Moraes, Jener Fernando 
  
LAND PLANNING FOR SUSTAINABLE DEVELOPMENT IN WATERSHEDS USING 
GEOGRAPHICAL INFORMATION SYSTEM 
Jener Fernando Leite de MORAES , Pedro Luiz DONZELI , Francisco LOMBARDI NETO’, 
André Ricardo MELO, Hélio do PRADO" 
"Instituto Agronómico de Campinas, Brazil 
jfmoraes(a)barao.iac.br 
Working Group: VII/2 
KEY WORDS: Watersheds, GIS, Remote Sensing, Erosion, Sustainability 
ABSTRACT 
The lack of adequate land use planning and soil knowledge have been one of the major problems to develop soil 
conservation politics to avoid environmental degradation in Brazil. The application of soil erosion models, like the 
Univesal Soil Loss Equation (USLE) through GIS to predict soil loss and to assess crops and soil management has been 
effectively used to elaborate soil erosion inventories by integration of physiography, soils, landuse/landcover, slope 
map layers and land evaluation. This paper describes the application of the above technologies in a watershed area at 
Säo Paulo-state southwestern region, Brazil. The main soil types of the area (Ultisol an Alfisol) are very susceptible to 
erosion due to the great difference in clay content between A and B horizons. Sugarcane and pasture are the main land 
use comprising almost 90% of the area. The soil loss rates varied from 0.1 t.ha'" yr' in forest areas to 30 t.ha "yr! in 
sugarcane areas. The erosion risk map obtained through USLE showed that 54% of the area was classified as medium to 
high erosion risk. Approximately 30% of sugarcane production occur in theses areas which indicates that a suitable land 
use for these areas should consider careful management practices. 
RESUME 
L'absence de planification de l'utilisation des terres adéquate et d'une connaissance des sols ont limité le développement 
de politiques de conservation du sol visant d'une maniére générale à limiter la dégradation de l'environnement au Brésil. 
Des modèles d'érosion des sols, dérivés de l'équation universelle de perte de sol (USLE) ont été efficacement utilisés 
pour prévoir les pertes de sol et effectuer des bilans sur de vastes surfaces grâce à l'utilisation de Systèmes 
d’Informations Géographiques (SIG). Les SIG permettent l'intégration d’information sur la morphologie des paysages, 
les sols, et leur utilisation . Cet article décrit l'application de tels outils au niveau d'un bassin versant de la région sud- 
ouest de l’état de Säo Paulo (Brésil). Les principaux types de sol rencontrés (Ultisol et Alfisol) sont très susceptibles à 
l'érosion du fait d'un fort gradient textural sur le premier mètre. La canne à sucre et les pâturages sont les principales 
utilisation des terres, couvrant presque 90%. Les taux de perte de sol sont passés de 0,1 t.ha”.yr dans les zones de 
forét 4 30 t.ha yr" dans les zones de canne à sucre. La carte des risques d'érosion obtenue par USLE montre que 54% 
de la zone d'étude présentent des risques d’érosion moyens à forts où approximativement 30% de production de la 
canne à sucre à lieu. Une utilisation adéquate de la terre pour ces zones doit considérer un management adapté. 
1 INTRODUCTION 
Land use changes, in Säo Paulo state, Brazil, have caused accelerated land degradation processes, due to soil erosion. 
Lal and Stewart (1992) reported that between 5 to 7 million hectares of arable land are lost every year via soil 
degradation. Soil erosion is now one of the most serious environmental problem in agricultural areas in Brazil. The 
Governmental incentives for alcohol production from sugarcane, increased the extent of agricultural area, with 
consequences to the environment due to monoculture and soil degradation. The intensive monoculture endangers the 
watersheds and results in massive soil erosion, declining soil productivity, silting up rivers channels (Trejo, 1997). 
Erosion may be accelerated as a result of two factors: (1) improper productive soil management and (2) marginal land 
exploitation (Dregne, 1982). The lack of adequate land use planning and soil knowledge have been one of the major 
problems to develop soil conservation politics to avoid environmental degradation. The technologies of remote sensing 
and geographical information system (GIS) have made available powerful tools to establish soil conservation and land 
use planning strategies at the watershed scale. A GIS can improve the understanding of the processes of land use 
planning and decision-making (Trejo, 1997). The application of soil erosion models, like the Universal Soil Loss 
Equation-USLE (Wishmeyer & Smith, 1978) through GIS to predict soil loss and to assess crops and soil management 
has been effectively used to elaborate soil erosion inventories by integration of physiography, soils, landuse/landcover, 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 895