ORIGIN OF HYDROPHOBIC COMPOUNDS AND THEIR EFFECTS IN Pinus AND Eucalyptus FORESTS

A hidrofobicidade pode ser entendida como a repel\ueancia do solo \ue0 \ue1gua, dificultando o seu molhamento. Esse fen\uf4meno est\ue1 associado ao recobrimento das part\uedculas do solo por subst\ue2ncias org\ue2nicas hidrof\uf3bicas, sendo que atualmente existem in\ufameros relatos de repel\ueancia \ue0 \ue1gua em \ue1reas de florestas de Eucalyptus e Pinus . Assim, este trabalho teve por objetivo revisar e elencar os aspectos relacionados \ue0 origem dos compostos hidrof\uf3bicos e os seus efeitos na din\ue2mica da \ue1gua no ambiente florestal, al\ue9m de implica\ue7\uf5es no crescimento e desenvolvimento das \ue1rvores em florestas de Eucalyptus e Pinus. Reconhece-se que a vegeta\ue7\ue3o local e algumas bact\ue9rias e fungos, em fun\ue7\ue3o da sua composi\ue7\ue3o qu\uedmica, podem liberar subst\ue2ncias org\ue2nicas hidr\uf3fobas. Outro fator condicionante \ue9 a ocorr\ueancia de inc\ueandios e queimadas, que induzem altera\ue7\uf5es nos compostos org\ue2nicos e promovem o secamento do solo. Al\ue9m disso, a composi\ue7\ue3o granulom\ue9trica e o pH do solo podem estar indiretamente associados \ue0 ocorr\ueancia de repel\ueancia \ue0 \ue1gua no solo. A exist\ueancia de hidrofobicidade exige uma aten\ue7\ue3o diferenciada, principalmente em rela\ue7\ue3o ao uso e manejo do solo, pois afeta diretamente o movimento da \ue1gua na superf\uedcie e no interior do perfil de solo. Altera\ue7\uf5es na sortividade, redu\ue7\ue3o da taxa de infiltra\ue7\ue3o, escoamento superficial elevado e ocorr\ueancia de fluxo preferencial s\ue3o os principais efeitos hidrol\uf3gicos desse fen\uf4meno. Em fun\ue7\ue3o das menores taxas de infiltra\ue7\ue3o h\ue1 aumento do escoamento superficial e redu\ue7\ue3o da quantidade de \ue1gua dispon\uedvel, potencializando o processo erosivo e, consequentemente, afetando o crescimento e o desenvolvimento das plantas.Hydrophobicity can be understood as the soil water repellency or difficulty to soil wetting. This is associated with the coating of soil particles by hydrophobic organic substances and currently there are numerous reports of water repellency in forest areas of Eucalyptus and Pinus . Thus, this study aims at reviewing and listing the aspects related to the origin of hydrophobic compounds and the effects of the water dynamics in the forest environment, as well as implications in growth and development of trees in Eucalyptus and Pinus forests. It is recognized that the local vegetation and some bacteria and fungi, depending on their chemical composition, may release hydrophobic organic substances. Another risk factor is the occurrence of burnings which induce changes in organic compounds and promote soil drying. Furthermore, the particle size distribution and the soil pH may be indirectly associated with the occurrence of soil water repellency. The occurrence of hydrophobicity requires special attention regarding the soil use and management, because this repellency affects the water movement on the surface and inside the soil profile. Changes in sorptivity, reduction in water infiltration, increase in runoff and occurrence of preferential flow are the main hydrological effects of this phenomenon. Due to their lower infiltration rates there is increased the surface flow and reducing the amount of water available, increasing the erosion and, consequently affecting the growth and development of plants

MANEJO DO SOLO E CRESCIMENTO INICIAL DE Eucalyptus grandis Hill ex Maiden EM ARGISSOLO1

