ABSTRACT Background: Litter is an important component of ecosystems, and its characteristics (e.g., production, decomposition, and nutrient and carbon content) are relevant for the ecological maintenance of different ecosystems. Previous studies on decomposition patterns have focused only on short time periods. Furthermore, there is no information regarding the actual decomposition time of organic matter in the Brazilian savanna biome known as the Cerrado. Thus, analysis of the total decomposition time can provide reliable estimates for other models. This study aimed to evaluate total litter decomposition (100%) and its relationship with seasonality and floristic composition in the savanna forest (Cerradão) formation in central Brazil. Litter bags were randomly distributed over the soil, with 10 samples collected per quarter from August 2014 to May 2020. Single- and double-entry linear regression models were used to analyze the total litter decomposition. Results: The half-life (time for which 50% of the litter was decomposed) occurred at 360 days, and 100% of litter decomposition occurred at 2070 days. The single-entry model was more satisfactory for estimating the decomposition speed. There was a positive correlation between litter decomposition and precipitation, and the floristic composition helped to explain the litter decomposition trends. Conclusion: Litter decomposition in the Cerradão is related to floristic diversity (quality of the material) and to the synergism of factors that occur mainly in the rainy season. Thus, the results of this study can contribute to conservation initiatives.

Abstract Brazil is considered a megadiverse country, but the soil fauna is still very poorly known. The aim of this study was to report, for the first time, the abundance and genus composition of terrestrial enchytraeids (Enchytraeidae, Oligochaeta) in Savanna Tall Woodland (Cerradão) and a pasture in Cerrado Biome and in Upper Montane Atlantic Forest and a grassland in Atlantic Forest Biome. The enchytraeid density in Pasture and Cerradao was 2,036 and 18,844 (204 and 2,094, on average) individuals per square meter, respectively. At the Atlantic forest and Grassland, density was 9,666 and 12,242 individuals per square meter (1,075 and 1,471 on average). About genus composition for the studied areas, Enchytraeus and Hemienchytraeus were found in the four ecosystems evaluated, while Tupidrilus and Fridericia were found only in Cerradão and Atlantic Forest, respectively. Achaeta was absent in Upper Montane Atlantic Forest, but dominant in pasture, while Guaranidrilus was absent in Pasture, but predominant in the other ecosystems.

ABSTRACT Forest soils are N2O sources and commonly act as CH4 sinks. This study evaluated the dynamics of the CH4 and N2O fluxes of soils under Eucalyptus plantations and native Cerrado vegetation, as well as possible interactions between environmental factors and fluxes. The study was carried out in the Distrito Federal, Brazil, during 26 months, in three areas: in two stands of the hybrid Eucalyptus urophylla × Eucalyptus grandis, planted in 2011 (E1), and in 2009 (E2) and native Cerrado vegetation (CE). Measurements to determine the fluxes in a closed static chamber were carried out from Oct 2013 to Nov 2015. Soil and climate factors were monitored. During the study period, the mean CH4 fluxes were –22.48, –8.38 and –1.31 μg CH4 m–2 h–1 and the mean N2O fluxes 5.45, 4.85 and 3.85 μg N2O m–2 h–1 from E1, E2 and CE, respectively. Seasonality affected plantations in the studied sites. Cumulative CH4 influxes were calculated (year-1: –1.86 to -0.63 kg ha–1 yr–1; year-2: –1.85 to –1.34 kg ha–1 yr–1). Cumulative N2O fluxes in the three sites were ≤ 0.85 kg ha–1 yr–1. The change in land use from Cerrado to Eucalyptus plantations did not significantly changed regarding greenhouse gases (GHG), compared to the native vegetation. Flux rates of both gases (N2O and CH4) were low. Temporal variations in GHG fluxes and different ages of the stands did not cause significant differences in cumulative annual fluxes.

ABSTRACT This study assessed the dynamics of the land use and cover changes, deforestation trends and the current status of the Legal Forest Reserves (LFR) and Permanent Protected areas (PPA) in the Nova Bonal Sustainable Development Project (SDP) between 1997-2014. Deforestation datasets and fieldwork were used in this analysis. Our results indicate that there was no trend in the estimated deforestation rate dataset for the SDP, but there was a decreasing trend in deforestation rates within its 10-km buffer zone, most likely due to the scarcity of native forests in that area. The negative environmental area balance of PPA and LFR were observed within the 10-km buffer zone of the SDP. Finally, we conclude that the alternative land and forest uses enforced within the SDP are more effective for environmental conservation than the commonly adopted land uses, especially pastures adopted by conventional colonization located around it.

