ABSTRACT
In this chapter, we will study the energy efciency to a more aggregate level than used in Chapter 5. We want to know if the processes described in the local case study have happened in the same way at national level or whether new properties have emerged that make energy throughput different. In particular, we want to know whether changes in energy efciency observed in the case of Santa Fe can be moved to a larger context. For this purpose, we will analyze the historical evolution of Spanish agriculture since the early twentieth century, when the main industrial transformations began with the introduction of chemical fertilizers.
