OR ( supplies closed irrigation schemes. ))~.
• Adding a wildcard symbol may retrieve word variants: (( import trade integration south. ) or ( supplies closed irrigation schemes. ))*.