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Accueil du site → Doctorat → Allemagne → Boden und Vegetation im Bereich von Huachacalla (Altiplano - Bolivien)- unter besonderer Berücksichtigung der Bodenversalzung

Universitat Dusseldorf (2007)

Boden und Vegetation im Bereich von Huachacalla (Altiplano - Bolivien)- unter besonderer Berücksichtigung der Bodenversalzung

Dörrie, Carola

Titre : Boden und Vegetation im Bereich von Huachacalla (Altiplano - Bolivien)- unter besonderer Berücksichtigung der Bodenversalzung

Auteur : Dörrie, Carola

Université de soutenance : Universitat Dusseldorf

Grade : Doktorgrade PhD 2007

Résumé
The dissertation represents the results of investigations of soil and vegetation in the area of Huachacalla - with particular emphasis on the salinization and alkalization of the soil. The small town of Huachacalla is located in the Bolivian Altiplano, about 30 km north of Salar de Coipasa, 3,740 meters above sea level, at the foot of two volcanic cones which extend 1,000 meters above plateau. The vegetation in the study area is treeless, open (mostly < 25 % cover) and is composed of (thorny) shrubs, bunch grasses, succulents and hard cushion plants. In the rainy season at most sites ephemeral species appear. It is to be assigned to the vegetation formation of semiarid puna.The main aims of the study were : a) the determination of the influence of relief on the nature of soil (especially the occurrence of soluble salts, gypsum and carbonates), b) determination of the influence of soil and relief on the nature of the vegetation, in particular the influence of soluble salts in the soil on vegetation and c) investigation of the distribution of soluble salts in the soil profile and of the seasonal changes in the distribution according with the alternation of dry and rainy season. The survey of the location, soil and vegetation parameters was carried out during the dry season in 1996 at 16 sites selected according to the catena principle ; during the following rainy season the investigation was extended to 35 sites. In total 316 soil samples and 21 ground water and surface water samples were taken and analyzed in the laboratory for different physical and chemical parameters.
On the basis of the results of field and laboratory work there were identified three main units and two transition units which are characterized by similar geomorphological, pedological and vegetational parameters :
1 Mountain range with shallow, weakly developed soils ((Lithic) Ustorthents according to Soil Taxonomy (USDA) and Ranker or Braunerde according to the German Soil Classification System (DBG)) and Fabiana densa - Vegetation with (thorny) shrubs, bunch grasses and cacti ; formerly used for agriculture and grazing
2 Transition area of pediment
3 Alluvial plain with eolian forms, with weakly developed soils (i.e. Entisols according to Soil Taxonomy (USDA) and Lockersyroseme according to the German Soil Classification System (DBG)) and Lampaya castellani - Vegetation with Festuca orthophylla (’iru-ichu’, ’paja brava’) and Parastrephia lepidophylla (’tola’) ; extensively used as lama and/or alpaca pasture
4 Transition area of alluvial plain weakly influenced by groundwater and salts
5 Alluvial plain influenced by groundwater and salts with saline-alkali soils according to RICHARDS (1954) (ECe > 4 mS/cm, SAR > 13 and pHe < 8.5) (Halaquepts according to Soil Taxonomy (USDA)), with phytotoxic amounts (to crops plants) of soluble boron, sodium and chloride in soil and groundwater and with Distichilis humilis - Salicornia pulvinata - Anthobryum triandrum - Vegetation (halophytes that grow in cushions or short lawns) ; partly intensely used as lama, alpaca and/or sheep pasture
The predominance of the capillary rise of saline-alkali groundwater opposed to the seepage of precipitation in soils of depressions on the alluvial plain results in an accumulation of soluble salts in these areas. The distribution of the salts in the soil depends on the seasonally changing amount of precipitation : in the dry season the salinity increases with the height in the soil profile, in the rainy season the highest concentration of soluble salts is located a few decimeters below the soil surface.

Mots Clés : Boden, Vegetation, Puna, Altiplano,Bolivien, Bodenversalzung, Salzgehalt, Natriumanteil, Bodenanalysensuelo, vegetación, puna, altiplano, Bolivia, salinización, sodificación, salinidad,sodicidad, análisis de suelos,soil, vegetation, puna, altiplano, Bolivia, salinization,alkalinization, salinity, sodicity, soil analysis

Présentation

Page publiée le 13 septembre 2010, mise à jour le 7 janvier 2019