Fluxo De Nutrientes Pela Precipitação Pluviométrica Em Dois Trechos De Floresta Ombrófila Densa Em Guaraqueçaba, Paraná

Abstract

ResumoEste trabalho teve o objetivo de avaliar os fluxos de K, Ca, Mg e Na através da precipitação no exterior e no interior de dois trechos de Floresta Ombrófila Densa (capoeira: estágio inicial/intermediário de sucessão secundária de floresta aluvial e floresta secundária submontana), na Reserva Natural Salto Morato, em Guaraqueçaba, Paraná. A capoeira e a floresta secundária apresentaram valores de interceptação da água da chuva em torno de 14%, sendo baixos comparados com outros da literatura. As estimativas para a deposição do Na pela precipitação foram elevadas se comparadas às de outros trabalhos, alcançando uma média anual de 83 kg/ha na precipitação externa e de 96 kg/ha na precipitação no interior da capoeira. Entre os macronutrientes analisados, para o mesmo processo, foram estimadas deposições anuais de 52 kg/ha de K, 5 kg/ha de Ca e 2,9 kg/ha de Mg, ocorrendo os maiores aportes durante o período mais quente e chuvoso. Os valores para a floresta secundária foram um pouco menores, principalmente para o K. Somando com dados da contribuição da serapilheira no mesmo período, disponíveis para a capoeira, a precipitação interna representou respectivamente, 65%, 5% e 15% da deposição total desses nutrientes no solo, indicando a importância desse processo para a restauração e/ou manutenção dos elementos minerais dentro dos ecossistemas estudados. Palavras-chave: Ciclagem de nutrientes; interceptação do dossel; precipitação interna; sucessão secundária; macronutrientes. Abstract Nutrient flow in rainfall and throughfall in two stretches in an Atlantic Rain Forest in southernBrazil. The returns of K, Ca, Mg and Na through rainfall and throughfall (in an early to midde successional alluvial forest and in a secondary lowland forest) were estimated in an Atlantic Rain Forest in Southern Brazil. The two forests showed interception rainfall values around 14%, considered low comparing to other studies. The Na values were very high, reaching in average 83 kg ha -1 y -1 in rainfall and 96 kg ha -1 y -1 in throughfall in the early to midde secondary forest. The annual nutrient returns in througfall were: of 52 kg ha -1 of K, 5 kg ha -1 of Ca and 2.9 kg ha -1 of Mg, with major contributions during the rainy season. The secondary forest presented lower values, mainly for K. Additioning to available litterfall data in early to midde secondary forest, througfall contributed to 65% of K, 5% of Ca and 15% of Mg returned to the soil pointing out the relevance of this process to the restoration and/or maintenance of these elements into the studied ecosystems.

Throughfall in different forest stands of Iperó, São Paulo

“…In the case of nonnative pine and eucalyptus forests, throughfall rates are usually higher in hardwood stands than in softwood stands (LIMA, 1976). Scheer (2009) studied the contribution of rainfall to nutrient flow in rain forests and noted that, by dragging the nutrients suspended in the atmosphere and subsequently washing them away from the surface of the leaves, rain precipitation plays an important part in returning such nutrients to the forest floor. The author observed that 65%, 15% and 5% of the flows of, respectively, potassium (K), magnesium (Mg) and calcium (Ca) to the forest floor was effected by throughfall.…”

Patterns of litter production in a secondary alluvial Atlantic Rain Forest in southern Brazil

“…Mean monthly rainfall was also measured in the study area using six 12.5 cm diameter, polyethylene funnels connected into fi ve liter polyethylene bottles. Each apparatus was mounted in a PVC tube so that each funnel rim was around 1 m above the soil surface (Scheer 2009). Rainfall was measured every two weeks corresponding to the same interval of litterfall collection.…”

Ion input via rainwater in the southwestern region of Rio Grande do Sul, Brazil

“…Existing nutrients in a forest ecosystem originate from two main natural sources: the weathering process and additions by rainfall. Maintenance of productivity over successive crop rotations depends on the speed with which new nutrients are released by weathering, addition through rainfall or artificial addition through fertilization (SCHRUMPF et al 2006).…”

“…The key role played by water in the current geopolitical context has prompted research studies to try and preserve water quality, improve its use and application conditions, and analyze its chemical composition in a given system. Rainfall, also known as wet precipitation, is a natural atmosphere cleansing process that draws existing chemical elements and compounds and deposits them on the earth's surface (SCHEER 2009). Atmospheric composition is influenced both by natural and anthropogenic sources, and results from the incorporation of particles and gases into water droplets (PANETTIERE et al 2000).…”