ABSTRACT The nutrient management in eucalyptus plantations it is a key practice, in this way, consistent efforts are necessary to optimize the use of nutriente. In this context, the objective of this work was to evaluate the adequate doses of slow release fertilizer (SRF), in comparison to the application of simple superphosphate (SPS) in the base fertilization (BF) and its impact on the need for top dressing (TD) in seedlings of a eucalyptus hybrid, grown in pots. The experiment was arranged in a randomized block design in a 6x3 factorial scheme, in which the first factor corresponds to six doses of AB (0, 50, 75, 100, 125% of P) of SRF and 100% of P, of simple superphosphate (SPS). The second factor corresponded to three CF applications (0, 1 and 2 portions of KCl and NH4NH3. The doses of N, P, K were based on the recommendation of fertilization in pots of 300, 100 and 100 mg dm-³, respectively at 120 days, height (H), stem diameter (D), leaf area (LA), number of leaves (NL), plant dry mass were evaluated. In addition, doses of maximum technical efficiency were calculated (DMTE). The averages obtained by BF with SLF, of all variables were higher than the SPS. For the H, it is recommended to use one CF, with a DMET of 252.56 mg dm-³, of P, for having obtained growth similar to SPS. For the other variables, DMTE for BF, ranged from 236.52 to 327 mg dm-³, of P. In relation to CF, the, D, NL and shoot dry mass, did not show differences significant, which evidences the quality of the fertilizer in supplying the nutrients supplied in the CF, enabling its reduction. Thus, the DMTE indicated for plantings of the species is 100% ALL, guaranteeing satisfactory initial growth and use of only one CF.

RESUMO O manejo de nutrientes em plantios de eucalipto é uma prática fundamental. Dessa forma, muitos esforços são realizados para otimizar o uso dos nutrientes pelas plantas. Nesse contexto, objetivou-se avaliar as doses adequadas do adubo de liberação lenta (ALL), em comparação à aplicação de superfosfato simples (SPS) na adubação de base (AB) e o seu impacto sobre a necessidade de adubação de cobertura (AC) em mudas de um híbrido de eucalipto, cultivadas em vaso. O experimento foi disposto em delineamento em blocos casualizados em esquema fatorial 6x3, em que o primeiro fator corresponde a seis doses de AB (0, 50, 75, 100, 125% de P) de ALL e 100% para P, de superfosfato simples (SPS). O segundo fator correspondeu a três aplicações de AC (0, 1 e 2 parcelas de KCl e NH4NH3). As doses de N, P, K foram baseadas na recomendação de adubação em vasos de 300, 100 e 100 mg dm-³, respectivamente. Avaliaram-se, aos 120 dias, a altura (H), o diâmetro do colo, a área foliar (AF), o número de folhas (NF) e as massas secas da planta. Ademais, calcularam-se as doses de máxima eficiência técnica (DMET). As médias obtidas pela AB via ALL, de todas as variáveis, foram superiores ao SPS. Em relação à H, recomenda-se o uso de uma AC, com DMET de 252,56 mg dm-³, de P, por ter obtido crescimento semelhante ao SPS. Para as demais variáveis, DMET, para a AB, variou de 236,52 a 327 mg dm-³, de P. Já em relação à AC, o D, NF e a massa seca aérea não apresentaram diferenças significativas, o que evidencia a qualidade do fertilizante em suprir os nutrientes fornecidos na AC, possibilitando sua redução. Assim, a DMET indicada para plantios da espécie é 100 % ALL, garantindo crescimento inicial satisfatório e uso de apenas uma AC.

