SOIL AND DEVELOPMENT IN AMAZONIA: LESSONS FROM THE BIOLOGICAL DYNAMICS OF FOREST FRAGMENTS PROJECT

Abstract

ABSTRACT 2Soils data from the 1000-km area covered by the Biological Dynamics of Forest Fragments (BDFFP) reserves (north of Manaus, Amazonas) provides detailed information of the type used in development planning, such as the economic-ecological zoning of the region now being carried out by the Brazilian government. The soil in the reserves is typical of vast areas of Brazilian Amazonia that are likely to be increasingly deforested for agriculture and ranching. These soils have low fertility, are acid and have high levels of toxic aluminum ions. They also have limitations due to topography, generally very high clay content, and low values of available water capacity. Agricultural potential is low, and the prospects for resilience are not bright given the reality of changing land-use patterns in the region. The soils under forest also give indications of the environmental impact of converting these areas to pasture and other uses, including the potential for release of greenhouse gases (which depends on forest biomass, a feature related to distribution of natural vegetation and favorability of soils for plant growth), the probable response of forest to fragmentation, and the probable response of forest to climatic change. Our soils research indicates that areas like this would produce little if converted to agriculture or ranching, and point to land uses that maintain forest cover intact as preferable. The value of the environmental services provided by the standing forest far exceeds the returns that can be expected from clearing it for agriculture or ranching. I.) INTRODUCTION A.) RELEVANCE OF SOILS TO PLANNING Soil quality is obviously fundamental to the potential of any area to produce and sustain agricultural yields. If planning decisions are made to encourage agriculture in areas with soils that are not suited to this purpose, crops can be expected to fail. Planning decisions opening vast areas to settlement are frequently made in a near vacuum of information on soils. For example, when the POLONOROESTE Project opened Rondonia to settlement through a World Bank-financed regional development program centered around paving the BR-364 (Cuiaba-Porto Velho) Highway, the soils information available for Rondonia (Brazil, Projeto RADAMBRASIL, 1978: Vol. 16) was based on only 85 soil cores. Such events are recurring today quite near the Biological Dynamics of Forest Fragments Project (BDFFP) reserves: on 24 June 1997, president Fernando Henrique Cardoso announced in his weekly radio program Palavra do Presidente that six million hectares (ha) along the BR-174 (Manaus-Caracarai) Highway would be opened to settlement, and suggested that the area farmed there would be so colossal that it would double the nation's agricultural production (de Cassia, 1997). Despite almost certain hyperbole