The forest species cultivation with rapid growth in Brazil has increased, mainly due to the diverse use of its wood and climate adaptation. The cultivation with minimum tillage in the forest sector stands out a way to increase productivity, combined with the maintenance of biodiversity and soil conservation. This study was conducted at the experimental area of State Foundation for Agricultural Research - Research Center for Forestry in Santa Maria - RS, with aimed to evaluate the effect of the soil tillage methods on soil physical properties and on initial development of Eucalyptus grandis , in a sandy loam Typic Hapludalf. Four soil management practices were compared: no-tillage; chisel tillage; chisel tillage plus harrowing and; rotary tillage (rotary tiller), installed in a randomized block design with three replications. The soil under no-tillage conditioned lower initial growth of eucalyptus due higher soil penetration resistance and bulk density, when compared with treatments with mobilization. The root distribution analysis in soil, despite being a qualitative method, was effective in demonstrating the effect of soil tillage for the Eucalyptus grandis plantation. The soil tillage with mobilization resulted in a higher initial growth of Eucalyptus grandis. The chisel tillage effects in the soil physical properties persisted after one year of soil tillage.O cultivo de esp\ue9cies florestais de r\ue1pido crescimento tem aumentado no Brasil, devido \ue0 diversifica\ue7\ue3o do uso de sua madeira e adapta\ue7\ue3o edafoclim\ue1tica. No setor florestal, a t\ue9cnica do cultivo m\uednimo tem se destacado como forma de aumentar a produtividade, garantindo a manuten\ue7\ue3o da biodiversidade e a conserva\ue7\ue3o do solo. O presente estudo foi realizado na \ue1rea experimental da Funda\ue7\ue3o Estadual de Pesquisa Agropecu\ue1ria - Centro de Pesquisa em Florestas em Santa Maria - RS, com o objetivo de avaliar o efeito dos m\ue9todos de preparo do solo na densidade, na resist\ueancia do solo \ue0 penetra\ue7\ue3o e no desenvolvimento inicial das ra\uedzes e parte a\ue9rea do Eucalyptus grandis , em um Argissolo Vermelho-Amarelo Distr\uf3fico ar\ueanico com textura franco-arenosa. Foram comparados quatro manejos do solo: plantio direto, escarificado, escarificado mais grade niveladora e enxada rotativa, instalados em blocos ao acaso com tr\ueas repeti\ue7\uf5es. O solo sob plantio direto condicionou menor crescimento radicular e a\ue9reo do eucalipto devido \ue0 maior resist\ueancia \ue0 penetra\ue7\ue3o e densidade do solo, quando comparado aos preparos com mobiliza\ue7\ue3o. A an\ue1lise da distribui\ue7\ue3o radicular no perfil, apesar de ser um m\ue9todo qualitativo, foi eficiente em demonstrar o efeito do preparo do solo para a implanta\ue7\ue3o do Eucalyptus grandis. O preparo e a mobiliza\ue7\ue3o do solo resultaram em maior crescimento inicial de Eucalyptus grandis. Os efeitos da escarifica\ue7\ue3o sobre as propriedades f\uedsicas do solo persistiram ap\uf3s um ano da mobiliza\ue7\ue3o do solo

COMPACTION CAUSED BY FELLER-BUNCHER AND SKIDDER TRAFFIC IN AN ENTISOL UNDER DISTINCT MOISTURES

This research evaluated the influence of water content on soil compaction of an Entisol under traffic of forest harvesting machines and developed models to estimate soil compaction. The study was conducted in areas of a forest company, located in the state of Santa Catarina, Brazil. The sampling was performed under various conditions of soil moisture, contemplating three classes: Ug1 (Ug < 0,30 kg kg-1); Ug2 (0,30 64 Ug < 0,40 kg kg-1); Ug3 (Ug 65 0,40 kg kg-1). The soil bulk density was determined (Ds), total (Pt) and air-filled porosity (PA) and penetration resistance (RP), under the conditions without traffic (WT) and after traffic (AT) of a Feller-buncher (CAT 522) and a Skidder (CAT 545) employed in wood harvesting of Pinus taeda stands. Multiple regression equations were adjusted to estimate the soil penetration resistance, through arithmetic and logarithmic models with pure and mixed variables. The results indicate that in moisture condition above than 0,40 kg kg-1 (Ug3), the traffic promoted increase in Bd and PR of 10 and 24%, respectively, and decrease in \u3b1t and \u3b1air, in order of 12 and 43%. In low moisture content (Ug < 0,30 kg kg-1), the increase of Bd and PR was 3 and 13%, respectively, and the decrease of \u3b1air of 8% and without effect in \u3b1t. The stepwise logarithmic model with mixed variables (SLMM) showed the best results for the estimation of soil penetration resistance, but caution must be raised in their employment due to the possible influence of other factors in the estimation and determination of PR.Esta pesquisa objetivou avaliar a influencia da umidade na compactacao de um Neossolo Regolitico submetido ao trafego de maquinas de colheita florestal e desenvolver modelos para estimativa da compactacao. O trabalho foi conduzido em areas de uma empresa florestal localizada no Estado de Santa Catarina. A amostragem foi realizada em diversas condicoes de umidade do solo, contemplando tres classes: Ug1 (Ug < 0,30 kg kg-1); Ug2 (0,30 64Ug < 0,40 kg kg-1) e Ug3 (Ug 650,40 kg kg-1). Determinou-se a densidade do solo (Ds), a porosidade total (Pt) e de aeracao (PA) e a resistencia a penetracao (RP), nas condicoes sem trafego (ST) e apos trafego (AT) de um Feller buncher (CAT 522) e um Skidder (CAT 545) utilizados na colheita da madeira de povoamentos de Pinus taeda . Foram ajustadas equacoes de regressao multipla para estimar a RP, por meio de modelos aritmeticos e logaritmicos com variaveis puras e mistas. Os resultados indicaram que em condicao de umidade superior a 0,40 kg kg-1 (Ug3), o trafego promoveu aumento da Ds e RP da ordem de 10 e 24% e reducao da Pt e da PA, da ordem de 12 e 43%, respectivamente. Em baixa umidade (Ug < 0,30 kg kg-1), o aumento da Ds e RP foi da ordem de 3 e 13%, respectivamente, e reducao da PA da ordem de 8% e sem efeito na Pt. O modelo por stepwise logaritmico com variaveis mistas (MSLM) (Ln RP =-1,11 + 0,64Ds-2 + 0,14Ug-1) apresenta os melhores resultados para estimativa da resistencia do solo a penetracao, mas deve haver cautela no seu emprego, devido a possibilidade de influencia de outros fatores na estimativa e determinacao da RP

