Perhaps you should try some spelling variations:
"support grid irrigation schemes." » "support grid irrigation scheme.", "support grid irrigation systems.", "support grain irrigation schemes.", "support drip irrigation schemes.", "support gray irrigation schemes.", "support agri irrigation schemes.", "support grant irrigation schemes.", "support group irrigation schemes."
"support crop irrigation schemes." » "support crop irrigation scheme.", "support crop irrigation systems.", "support drip irrigation schemes.", "support scale irrigation schemes.", "support canal irrigation schemes.", "support crops irrigation schemes.", "support cross irrigation schemes.", "support across irrigation schemes."

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