ABSTRACT This study applied a deforestation model for the entire State of Rondônia assuming three scenarios of deforestation: business as usual, optimistic and pessimistic. Those scenarios were constructed for the time-period of 2012-2050 using the Dinamica EGO software. Rondônia deforestation dataset was provided by the Agência Ambiental do Estado de Rondônia (Rondônia State Environmental Agency) and was used as input of the deforestation modeling. Based on this study results, we estimated that 32%, 37% and 47% of Rondônia’s native forest could be fully deforested by 2050 assuming the optimistic, business as usual and pessimistic scenarios, respectively. Regardless of the chosen scenario, we expect that deforestation will be spatially concentrated in Northern Rondônia in the next decades. The greatest concern, however, could be the integrity of the protected areas assuming the business as usual and/or pessimistic scenario. In addition, we expect a substantial increase of the forest fragmentation by 2050.

ABSTRACT The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30) using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests. The best UCS value (786.59 kPa) for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads.

RESUMO O estudo teve como objetivo avaliar o estoque mensal e anual de serapilheira e sazonalidade em duas fitofisionomias (Cerrado stricto sensu e Mata de Galeria) e em um povoamento de eucalipto, localizados na Fazenda Água Limpa, DF. O estoque de serapilheira foi coletado mensalmente, pelo período de um ano, com auxílio de um gabarito metálico de 0,25 m2. O material foi separado manualmente nas frações folhas, cascas, galhos, raízes, flores/frutos e material particulado. O estoque de serapilheira na Mata de Galeria (9,36 t ha-1) foi estatisticamente igual ao observado no povoamento de eucalipto (9,12 t ha-1), valores maiores que o verificado no Cerrado Típico (6,08 t ha-1). A fração folha apresentou maior quantidade nas fitofisionomias e no povoamento quando comparada às demais frações. Verificaram-se dois padrões divergentes de sazonalidade do estoque de serapilheira: maior estoque no Cerrado Típico e no povoamento de eucalipto na estação seca e maior estoque na Mata de Galeria na estação chuvosa.

ABSTRACT The aim of this study was to evaluate the monthly and annual litter stock, and the seasonality in two phytophysiognomies (Cerrado stricto sensu and Gallery Forest) and one eucalyptus plantation, located in Fazenda Água Limpa, DF. The litter stock was monthly collected by using a metal jig of 0.25 m2, during one year. The material was manually sorted into leaves, bark, twigs, roots, flowers/fruits and particulate matter. There were no significant differences in the litter stock between the Gallery Forest (9.36 t ha-1) and the eucalyptus plantation (9.12 t ha-1), which were both higher than the Cerrado stricto sensu (6.08 t ha-1). The leaf fraction presented a larger amount in the three vegetation types when compared to the other fractions. There were two different patterns of litter stock seasonality: higher litter stock in the Cerrado stricto sensu and eucalyptus plantation in the dry season; and higher stock in Gallery Forest in the rainy season.

RESUMO O pequizeiro fornece frutos tradicionalmente utilizados na culinária goiana e regiões do bioma Cerrado. Partindo da análise da comercialização de pequi na Central de Abastecimento de Goiás S/A (Ceasa - GO) e em feiras locais (Ipameri e Pires do Rio - GO), o presente estudo avalia a importância da espécie e ameaças relacionadas ao extrativismo. Os dados revelaram 12 microrregiões produtoras de pequi no estado, sendo comercializados 5,5 mil toneladas de pequi em 2011, com o preço da caixa variando de 25 a 40 reais. Nas feiras, o preço pago por litro em 2010 foi de cinco reais, com um percentual crescente de interessados na venda desse produto não madeireiro. Chama atenção a variação no preço pago ao pequi e mudanças nas regiões produtoras em Goiás, além da aquisição desse produto de outros estados. Para suprir a demanda crescente de pequi, sugere-se, além do extrativismo responsável, o plantio da espécie no Cerrado, em pomares ou sistemas agroflorestais.

