Silvio Nolasco de Oliveira Neto

Deposição de serapilheira e de nutrientes no solo em Sistema Agrossilvipastoril com eucalipto e acácia

RESUMO – Este estudo teve como objetivo avaliar o efeito do componente arboreo no aporte de serapilheira e de nutrientes em dois Sistemas Agrossilvipastoris, sendo o sistema 1: milho (Zea mays) + eucalipto (hibrido – Eucalyptus grandis x E. urophylla) + acacia (Acacia mangium) + braquiaria (Brachiaria decumbens); e o sistema 2: milho + eucalipto + braquiaria, que foram comparados com monocultivo de pasto, em Vicosa, MG. A serapilheira do componente arboreo e da forrageira foi coletada mensalmente, a partir dos 34 meses apos a implantacao, no periodo de outubro de 2010 a setembro de 2011, em distâncias a partir das linhas centrais do plantio das arvores, que consistiram nos subtratamentos: 1, 3 e 6 m; e realizadas a analise e quantificacao de nutrientes: N, P, K, Ca, Mg e S. A deposicao da serapilheira da forrageira foi superior no monocultivo de pasto. Entretanto, a maior deposicao de serapilheira total (forrageira + componente arboreo) foi observada em ambos os sistemas agrossilvipastoris, comprovando a influencia positiva do componente arboreo no incremento de material vegetal depositado sobre o solo. A distância da linha de plantio das arvores tambem influenciou a deposicao, que foi maior a 1 m, seguida das distâncias 3 e 6 m. Com excecao do P, os sistemas agrossilvipastoris depositaram maior quantidade de nutrientes por meio da serapilheira, destacando-se o sistema com acacia, que promoveu maior deposicao de N. O componente arboreo, a especie leguminosa e a distância da linha de plantio das arvores dos sistemas agrossilvipastoris influenciaram a deposicao de serapilheira e de nutrientes no solo, indicando a potencialidade desses sistemas para recuperacao e manutencao de pastagens degradadas. Palavras-chave: Sistemas agroflorestais; Ciclagem de nutrientes; Leguminosas. LITTER FALL AND NUTRIENT DEPOSITION ON SO IL IN AN AGROSILVOPASTORAL SYSTEM WITH EUCALYPT AND ACACIA

Quantificação de biomassa e estocagem de carbono em uma floresta estacional semidecidual, no Parque Tecnológico de Viçosa, MG

The objectives of this study were to quantify the biomass and carbon storage in a seasonal semideciduous Forest in Vicosa, MG, with an area of 44.11 ha, and to evaluate the differences between the methods of biomass quantification proposed by the Intergovernmental Panel on Climate Change (IPCC) and by using regional equations. For biomass quantification and carbon storage in the area, were used two different methodologies, one using regional equations and another one suggested by the IPCC. The total biomass and carbon stock were 116.98 t ha-1 and 56.31 t ha-1, respectively, using the methodology of regional equations, considering the values above and below the ground, understory and litter. For the methodology suggested by the IPCC, the total biomass and carbon stock were 107.59 t ha-1 and 48.70 t ha-1, respectively. According to the results, the IPCC methodology underestimated the biomass and carbon stock, in relation to regional equations.

Efeito do volume de tubetes na produção de mudas de Calophyllum brasiliense e Toona ciliata

The search for silvicultural information, including the seedling production methods, about alternative forest tree species for forestry with economic purposes have increased in the last years. In this work, the influence of the volume of tubes at sizes of 115, 180 and 280 cm3, on the growth of seedlings of Guanandi (Calophyllum brasiliense Cambess.) and Australian Cedar (Toona ciliata M. Roem. var. australis (F. Muell.)) was evaluated. The substrate used was composed by mixture of 80% of commercial substrate and 20% of clay. The collar diameter and the height of the seedlings were evaluated at 60, 90, 120 and 150 days after transplantation. In the last mensuration the dry weight of the aerial plant, of the root system and the total weight, and the Quality Index of Dickson were also determined. There was an effect of the tube volume on the growth and the quality of the seedlings, and the reaction of the Australian Cedar was greater. It was concluded the, for the Guanandi, the best tube is that of 180 cm3 and for the Australian Cedar is the tube of 280 cm3.

