Key concepts from three thesauri about agriculture and nutrition -- AGROVOC, CAB Thesaurus, and NAL Thesaurus -- have been merged into a Global Agricultural Concept Scheme (GACS). The respective partner organizations -- Food and Agriculture Organization of the UN (FAO), CAB International (CABI), and the USDA National Agricultural Library (NAL) -- undertook this initiative in 2013 with the goal of facilitating search across databases, improving the semantic reach of their databases by supporting queries that freely draw on terms from any mapped thesaurus, and achieving economies of scale from joint maintenance. The GACS beta release of May 2016 has 15,000 concepts and over 350,000 terms in 28 languages. Some inevitable results of this process of aggregation, such as overlapping labels, have already been fixed. Other issues, such as concepts with multiple hierarchical relations ("polyhierarchy"), have yet to be tackled. GACS is seen as a first step for Agrisemantics, an emerging community network of semantic assets relevant to agriculture and food security.