At present, agroecology can be interpreted as a scientific discipline, as a movement or as a practice. In this paper we analyse the historical evolution of the scientific discipline of agroecology with a quantitative bibliometric analysis of 711 publications using the term agroecology and the derived term agroecological, as well as a qualitative analysis of definitions, topics and scales, where we also include further important works on agroecology.

Agroecology emerged in the 1930s and the period up until the 1960s was the initial phase of agroecology. During the 1970s and 1980s, agroecology as a science expanded, and in the 1990s became institutionalized and consolidated. Since the 2000s, broader definitions have provided the basis for new dimensions in agroecology. During the last two decades the range of topics treated within agroecology grew enormously; also the publication rate has exploded within the last 10 years. The scale and dimension of scientific research in agroecology has changed over the past 80 years from the plot or field scale to the farm or agroecosystem scale and finally to the food system.

Currently, three approaches persist: (1) the plot/field scale; (2) the
agroecosystem/farm scale; and (3) the food system approach. In spite of a vague utilization of the term agroecology through its different meanings and definitions, the new views and dimensions brought to agroecology as a scientific discipline will probably facilitate efforts to respond to actual important questions on sustainable agriculture, global land use and climate change, or food security, due to increasingly applied systems thinking and interdisciplinary research approaches.