Resumo Um dos principais componentes orgânicos utilizados em mudas é a casca de arroz, entretanto, não é encontrada com facilidade, principalmente no sul de Minas Gerais, enquanto que a palha de café é um dos principais resíduos gerados nesta região. Sendo assim, objetivou-se avaliar a viabilidade técnica da utilização de substratos à base de palha de café carbonizada (PCC) em detrimento da utilização de casca de arroz carbonizada (CAC), em formulação com fibra de coco (FC), para a produção de mudas de Eucalyptus urophylla e Anadenanthera macrocarpa. Foram testados quatro substratos, com cinco repetições e 20 mudas por parcela, utilizando delineamento em blocos casualizados. As proporções das misturas foram S1 (60% FC e 40% CAC), S2 (80% FC e 20% CAC), S3 (60% FC e 40% PCC) e S4 (80% FC e 20% PCC). Foram mensurados, aos quatro meses, a altura das mudas (H), o diâmetro de coleto (DC), a massa seca da parte aérea (MSPA), a massa seca do sistema radicular (MSSR) e calculados o índice de robustez (H/DC), a densidade de raízes (DR) e o Índice de Qualidade de Dickson (IQD). Também foram feitas avaliações de facilidade de retirada das mudas do tubete e agregação das raízes ao substrato. Para o Eucalyptus urophylla, todos os parâmetros avaliados estiveram dentro do recomendando para expedição das mudas, contudo, os substratos à base de palha de café carbonizada obtiveram melhores resultados. Para a Anadenanthera macrocarpa, os parâmetros altura, diâmetro de coleto, índice de robustez e índice de qualidade de Dickson apresentaram-se dentro do exigido para expedição das mudas, em relação à formação do torrão, o tratamento empregando 60% de Fibra de coco e 40% de casca de arroz carbonizada apresentou maior média. Sendo assim, indica-se a utilização de palha de café carbonizada em detrimento da CAC para produção de mudas das duas espécies.

Abstract One of the following types of substrates is rice husk, although it is not easily found, mainly in the southern of Minas Gerais state, while coffee straw is one of the main generators of the region. The objective of this study was to use a technique for the use of carbonized coffee straw (PCC) substrates in preference to the use of carbonized rice husk (CAC) in the coconut fiber (CF) formulation for the production of Eucalyptus urophylla and Anadenanthera macrocarpa seedlings. Four substrates were tested, with five replications and 20 seedlings per plot, using a randomized block design. As proportions of the mixtures were S1 (60% FC and 40% CAC), S2 (80% FC and 20% CAC), S3 (60% FC and 40% PCC) and S4 (80% FC and 20% PCC). The height (H), collection diameter (DC), shoot dry mass (MSPA), dry mass of the root system (MSSR) and robustness index (H/DC), root density (DR) and the Dickson Quality Index (IQD), were measured at four months. Evaluations of ease of removal of seedlings and aggregation of roots were also made to the substrate. For Eucalyptus urophylla, all the evaluated parameters are within the recommended for the removal of the seedlings. However, the substrates are based on PCC results. For the Anadenanthera macrocarpa, the parameters H, DC, H/DC and IQD, presented within the required for the expedition of the seedlings, in relation to the formation of the clod, S1 presented higher average. Therefore, the use of CCPs in detriment of CAC is indicated for the production of seedlings of both species.

Abstract Acrocarpus fraxinifolius stands out due to its uses in the timber industry and rapid growth. However, information is scarce regarding its fertilization. We aim to understand how soil preparation and phosphorus doses affect A. fraxinifolius initial development. The experimental design used was a randomized block design in a 2 x 5 factorial scheme, consisting of two types of soil tillage (minimum and conventional) and five doses of phosphorus (P) (0, 50, 100, 150, and 200 g of simple superphosphate) with four replications, and plots formed by two plants. The measurement occurs at 30 and 210 days after planting, assessing the height and diameter at the stem height. Initially, the minimum tillage provided had a higher average height and diameter. However, conventional tillage, acidity correction, and fertilization with 108 g of simple superphosphate per plant resulted in Acrocarpus fraxinifolius plants with better growth at 210 days after planting.

Abstract Urban growth promotes changes in the environment and in the quality of life. Urban afforestation enables environmental services. But afforestation requires planning and maintenance to avoid conflicts with other urban equipment. The objective of this work was to analyze the interaction between urban afforestation and energy distribution systems in the Metropolitan Region of Belo Horizonte. The state-owned energy concessionaire’s database was used, seeking to analyze the relationship between the history of outages in energy supply and the environmental factors associated with the fact, in the period between 2010 and 2015. It was found that the most relevant factors were the type of electrical energy distribution system (bare or isolated) and the maintenance (pruning) of the trees. The size of the tree and the strength of the wood are decisive in defining the demand for maintenance pruning to ensure a harmonious relationship between the trees and the electrical energy distribution system.

