Litter production and nutrients transfer in a second rotation area with Pinus taeda L. forest in Cambar\ue1 do Sul, RS

Objetivou-se avaliar a transfer\ueancia de serapilheira e nutrientes das copas ao solo em \ue1rea de segunda rota\ue7\ue3o com floresta de Pinus taeda L. num per\uedodo de 3 anos (5o ao 7o ano de idade) no munic\uedpio de Cambar\ue1 do Sul, RS. Para tanto, foram alocadas tr\ueas parcelas de 48 m x 50 m, cada uma com cinco coletores de 1 m2. Todo material depositado foi coletado mensalmente entre abril de 2004 e mar\ue7o de 2007. Ap\uf3s cada coleta, o material foi identificado e levado para o laborat\uf3rio de Ecologia Florestal da Universidade Federal de Santa Maria onde posteriormente foi seco em estufa, pesado, mo\ueddo e analisado quimicamente quanto aos teores de macro e micronutrientes. A deposi\ue7\ue3o m\ue9dia anual de serapilheira foi de 4.519,1 kg ha-1, mostrando-se vari\ue1vel no decorrer dos tr\ueas anos de estudos. O aporte total de macronutrientes ao solo, em kg ha-1 ano-1, foi de: 28,7 de Ca; 27,3 de N; 4,8 de Mg; 4,6 de K; 2,4 de S e 1,8 de P e o aporte de micronutrientes, em g ha-1 ano-1, foi de: 6.689,7 de Mn; 1.092,9 de Fe; 142,8 de Zn; 60,0 de B e 16,7 de Cu.This study had the objective of evaluating the litter and nutrients transfer to the soil in a second rotation area with Pinus taeda L. forest, during three years (5th to 7th year) in Cambar\ue1 do Sul, RS. Three plots (48 m x 50 m) were allocated, each one with 5 collectors (1 m2). All the material deposited was collected monthly between April, 2004 and March, 2007. After each collection, the material was identified and sent to the Forest Ecology Laboratory at Universidade Federal de Santa Maria, where it was dried in a stove, weighed, milled and analyzed considering macro and micronutrient amounts. The litter annual average deposition was 4.519,1 kg ha-1, showing to be variable during the three years of study. The total return of macronutrients to the soil (kg ha-1 year-1) was 28,7 of Ca; 27,3 of N; 4,8 of Mg; 4,6 of K; 2,4 of S and 1,8 of P and the total of micronutrients (g ha-1 year-1) was 6.689,7 of Mn; 1.092,9 of Fe; 142,8 of Zn; 60,0 of B and16,7 of Cu

Mixed stands of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system: I - Biomass production

Objetivou-se com o presente estudo quantificar a biomassa de um plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal com milho ( Zea mays L.) no munic\uedpio de Bag\ue9, RS. O delineamento utilizado foi blocos ao acaso com cinco tratamentos e tr\ueas repeti\ue7\uf5es (T1- 100E; T2-100A; T3-50E:50A; T4-75E:25A e T5-25E:75A), com espa\ue7amento de 4,0 m x 1,5 m. Foram plantadas tr\ueas linhas de milho, entre as fileiras de eucalipto e/ou ac\ue1cia-negra. Aos 10 meses de idade, foi quantificada a biomassa das esp\ue9cies florestais, que foram separadas por fra\ue7\uf5es (folha, galho e tronco). A biomassa do milho foi coletada no final do ciclo e tamb\ue9m separada por fra\ue7\uf5es (folha, palha, gr\ue3o, sabugo e colmo). Em plantio misto o tratamento T5 (25E:75A) apresentou o maior ac\ufamulo de biomassa, sendo 35,1% nas folhas, 25,8% nos galhos e 39,1% no tronco. A ac\ue1cia-negra apresentou maior crescimento inicial do que o eucalipto, tanto em monocultivo como em plantio misto. A produtividade do milho ficou entre 1,01 a 1,26 Mg ha-1, n\ue3o diferindo estatisticamente (p < 0,05) entre os tratamentos.This study aimed to evaluate a mixed stand of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system with corn ( Zea mays L.) in Bag\ue9, 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

TEORES DE NUTRIENTES EM POVOAMENTOS MONOESPEC\ucdFICOS E MISTOS DE Eucalyptus urograndis e Acacia mearnsii em SISTEMA AGROSSILVICULTURAL