ABSTRACT The pequizeiro provides fruits traditionally used in cooking Goiás and regions of the Cerrado biome. Based on the pequi marketing analysis in CEASA-GO and local fairs (Ipameri and Pires do Rio, GO), this study assesses the importance of the species and threats related to extraction. The data revealed 12 micro-regions producing pequi in the state, being sold 5500 tons of pequi in 2011, with the box price ranging from 25 to 40 reais. The price paid in the fairs per liter in 2010 was five Brazilian Reais, with an increasing percentage of interested in the sale of non-timber product. The variation in the price paid to the pequi and changes producing regions in Goiás is noteworthy, in addition to the purchase of this product from other states. To meet the growing demand of pequi, it is suggested, besides the responsible extraction, planting the species in the cerrado, in orchards or agroforestry systems.

O objetivo deste trabalho foi avaliar a eficiência dos regenerantes como indicador ecológico de restauração em matas ripárias no Cerrado, DF, no período de janeiro/2012 a janeiro/2013. O experimento de restauração constou de seis tratamentos com três repetições cada (T1 = nucleação; T2 = nucleação + poleiros artificiais; T3 = poleiros artificiais; T4 = linha de recobrimento e linha de diversidade; T5 = controle com braquiária; T6 = supressão da braquiária). A análise do incremento da cobertura foi pelo método de Braun-Blanquet e, em seguida, aplicado o teste não paramétrico de Kruskal-Wallis. Houve diferença significativa entre a percentagem de cobertura inicial e final dos regenerantes para o T1. Nos demais tratamentos observou-se ligeiros aumentos, mas, não significativos, assim como não houve diferença significativa no incremento entre os tratamentos. Não houve diferenças entre os tratamentos ao se analisar somente a densidade de regenerantes, o que pode estar associado a alta taxa de mortalidade de determinadas espécies. Embora iniciais, a avaliação da percentagem de cobertura dos regenerantes como indicador do processo de restauração ecológica, o enquadra em todos os aspectos de eficiência de indicadores (sensibilidade, resultabilidade, custo, compreensão e interpretação, previsibilidade ou tendência e escala). Dessa forma, pode-se concluir que a cobertura dos regenerantes demonstrou eficiência como indicador, mesmo nesta fase de implantação da restauração, porque foi capaz de mostrar as variações entre os tratamentos, ainda que não significativas.

The objective of this study was to evaluate the efficiency of regenerating as an ecological indicator of restoration in riparian forests in the Cerrado, DF, from January/2012 to January/2013. The restoration experiment contained six treatments with three repetitions each (T1 = Nucleation; T2 = Nucleation + perches; T3 = perches; T4 = planting in rows: lines with fast growing and good covering species and diversity lines; T5 = control with brachiaria; T6 = brachiaria suppression). The percentage of coverage of saplingwas made using the Braun-Blanquet method, and then applied the nonparametric Kruskal-Wallis test. There was a significant difference between the initial and final cover for the T1. The other treatments there was little increase in the coverage of sapling, but not significant, even as in the increase between treatments. There were no differences between treatments when analyzing only the density of sapling, which may be associated with high mortality rate of certain species. Although early, the percentage of coverage of sapling was a good indicator of the ecological restoration process, according with aspects: sensitivity, results, cost, understanding and interpretation, predictability or trend and scale. Thus, it can be concluded that the percentage of coverage of sapling demonstrated efficiency as an indicator.

As espécies do gênero Eucalyptus são as mais plantadas no mundo, tornando-se solução para diminuir a pressão sobre as florestas nativas. Este trabalho objetivou avaliar a biomassa seca e sua distribuição nos diferentes compartimentos das árvores (folhas, galhos, casca, lenho e raízes), bem como examinar o conteúdo de macronutrientes dela e o balanço de nutrientes no sistema solo-planta, em um plantio de Eucalyptus urophylla x E. grandis, aos 60 meses de idade, na Fazenda Água Limpa, no Distrito Federal. Os dados foram obtidos de três árvores de eucalipto, que foram cubadas rigorosamente e tiveram as raízes escavadas até a profundidade de 60 cm. Esses dados foram submetidos à análise estatística pela correlação de Pearson. Grande parte da biomassa seca das árvores foi verificada no compartimento lenho (69,19 %), seguido de raízes (10,15 %), galhos (9,75 %), casca (6,06 %) e folhas (4,85 %). Os maiores teores de macronutrientes foram detectados nas folhas (N = 13,55 g kg-1; P = 1,33 g kg-1; K = 8,52 g kg-1; Ca = 7,12 g kg-1; Mg = 2,44 g kg-1; e S = 1,76 g kg-1), enquanto o lenho apresentou os menores (N = 1,73 g kg-1; P = 0,23 g kg-1; K = 0,34 g kg-1; Ca = 0,20 g kg-1; Mg = 0,03 g kg-1; e S = 0,43 g kg-1). A ordem dos conteúdos totais de macronutrientes verificada para a parte aérea foi: N > K > Ca >S > Mg > P, enquanto para as raízes, N > Ca > K > Mg > S > P. As raízes são responsáveis por acumular aproximadamente 11,90 % dos nutrientes contidos na biomassa das árvores; essa quantidade diminui com o aumento da profundidade. O balanço de nutrientes indica que P e S não são suficientes para um novo ciclo da floresta.