Abstract Fertilization in the seedling production phase is essential to form quality seedlings. Thus, the aim of this study was to evaluate the appropriate doses of two slow-release fertilizers (SRF1 and SRF2) and their nutrient leaching behavior. For this, five different doses of fertilizers were tested. 0, 2, 4, 6, and 8 kg m-³. The height, stem diameter, leaf area, shoot dry mass, root system dry mass, total dry mass, and the Dickson Quality Index were measured, and for each variable the maximum dose of technical efficiency was determined. In addition, was evaluated the electrical conductivity, over time, for determinate the leaching of the nutrients. All the variables had satisfactory growth for field planting. However, the SRF2 resulted in greater seedling growth and also experienced less nutrient loss by leaching, when compared with the SRF1. The both fertilizers could be utilized to seedlings production, at doses of 4.00 kg m-³.

RESUMO Avaliou-se o crescimento pós-poda das 16 principais espécies plantadas em arborização urbana na Região Metropolitana de Belo Horizonte com objetivo de adequar o regime de podas e avaliar o efeito de fatores ambientais, de manejo e da árvore no desenvolvimento das brotações. Foram selecionados seis indivíduos por espécie e acompanhado o crescimento mensal das cinco maiores brotações nos pontos podados, criando-se dois cenários, considerando os valores da mediana e do terceiro quartil dos dados de crescimento. Procedeu-se a análise de agrupamento dos dados de crescimento, definindo-se grupos de regime de poda de acordo com a similaridade de hábito de crescimento das espécies. Realizou-se também análises de correlação e regressão linear para fatores climáticos, intensidade de poda, diâmetro a altura do peito, estado fitossanitário, intensidade de luz na copa e área permeável no solo. Constatou-se que as espécies arbóreas estudadas apresentam resposta diferenciada de crescimento das brotações pós-poda, podendo ser reunidas em grupos de regimes de manejo de podas, variando entre 6 e 24 meses. Fatores ambientais, do indivíduo arbóreo e de manejo podem afetar o desenvolvimento da brotação das árvores.

ABSTRACT The post-pruning growth of the 16 main species planted in urban afforestation in the Metropolitan Region of Belo Horizonte was evaluated in order to adjust the pruning regime, as well as to evaluate the effect of environmental, management, and tree factors on shoot development. Six individuals were selected per species, and the monthly growth of the five largest shoots at the pruned points was monitored to create two scenarios, considering the median and third quartile of the growth data. The grouping analysis of the growth data was carried out, defining groups of pruning regime according to the similarity in the species growth. Correlation and linear regression analyses were also performed for climatic factors, pruning intensity, diameter at breast height (DBH), phytosanitary status, luminosity in the crown, and permeable area in the soil. It was verified that the arboreal species studied presented a differentiated growth response of post-pruning shoots and can be combined into groups of pruning management regimes ranging from 6 to 24 months. Environmental, individual, and management factors can affect tree sprouting.

Abstract Annona crassiflora is a medicinal species and source of food with little information about its nutritional requirements during the initial phase. Therefore, the objective of this study was to evaluate liming, phosphate fertilization and its interaction in A. crassiflora seedlings. The experiment was in a 4 × 4 factorial scheme with four replications in a randomized block design. The base saturations were: 8.3%, 25%, 50% and 75% and phosphorus: 0 mg dm-3, 100 mg dm-3, 200 mg dm-3 and 400 mg dm-3. The variables evaluated were biometrics, biomass and nutritional analysis. The species responded to the factors in isolation, and the increase in base saturation levels and phosphorus doses promoted significant effects for biometric variables, biomass, calcium, magnesium, nitrogen, phosphorus and potassium content. The saturation level promoted the best results, being 75% base saturation, while the highest phosphorus dosage was 400 mg dm-3.

RESUMO Objetivou-se, neste estudo, avaliar os requerimentos nutricionais e o efeito da limitação de nutrientes no desenvolvimento de mudas de baru (Dipteryx alata Vogel) utilizando a técnica da limitação nutricional. O ensaio foi estabelecido em delineamento inteiramente casualizado com 12 tratamentos e oito repetições. Os tratamentos adotados foram os seguintes: completo 1 (C1 - adubado com N, P, K, S, B, Cu, Zn e calagem), completo 2 (C2 - adubado com N, P, K, S, Ca, Mg, B, Cu, Zn, sem calagem), tratamentos completos com omissão de um nutriente por vez (completo 1 - N, completo 1 - P, completo 1 - K, completo 1 - S, completo 1 - B, completo 1 - Zn, completo 2 - Ca, completo 2 - Mg, completo 1 - calagem) e controle (solo natural). Aferiu-se o diâmetro e a altura das plantas, separando-as em parte aérea e sistema radicular. As mudas foram secas, pesadas, moídas e foi determinado o teor de nutrientes na matéria seca da parte aérea. De acordo com os resultados, as limitações de S e B não afetaram o crescimento das mudas de Dipteryx alata. P e N foram, de forma geral, os nutrientes que mais limitaram o crescimento das mudas de baru. A sequência de exigência nutricional apresentada pelas mudas de baru, considerando a produção de biomassa seca da parte aérea, em ordem decrescente foi: P = N > Ca = Mg = Zn = K = S = B.

