Resumo

OTONDO, JOSÉ; JACOBO, ELIZABETH JULIANA  e  TABOADA, MIGUEL ÁNGEL. MEJORA DE PROPIEDADES FÍSICAS POR EL USO DE ESPECIES MEGATÉRMICAS EN UN SUELO SÓDICO TEMPLADO. Cienc. suelo [online]. 2015, vol.33, n.1. ISSN 1850-2067.

Warm-season grasses may decrease soil pH and sodicity levels when planted in sodic soils, but little is known about their capacity to improve topsoil physical condition in temperate sodic soils. A randomized complete block design field experiment with three treatments was conducted during four years in order to evaluate the reclamation of a temperate sodic soil by Rhodes grass (Chlorisgayana Kuhn) and perennial millet (Panicum coloratum L) in the north flooding Pampa of Buenos Aires Province.Both warm-season grasses increased aboveground net primary production by 74-157% and decreased by ten-fold bare soil surface as compared with the native short-grass steppe. However, grasses replacement caused only slight decreases in topsoil pH (always higher than 9) and no change in salinity or sodicity. In contrast, both warm season grasses improved topsoil physical condition, as shown by significant decreases in: a) topsoil bulk density (from 1.26-1.35 to 1.17-1.31 Mg m³); b) soil bearing capacity at low soil water contents (from 7.48-8.88 MPa to 4.63-6.08 MPa); and c) soil structural instability (50 to 200 %). Only perennial millet increased organic carbon stock of the A horizon (0-12 cm) by 620 Mg ha^-1. Hence, warm season grasses mainly improved topsoil physical condition in the studied temperate sodic soil rather than decreasing soil halomorphism. This shows a different pathway of phyto-stabilization of sodic soils in temperate climates.

Palavras-chave : halomorphism, soil bulk density, structural instability, phyto-stabilization.

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