ABSTRACT: Tolerance to acid soil is an important trait of Eucalyptus and Pinus species introduced into commercial forestry plantations in tropical ecosystems. The objective of this study was to evaluate the effect of the exchangeable Al on growth of the seedlings of two species and one hybrid of Eucalyptus and two species of Pinus. We also wanted to identify the role of the root cation exchangeable capacity (CEC) on Al tolerance. The experiment was conducted under controlled conditions in a greenhouse. The soil used was collected from the top layer of a red yellow Oxisol, from the Brazilian savanna region. The treatments consisted of different rates of P and the presence or absence of liming with CaCO3 and MgCO3. The species of Eucalyptus and Pinus showed no growth differences between the treatments. For all species, a higher density of fine roots was found in treatments with lower levels of bases and a higher Al exchangeable concentration. The Pinus species had a higher root CEC than the Eucalyptus species, which had a lower leaf Al concentration. Al concentration in the fine roots was 50 fold greater than in the leaves of all species. Similar to Al, concentrations of Fe, Cu and Zn in the roots were significantly higher than in the leaves in all species. In contrast, higher Mn concentration was found in the leaf tissue. This may lead species of Eucalyptus and Pinus to be more susceptible to Mn than to Al toxicity.

RESUMOObjetivou-se com o trabalho avaliar a influência do reflorestamento com essências nativas da Floresta Estacional Semidecidual, plantio de eucalipto e pastagem nos atributos químicos e físicos do solo de áreas degradadas. Foram selecionadas cinco áreas na bacia hidrográfica do Rio Aguapeí, na cidade de Garça, SP, sendo dois reflorestamentos com essências nativas, com 4 e 9 anos, um plantio de eucalipto, uma área de pastagem e um fragmento florestal utilizado como referência. O fragmento florestal apresentou a menor soma de bases e os maiores teores de P, Corg e CTC. Ele também apresentou a menor resistência à penetração, maior diâmetro e estabilidade dos agregados. Os atributos químicos e físicos do solo das áreas reflorestadas diferiram dos observados no fragmento florestal, mostrando que o período de recuperação não foi suficiente para restaurar esses atributos. Porém o reflorestamento com 9 anos melhorou significativamente nesses atributos do solo, tendendo a aproximar-se aos do fragmento florestal.

ABSTRACTThe objective with this study was to evaluate the influence of reforestation with native species from seasonal semideciduous forest, eucalyptus plantation, and pasture in the soil chemical and physical properties of degraded areas. Five sites were selected in the watershed of the Aguapeí River in the Garça city, Sao Paulo state: two reforestation areas with native species, with four and nine years old; a reforestation area with eucalyptus plantation, a pasture area, and a forest fragment used as control. The forest fragment presented the lowest exangeable bases and the highest levels of P, SOC and CEC; it also showed the lowest penetration resistance, and the largest diameter and aggregate stability. The chemical and physical soil attributes of the reforestation areas differed from those of the forest fragment (control), showing that the recovery period was not sufficient to restore these attributes. However, the 9-year-old reforestation area presented significant improvement of these soil attributes, tending to approach those of the control area.

Por fazer parte de inúmeros compostos e estar diretamente relacionado com a capacidade fotossintética das plantas, o nitrogênio (N) pode influenciar significativamente na produção e enraizamento de estacas. Com base nesse contexto, o trabalho teve por objetivo avaliar o efeito de doses crescentes de N na produtividade, capacidade e velocidade de enraizamento das miniestacas produzidas de minicepas do clone híbrido de Eucalyptus grandis x Eucalyptus urophylla (I-224), além da qualidade das mudas formadas. O presente trabalho foi realizado no viveiro de mudas clonais de Eucalyptus, em minijardim de leito de areia da FAEF - Garça - SP. O delineamento experimental utilizado foi o inteiramente casualizado com 4 repetições, sendo os tratamentos constituídos por 5 doses de nitrogênio diferentes na solução nutritiva (0; 80; 160; 240 e 320 mgL-1). As variáveis analisadas foram: número de estacas produzidas, índice de produtividade, enraizamento das estacas produzidas e determinação da massa seca das mudas. A dose de nitrogênio aplicada no minijardim influenciou a produção de estacas, apresentando comportamento quadrático, atingindo a produção máxima (13,1 estacas cepa-1 mês-1) com a dose estimada de 129 mg L-1. O percentual de enraizamento apresentou comportamento linear crescente. A dose que proporcionou o maior índice de produtividade do minijardim foi de 194 mg L-1. A dose de nitrogênio aplicada no minijardim influenciou significativamente na velocidade de enraizamento, e o acúmulo de matéria seca das mudas formadas.