ABSTRACT This study was conducted with the objective of evaluating the nutritional requirements and the effect of nutrient limitation over the development of baru seedlings (Dipteryx alata Vogel), using the nutrient limitation technique. The trial was established in a completely randomized design, with 12 treatments and 8 replicates. The adopted treatments were the following: complete 1 (C1 - fertilization with N, P, K, S, B, Cu, Zn and liming), complete 2 (C2 - fertilization with N, P, K, S, Ca, Mg, B, Cu, Zn, with no liming), complete treatment with the omission of a nutrient at a time (C1-N, C1-P, C1-K, C1-S, C1-B, C1-Zn, C2-Ca, C2-Mg, C1-liming) and control (natural soil). We assessed plant height and diameter, and separated them into shoot and root system. The seedlings were dried, weighed, ground for the determination of nutrient content of the shoot dry matter. According to the results, the limitation of S and B did not affect the growth of Dipteryx alata seedlings. In general, P and N were the nutrients that most limited the growth of Baru seedlings. The sequence of nutritional requirements presented by the Baru seedlings, in decreasing order, considering the production of shoot dry biomass, was: P = N > Ca = Mg = Zn = K = S = B.

ABSTRACT This study aimed to verify the effect of phosphorus and liming doses on the morphological and nutritional characteristics of D. nigra seedlings. The experiment was conducted using a completely randomized 4x4 factorial design. The treatments consisted of 4 levels of liming and 4 phosphorus doses. Morphological characteristics and nutritional analyses of plants were measured. There were no significant interactions between liming x P. Morphological characteristics presented differences for liming and phosphorus when analyzed separately. The best productive performances were found between an increase in base saturation between 48.07% and 54.76%. Morphological characteristics showed a linear behavior for P. Both the application of liming and P promoted positive effects on D. nigra growth.

RESUMO: Objetivou-se com este trabalho avaliar o desempenho silvicultural de quatro espécies florestais introduzidas em arranjo para Integração Pecuária Floresta (IPF) sobre pastagem, em Lavras, Minas Gerais. As espécies estudadas foram o cedro australiano (seminal e clonal), mogno africano, teca e guanandi. Utilizou-se o delineamento de blocos casualizados completos, em esquema de parcelas subdivididas no tempo, com quatro repetições e 48 plantas por parcela no arranjo (3(3x2)+7x2)m. As subparcelas corresponderam às épocas de avaliações (12, 18, 31, 36 e 43 meses pós-plantio). Os desempenhos das espécies foram avaliados por meio dos parâmetros de sobrevivência, diâmetro à altura do peito e altura. Com base no desempenho das espécies, o cedro australiano clonal apresentou maior crescimento em DAP e altura no arranjo para IPF sendo esta a espécie indicada para Lavras/MG, desde que na fase de implantação ocorra o controle da sobrevivência.

ABSTRACT: The objective of this study was to evaluate the silvicultural performance of four forest species introduced in a setting for integrated livestock forest (ILF) in a pasture in Lavras, Minas Gerais, Brazil. The species included were the Australian red cedar (seminal and clonal), African mahogany, teak, and guanandi. A split plot scheme with a randomized complete block design comprising four replicates and 48 plants per plot, was used in the following arrangement: (3(3x2) +7x2) m. The evaluation times (12, 18, 31, 36, and 43 months after planting) corresponded to the subplots. Performances of all four species were evaluated on the basis of their survival rate, height (H) and diameter at breast height (DBH). Based on the performance of the species with regard to these parameters, the clonal Australian red cedar showed a greater growth in DBH and height in the ILF setting as compared to the other species, which indicates it to be a suitable species for the region of Lavras, MG as long as its survival control occurs in the implantation phase.