The study had as objective compare the nutrients content in the different species involved in monospecific and mixed stands of Eucalyptus urograndis and Acacia mearnsii and in a consortium with Zea mays . The determination for forest species nutrients concentration, the treatments 100E (100 % eucalyptus + maize); 100A (100 % black-wattle + maize) and 50E:50A (50 % eucalyptus + 50 % black-wattle + maize), and in the maize were done in treatments 100E; 100A, 50E:50A; 75E:25A (75 % eucalyptus + 25 % black-wattle + maize) and 25E:75A (25 % eucalyptus + 75 % black-wattle + maize). The experimental design was a randomized block design with three replications. Forests species sampling was made in average tree in each plot, based on diameter at breast height (DBH), in three trees six month-old per treatment. Within all treatments and your replicates, installed one subplot with long 3.0 m by three corn-rows as wide, where the plants were harvested in stem, leaf, grain, cob and straw. With the exception of Ca, which was more concentrated in the bark fraction and Mg and B in the bark and leaves, the other nutrients in Eucalyptus urograndis, so in monoculture much in mixed stands, contained higher concentration just in leaves. The grain component has the highest concentrations of nitrogen and phosphorus, as straw and cob have the highest potassium concentration and the leaf component has the largest concentrations of other nutrients. The forest species did not influence significantly the levels of nutrients in components of aboveground biomass of maize.O estudo teve por objetivo comparar o teor de nutrientes das diferentes esp\ue9cies envolvidas em plantios monoespec\uedficos e mistos de Eucalyptus urograndis e Acacia mearnsii em cons\uf3rcio com Zea mays no munic\uedpio de Bag\ue9, RS. A determina\ue7\ue3o dos teores de nutrientes das esp\ue9cies florestais foi realizada nos tratamentos: 100E (100 % de eucalipto + milho); 100A (100 % de ac\ue1cia-negra + milho) e 50E:50A (50 % de eucalipto + 50 % de ac\ue1cia-negra + milho), e do milho nos tratamentos 100E; 100A; 50E:50A; 75E:25A (75 % de eucalipto + 25 % de ac\ue1cia-negra + milho) e 25E:75A (25 % de eucalipto + 75 % de ac\ue1cia-negra + milho). O delineamento adotado foi de blocos ao acaso com tr\ueas repeti\ue7\uf5es. A amostragem das esp\ue9cies florestais foi realizada tendo como refer\ueancia a \ue1rvore m\ue9dia de cada parcela, baseada no di\ue2metro a altura do peito (DAP), amostrando-se tr\ueas \ue1rvores por tratamento, aos seis meses de idade. No interior de todos os tratamentos e suas repeti\ue7\uf5es, alocou-se uma subparcela, com 3,0 m de comprimento por tr\ueas fileiras de milho como largura, onde se fracionou as plantas em colmo, folha, gr\ue3os, sabugo e palha. Com exce\ue7\ue3o do Ca, que est\ue1 mais concentrado na fra\ue7\ue3o casca e do Mg e B na casca e folhas, os demais nutrientes no Eucalyptus urograndis, tanto em monocultivo como em plantio misto, apresentam maior teor apenas nas folhas. J\ue1 na Acacia mearnsii, todos os teores de nutrientes s\ue3o superiores nas folhas. O componente gr\ue3o do milho possui os maiores teores de nitrog\ueanio e f\uf3sforo, j\ue1 a palha e o sabugo registram as maiores teores de pot\ue1ssio e o componente folha possui os maiores teores dos demais nutrientes. As esp\ue9cies florestais n\ue3o influenciam nitidamente nos teores de nutrientes nos componentes da biomassa a\ue9rea do milho