Crescimento inicial de seis espécies florestais em diferentes espaçamentos

O objetivo deste trabalho foi verificar a influencia do espacamento de plantio no crescimento de seis especies florestais, aos 22 meses de idade, em plantios de recomposicao florestal, na Bacia do Rio Guandu. O experimento foi instalado na SFE - Usina Termeletrica Barbosa Lima Sobrinho, Municipio de Seropedica-RJ. Foram utilizadas 48 especies arboreas, estabelecidas nos espacamentos 1,0 x 1,0; 1,5 x 1,5; 2,0 x 2,0 e 3,0 x 2,0 m, os quais constituem os tratamentos. Aos 22 meses apos plantio, avaliou-se o crescimento em altura, diâmetro ao nivel do solo (DNS) e largura da copa para as especies Anadenanthera macrocarpa Benth. Brenan (angico vermelho), Schinus terebinthifolius Raddi (aroeira pimenteira), Schizolobium parahyba Blake (guapuruvu), Chorisia speciosa St. Hill (paineira), Cordia sp. (babosa branca) e Inga marginata (inga). Foi constatado que o crescimento das especies comportou de maneira diferenciada nos espacamentos de plantio, sendo que os mesmos influenciaram significativamente no crescimento inicial de todas as especies. Concluiu-se que, de modo geral, nos espacamentos mais amplos, as plantas apresentaram maior crescimento.

Modelo de Clutter na modelagem de crescimento e produção de eucalipto em sistemas de integração lavoura-pecuária-floresta

The objective of this work was to define the best form of use of the Clutter model, in order to estimate growth and yield of eucalyptus clones in crop-livestock-forest integration systems. Data were collected from integration systems located in the northwest region of the state of Minas Gerais, Brazil. The data were originated from 180 continuous inventory permanent plots of 30x40 m, with three ten-plant rows and stratified random sampling of one plot per 10 ha. The average number of trees per hectare was 242. Plants with ages from 20 to 95 months were evaluated. The best functional relationships were obtained using the original Clutter model, based on the significance and on the expected signs of its estimated parameters. The Clutter model should be adjusted on its unreduced form.

Sistema de blocos prensados para produção de mudas de três espécies arbéreas nativas

The objective of this work was to evaluate the feasibility of using pressed blocks as containers for the production of Inga marginata, Jacaranda puberula and Zeyheria tuberculosa seedlings. The pressed block system (440 cm3) was compared to plastic bags (330 cm3) and circular section tubes (280 cm3). The substrate used was a mixture of organic matter, ground charcoal and clayish soil (6:2:2). After pressing, the size of the blocks was 60 x 40 x 12 cm (length, width and height). Height and diameter of the seedlings were measured monthly, starting at 60 to 150 days after transplantation. The next step was to determine the dry matter weight of the aerial part and root system. To evaluate the behavior of the seedlings produced in the various treatments under field conditions, the survival rate at two months from planting was measured. The seedlings produced by the pressed block system showed a growth higher than or similar to those produced in plastic bags or tubes. Under field conditions, no statistical differences were observed for survival rate and growth of the seedlings from the pressed blocks, plastic bags and tubes. The pressed block system was found to be technically feasible for the production of seedlings of the forest trees species studied.

La agroforestería como estrategia para la recuperación y conservación de reservas de carbono en bosques de la Amazonía

Durante los ultimos anos los continuos cambios en el uso de la tierra en la Amazonia, principalmente a traves de la conversion de bosques por practicas agropecuarias y de extraccion, han generado graves transformaciones en la estructura y funcionamiento de los ecosistemas con impactos a escala regional y global. La deforestacion para establecer sistemas agricolas itinerantes es uno de los principales factores que contribuyen con las emisiones de carbono a la atmosfera como uno de los servicios de mayor repercusion ambiental. Sin embargo, existen reconocidos mecanismos de reduccion de emisiones de carbono por deforestacion y degradacion (REDD+), i) bien sea controlando la reduccion de emisiones de las fuentes a traves de la conservacion y manejo sustentable de los bosques, y ii) recuperando e incrementando la biomasa vegetal como importantes sumideros a traves de estrategias de rehabilitacion y restauracion forestal. Con la finalidad de incrementar la eficiencia en la recuperacion y conservacion de carbono en areas vulnerables de deforestacion y degradacion forestal en la Amazonia, se propone como objetivo desarrollar un analisis de los impactos ambientales potenciales de la Agroforesteria como alternativa REDD+, a traves de i) la rehabilitacion de areas degradadas sometidas a ciclos sucesivos de fuego y cultivos, ii) la restauracion pasiva de bosques secundarios, e iii) implementacion de barbechos mejorados con el manejo de especies agroforestales. La agroforesteria representa una importante alternativa para recuperar y conservar reservas de carbono a traves de las principales actividades REDD+ frente a la presion generada por la agricultura itinerante en la Amazonia.

