, Volume 17, Issue 5, pp 419-431

Landscape dynamics and equilibrium in areas of slash-and-burn agriculture with short and long fallow period (Bragantina region, NE Brazilian Amazon)

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Fallow periods used in slash-and-burn agriculture in the Bragantinaregion, the oldest agricultural frontier in the Brazilian Amazon, are beingreduced. The objective of this study was to analyze the effects of a shortenedfallow period on the Bragantina landscape dynamics and equilibrium. Dynamicswere characterized by landscape structural changes, particularly in the spatialdistribution of secondary forests, and by transition matrix. Equilibrium wasdefined by temporal and spatial parameters, and by the increment ofagriculturalareas from 1985 to 1996, analyzed with 6 LANDSAT-TM images. I worked with 6areas of 250 ha each, 3 with short fallow periods (2–4years)and 3 with long fallow periods (about 10 years). Results showed that shortfallow period areas did not present an equilibrium situation. In these areas,developed secondary vegetation tended to disappear and agricultural areas werebeing expanded at an average rate of 3% per year. Landscape structure changespointed out that a reduction in fallow period was occurring in already shortfallow period areas. Long fallow period areas presented a shifting mosaicsteady-state condition, where punctual changes due to agricultural uses werecompensated by field abandonment rate. Both agricultural uses and fieldabandonment rates were lower in long fallow period areas when compared withshort ones. Comparisons with indigenous traditional cropping-fallow cyclesindicate that sustainable conditions could be maintained with 11 years offallowfor each cropping year, while shorter cycles would break down the system ifagricultural improvements are not implemented.

This revised version was published online in May 2005 with corrections to the Cover Date.