ResumenLa distribución espacial y temporal de la vegetación esta influenciada por factores edáficos, ambientales y alteraciones. En ese contexto, el objetivo del estudio fue caracterizar el patrón de distribución y la dependencia espacial de la diversidad de especies en un fragmento de bosque estacional semideciduo, donde ocurrió un incendio, e identificar alteraciones a lo largo del proceso de regeneración natural. El incendio ocurrió en 1999, y en 2000, 2005 y 2014, se hicieron inventarios florísticos en 26 parcelas (400 m2) georreferenciadas y distribuidas en dos transectos. El índice de daño del fuego (IDF) se evaluó en cada parcela con base en una escala de 0 a 5. En cada inventario se identificaron las plantas arbóreas con diámetro a altura de pecho (DAP) ≥ 5 cm, calculando la diversidad de especies con base en el índice de Shannon (H’) y estimando la riqueza de especies (S). Esas variaciones fueron analizadas utilizando la curva de acumulación de especies, y la variación entre inventarios fue comparada con base en las medias y el error estándar. Los datos de S, H’ e IDF fueron sometidos a análisis exploratorio no espacial y a análisis geoestadístico. Después del ajuste de los semivariogramas, se clasificó el nivel de dependencia espacial y se hizo la interpolación de datos por Krigeado ordinario para caracterizar, en mapas, el patrón de distribución espacial de esas variables. Se encontró diferencia entre los inventarios realizados después del incendio, como en la configuración de la comunidad arbórea, por lo que el análisis espacial permitió identificar y caracterizar este hecho. El incendio afectó la estructura espacial y temporal de las variables S y H’. Estas variables presentan dependencia espacial y la distribución agregada, con distancias más pequeñas bajo influencia espacial, y la uniformidad de la distribución de los individuos en el fragmento de bosque durante las distintas etapas. Por último, se caracterizó la distribución y la dependencia espacial de las variables S e H ‘en un fragmento de bosque después de un incendio, y las alteraciones en la estructura de la comunidad arbórea durante la regeneración natural.

AbstractThe spatial and temporal distributions of vegetation can be influenced by edaphic and environmental factors as well as disturbances. The present study was undertaken to characterize the distribution and spatial dependence of species diversity in a fragment of semideciduous seasonal forest after a disturbance event by fire and to identify changes during natural regeneration. The fire, occurred in 1999, and surveys were undertaken in 2000, 2005 and 2014 in 26 geo-referenced plots (400 m²) distributed along two transects. The Fire Damage Index (FDI) in each plot was based on a scale from 0 to 5, and all of the arboreal individuals with diameters at breast height (DBH) ≥ 5 cm were identified in each plot. Species diversity was calculated using the Shannon index (H’), and species richness (S) was estimated using species accumulation curves; variations between the surveys compared based on the means and standard errors. The S, H’ and FDI data were submitted to non-spatial exploratory and geostatistical analyses. After adjusting the semivariograms, the levels of spatial dependence were classified, and interpolation of the variables values were performed using ordinary kriging to characterize their spatial distributions in the form of maps. Spatial analysis was used to identify and characterize differences between the post-fire surveys in terms of the configurations of the arboreal community. The fire event influenced the spatial and temporal structures of the variables S and H’. These variables showed spatial dependence and aggregated distributions, with reduction in the distance under spatial influences and a uniformity of individuals distribution in the forest fragment at the different surveys. This research characterized the distribution and spatial dependence of the variables S and H’ in a forest fragment after a fire event and the alterations in the arboreal community structure during natural regeneration.

RESUMO O objetivo do trabalho foi avaliar a capacidade de brotação de cepas de teca sob regime de talhadia composta. O experimento foi implantado nos espaçamentos 3,0 × 2,0 m e 3,0 × 3,0 m. Aos 8 anos de idade, o experimento foi desbastado sistematicamente, em 50%. Após o desbaste, foi avaliado o potencial de brotação das cepas das árvores desbastadas. O delineamento experimental utilizado foi o de blocos ao acaso, com 2 tratamentos e 5 repetições. Os tratamentos foram T1 = brotação conduzida sob regime de talhadia composta no espaçamento 3,0 × 4,0 m e T2 = brotação conduzida sob regime de talhadia composta no espaçamento 3,0 × 6,0 m. A teca apresentou capacidade de brotação de cepas sob regime de talhadia composta até o período avaliado de 12 anos de idade, para ambos tratamentos.

