A carregar...
Publicação
Efeitos de Incêndios Rurais nas Propriedades Químicas de Solos do Parque Natural do Alvão, Norte de Portugal
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 1.06 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
Os incêndios rurais, definidos como qualquer fogo não planeado que ocorre em espaços rurais, incluindo áreas florestais, agrícolas, agroflorestais e matos, provocam perturbações frequentes nas regiões mediterrâneas, impactando consideravelmente as propriedades químicas dos solos de montanha. Este estudo avaliou o efeito do fogo sobre atributos químicos do solo no Parque Natural do Alvão (PNAL), Norte de Portugal, comparando diferentes condições de cobertura vegetal e perturbação (tratamentos): (1) pastagem herbácea de montanha (PM), (2) urzal/tojal (UT), (3) urzal (U) e (4) áreas afetadas por incêndios severos (IS), em três profundidades de amostragem (0–5 cm, 5–10 cm e 10–20 cm). As análises de laboratório incluíram matéria orgânica, pH em H₂O, fósforo e potássio extraíveis, bases de troca, capacidade de troca catiónica efetiva (CTCe), acidez de troca, alumínio de troca, boro e manganês. Os resultados mostram que o tratamento UT apresenta os maiores teores de matéria orgânica, CTCe, potássio, cálcio e manganês, sobretudo na camada superficial (0–5 cm). O aumento destes atributos poderá estar associado à acumulação de cinzas e à maior disponibilidade de nutrientes após o fogo. Os valores de pH do solo variaram de ácido a subácido em todos os tratamentos, sem apresentar diferenças estatisticamente significativas entre os tratamentos nas camadas mais profundas. O fósforo extraível foi mais elevado no tratamento PM, o que pode refletir diferenças na dinâmica da matéria orgânica e dos nutrientes entre as coberturas vegetais. Em todas as profundidades, a acidez e o alumínio trocáveis permaneceram elevados, o que indica que as condições de fitotoxicidade potencial persistiram após o incêndio. Na camada de 10–20 cm, a menor influência do calor direto das chamas resultou em alterações químicas menos expressivas. As mudanças observadas parecem estar principalmente relacionadas com processos de redistribuição de nutrientes e com modificações na dinâmica do carbono orgânico do solo induzidas pelo fogo. Os resultados demonstram a importância da adoção de estratégias de gestão pós-fogo adaptadas às condições locais, incluindo a utilização do fogo prescrito como ferramenta potencial de gestão da vegetação e medidas de correção da acidez do solo, de modo a favorecer a recuperação da fertilidade química e a regeneração da vegetação.
Rural fires, defined as any unplanned fire occurring in rural areas, including forest, agricultural, agroforestry, and scrubland areas, are a frequent source of disturbance in Mediterranean regions, with considerable impacts on the chemical properties of mountain soils. This study assessed the effect of fire on soil chemical attributes in the Alvão Natural Park (PNAL), Northern Portugal, comparing different vegetation cover and disturbance conditions (treatments): (1) mountain herbaceous pasture (PH), (2) heath/gorse shrubland (UT), (3) heathland (U), and (4) areas affected by severe fires (IS), at three sampling depths (0–5 cm, 5–10 cm, and 10–20 cm). Laboratory analyses included organic matter, pH (H₂O and KCl), available phosphorus and potassium, exchangeable bases, effective cation exchange capacity (CEC), exchangeable acidity, exchangeable aluminum, boron, and manganese. The results show that the UT treatment presented the highest contents of organic matter, CEC, potassium, calcium, and manganese, particularly in the surface layer (0–5 cm). The increase in these attributes may be associated with ash accumulation and greater nutrient availability after fire. Soil pH values ranged from acidic to slightly acidic across all treatments, with no statistically significant differences among treatments in the deeper layers. Available phosphorus was highest in the PH treatment, which may reflect differences in organic matter and nutrient dynamics between the vegetation covers. At all depths, exchangeable acidity and aluminum remained high, indicating that conditions of potential phytotoxicity persisted after fire. In the 10–20 cm layer, the weaker influence of direct flame heat led to less pronounced chemical changes. The observed changes appear to be mainly related to nutrient redistribution processes and to fire-induced modifications in soil organic carbon dynamics. The results demonstrate the importance of adopting post-fire management strategies adapted to local conditions, including the use of prescribed fire as a potential vegetation management tool and soil acidity correction measures, in order to promote the recovery of chemical fertility and vegetation regeneration.
Rural fires, defined as any unplanned fire occurring in rural areas, including forest, agricultural, agroforestry, and scrubland areas, are a frequent source of disturbance in Mediterranean regions, with considerable impacts on the chemical properties of mountain soils. This study assessed the effect of fire on soil chemical attributes in the Alvão Natural Park (PNAL), Northern Portugal, comparing different vegetation cover and disturbance conditions (treatments): (1) mountain herbaceous pasture (PH), (2) heath/gorse shrubland (UT), (3) heathland (U), and (4) areas affected by severe fires (IS), at three sampling depths (0–5 cm, 5–10 cm, and 10–20 cm). Laboratory analyses included organic matter, pH (H₂O and KCl), available phosphorus and potassium, exchangeable bases, effective cation exchange capacity (CEC), exchangeable acidity, exchangeable aluminum, boron, and manganese. The results show that the UT treatment presented the highest contents of organic matter, CEC, potassium, calcium, and manganese, particularly in the surface layer (0–5 cm). The increase in these attributes may be associated with ash accumulation and greater nutrient availability after fire. Soil pH values ranged from acidic to slightly acidic across all treatments, with no statistically significant differences among treatments in the deeper layers. Available phosphorus was highest in the PH treatment, which may reflect differences in organic matter and nutrient dynamics between the vegetation covers. At all depths, exchangeable acidity and aluminum remained high, indicating that conditions of potential phytotoxicity persisted after fire. In the 10–20 cm layer, the weaker influence of direct flame heat led to less pronounced chemical changes. The observed changes appear to be mainly related to nutrient redistribution processes and to fire-induced modifications in soil organic carbon dynamics. The results demonstrate the importance of adopting post-fire management strategies adapted to local conditions, including the use of prescribed fire as a potential vegetation management tool and soil acidity correction measures, in order to promote the recovery of chemical fertility and vegetation regeneration.
Descrição
Palavras-chave
Incêndios rurais Qualidade do solo Propriedades químicas Fogo Solos de montanha