For being part of innumerable compounds and being directly related with the photosynthetic capacity of plants, Nitrogen (N) can significantly influence the production and rooting of cuttings. On the basis of this context, the work aimed to evaluate the effect of increasing doses of N in the productivity, capacity and speed of rooting mini-cuttings produced from mini-stumps of hybrid clones of Eucalyptus grandis x E. urophylla (I-224), beyond the quality of the formed changes. The present work was carried through in nursery seedlings of Eucalyptus, in a mini-garden of sand stream bed of FAEF, in Garça, São Paulo state. The used experimental delineation was complete randomized design with 4 replications, being the treatments consisted of 5 different doses of Nitrogen in nutritional solution (0; 80; 160; 240 and 320 mg L-1). The variables analyzed were: number of cuttings produced, the productivity index, rooting of cuttings produced and determination of the dry mass of seedlings. The dose of nitrogen applied in the mini-garden influenced the production of stakes, with a quadratic, reaching maximum production (13,1 stakes strain-1 month-1) with the estimated dose of 129 mg L-1.The percentage of rooting presented increasing linear behavior. The dose that provided the biggest index of productivity of the mini-garden was of 194 mg L-1. The dose of nitrogen applied in the mini-garden influenced the rooting significantly and the dry mass of formed seedlings.

Objetivou-se, com o trabalho, quantificar o acúmulo de serapilheira, bem como os macronutrientes e o carbono orgânico na Floresta Estacional Semidecidual Submontana, localizada em Cachoeiro de Itapemirim, ES. A amostragem da serapilheira foi realizada em 12 parcelas (20 m x 50 m), sendo as mesmas distribuídas de forma sistemática no campo. Em cada uma das 12 parcelas, foram coletadas mensalmente 12 amostras de serapilheira acumulada, de forma aleatória, com o auxílio de um gabarito de metal de 0,25 m x 0,25 m. O estudo de acúmulo de serapilheira na floresta foi analisado segundo o delineamento inteiramente casualizado, com 12 tratamentos (meses do ano) e 12 repetições. O acúmulo de serapilheira mostrou-se sazonal, com maiores acúmulos, ocorrendo no final da estação seca e de menores temperaturas do ar (Dez/09, Jan/10, Set/10 e Out/10), contendo em média 5,5 Mg ha-1 de serapilheira acumulada. O Cálcio foi encontrado em maior teor e conteúdo, sendo o conteúdo médio de macronutrientes contidos na serapilheira de 293,59 kg ha-1.

The objective of the study was to quantify the accumulation of litter, macronutrients and organic carbon in the Submontane Seasonal Semideciduous Forest, located in Cachoeiro de Itapemirim, ES. A sampling of litter was performed in 12 plots (20 m x 50 m), and was distributed systematically in the field. In each of the 12 plots were collected monthly 12 samples of litter accumulated at random, with the aid of a metal template of 0.25 m x 0.25 m. The study of accumulation of litter in the forest was analyzed according to completely randomized design with 12 treatments (months of the year) and 12 repetitions. The accumulation of litter was found to be seasonal, with higher accumulations occurring at the end of the dry season and lower air temperatures (Dec/09, Jan/10, Sep/10 and Oct/10), containing on average 5.5 Mg ha-1 of accumulated litter. Calcium was found in higher level and content, and the average content of macronutrients in the litter was 293.59 kg ha-1.

No presente trabalho, objetivou-se avaliar o efeito de doses de fósforo (P) na qualidade de mudas clonais de Eucalyptus urophylla x Eucalyptus grandis no viveiro e a sobrevivência e desenvolvimento inicial no campo. O delineamento experimental utilizado foi o inteiramente casualizado com 4 tratamentos e 5 repetições, com 30 plantas por repetição. Ao final do ciclo (90 dias), foram utilizadas 15 mudas para a determinação do acúmulo de massa seca e concentração de nutrientes na parte aérea e o restante foi plantado no campo para determinar o percentual de sobrevivência e o desenvolvimento inicial. Os tratamentos foram compostos por 4 doses de adubação fosfatada (0,0; 1,3; 2,6 e 5,2 mg planta-1). Para a obtenção de mudas de qualidade em condiçoes semelhantes a desse experimento, devem ser utilizados doses de P na faixa de 3,6 a 3,8 mg planta-1. Doses superiores a 4 mg planta-1 prejudicam o desenvolvimento e a qualidade das mudas de eucalipto. A adubação fosfatada adequada em mudas de eucalipto aumenta em 30% o percentual de sobrevivia das mudas no campo.

This study evaluated the effect of phosphorus (P) on the survival in the nursery and early development in the field of clonal Eucalyptus urophylla x Eucalyptus grandis seedlings. The experimental design was completely randomized with four treatments and five replicates of 30 plants per replicate. At the end of the cycle (90 days), 15 seedlings were used for determining the dry matter accumulation and nutrient concentration in the shoot. The rest was planted in the field to determine the percentage of survival and early development. The treatments consisted of four doses of P fertilization (0.0, 1.3, 2.6 and 5.2 mg plant-1). To obtain high quality seedlings in conditions similar to this experiment it is required doses of P in the range from 3.6 to 3.8 mg plant-1. Doses greater than 4 mg plant-1 affect the development and quality of eucalyptus seedlings. An adequate phosphorus fertilization of eucalyptus seedlings increase, by about 30%, the percentage of surviving seedlings in the field.