The species of the Eucalyptus genus are the most cultivated in the world and have become a solution for reducing the pressure on native forests. The aim of this study was to evaluate the dry biomass and its distribution in the different compartments of the trees (leaves, branches, bark, wood and roots), and assess their macronutrient content and nutrient balance in the soil-plant system in a Eucalyptus urophylla x E. grandis plantation at 60 months of age on the Água Limpa Farm in the Distrito Federal, Brazil. Data were obtained from three eucalyptus trees that had been rigorously scaled and the roots dug to a depth of 60 cm. Data were statistically analyzed by Pearson correlation. Most of the dry weight of the trees was observed in the wood compartment (69.19 %), followed by roots (10.15 %), branches (9.75 %), bark (6.06 %) and leaves (4.85 %). The highest levels of macronutrients were observed in leaves (N = 13.55 g kg-1, P = 1.33 g kg-1, K = 8.52 g kg-1, Ca = 7.12 g kg-1, Mg = 2.44 g kg-1, and S = 1.76 g kg-1), while the wood had the lowest concentrations (N = 1.73 g kg-1, P = 0.23 g kg-1, K = 0.34 g kg-1, Ca = 0.20 g kg-1, Mg = 0.03 g kg-1, and S = 0.43 g kg-1). The order of total contents of macronutrients observed for tree shoots was N > K > Ca > S > Mg > P while for the roots it was N > Ca > K > Mg > S > P. The roots accumulate approximately 11.90 % of the nutrients in the biomass of trees, and this amount decreases with increasing depth. The nutrient balance indicates that P and S are not enough for a new growth cycle in the forest.

Os ecossistemas florestais representam alternativa viável para mitigar o aumento da concentração de CO2 na atmosfera, via fixação do carbono (C) pelas árvores e seu armazenamento na biomassa e no solo, mas tais informações são escassas. Este trabalho teve como objetivo avaliar a produção de matéria seca da parte aérea, de raízes e da manta orgânica depositada sobre o solo e o estoque de C de árvores em plantações de eucalipto com diferentes idades na região Centro-Leste do Estado de Minas Gerais, abrangendo cinco regiões: Cocais (CO), Rio Doce (RD), Sabinópolis (SA), Santa Bárbara (SB) e Virginópolis (VI). Quanto à produção de matéria seca, a região mais produtiva, aos 84 meses de idade, foi SA, com 32,80 t ha-1 ano-1 de parte aérea e raízes, decrescendo nos anos seguintes até atingir 31,18 t ha-1 ano-1 aos 120 meses de idade. Para essa mesma comparação, nas regiões de RD e SB observaram-se produtividades de 29,92 e 29,70 t ha-1 ano-1 aos 84 meses e 21,09 e 25,21 t ha-1 ano-1 aos 120 meses de idade, respectivamente. Constatou-se que a estabilização da produtividade ocorreu após 96 meses de idade em SA e aos 84 meses para as regiões de RD e SB. No tocante às regiões de CO e VI, a produtividade e o estoque de C médio anuais mantiveram taxas crescentes até 120 meses de idade, indicando que a maior produtividade ocorre em idades mais avançadas. A produtividade e o estoque de C médio dessas plantações foram, respectivamente, de 26,96 t ha-1 ano-1 de biomassa e 13,64 t ha-1 ano-1 de C.

