Márcio Viera

CONCENTRAÇÃO E RETRANSLOCAÇÃO DE NUTRIENTES EM ACÍCULAS DE Pinus taeda L.

Aiming at evaluating nutrients concentration and retranslocation in the Pinus taeda L. needles, this study was developed in two stands, in native grass area and in second rotation area, with same species and same age (7.5 years old) in Cambara do Sul, RS. The needles were collected in plants in four orthogonal points (South, North, East and West), sampled new needles, mature needles and old needles. The material was dried in a stove, milled and chemically analyzed (macro and micronutrients). The concentrations of N, P, K, B, Cu and Zn had decreased, of Ca, Fe and Mn increased, and the Mg and S have remained constant with the age of the needles. The retranslocation rate (old-new needles) was more than 50% for most nutrients, except for Mn and Fe, showed that cumulative effect and the Ca reference element.

Teores e aporte de nutrientes na serapilheira de Pinus taeda L., e sua relação com a temperatura do ar e pluviosidade

The objective of this study was to evaluate the contents and input of nutrients to forest floor in a Pinus taeda L. stand and the relation with rainfall and air temperature, in an area previously occupied with native grass, in Cambara do Sul, RS, through litterfall, evaluated during a three-year period, from the 5th to the 7th year of the stand. Litter was monthly collected in 1.0 m2 (1.0 x 1.0 m) collectors, from April/ 2004 to March/2007. After each collection, litter samples were chemically analyzed for macro and micronutrients. The contents of K, Mg and Cu showed a positive correlation (p < 0,05) with air temperature, while Fe (p< 0.01), Mn and Zn (p < 0,05) showed a negative correlation with this climatic variable. The contents of N and K showed a negative correlation (p < 0.01 e p < 0,05, respectively). The contents of K, Mg and Cu showed a positive correlation (p < 0,05) with rainfall and the contents of S showed a positive correlation (p < 0,05) with air temperature, while the contents of Fe (p < 0.01), Mn and Zn (p < 0,05) showed a negative correlation with this variable.The contents of N and K showed a negative correlation (p < 0.01 and p < 0,05, respectively) with litter amount monthly deposited. Macronutrient mean annual input to soil, through litter deposition, in kg ha-1 was: 18.8 of Ca; 13.0 of N; 3.0 of Mg; 1.6 of K; 1.3 of S and 1.1 of P and for micronutrients the transference, in g ha-1 was: 4,708.3 of Mn; 592.3 of Fe; 74.1 of Zn; 34.0 of B and 7.6 of Cu. The results demonstrate the importantance of keeping the litter over the soil to maintain nutrient cycling.

Deposição de serapilheira e de macronutrientes em um povoamento de acácia-negra ( Acacia mearnsii De Wild.) no Rio Grande do Sul.

This study evaluated litter and macronutrient deposition in a six year-old black wattle ( Acacia mearnsii De Wild.) stand, in Butia-RS. Five plots (18mx24m) of litter were systematically allocated, each one with four trap collectors of 1 m 2 . The litter intercepted was collected monthly between January 2002 and December 2003. After collection, litter was divided into leaves, flowers, fruits and caterpillar ( Adeloneivaia subangulata ) feces, oven dried, weighed, milled and analyzed for N, P, K, Ca and Mg contents. The average annual litter deposition reached 4.32 Mg ha -1 , and was composed of 75.5, 11.1, 11.2 and 2.2% of leaves, flowers, fruits and feces, respectively. Litter deposition was more concentrated in the spring. The higher deposition of nutrients was through the leaf fraction, which contributed annually with a great amount of litter biomass, although not showing the highest nutrient concentrations. The supply of total amount of macronutrients to the soil was of 74.8 of N, 26.8 of K, 23.1 of Ca, 7.9 of Mg and 2.4 of P (kg ha -1 ).

