Soil properties in burned and unburned Mediterranean shrublands of Montesinho Natural Park, Northeast Portugal
Conference Paper
Overview
Research
Additional Document Info
View All
Overview
abstract
Anthropogenic fire in shrublands for obtain better pastures for cattle, is relatively common practice in the region of Trás-os-Montes, Northeast Portugal. During burning, plant cover and litter layers are consumed, and the mineral soil is heated, resulting in changes to physical, chemical, mineralogical, and biological soil properties. In order to evaluate the effect of this kind of fires on some physical and chemical soil properties, two sites under similar climatic and soil conditions in adjacent areas of burned and unburned shrublands in Montesinho Natural Park, Northeast Portugal, were selected for sampling, 6 months after burning. The fire occurred in early October 2009 and the samples were collected in March 2010. During this period the precipitation was 1384 mm and in October was 151 mm. Disturbed soil samples were collected at depths 0-5, 5-10, 10-15, 15-20 and 20-30cm, for assess organic matter, nutrients concentration, soil pH and soil texture. Bulk density and permeability were determined in undisturbed samples, collected in 100 cm3 cylinders (bulk density in the same depths above referred and permeability only in layer 0-5 cm). When compared burned with unburned areas the results show that: (1) bulk density increased in all layers, and permeability show similar behavior between both areas; (2) content of silt and clay varied in opposite directions, with gains of silt and losses of clay in soil; (3) soil acidity increased, P and K concentration decreased mainly in 0-5 cm layer, organic matter increased in the first 15 cm, decreasing in deeper layers.
The climatic conditions after fire (with high precipitation amounts, eventually leading high leaching rates and surface erosion) and low fire intensities (indicated by the presence of incompletely burnt materials), and consequently lower ash deposition, may partly explain the changes in soil properties found among burned and unburned shrublands.
