Resumo

SCHMIDT, ERICA SUSANA  e  AMIOTTI, NILDA MABEL. PROPIEDADES EDÁFICAS SUPERFICIALES EN SISTEMAS DE AGRICULTURA DE CONSERVACIÓN EN LA REGIÓN PAMPEANA SEMIÁRIDA SUR. Cienc. suelo [online]. 2015, vol.33, n.1. ISSN 1850-2067.

Agriculturization and intense soil cultivation causes soil erosion and impacts negatively on chemical and physical soil quality parameters. Conservation Agricultural (AC) practices could mitigate or reverse these processes. No-tillage (SD) extends from the Humid Pampa to the southern semiarid region replacing other conventional and conservation tillage systems. The impact of SD on the magnitude and direction of changes in the dynamic properties of soils is not clearly elucidated. Our objective was to determine and compare the effects of two AC systems (SD and reduced tillage, LR) on the content of total organic carbon (COT) and some associated physical properties in the surface horizon (epipedon) of Petrocalcic Paleustoles. Random samples were taken in production plots at three depths: 0-5, 5-10 and 10-18 cm, with the aim of detecting stratifications in the evaluated parameters. Laboratory tests included COT, bulk density (Dap), total porosity (Pt) and pore size distribution, differentiating macropores (MP), mesopores (mP) and micropores (uP). Penetration resistance (RP) was measured at field conditions and the InfoStat program was used for statistical analysis of the data (N = 30). Compared to LR, SD showed a decline in the physical condition of the epipedon expressed by increases in Dap and RP, and decreases in the volume of Pt and MP. Differences between treatments were particularly evident below 5 cm. Continuous SD, the current management practice in the region, did not contribute to improve the physical properties or to increase the COT stock in the epipedon in the medium to long term compared to LR.

Palavras-chave : No-till; reduced tillage, total organic carbon, physical properties.

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