Long-term sustainability of agricultural systems depends on creative and adaptive responses to continuing challenges. How did farmers maintain soil fertility as they cultivated the same land over decades and centuries? How did they transfer energy and nutrients (nitrogen, potassium, phosphorous) across the landscape to fertilize crops? How did farmers structure landscapes (field, pasture, woodland) to sustain communities, ensure long-term productivity, and produce profits? The way Western agriculture faced these challenges changed considerably over three centuries. In the transition from traditional to industrial agriculture, production and profits expanded but ecosystem functions degraded, threatening long-term sustainability. This project is an international effort to reconstruct patterns of sustainability in farm systems. Addressing these questions requires interdisciplinary expertise in environmental, agricultural, and economic history, plus demography, agronomy, landscape ecology, and soil science. This partnership integrates scholars across a broad range of disciplines. One source of guidance about options for sustainable agriculture resides in the rich historical record of rural communities on either side of the Atlantic Ocean. The move from traditional to industrial agriculture in the 19th and 20th centuries was a major transformation. Researchers will investigate the drivers of that transition, explore why it began at different times in different places, and consider why the manufacturing sector industrialized decades earlier than the agricultural sector. A collaboration of experts drawing upon multiple case studies of historical farm communities in Europe, North America and Latin America will create a common database of agricultural systems over the past 300 years. The research program employs "socio-ecological metabolism" methods, an approach that views farms as ecosystems and measures flows of energy and soil nutrients through the landscape. For example, we calculate the amount of nitrogen resident in soil, subtract quantities of the element lost through tillage and exported in annual grain harvests, then add the amount of nitrogen contributed by natural deposition, livestock manure, or synthetic fertilizer. The nitrogen balance, over years and decades, indicates whether farmers sustained soil fertility or depleted it. Farming also has energy implications, since maintaining livestock, hauling manure, ploughing, and cultivating all require physical work. Modern agriculture derives most of its energy from fossil fuels, in the form of nitrogen fertilizer, fuel for machinery, and global transportation of commodities. The project will measure the flow of energy into, through, and out of farm systems to evaluate their efficiency. The socio-ecological metabolism approach makes it possible to link ecosystem processes with resource use and socio-economic structures, specifying indicators that describe the sustainability and efficiency of farm systems. This project's overarching goal is to understand the choices and trade-offs available to farmers and the options that are possible for long-term sustainability. These socio-ecological indicators describe a transformation from traditional farming that relied on sunlight and local environments to industrial farming that relies on fossil fuels and distant environments. With world population dependent on industrial farming for food, with two-thirds of farmers in the world only now beginning to undergo this transition, and with the eventual decline of fossil fuel availability, it is crucial to understand the socio-ecological metabolism of historical agriculture in order to inform policies for future sustainability.