Nutrients in the litter of a seasonal deciduous forest fragment of Itaara, RS

O presente estudo teve por objetivo quantificar a massa e o estoque de nutrientes da serapilheira sobre o solo em um fragmento de Floresta Estacional Decidual no munic\uedpio de Itaara, RS. Para a quantifica\ue7\ue3o da serapilheira, a amostragem foi realizada conforme fra\ue7\uf5es estabelecidas em metodologias: uma para folhas e galhos com di\ue2metro menor a 1 cm (S0) e outra para material lenhoso com di\ue2metro de 1 cm a 3 cm (S1), 3,1 cm a 6 cm (S2) e maior que 6 cm (S3). Para a avalia\ue7\ue3o da fra\ue7\ue3o S0, foram coletadas aleatoriamente cinquenta amostras com moldura met\ue1lica de 25 cm x 25 cm, j\ue1 para a avalia\ue7\ue3o das fra\ue7\uf5es S1, S2 e S3, foram distribu\ueddas aleatoriamente dez parcelas de 3 m x 2 m na \ue1rea de estudo. O material amostrado foi acondicionado e levado ao Laborat\uf3rio de Ecologia Florestal da Universidade Federal de Santa Maria onde foram secas, pesadas, mo\ueddas e analisadas quanto aos teores de macro e micronutrientes. Cerca de 45% da serapilheira depositada sobre o solo \ue9 formada por materiais lenhosos senescentes (galhos e troncos). As fra\ue7\uf5es da serapilheira diferiram significativamente (p < 0,05), quanto aos teores de nutrientes, com exce\ue7\ue3o de Mg e Cu; geralmente a fra\ue7\ue3o S0 apresentou teores mais altos de nutrientes. As fra\ue7\uf5es S1, S2 e S3 apresentaram um ac\ufamulo de nutrientes variando de 53,3% para o K a 8,7% para o Fe em rela\ue7\ue3o ao total da serapilheira, demonstrando a import\ue2ncia da quantifica\ue7\ue3o desses componentes durante a avalia\ue7\ue3o do estoque de nutrientes contidos na serapilheira de ecossistema florestal.The aim of the present study was to quantity aboveground mass and nutrients in a deciduous seasonal forest fragment in the district of Itaara, RS, Brazil. For quantification and fractionation of the litter, sampling was carried out using two methodologies: the first one for leaves and branches with diameter smaller than 1 cm (S0) and the second one for woody material with diameter varying from 1 cm to 3 cm (S1), 3.1 cm to 6 cm (S2), and greater than 6 cm (S3). To evaluate the S0 fraction, 50 randomly sample were collected with a metallic frame of 25 cm x 25 cm, and for S1, S2 and S3 10 plots of 3 m x 2 m were distributed randomly in the area of study. Samples was packed and taken to the Laboratory of Forest Ecology of the Universidade Federal de Santa Maria, where they were dried, weighed, ground and analyzed for nutrient contents. The woody senescent litter represented about 45% of the litter layer. Litter classes differed statistically in relation to nutrient content (p < 0.05), except for Mg and Cu; usually the S0 fraction presented higher contents. The fractions S1, S2 and S3 showed an accumulation of nutrients ranging from 53.3% to 8.7% K for Fe in the total litter, demonstrating the importance of quantification of these components during the evaluation of nutrient stocks contained in the litter of the forest ecosystem

Biomass production after clear cutting in a 27-year-old stand of Araucaria angustifolia (Bertol.) Kuntze in Quedas do Igua\ue7u, PR

Este trabalho, realizado em um povoamento de Araucaria angustifolia de 27 anos de idade no munic\uedpio de Quedas do Igua\ue7u (PR), teve como objetivos: estimar a biomassa nos diferentes componentes das \ue1rvores, no sub-bosque e na serapilheira acumulada sobre o solo. A biomassa foi estimada por meio do ajuste de equa\ue7\uf5es de regress\ue3o, com coleta de 21 \ue1rvores distribu\ueddas em sete classes diam\ue9tricas, serapilheira e o sub-bosque com base em unidades amostrais de \ue1rea conhecida. A biomassa total do povoamento foi de 241,92 Mg ha-1, sendo 82,2% de Araucaria angustifolia, 9,6% de sub-bosque e 8,2% de serapilheira. Considerando apenas a biomassa de Araucaria angustifolia, 198,62 Mg ha-1, madeira do tronco (51,5%), casca do tronco (14,7%), raiz (13,0%), galhos vivos (11,8%), grimpas (ramos aciculados) (8,6%) e galhos mortos (0,5%). A produ\ue7\ue3o relativa de biomassa no componente madeira do tronco pode ser menor, quando comparado com outras esp\ue9cies florestais, sobretudo por causa da elevada aloca\ue7\ue3o no componente casca do tronco.This study, conducted in a 27-year-old Araucaria angustifolia stand in the municipality of Quedas do Igua\ue7u (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