Deposição de nutrientes pela serapilheira em um fragmento de Floresta Estacional Decidual no Rio Grande do Sul

Knowledge on nutrient deposition from species that compose the Deciduous Forest is incipient. The objective of this study was to determine the nutrient input by different species, from litter deposition in a Seasonal Deciduous Forest in Itaara, RS. Six plots (25.0 m x 17.0 m) were installed for litter collection,. In each plot, 5 mesh-screen traps were allocated. The litter was monthly collected from January 2006 to December 2007. Litter was sorted out in leaves, twigs (diameter < 0.5 cm) and mixture (flowers, fruits, seeds and non identified plant parts). Leaves were separated regarding the most representative species in the forest. The material was analyzed for the levels of macro and micronutrients. The concentration of nutrients differed between species. The highest nutrient input occurred from the leaf fraction, followed by twigs and mixture. Among the evaluated species, Parapiptadenia rigida showed the highest nutrient transfer, except for Mn that was highest in Matayba elaeagnoides, and Ocotea pulchella.

Biomassa em povoamentos monoespecíficos e mistos de eucalipto e acácia-negra e do milho em sistema agrossilvicultural

Objetivou-se, com este estudo, quantificar a producao e a distribuicao de biomassa da parte aerea nas plantas em povoamentos monoespecificos e mistos de eucalipto (hibrido E. urophylla x E. grandis) e acacia-negra (Acacia mearnsii) e do milho (Zea mays) em sistema agrossilvicultural. As avaliacoes de biomassa (folha, galho, casca e madeira) das especies florestais, aos 6 e aos 18 meses de idade, foram realizadas nos tratamentos: 100E (100% de eucalipto + milho); - 100A (100% de acacia-negra + milho); - 50E:50A (50% de eucalipto + 50% de acacia-negra + milho). A avaliacao da biomassa do milho (colmo, folha, palha, sabugo e graos) foi realizada nos tratamentos 100E; 100A; 50E:50A; 75E:25A (75% de eucalipto + 25% de acacia-negra + milho); e - 25E:75A (25% de eucalipto + 75% de acacia-negra + milho). A producao de biomassa do eucalipto e da acacia-negra, tanto em monocultivo quanto em plantio misto, nao diferiu em todas as idades avaliadas, mas, quando avaliada por compartimentos das plantas, verificou-se interacao competitiva interespecifica do eucalipto sobre a acacia-negra, ocasionando a reducao da formacao de biomassa de copa. A producao total de biomassa do milho em sistema agrossilvicultural com eucalipto e acacia-negra em plantios monoespecificos e mistos nao diferiu entre os tratamentos estudados.

PRODUÇÃO E DECOMPOSIÇÃO DE SERAPILHEIRA EM UM POVOAMENTO DE Eucalyptus urophylla x Eucalyptus globulus maidenii

A producao continuada de madeira em plantios comerciais exige conhecimento do processo de ciclagem de nutrientes, que envolve, entre outros aspectos, a producao e a decomposicao de serapilheira. Assim, neste estudo, objetivou-se verificar a influencia das variaveis climaticas na producao de serapilheira e de seus componentes, alem de avaliar a taxa de decomposicao de serapilheira em um povoamento de Eucalyptus urophylla x E. globulus maidenii. Para a execucao do estudo, foram instaladas 4 parcelas de 20 m x 20 m, em cada uma foram instalados 4 coletores para as fracoes folhas, galhos finos e miscelânea da serapilheira e 3 subparcelas para a coleta da fracao galhos grossos. O tecido vegetal coletado foi utilizado para o calculo da deposicao e da correlacao existente entre variaveis climaticas e deposicao. As variaveis climaticas utilizadas, com base mensal, foram temperatura media, temperatura maxima media, temperatura minima media, precipitacao pluviometrica, umidade relativa media, velocidade media do vento, evapotranspiracao e radiacao solar media, ambas fornecidas por uma estacao experimental. Ja, para a avaliacao da decomposicao da serapilheira foram coletadas aleatoriamente 4 amostras quadradas de 0,25 m de lado em cada parcela, utilizadas para a determinacao do coeficiente de decomposicao (K), meia vida (t0,5) e tempo de decomposicao de 95% da serapilheira (t0,95). A producao mensal de serapilheira foi fracamente correlacionada com variaveis climaticas e apresentou media anual de 7,4 Mg ha-1, sendo composta predominantemente pela fracao folhas (60%). A decomposicao de serapilheira foi considerada lenta.