MANEJO DO SOLO E CRESCIMENTO INICIAL DE Eucalyptus grandis Hill ex Maiden EM ARGISSOLO

The forest species cultivation with rapid growth in Brazil has increased, mainly due to the diverse use of its wood and climate adaptation. The cultivation with minimum tillage in the forest sector stands out a way to increase productivity, combined with the maintenance of biodiversity and soil conservation. This study was conducted at the experimental area of State Foundation for Agricultural Research - Research Center for Forestry in Santa Maria - RS, with aimed to evaluate the effect of the soil tillage methods on soil physical properties and on initial development of Eucalyptus grandis , in a sandy loam Typic Hapludalf. Four soil management practices were compared: no-tillage; chisel tillage; chisel tillage plus harrowing and; rotary tillage (rotary tiller), installed in a randomized block design with three replications. The soil under no-tillage conditioned lower initial growth of eucalyptus due higher soil penetration resistance and bulk density, when compared with treatments with mobilization. The root distribution analysis in soil, despite being a qualitative method, was effective in demonstrating the effect of soil tillage for the Eucalyptus grandis plantation. The soil tillage with mobilization resulted in a higher initial growth of Eucalyptus grandis. The chisel tillage effects in the soil physical properties persisted after one year of soil tillage.O cultivo de esp\ue9cies florestais de r\ue1pido crescimento tem aumentado no Brasil, devido \ue0 diversifica\ue7\ue3o do uso de sua madeira e adapta\ue7\ue3o edafoclim\ue1tica. No setor florestal, a t\ue9cnica do cultivo m\uednimo tem se destacado como forma de aumentar a produtividade, garantindo a manuten\ue7\ue3o da biodiversidade e a conserva\ue7\ue3o do solo. O presente estudo foi realizado na \ue1rea experimental da Funda\ue7\ue3o Estadual de Pesquisa Agropecu\ue1ria \u2013 Centro de Pesquisa em Florestas em Santa Maria \u2013 RS, com o objetivo de avaliar o efeito dos m\ue9todos de preparo do solo na densidade, na resist\ueancia do solo \ue0 penetra\ue7\ue3o e no desenvolvimento inicial das ra\uedzes e parte a\ue9rea do Eucalyptus grandis , em um Argissolo Vermelho-Amarelo Distr\uf3fico ar\ueanico com textura franco-arenosa. Foram comparados quatro manejos do solo: plantio direto, escarificado, escarificado mais grade niveladora e enxada rotativa, instalados em blocos ao acaso com tr\ueas repeti\ue7\uf5es. O solo sob plantio direto condicionou menor crescimento radicular e a\ue9reo do eucalipto devido \ue0 maior resist\ueancia \ue0 penetra\ue7\ue3o e densidade do solo, quando comparado aos preparos com mobiliza\ue7\ue3o. A an\ue1lise da distribui\ue7\ue3o radicular no perfil, apesar de ser um m\ue9todo qualitativo, foi eficiente em demonstrar o efeito do preparo do solo para a implanta\ue7\ue3o do Eucalyptus grandis. O preparo e a mobiliza\ue7\ue3o do solo resultaram em maior crescimento inicial de Eucalyptus grandis. Os efeitos da escarifica\ue7\ue3o sobre as propriedades f\uedsicas do solo persistiram ap\uf3s um ano da mobiliza\ue7\ue3o do solo