Forest ecosystems are a viable possibility to mitigate the increase in concentration of CO2 in the atmosphere by carbon (C) sequestration by the trees and its storage in biomass and in the soil, but such information are scarce. The main objective of this study was to assess production of dry matter of aerial section, roots and litter layer on the soil and C stock of trees in eucalyptus crops in the Central-East region of Minas Gerais State, Brazil, in five regions: Cocais (CO), Rio Doce (RD), Sabinópolis (SB), Santa Bárbara (SA), and Virginópolis (VI). Regarding dry matter production, the most productive region was SA, with 32.80 t ha-1 yr-1, in trees at 84 months of age and 21.09 and 25.21 t ha-1 yr-1 in trees at 120 months of age, respectively. Stabilization of productivity was after 96 months of age in SA and at 84 months of age for RD and SB. For region CO and VI, productivy and average year C stock maintained increasing rates until 120 months of age, showing that the greatest productivy occurs in advanced ages. Productivity and average C stock of those crops were 26.96 t ha-1 yr-1 of biomass and 13.64 t ha-1 yr-1 C.

O eucalipto é a principal espécie florestal plantada no Brasil. Todavia, são escassas informações acerca do C estocado no solo e na biomassa desses plantios. Este trabalho teve como objetivos avaliar o estoque de C no solo (ECS) em plantações de eucalipto e determinar quais características edafoclimáticas determinam esse estoque. O estudo foi conduzido em eucalipto cultivado na região centro-leste do Estado de Minas Gerais, abrangendo cinco regiões: Cocais (CO), Rio Doce (RD), Sabinópolis (SA), Santa Bárbara (SB) e Virginópolis (VI). Foi calculado o estoque de C no solo até 100 cm de profundidade em plantações de eucalipto em áreas com predomínio de seis classes de solo: Cambissolo Háplico (CX), Latossolo Amarelo (LA), Latossolo Vermelho (LV), Latossolo Vermelho-Amarelo (LVA), Neossolo Flúvico (RU) e Plintossolo Pétrico (FF). Os estoques de C no solo variaram entre regiões e classes de solo. O maior ECS ocorreu no LV, com 183,07 t ha-1 de C, seguido pelas classes de CX, LVA, LA, FF e RU, com 135,65, 130,95, 121,58, 112,01 e 95,08 t ha-1 de C, respectivamente. Em relação ao estoque médio de C no solo por região, considerando todas as classes de solo, o maior ECS foi de 141,22 t ha-1; determinado na região de VI, na profundidade até 100 cm de profundidade, seguida pelas regiões SA, CO, SB e RD, com 135,54, 127,26, 112,89 e 80,79 t ha-1 de C, respectivamente. Ao se considerar o estoque de C total no sistema solo-planta, aos 84 meses de idade, a região de SA foi a que apresentou maior estoque, com 251,61 t ha-1; e a região de RD, o menor estoque, com 186,84 t ha-1 de C. O ECS pode ser estimado por equações compostas por características edofoclimáticas, sendo a variação em ECS explicada por características como teor de argila e de Al3+; pela altitude e pelo déficit hídrico da região.

Eucalypt is the main commercial forest species in Brazil, but very little information is available in the literature on the amount of carbon stored in the soil and in the biomass of these forest stands. The main objective of this study was to estimate the amount of soil-stored carbon (SSC) of eucalypt plantations and determine soil and climate characteristics that influence SSC. The study was carried out in the Central-Eastern region of Minas Gerais State, Brazil, in five micro-regions (CO, RD, SB, SA, and VI) with varying soil and climatic conditions. Soil carbon was determined to a depth of 100 cm. Carbon in the forest floor was estimated by allometric equations. The carbon stored in the soil-plant system differed among micro-regions and soil classes. SSC ranged from 183.1 t ha-1 in Red Latosol to 95.1 t ha-1 in Inceptisol, and was negatively correlated to soil K, Ca2+; and Mg2+ content and density in the top soil layer. SSC was highest in the micro-region VI (141.2 t ha-1; average value for all soil types) and lowest in RD (80.8 t ha-1). Considering the soil-plant ecosystem and the usual rotation age (84 months), the absolute SSC value was greatest in the micro-region SA (251.6 t ha-1) and lowest in RD (186.8 t ha-1). Regression equations showed that the clay and aluminum content and altitude and water stress explained most of the SSC variation.