DEPOSIÇÃO DE SERAPILHEIRA EM POVOAMENTO DE PINUS

Litterfall is the main responsible for maintaining forest stands yield in soils with low natural fertility. This study aimed to evaluate seasonal and monthly litterfall deposition in a Pinus taeda L. stand, in Quedas do Iguacu, Parana State, Brazil. Three plots with 21.0 m x 20.0 m were randomly allocated, where four collectors of 1.0 m 2 each were systematically distributed. The litterfall was monthly collected, between April 2007 and March 2009, respectively at eight and nine years after the stand plantation, and divided in needles, thin branches (diameter < 0.5 cm), and miscellaneous, being subsequently determined its dry mass. The litterfall annual deposition reached 7.1 Mg ha -1 , being higher in the autumn. The average maximum temperature and average air temperature had inverse and significant influence on needles deposition and total litterfall.

Monthly variation of litter deposition in Pinus taeda L. stand in native grass area in Cambará do Sul-RS

Objetivou-se com este trabalho avaliar a deposicao de serapilheira em Pinus taeda L., implantado em area de campo nativo, durante um periodo de tres anos (5o ao 7o ano de idade da floresta), no Municipio de Cambara do Sul, na regiao dos Campos de Cima da Serra, no Rio Grande do Sul. Foram alocadas quatro parcelas de 18 m x 50 m, de forma aleatoria, e nelas foram distribuidos 20 coletores de serapilheira de 1 m2 (cinco em cada). A serapilheira interceptada nos coletores foi coletada mensalmente entre abril/2004 e marco/2007. Apos cada coleta, a serapilheira foi posta em estufa para secagem e determinacao do peso de materia seca. A deposicao media anual de serapilheira foi de 2.545,1 kg ha-1, tendo a seguinte ordem estacional media: outono > verao > inverno > primavera. A umidade relativa foi a unica variavel climatica que apresentou correlacao significativa (r = 0,365; p<0,05) com a deposicao de serapilheira.

Plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal: I - Produção de biomassa

This study aimed to evaluate a mixed stand of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system with corn ( Zea mays L.) in Bage, RS. The design entailed a randomized block with five treatments and three replicates (T1- 100E; T2- 100A; T3- 50E:50A; T4- 75E:25A e T5- 25E:75A), with 4.0 m x 1.5 m planting space. Three lines of corn were planted, between the eucalyptus and/or black-wattle lines. Ten months after the installation, the biomass from forest species were quantified and separated in fractions (leaf, branch and stem). Corn biomass was collected at the end of the cycle and separated in fractions (leaf, straw, grain, corn cob and stem). In mixed stands, the treatment T5 (25E:75A) showed the highest biomass accumulation, being 35.1% in the leaves, 25.8% in branches and 39.1% in stem. The black wattle showed higher growth than the initial eucalyptus, both alone and in the mixed stand. The yield of corn was between 1.01 to 1.26 Mg ha -1 , which was not statistically different (p>0.05) between treatments.

Produção de biomassa no corte raso em plantio de Araucaria angustifolia (Bertol.) Kuntze de 27 anos de idade em Quedas do Iguaçu, PR

This study, conducted in a 27-year-old Araucaria angustifolia stand in the municipality of Quedas do Iguacu (PR) county, aimed to estimate tree components, understory and accumulated litter biomasses. Biomass was estimated through regression equation adjustments, with 21 trees felled, distributed among 7 diametric classes, and with litter and understory based on known sample unit areas. Total stand biomass was 241.92 Mg ha -1 , with 82.2% composed of Araucaria angustifolia , 9.6% composed of understory and 8.2% composed by litter. Considering only Araucaria angustifolia , the biomass was of 198.62 Mg ha -1 , composed of wood (51.5%), bark (14.7%), roots (13.0%), lives branches (11.8%), aciculated branches (6.6%) and dead branches (0.5%). Relative biomass production for the wood component may be low, when compared to other forest species, mainly due to the high allocation in the bark component.