AGGREGATION OF A HAPLUMBREPT IN Pinus taeda L. STANDS WITH DIFFERENTS ROTATIONS

O estudo tem como objetivo verificar se a introdu\ue7\ue3o da esp\ue9cie Pinus taeda L. em solo sob campo natural altera a agrega\ue7\ue3o de um Cambissolo H\ufamico, em diferentes rota\ue7\uf5es. O estudo foi conduzido na regi\ue3o dos Campos de Cima da Serra, no munic\uedpio de Cambar\ue1 do Sul - RS, Brasil. A fim de alcan\ue7ar o objetivo acima descrito, foram selecionadas duas \ue1reas de estudo, uma em primeira (RT1) e a outra em segunda rota\ue7\ue3o (RT2), com 13 anos de idade. Para cada povoamento, foi avaliada conjuntamente uma \ue1rea de campo natural adjacente (testemunha). Em cada \ue1rea, foram abertas cinco trincheiras e coletadas amostras de solo nas camadas 0,0-0,05, 0,05-0,20 e 0,20-0,40 m para a determina\ue7\ue3o da porcentagem de agregados est\ue1veis em cada classe (AGRi) e do di\ue2metro m\ue9dio geom\ue9trico de agregados est\ue1veis em \ue1gua (DMG). N\ue3o houve altera\ue7\ue3o da estabilidade de agregados na camada superficial (0,0-0,05 m). No entanto, nas camadas mais subsuperficiais (0,05-0,20 e 0,20-0,40 m), apenas a RT1 manteve a estabilidade de agregados maiores. Devido ao manejo adotado na RT2, como a queima e o corte raso, verificou-se a redu\ue7\ue3o da estabilidade dos macroagregados e aumento dos agregados menores, ao passo que no campo natural a estabilidade em profundidade foi mantida.The study aims to verify whether the introduction of the specie Pinus taeda L. in soil under natural field alters the aggregation of Haplumbrept, at differents rotations. The study was conducted in the region of Campos de Cima da Serra, in the municipality of Cambar\ue1 do Sul \u2013 RS state, Brazil. In order to achieve the goal above described, were selected two study areas, one in the first rotation (RT1) and another in the second rotation (RT2), with 13 years of old. For each stand, a combined area of natural field adjacent (control) was assessed. In each area, five trenches were opened and soil samples collected at depths from 0.0 to 0.05, 0.05 to 0.20 and 0.20 to 0.40 m to determine the percentage stable aggregates in each class (AGRI) and geometric mean diameter water stable aggregates (DMG). There was no change in the aggregate stability in the surface layer (0.0 to 0.05 m). However, the subsurface layers (0.05 to 0.20 and 0.20 to 0.40 m), just RT1 maintained stability of larger aggregates. Due to management adopted in RT2, such as burn and clear cut, there was a reduction in stability and increase in macro-aggregates smaller aggregates, whereas in the natural field stability in depth was maintained

