Rainfed Agroecosystems in South America

Abstract

Farming and grazing in South America are essentially rainfed activities, with over 98% of the agricultural lands and systems depending on natural rainfall. There is great diversity in latitude, elevation, climate, topography, and soil types across the continent, supporting a wide range of crops, animals and farming systems. This chapter is focused on four important ecoregions that represent the rainfed systems of South America: Pampas of Argentina, Cerrado of Brazil, Llanos of Colombia and Venezuela and Savanna Guyana, and the Andean Puna region in the highlands. Regions vary greatly in their lengths of growing season, complexity of farming systems, and potential productivity. New technologies have reached farmers in the more accessible areas with better soils and conditions for crop and pasture growth, yet many farm families in remote areas still practice traditional subsistence systems. There is still much to be learned about the diverse array of crops and indigenous systems across South America, and research in agroecology is exploring farmers’ current systems and how they can inform the choice of appropriate technologies. Various agro-ecosystems are compared using the emergy concept and method, also described in the Supplement of Chap. 1, which account for the energy, matter, information and labour flows that directly and indirectly contribute to generate the products and services yielded by the system, expressed in a common unit ( joule of solar energy).