Resumo

ROLLAN, Adriana Ana del Carmen  e  BACHMEIER, Omar Antonio. Effect of continuous zero tillage on the physical-functional behavior of silty loam soils of the semiarid central region of the province of Córdoba (Argentina). Terra Latinoam [online]. 2015, vol.33, n.4, pp.275-284. ISSN 2395-8030.

The silty loam soils are characterized by susceptibility to compaction and forming massive homogeneous structures. The use of zero tillage practices (SD) requires exploring new aspects of physical degradation of these soils. Therefore, the aim of this study was to evaluate the effect of continuous SD on the physical-functional behavior of silty loam soils of the semiarid central region of the province of Córdoba (Argentina). Content of organic carbon (OC), particle size distribution, bulk density (Db), particle density and saturated hydraulic conductivity (Ksat) from 0 - 7 (Prof.1) and 7 - 14 cm (Prof.2) were measured. The average silt content was 54 %. In most cases, Prof.1 OC doubled the measured values in Prof.2. Bulk density values of Prof.2 were up to 20 % higher than those for the Prof.1. The decrease in the steady state flow of lower porosity sites shows that the degree of compaction processes affects movement of water in the soil and may indicate dominance of macropores in the saturated water flow. In most cases, higher values of Ksat were associated with the lowest values of Db; this behavior was not widespread. Continuous SD affected the physical and functional characteristics of the silty loam soils studied. From a physical standpoint, stratification of OC did not offset the densification induced by the tillage system. From the functional point of view, compaction causes changes in soil hydraulic properties 0-14 cm deep.

Palavras-chave : soil porosity; compaction; bulk density; hydraulic conductivity.