CRESCIMENTO E QUALIDADE DE MUDAS DE Cassia grandis Linnaeus f. EM RESPOSTA À ADUBAÇÃO FOSFATADA E CALAGEM

This study aimed at evaluating the growth and seedling quality of Cassia grandis Linnaeus f. in response to liming and phosphate fertilization. The treatments were arranged in a factorial design of 6 phosphorus levels (0, 120, 240, 360, 480 and 600 mg dm -3 ) by 5 base saturation levels (3,5 (original), 25, 40, 55, 70 %), in randomized blocks with four replicates. The height of the aerial part (H), collar diameter (DC), dry matter of shoot (MSPA), dry matter of root (MSRA), and total dry matter (MST) were determined at 65 days after the transplanting. The relation between dry matter of shoot and dry matter of root (MSPA/MSRA) and Dickson quality index (IQD) were calculated at this stage. There were significant effects from the phosphate fertilization to all studied variables. Based on this study, the recommended P dose for quality seedling production of Cassia grandis is 600 mg dm -3 , for 25% of substratum’s base saturation .

Physiological characteristics of eucalypts in association with signal grass

ABSTRACT The objective of this work was to evaluate the physiological characteristics of eucalypts growing alongside the signal grass species Urochloa brizantha and U. decumbens (weeds). The experiment was conducted in a controlled environment using randomised blocks with four replications. Three different treatments were studied: no weeds, addition of U. brizantha and addition of U. decumbens, with both weeds at a density of 50 plant m–2. Physiological characteristics were evaluated at 18, 38 and 48 days after transplanting (DAT) and root collar diameter and height of the plants were measured at 2, 22, 34 and 44 DAT. The coexistence of eucalypts with these two species of signal grass did not modify the physiological variables of the eucalypts at 18 DAT and 38 DAT. However, at 48 DAT, the eucalypts in the two weed treatments showed reduced photosynthetic activity. When with U. decumbens, the eucalypts showed reduced transpiration, CO2 consumption, stomatal conductance and the ratio between internal carbon concentrations and atmospheric carbon concentrations. The root collar diameter was more sensitive to competition with weeds than was the total height of the plants. We conclude that both U. brizantha and U. decumbens have negative effects on physiological characteristics and growth parameters of the eucalypts at 48 DAT.

ECONOMIC ANALISYS OF A COFFEE-BANANA SYSTEM OF A FAMILY-BASED AGRICULTURE AT THE ATLANTIC FOREST ZONE, BRAZIL

Agroforestry systems can reduce the risks of investing in just one crop. However, there are uncertainties like other agricultural and forestry activities. Therefore, there is the need for economic studies under conditions of economic risk of agroforestry systems. This work reports an analysis of the main components of costs and revenues of an agroforestry system with coffee and banana, as well as an analysis of its economic performance through indicators: net present value, equivalent period benefit (or cost), family labor revenue and a sensitivity analysis of net present value. The main cost components in the system are the human labor and mineral and organic fertilizers applied in coffee, and the costs for the production of coffee outweigh the costs of banana production. The monthly income from the production of bananas balances the costs of coffee production, generating a positive cash flow in the studied period. Financial indicators showed positive values, demonstrating the economic viability of the system with coffee and banana. The agroforestry system is economically feasible, even with variations of ± 20% in production costs and selling prices of their products. Variables that showed greater sensitivity on the net present value were the selling price of coffee and bananas, and the cost of coffee production.