Wildfires in NW Patagonia: long-term effects on a Nothofagus forest soil
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In NW Patagonia, Argentina, poor regeneration after fires of Nothofagus pumilio (Poepp. and Endl.) Krasser forests located in drier environments has been attributed to probable edaphic changes. We studied the long-term effects of wildfire on the mineralogical, physical, chemical and biological properties of a soil developed from volcanic-ashes under N. pumilio forests. Soils from six small patches burned in January 1996 and of undisturbed forest were sampled at a depth of 0-10 cm in March 1996,1997, 1998 and 2000. As biological soil indicators we assessed N in microbial biomass (N-MB) and potential N mineralization (pNmin). Chemical properties were analyzed for all 4 years in dry samples, N-BM and pNmin in rewetted samples in 1996 and 1997, and in field-moist samples in 1998 (pNmin) and 2000 (N-MB). Additionally, we measured soil moisture twice during the growing seasons of 1998 and 2000 at 0-16 cm, and mineralogical and physical properties once in 1998. The main effects of fire were: (i) a significant increase in pH, electrical conductivity, extractable P and cations (Ca, Mg, Na, K) and a significant decrease in organic C and total N; 4 years after the fire, C and N were still, respectively, 52 and 20% lower, pH was one unit higher, and electrical conductivity and extractable P were twice as high as in the unburned control; (ii) a considerable decrease in N-MB (>90%), without significant recovery in subsequent years; (iii) an increase of pNmin at the beginning of the incubation period, decreasing afterwards to only 4-44% the levels in the unburned soil; and (iv) a decrease of 31% in field capacity and 56% in soil moisture. No mineralogical changes in the amorphous soil components were observed. Although volcanic soils show a high capacity to stabilize organic matter, buffer pH, retain P and store water, the magnitude of the changes of all soil properties indicated that the intensity of the fire was very high, and might have a powerful effect on seedling emergence and survival. (C) 2003 Published by Elsevier B.V.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Forest Ecology and Management|
|Publication status||Published - 2004|
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Plant Ecology and Systematics (Closed 2011) (011004000)