Methodology and conversion factors to estimate the net primary productivity of historical and contemporary agroecosystems

This methodological manual provides basic information to estimate the net primary productivity (NPP) of historical and contemporary cropland, in terms of fresh and dry matter, and gross energy. The methodology and the proposed conversion factors can be applied to any region of the planet, with some exception to be noted in the text. The biomass produced in agro-ecosystems by transforming energy flows (solar and, currently, fossil) and mobilizing nutrients and water are the operational basis of traditional and, to some extent, industrialised societies. The quantification of NPP of agroecosystems, and biomass flows that are configured from this, is essential to build metabolic profiles and to inquire in agrarian sustainability of traditional agrarian and industrial societies. The provided information herein may be useful for researchers working in Agrarian Social Metabolism, Greenhouse Gas Balances of agroecosystems and Climate Change, and Energy Return on Investment (EROI’s) in agro-ecosystems among other methodological approaches.