Ontologies in agronomy facilitate data integration, information exchange, search and query of agronomic data, and other knowledge-intensive tasks. We have developed AgroPortal, an open community-based repository of agronomy and related domains semantic resources. From a corpus of ontologies, terminologies, and thesauri taken from Agro-Portal, we have generated, extracted and analyzed more than 400,000 mappings between concepts based on: (i) reuse of the same URI between concepts in different resources-term reuse; (ii) lexical similarity of concept names and synonyms-term overlap; and (iii) declared map-pings properties between concepts-extracted mappings. We developed an interactive visualization of each mapping construct separately and combined which helps users identify most prominent ontologies, relevant thematic clusters, areas of a domain that are not well covered, and pertinent ontologies as background knowledge. By comparing the size of the semantic resources to the number of their mappings, we found that most of them have under 5% of their terms mapped. Our results show the need of an ontology alignment framework in AgroPortal where map-pings between semantic resources will be assembled, compared, analysed and automatically updated when semantic resources evolve.