Temporal and spatial variability of structure dependent properties of a volcanic ash soil under pasture in southern Chile

Abstract

Prairies are a main source for livestock feeding in southern Chile. The aim of this research was to define how grazing events and natural wetting and drying cycles (WD) affect the spatial and temporal variability of the soil's structural properties. The investigation was conducted in a Duric Hapludand, Valdivia Series. Penetration resistance (PR) and volumetric water content (WC), measured in situ, were used to prepare maps which show i) temporal (1383 to 3047 kPa for 46 to 16% WC) and spatial changes, and ii) grazing events as an important factor influencing spatial changes in PR (differences of 3421 kPa between max and min values). Grazing and WD cycles induced changes in the soil's mechanical stability and pore functions, which indicate that structure-dependent properties are dynamic. During the study, variations between 0.3 and 0.9 log µm 2 were detected for air permeability (ka), whereas air capacity (ACp) ranged between 5 and 18%. Soil mechanical strength also varied over time and showed changes in PR. The same instrument, however, cannot be used to identify changes in soil pore functions. Generally, after grazing events, soil deformation induced a reduction of air capacity and permeability; however, after WD cycles, soil pores were able to recover their functional integrity.

The development of nutrient contents on a new conservation area in the far North of Germany concerning different types of use. A proposal for a sustainable development in nature conservation practice

“…Animals have certain preferred areas, e.g. entrance area, where the trampling intensity is much higher (Dec et al 2011). Thus, recording maximum values at the border of the field was reasonable.…”

“…Additionally, the comparison with the results of the measurement of soil penetration resistance is quite difficult, for example, Dec et al (2011) could not detect any dependencies.…”

Parámetros de capacidad e intensidad del sistema poroso para evaluar la calidad física de un Andisol bajo pastoreo

“…ciclos de mojado y secado del suelo) que alteran la estructura del suelo y, en consecuencia, el ordenamiento espacial de sus poros (Horn y Smucker, 2005;Reszkowska et al, 2011;Dec et al, 2012;Dörner et al, 2012). Esto, es particularmente relevante para los suelos derivados de cenizas volcánicas del Centro-Sur de Chile, ya que éstos sustentan praderas que son pastoreadas por animales durante gran parte del año (Dec et al, 2011), por lo tanto, quedan expuestos a estrés de tipo mecánico e hidráulico.…”

La regeneración natural del pino silvestre (Pinus sylvestris L.) en el Valle del Lozoya (Madrid): germinación y supervivencia inicial

“…La RP estima adecuadamente la resistencia mecánica del suelo en un momento puntual y con las condiciones reinantes en ese instante. Pero, si no se dispone de más datos, no permite extraer conclusiones fiables acerca de la estructura porosa subyacente ni del comportamiento hídrico, térmico y gaseoso esperado en el suelo (Manoel et al, 2001;Dec et al, 2011).…”

“…), la imagen obtenida nos indica dónde la resistencia es más alta y más baja en el momento en el que se debería estar produciendo el pico de crecimiento de la vegetación. Este tipo de muestreo comparativo resulta también adecuado si lo que se desea es analizar el efecto de agentes compactadores sobre el suelo (Dec et al, 2011;Schmalz et al, 2013).…”