REMOTE SENSING OF LAND USE RELATING CHANGES IN 
CROPPING PATTERNS TO SOIL EROSION IN THE ARRECIFES 
RIVER BASIN OF ARGENTINA 
Raul Alberto Diaz 
S. M. Carballo 
R. M. Digiacomo 
C. B. Irurtia 
Instituto de Clima y Agua - INTA/CIRN 
Agrohidrologia 
Las Cabanas y Los Reseros 
Castelar, Buenos Aires 1712, Argentina 
ISPRS Commission VII / Working Group 6 
ABSTRACT 
In the 1,170,000 ha of the Arrecifes River basin continuous cropping and Rainfall erosion have been 
taking place for the last 25 years. Cereal and oil crop production amount to 4-746 of the national output. 
Slight to severe erosion limitation to land capability has already been identified in 100,000 ha of 
agricultural lands. Steady changes in the cropping rotation with time may signal irreversible land 
degradation. The objective of the study is to verify if a contrasting pattern of land use related to erosion 
actually exists in the basin. Two underlying hypothesis are examined: a) areas having different erosion 
risk also differ in the proportion of agricultural land planted to summer crops, and b) erosion/productivity 
relations vary with each crop. An area of 40,000 ha (from 34°00'S, 60°00'W to 34°10'S, 60°15'W), 
covering a wide range of soil erosion classes, was selected for the study. Landsat scenes in three channels 
(TM 3, 4 and 5) were processed using the ERDAS program in order to identify the following landuse 
classes: winter and summer crops, annual and perennial pastures, forest and unproductive lands (flooding 
plains, lagoons, cities). Scenes in strategic dates on 1992, 1993 and 1994 were used to improve 
classification results (using multispectral and multitemporal analysis). Ground truth dates were applied to 
the supervised classification and in testing mapping accuracy. Soils map, at 1:50,000 scale (from a 1973 
semidetailed soil survey by INTA), was digitized using ARC/INFO package. Field property limits were 
also digitized at the 1:50,000 scale. Both maps were adjusted to Landsat scenes with geometrical 
corrections. Result on the proportion of summer crops and on the relationship between soil erosion and 
crop productivity with field measurements and computer simulations with the EPIC model per soil unit 
will be presented. They may in turn provide a starting point for using remote sensing to monitor future 
changes in soil productivity. 
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