In agricultural research targeted at food security, crop experiments in fields are a crucial source of information for statistical or model based analyses or purely a system description. In these crop experiments or field trials, crop responses are investigated to a change a management or in different climatic or soil conditions, and thus provide an understanding of production potential in different circumstances. Though crucial, these crop experiments are currently poorly available to the crop research community, which proves an obstacle to developments in the domain. The aim of this paper is to propose a generic data schema, Spatial Temporal Attribute Catalogue, that can be used to store data on agricultural systems compiled with many different purposes and scopes. The generic data schema covers aspects of soil, climate, location, crop management and crop variety characteristics. The data schema is developed in a context of different ongoing and past efforts in structuring this crop experiment data, e.g. the AgMIP crop experiment database, the Global Yield Gap Atlas, and the MOCASSIN project on winterkill. Future developments on the data schema include assessing the possibilities to broaden it to different domains (i.e. socio-economic, ecology, and animal sciences) and the use of semantic technologies for storage and availability.