[en] This PhD dissertation is part of an international research project, Sustainable Farm Systems, which seeks to analyze pre-industrial to industrial agriculture transition from a biophysical perspective. The main objective is to better define the explanatory elements that help us understand the causes of socio-ecological transitions, as well as the distinctive patterns between the different historical moments and characteristics of the transition in different parts of the planet. The first part of this dissertation (Chapter 3) represents the starting point, from which we show, through energy and nutrient balances, the main features of the agricultural system of our case study (Vallès County, Catalonia) for three time points which represent three stages of the transition: (i) in the mid-nineteenth century to observe the characteristics of an advanced organic agriculture, (ii) 1956 as an intermediate moment in the process of industrialization, in which the traits of organic agriculture coexist with the first inputs of industrial agriculture (mainly chemical fertilizers), and (iii) late twentieth century, where agriculture was fully industrialized. We highlighted the role of the nutritional transition and the energy transition as two relevant factors in understanding the socio-ecological transition. Both transitions have entailed a disconnection of human communities and their basic needs (food and fuel) from the territory. While more and more basic needs were covered from other territories (through markets), the territory itself was functionally adapted to the needs of external consumers and markets. The local agroecosystem was then traversed by enormous energy and material flows that simply moved across this territory. Our results highlight that changes in agroecosystem energy efficiency cannot be explained only by a different distribution of flows, but also by the ongoing change in the composition of funds. Therefore, the fund-flow scanning methodology is a useful tool to explain how the energy performance of an agro-ecosystem is strongly related to structural change in their underlying funds. The second part of the dissertation, which includes Chapters 4 and 5, focuses on the advanced organic agriculture of the mid-nineteenth century. Our main goal is to advance in theoretical and methodological developments that allow including gender and class inequalities analysis among the defining elements of the socio-ecological transition. To do this, we articulate some fundamental elements raised by Marxist, Feminist and Sraffian Economics, which allow us to propose an integrated theoretical framework. The results show the strong explanatory capacity of the proposed methodology, a multivariable balance at household scale, which includes energy, nutrients, time, and cash flows. We contrasted the main proposed hypothesis, that the large landowners and landless peasants or smallholders maintained relations of interdependence, mainly through labour and commodity markets. Through land grabbing, the landowners ensured the appropriation of the labour surplus, which is estimated around 12 and 22% of energy labour productivity. Indeed, every hired working day included an amount of "embodied domestic labour", which shows the links between gender and class exploitation relations. Domestic and care work was relevant, and accounted for 35% of the total labour flows. Results also show a large mismatch between land and labour property, which implied that a broad part of labour was directly controlled though hired labour or indirectly through land arrangements. Finally, from the observation of low levels of inequality but high levels of Inequality Extraction Ratios, which is estimated in 95%, we hypothesize that the increase of social metabolism, represented by industrialization processes, was intrinsically linked to social inequality-exploitation relations. Increases of Total Produce, through technical change, could allow for higher surplus expropriation processes and being at the same time and will work as a damper for social conflicts.

[es] Esta tesis doctoral forma parte del proyecto internacional de investigación Sustainable Farm Systems, que analiza las causas de la transición socio-ecológica a partir del estudio de la evolución de los balances de energía y nutrientes en los sistemas agrarios. La primera parte de esta tesis (Capítulo 3) muestra los rasgos principales de nuestro caso de estudio en tres cortes temporales : (i) mediados del siglo XIX (agricultura orgánica avanzada), (ii) 1956 (momento intermedio), y (iii) finales del siglo XX (agricultura industrial). Destacamos el papel de la transición nutricional y la transición energética como dos factores relevantes para comprender la transición socio-ecológica. También destacamos que los cambios en la eficiencia energética de los agroecosistemas no pueden explicarse solo por la distribución de los flujos, sino también por la composición de los fondos. La segunda parte de la tesis (Capítulos 4 y 5) se centra en las agriculturas orgánicas avanzadas de mediados del siglo XIX. El objetivo es avanzar en el desarrollo teórico y metodológico que permita analizar el papel de las desigualdades de género y clase en las transiciones socio-ecológicas. Para ello, planteamos la articulación de elementos fundamentales propuestos por la Economía Marxista, Feminista y Sraffiana. A partir de balances multicriteriales elaborados a escala de unidad doméstica contrastamos la interdependencia de distintos grupos sociales ordenados según su capacidad de controlar la tierra. Observamos que el acaparamiento de tierra permitía que los terratenientes aseguraran la apropiación del excedente, estimada en torno al 12-22% de la productividad del trabajo energético. Cada jornal contratado incluía a su vez una cantidad de "trabajo doméstico incorporado" (mientras estos trabajos representaban el 35% de los flujos laborales totales en el municipio), lo que evidencia la articulación entre las relaciones de explotación de género y clase. La distribución desigual de la tierra también implicaba que parte de la producción se realizada a través del trabajo asalariado o de los contratos sobre la tierra. Los bajos niveles de desigualdad junto con un alto Inequality Extraction Ratio nos permiten plantear la posibilidad de que el incremento del metabolismo social estuviera intrínsecamente vinculado a las relaciones de desigualdad y explotación social.