Perhaps you should try some spelling variations:
irrigation schemes » irrigation scheme, irrigation systems
maturity theory » matrix theory, parity theory, minority theory
water maturity » water security, term maturity, age maturity
5 irrigation » _ irrigation, 4 irrigation, 2.5 irrigation
supply 5 » supply _, supply a, supply 3

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• Performing a fuzzy search may retrieve terms with similar spellings: (( supply water maturity theory. ) or ( supply 5 irrigation schemes. ))~.
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