Resumo

COPA BOBARIN, Roxana  e  MIRANDA CASAS, Roberto. Soil Hydrophysical properties forthe implementation of irrigation systems in a semiarid zone (Centro Rivera-Central Bolivian Highlands). RIIARn [online]. 2014, vol.1, n.1, pp.73-80. ISSN 2409-1618.

Semiarid zones have low water availability, quantified in base of the average annual rainfall related to evaporation. Soluble salts accumulate in soils and the distribution, composition and concentration depends on the soil profile characteristics and water flow. In this work, the physical, chemical and hydraulic soil properties were evaluated in four sampling points in the Centro Rivera community in alfalfa irrigated plots. The results show that mainly in the dry season, soils are irrigated with water from the Desaguadero river, characterized as highly saline waters. Soil properties, both physical and hydrochemical are affected by irrigation water quality and climate. The high sediment content of water (555 mg.l-1) promotes the formation of surface horizons with higher content of fine particles, silt and clay, providing more than 700 kg.ha-1 of sediment per year. This causes lower values of bulk density, low infilíraíion rate and difficulíy for water percolation, resulting in slow to moderately slow permeability through the soil profile. Soils are classified as saline, process favored by high evapotranspiration rates (ETo>1500 mm.yr-1) and low rainfall (<400 mm.yr-1) in this region. The water holding capacity of the soil is also strongly affected by the soil salinity.

Palavras-chave : Soil physics; soil chemistry; soil hydraulics; water retention capacity of the soil; Salinity.

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