Year of publication
1997
Excerpt
Land units may differ in their resistance to erosion and in their resilience to human-induced and climatic changes. Moreover, the impact of degradation on functional
properties of land and its productive capacity may differ between land units and/or soils. The present study elaborates a mixed qualitative/quantitative methodology for
assessment of the impact of erosion on productivity of a land use system, given the variability in natural conditions (e.g. soils, landform and climate). This approach is
applied to three countries, situated in two regions; South America (Uruguay and part of Argentina) and East Africa (Kenya), with different types of land use and in highly
varying agro-ecological conditions. A chain of models was used to study the impact of erosion on crop production. The studies were based on national 1:1 M scale Soil and
Terrain (SOTER) databases that were compiled for northern Argentina, Kenya and Uruguay. Soils and terrain attributes are linked to a Geographical Information System
(GIS), permitting spatial analysis. For stratification of climatic data the Agro-Ecological Zones (AEZ) map of South America (in the case of Uruguay and Argentina) and of
Africa (for the case of Kenya), (FAO, 1994) were used. Only the spatially dominant soil component by AEU was considered in the analysis. For these dominant soils of
each mapping unit suitable for the land use, the potential yield before and after an erosion scenario of 20 years was calculated. The impact of change in soil properties,
influencing crop performance, induced by removal of topsoil through sheet erosion, is analyzed in this study. In the two countries in Latin America the soil erosion affected
mostly the physical properties of the soils, resulting in a calculated yield reduction between 25 and 50%. In Kenya the largest yield reduction was mainly due to loss in
soil fertility. Potential yields after erosion were mostly ranging from 25 to more than 50% of the current situation. A complete set of maps of Uruguay and a selection of
maps of Argentina and Kenya Figure in this report, while the remaining maps of Argentina and Kenya, together with Pedo-Transfer Functions are published in a
separate volume.
properties of land and its productive capacity may differ between land units and/or soils. The present study elaborates a mixed qualitative/quantitative methodology for
assessment of the impact of erosion on productivity of a land use system, given the variability in natural conditions (e.g. soils, landform and climate). This approach is
applied to three countries, situated in two regions; South America (Uruguay and part of Argentina) and East Africa (Kenya), with different types of land use and in highly
varying agro-ecological conditions. A chain of models was used to study the impact of erosion on crop production. The studies were based on national 1:1 M scale Soil and
Terrain (SOTER) databases that were compiled for northern Argentina, Kenya and Uruguay. Soils and terrain attributes are linked to a Geographical Information System
(GIS), permitting spatial analysis. For stratification of climatic data the Agro-Ecological Zones (AEZ) map of South America (in the case of Uruguay and Argentina) and of
Africa (for the case of Kenya), (FAO, 1994) were used. Only the spatially dominant soil component by AEU was considered in the analysis. For these dominant soils of
each mapping unit suitable for the land use, the potential yield before and after an erosion scenario of 20 years was calculated. The impact of change in soil properties,
influencing crop performance, induced by removal of topsoil through sheet erosion, is analyzed in this study. In the two countries in Latin America the soil erosion affected
mostly the physical properties of the soils, resulting in a calculated yield reduction between 25 and 50%. In Kenya the largest yield reduction was mainly due to loss in
soil fertility. Potential yields after erosion were mostly ranging from 25 to more than 50% of the current situation. A complete set of maps of Uruguay and a selection of
maps of Argentina and Kenya Figure in this report, while the remaining maps of Argentina and Kenya, together with Pedo-Transfer Functions are published in a
separate volume.