Can biosolids compost improve, in the short term, native vegetation and soils fertility in burned Nothofagus pumilio forest in Patagonia, Argentina?

Abstract

In the Patagonian Andean forests, wildfires principally have an anthropic origin and constitute one of the most important disturbances. They lead to severe losses of soil fertility and vegetation; particularly compromising the regeneration of native vegetation. Organic amendments can facilitate the regeneration of vegetation, enhancing principally soil fertility conditions. Our objective was to evaluate the effects of biosolids compost application as a tool for recovering soil fertility and regenerating vegetation in burnt areas of a Nothofagus pumilio forest along two growing seasons. Considering the National Park status of the study area, low rates (2 kg m^-2) of biosolids compost application were used to minimize the polluting effect of this amendment. We considered two types of microsites, with and without litter accumulation, in order to test whether biosolids application had a differential effect related to microsite type. Soil properties, composition and cover vegetation were evaluated. We concluded that biosolids compost application improved some of the physical-chemical, chemical and biological soil properties but did not contribute, over a period of almost two growing seasons, to vegetation recovery. These results confirm that organic amendment application may be used as an initial restoration strategy at microsite level in burnt N. pumilio forests related principally to a beneficial effect on soil fertility. The creation of fertility islands can be a valid restoration strategy, but mechanisms to increase the reinstallation of native vegetation should be also applied.