Energy balances and land uses in the Catalan agriculture: A comparison between mid-19th century and the end of the 20th century

From the analytical perspective of the social metabolism, the present work analyses and compares the ground uses and the energetic assessment derived from the uses of the agrarian systems in five towns of the Catalan area of the Vallès in two historical moments. Both illustrate the characteristics and magnitude of the transformations occurred in the Catalan agricultural systems during the last 150 years. The former corresponds to mid-19th century, as a representation of how an advanced organic agriculture worked; the latter, in the late 20th century, represents an industrialized agricultural system where the fossil energy and other inputs external to the system are essential. From the information contained, on the one hand, in the amillaramientos, in the cattle censuses and in the assessing forms available for the towns studied here, and, on the other hand, in the current data of censuses in agriculture, forests, yield and uses of the different products, we have built up the energetic results of the two analysed periods. From these results, all through the 150 years, we have seen how an incredible lost of energetic efficiency and of sustainability of the agricultural systems have occurred in spite of the great increase of productivity per hectare of the different crops and in cattle raising, totally attributed to a change from an advanced organic agriculture to some agricultural systems with a high consumption of fossil fuel in the shape of fuel, synthesis fertiliser and pesticides, and especially to the huge weight of the cattle activity, completely developed outside the territory.