SOIL-LANDSCAPE RELATIONSHIP AND ITS TEMPORAL VARIATION IN A FORESTRY EXPERIMENTAL STATION

A caracteriza\ue7\ue3o de componentes da paisagem e de suas rela\ue7\uf5es na Esta\ue7\ue3o Experimental de Silvicultura de Santa Maria - RS e o monitoramento da varia\ue7\ue3o temporal solo/paisagem entre os anos de 1987 e 2009 (22 anos) foram realizados, por meio de levantamentos de campo e mapeamento digital da cobertura vegetal, relevo e solos. Cruzaram-se informa\ue7\uf5es do hist\uf3rico de uso e ocupa\ue7\ue3o do solo, de transec\ue7\uf5es realizadas em 2009, do modelo num\ue9rico do terreno, de mapas de cobertura vegetal para 1987 e 2009 e de solos. Derivou-se assim um car\ue1ter transit\uf3rio dos componentes da paisagem, entre o Rebordo do Planalto Sul-Riograndense e a Depress\ue3o Central do Rio Grande do Sul, com uma descaracteriza\ue7\ue3o das fitofisionomias naturais e exist\ueancia de conflitos de uso do solo, bem como a influ\ueancia do relevo e da g\ueanese dos solos sobre o desenvolvimento fitofision\uf4mico. Houve expans\ue3o, em 22 anos, dos cultivos de Eucalyptus e Pinus , e da floresta nativa sobre o campo antr\uf3pico, principalmente em \ue1reas com Argissolos Bruno-Acinzentados e Argissolos Vermelhos.The characterization of landscape components and their relationships for the Forestry Experimental Station of Santa Maria,Rio Grande do Sul state, Brazil, and the monitoring of soil-landscape temporal variation between the years 1987 and 2009 (22 years) were performed by means of field surveys and digital mapping vegetation, soil and topography. Crossed the historical information of use and occupation of transects conducted in 2009, the digital terrain model, maps of land cover for 1987 and 2009 and soil, thus deriving a transitory component landscape, between the plateau border Southern and Central Depression of Rio Grande do Sul state, with a distortion of the natural vegetation types and conflicts of land use, as well as the influence of topography and soil genesis on the vegetation development. There was expansion in 22 years of Eucalyptus and Pinus crops and the natural forest on the anthropic field, especially in areas with Argissolos Bruno-Acinzentados and Argissolos Vermelhos

A IDADE DAS PLANTA\u106 5ES DE EUCALYPTUS sp. INFLUENCIANDO OS ESTOQUES DE CARBONO

The tree growth and biomass accumulation, as well as the maintenance of forest residue at the soil surface can act in the removal of carbon from the atmosphere through the cycling process of plant material. The objective was to study the influence of Eucalyptus sp. Plantations with 20, 44 and 240 months of age on the variation of carbon in soil and biomass. The carbon in the soil depth was determined by CHNS auto-analyzer and carbon in the vegetation was determined by the biomass in each forest, considering a factor of 0.45 of the dry mass. We determined the density and particle size distribution of soil. For the comparison between plantations, there was analysis of variance and comparison of means of carbon in vegetation and soil, considering the 5 % level of probability. The carbon content and stock in the soil were low, indicating that a natural feature of the category of Paleuldt, or the growth of eucalyptus forests, replacing the field native vegetation did not aggregate a significant increase in the carbon. Although, there was a significant increase carbon in aboveground biomass. It includes forest biomass and litter. So, despite the values of carbon stocks are low, it identified a greater average total in the soil compared to the stock aboveground. Furthermore, this increase aboveground (tree and litter compartments) can be considered significant between the eucalyptus plantations of different ages.O crescimento das \ue1rvores e ac\ufamulo de biomassa, bem como a manuten\ue7\ue3o do res\uedduo florestal na superf\uedcie do solo pode atuar na retirada de carbono da atmosfera gra\ue7as ao processo de ciclagem de material vegetal. O objetivo foi estudar a influ\ueancia das planta\ue7\uf5es de Eucalyptus SP. com 20, 44 e 240 meses de idade sobre a varia\ue7\ue3o de carbono no solo e na biomassa. O carbono no solo foi determinado em profundidade por meio de autoanalisador CHNS e o carbono na vegeta\ue7\ue3o foi determinado pela biomassa em cada floresta, considerando um fator de 0,45 da massa seca. Determinaram-se a densidade e a an\ue1lise granulom\ue9trica do solo. Para a compara\ue7\ue3o entre planta\ue7\uf5es, realizou-se a an\ue1lise de vari\ue2ncia e compara\ue7\ue3o de m\ue9dias do carbono na vegeta\ue7\ue3o e no solo, considerando o n\uedvel de 5 % de probabilidade. O teor e estoque de carbono no solo foram baixos, indicando ser uma caracter\uedstica natural da categoria dos Argissolos ou que o crescimento das florestas de eucalipto em substitui\ue7\ue3o \ue0 vegeta\ue7\ue3o campo nativo n\ue3o agregou um aumento significativo no carbono, apesar de ter ocorrido um aumento significativo de carbono na biomassa acima do solo, a qual inclui a biomassa florestal a\ue9rea e a serapilheira. Portanto, apesar dos baixos valores de estoque de carbono, identificou-se um maior estoque m\ue9dio total no solo quando comparado ao estoque acima do solo. Al\ue9m disso, esse aumento acima do solo (compartimentos arb\uf3reos e serapilheira) pode ser considerado significativo entre as planta\ue7\uf5es de eucalipto com diferentes idades

Guidelines for the use and interpretation of assays for monitoring autophagy

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field