CROP CULTIVATION OR LIVESTOCK? ROLE OF SOIL QUALITY IN THE DIFFERENTIATION AND TRANSFORMATION OF PIONEER AGRARIAN SYSTEMS IN BRAZIL

Abstract

Brazil's land long belonged to pioneers who went along mining soil fertility: after eroding it where they settled, they would move on ahead to continue farming on previously uncultivated soils. Hence naturally forested areas have almost disappeared except for Amazônia. Since this trend can no longer continue, a more useful goal is to settle the areas for agricultural activities and ensure their sustainability. With this in mind, we studied 2 examples of frontiers: the first, opened 70 years ago in North Paraná, ended with destruction of the forest, and the second continues in eastern Amazônia. In both cases, we focused on the role of the soil quality in the differentiation and transformation of farming systems after forest clearing and found that soil plays no part at all in the decision to clear forestland. After that, however, once the fertility inherited from the forest has been worn out, farming activity appears to depend on the type of soil, regardless of the farmers' characteristics (geographical origin, culture, technical and biological knowledge, capital, etc.). With no external constraints on farmers' activities, when soil type differs greatly, agriculture is practised on the best soils (that is, those with the best physical, chemical and biological properties) whereas livestock are raised on those with less clay, since their sensitivity to erosion can be better controlled in pastureland than cultivated fields. This can be observed in North Paraná as well as in a few places in Amazônia. Paraná is famous for its extended basaltic areas, and on their most fertile plots, successful cultivation of soy and wheat rapidly developed\; but now, 70 years after the forest was almost entirely cleared, farmers require advice to sustain their soils. Amazônia is well known for its widespread areas of acid rock, where cattle breeding is today developing. Despite governmental administrative and financial aid, there are very few alternatives. Farmers there too need technical support to practice sustainable agriculture.