Perhaps you should try some spelling variations:
"support group irrigation schemes." » "support group irrigation scheme.", "support group irrigation systems.", "support drip irrigation schemes.", "support from irrigation schemes.", "support grain irrigation schemes.", "support grant 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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