Estudio de suelos en la zona de colonización Alto Beni, La Paz, Bolivia
Abstract
Se realizó un mapeo y análisis físico-químico y mineralógico de suelos en el Alto Beni, cuyo resultado sirvió como base para elaborar un mapa de suelos detallado del área de estudio, que abarca una superficie de 660 ha. En total, se analizaron 12 perfiles de suelo en el laboratorio de los cuales 5 aparecen en anexo del presente trabajo. La clasificación de los suelos dio por resultado Cambisoles, Lixisoles y Acrisoles, suelos fersialíticos menos intensamente meteorizados. La formación de suelo ocurrió sobre areniscas, lutitas y conglomerados terciarios y sobre terrazas aluviales. Los suelos mapeados son característicos para las zonas de colinas formadas por sedimentos terciarios en la zona de colonización Alto Beni. Con excepción de las areniscas calcáreas se encuentran todos los tipos de roca madre existentes en esta región. Respecto a la fertilidad se clasificaron los suelos en dos grupos. Al primer grupo pertenecen los Acrisoles háplicos y los Cambisoles dístricos, que tienen características de fertilidad malas. Son suelos franco arenosos, fuertemente ácidos, pobres en nutrientes, con capacidad de intercambio, catiónico baja y saturación de bases baja. El segundo grupo está formado por los Cambisoles crómicos y los Lixisoles háplicos, que poseen características de fertilidad relativamente buenas. Se trata de suelos con textura más fina (franca, franco arcillosa), moderadamente a muy poco ácidos, con capacidad de intercambio catiónico baja a moderada y saturación de bases moderada a alta.
The study included a detailed mapping and the physico-chemical and mineralogical analysis of soils in the Alto Beni región, the result served as a basis for a detailed soil map of the investigation area, which covers a surface of 660 ha. In all, 12 soil perfiles were analyzed in the laboratory (5 of them are listed in the appendix of the study). The soil classificaüon gave as result the soil units Cambisols, Lixisols and Acrisols, fersialitic, less intensive developed soils of the tropics. The soil formation took place on tertiary sandstones, claystones and conglomerates and on alluvial tenaces. The mapped soils are caracteristic for the hilly areas built up from tertiary sediments in the Alto Beni colonization zone. With the exception of limy sandstones we find all the original rocks existing in this zone. With regard to fertility the soils have been classified into two groups. The first group is formed by Haplic Acrisols and Dystric Cambisols, soils with bad properties of fertility. These are sandy loam soils, strongly acid, poor in nutrients, with a low cation exchange capacity and a low base saturation. To the second group belong the Chromic Cambisols and the Haplic Lixisols, having relatively good properties of fertility. It is a matter of soils with a finer texture (loam, clayey loam), moderate to very weakly acid, with a low to moderate cation exchange capacity and a moderate to high base saturation.
The study included a detailed mapping and the physico-chemical and mineralogical analysis of soils in the Alto Beni región, the result served as a basis for a detailed soil map of the investigation area, which covers a surface of 660 ha. In all, 12 soil perfiles were analyzed in the laboratory (5 of them are listed in the appendix of the study). The soil classificaüon gave as result the soil units Cambisols, Lixisols and Acrisols, fersialitic, less intensive developed soils of the tropics. The soil formation took place on tertiary sandstones, claystones and conglomerates and on alluvial tenaces. The mapped soils are caracteristic for the hilly areas built up from tertiary sediments in the Alto Beni colonization zone. With the exception of limy sandstones we find all the original rocks existing in this zone. With regard to fertility the soils have been classified into two groups. The first group is formed by Haplic Acrisols and Dystric Cambisols, soils with bad properties of fertility. These are sandy loam soils, strongly acid, poor in nutrients, with a low cation exchange capacity and a low base saturation. To the second group belong the Chromic Cambisols and the Haplic Lixisols, having relatively good properties of fertility. It is a matter of soils with a finer texture (loam, clayey loam), moderate to very weakly acid, with a low to moderate cation exchange capacity and a moderate to high base saturation.
Description
No. 25