A determinação de C orgânico do solo tem sido realizada, principalmente, por métodos baseados na oxidação química. Contudo, recentemente, o C tem sido determinado por métodos de combustão seca, como o CHNS/O. Este trabalho teve como objetivo comparar três métodos para determinação do C de solos cultivados com eucalipto em regiões com diferentes características edafoclimáticas. Foram comparados os métodos: Walkley-Black, Yeomans & Bremner e combustão seca (CHNS/O), utilizando amostras de diferentes classes de solos obtidas nas seguintes profundidades: 0-20, 20-80 e 80-130 cm nos Cambissolos; 0-25, 25-70 e 70-110 cm nos Latossolos; e 0-18, 18-50 e 50-110 cm nos Neossolos. Amostras de TFSA foram trituradas em almofariz, passadas em peneira de malha de 0,2 mm e submetidas aos três métodos de determinação de C. Os teores de C obtidos correlacionaram-se positiva e significativamente entre si. Os métodos Walkley-Black e Yeomans & Bremner tenderam a subestimar os teores de C em relação ao método de referência, CHNS/O, tanto no que se refere às camadas superficiais quanto àquelas mais profundas, com menores teores de C. Equações de regressão linear com elevados valores de R² permitiram transformar os teores de C obtidos por Walkley-Black e Yeomans & Bremner em C por combustão seca.

The soil C content has been determined most frequently by wet combustion methods. More recently, however, the dry combustion method has been used as the reference method for soil C determination. The main purpose of this study was to compare three C determination methods for soils under eucalypt plantations in southeastern Brazil. Samples of different soil types and located under distinct climate conditions were collected. Soil C contents were determined by two wet (Walkley-Black and Yeomans & Bremner) and one dry combustion method (CHNS/O Analyzer) in samples from six soil classes and different horizons: 0-20, 20-80 and 80-130 cm in Inceptsols; 0-25, 25-70 and 70-110 cm in Oxisols; and 0-18, 18-50 and 50-110 cm in Entisols. The soil samples were ground and sieved (0.2 mm) and the C concentration was determined by the three methods. The soil C contents determined by the three methods were positively correlated. However, the C content tended to be underestimated by the Walkley-Black and Yeomans & Bremner methods as compared to the reference dry combustion method, for surface as well as for the deeper soil layers with lower C contents. Linear regression equations with high R² values were adequate to transform C contents determined by the wet combustion methods into C contents equivalent to that determined by the dry combustion method.

O preparo do solo para o plantio de espécies florestais visa disponibilizar água e nutrientes para o rápido estabelecimento das mudas. Apesar de recentemente técnicas menos intensivas de preparo serem preconizadas, há situações em que o preparo mais intensivo é necessário. Neste trabalho avaliou-se o efeito de quatro métodos de preparo nas propriedades físicas e químicas do solo, na produção de biomassa e na composição mineral de plantação reformada de Eucalyptus grandis. Os tratamentos T1) queima dos resíduos da floresta anterior, destoca e subsolagem; T2) queima e destoca; T3) somente queima; e T4) cultivo mínimo (coveamento manual) foram aplicados em área anteriormente usada com plantação de eucalipto manejado por talhadia, em terceira rotação, e situada em Latossolo Vermelho distrófico no município de Santa Bárbara-MG. Aos 38 meses após o plantio, a maior produção de biomassa (81,6 t/ha) foi verificada no tratamento com maior intensidade de preparo do solo, com decréscimo significativo à medida que o preparo era menos intenso. A menor produtividade (50,4 t/ha) foi obtida com o cultivo mínimo. Entretanto, o solo deste tratamento, na época de avaliação, apresentou melhores características químicas e maior acúmulo de manta orgânica. Portanto, o coveamento foi o método de preparo que levaria à maior sustentabilidade da produção florestal, em razão da menor exportação de nutrientes.

Tillage system is a silvicultural technique used to increase water and nutrient availability for forest plantation establishment. Low intensity techniques have been recommended in recent years. However, under certain conditions more intensive soil preparation is required. This paper reports the effect of four methods of soil tillage systems on the physical and chemical properties and biomass production and mineral composition of Eucalyptus grandis plantation. The treatments applied were: T1 ) slash burning + blade + sub soiling; T2 ) slash burning + blade; T3) slash burning and T4 ) unburnt. In all cases, eucalypt seedlings were planted in a hole of 20 × 20 × 20 cm. The previous plantation had been conducted by coppicing and the trees harvested three times. The soil was a Red Latosol (Oxisol) located in Santa Barbara, Minas Gerais, Brazil. At the age of 38 months, the largest total biomass (81.6 t/ha) was measured in treatment T1 , decreasing as site preparation intensity was reduced. The lowest yield (50.4 t/ha) was observed in treatment T4 . However, the soil under this treatment presented the best chemical characteristics and the largest amount of forest floor, thus favoring forest yield sustainability due to a smaller nutrient removal.