ABSTRACT This work aimed to evaluate the teak stump sprouting capacity under compound coppice process. The experiment was implemented at spacing of 3.0 × 2.0 m and 3.0 × 3.0 m. At 8-years old, the experiment was systematically thinned in 50%. After thinning, with new spacing of 3.0 × 4.0 m and 3.0 × 6.0 m, the stump sprouting capacity of the thinned trees was evaluated. The experimental design used was randomized blocks, whit two treatments and 5 repetitions. The treatments were T1 = conduced sprouting under compound coppice process at the spacing 3.0 × 4.0 m and T2 = conduced sprouting under compound coppice at the spacing 3.0 × 6.0 m. Teak presented sprouting capacity under compound coppice until 12-years old for both treatments.

RESUMO Analisou-se, neste trabalho, o crescimento inicial do baru em solução nutritiva com omissão individualizada dos nutrientes minerais em casa de vegetação. O delineamento experimental utilizado foi o inteiramente casualizado com 13 tratamentos e quatro repetições, sendo: Solução Hoagland & Arnon completa e omissões individualizadas de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Mo e Zn. Avaliaram-se, aos 60 dias após, a instalação do experimento, características morfológicas: altura, diâmetro do coleto, número de folhas e de folíolos. Foram calculados o índice de Dickson e a relação da massa seca da raiz/massa seca da parte aérea. A massa seca das raízes e da parte aérea foi determinada e analisados os teores e acúmulo de nutrientes na parte aérea das mudas. Realizou-se a análise de variância dos dados coletados por meio do programa computacional Sisvar. O crescimento de mudas de baru, com exceção da variável altura, foi influenciado pela omissão de nutrientes na solução nutritiva sendo os principais nutrientes limitantes o K, Ca, Mg, Fe, Mn e Mo. A absorção dos nutrientes pelo baru ocorre de forma diferenciada em função das omissões nutricionais individualizadas aplicadas à solução de cultivo.

ABSTRACT This study analyzed the initial growth of baru in nutrient solutions with individualized omission of mineral nutrients in greenhouse. The experimental design was completely randomized with 13 treatments and four replicates: Complete Hoagland & Arnon solution and with individualized omissions of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Mo and Zn. At 60 days the following morphological characteristics were evaluated: height, root collar diameter, number of leaves and number of leaflets. In addition, the Dickson quality index and root/shoot ratio were calculated and root dry matter, shoot dry matter and the contents and accumulations of nutrients in the shoots of the seedlings were analyzed. Analysis of variance of the collected data was performed using the computational program Sisvar. The growth of baru seedlings, except for the variable height, was influenced by the omission of nutrients in the nutrient solution and the main limiting nutrients are K, Ca, Mg, Fe, Mn, and Mo. The absorption of nutrients by baru plants occurs differently under the individualized nutritional omissions applied to the nutrient solution.

RESUMO O estabelecimento do plantio florestal com mudas bem noduladas favorece o seu crescimento inicial e sobrevivência após a fase de estabelecimento. As espécies leguminosas arbóreas ingá (Inga edulis), orelha-de-macaco (Enterolobium schomburgkii) e palheteira (Clitoria fairchildiana) têm sido recomendadas para recuperação de áreas degradadas e composição de sistemas agroflorestais pela sua rusticidade e capacidade de estabelecer simbiose com bactérias do solo do grupo dos rizóbios, eficientes em fixar N2. Foi conduzido estudo experimental para analisar o efeito da adição de carvão vegetal em mistura substrato sobre a qualidade de mudas produzidas em viveiro. Os tratamentos utilizados foram: mistura 3:2:0,5 (v:v) de solo argiloso, areia e esterco bovino e de solo argiloso e areia 3:2 (v:v), combinado com carvão vegetal em dosagem de 0, 10, 19 e 29 % de carvão em mistura. Amostras das misturas substratos foram coletadas e analisadas quimicamente. O delineamento foi o inteiramente casualizado com cinco tratamentos e dez repetições. As mudas foram inoculadas com estirpes homólogas de rizóbios, sendo que 5 mL planta-1 foram aplicados na base do coleto das mudas. O crescimento das mudas foi acompanhado mensalmente e as plantas foram coletadas para contagem do número de nódulos formados e determinação da biomassa das raízes, parte aérea e nódulos após secagem a 65ºC/72 h. O uso de esterco na composição dos substratos inibiu a nodulação em todas as três espécies estudadas. Foi também possível verificar aumento na qualidade das mudas pelo uso de carvão no substrato.

ABSTRACT Native legume trees are planted in agroforestry systems for their hardiness and symbiosis with soil bacteria of the genus rhizobium, efficient in N2 fixation. The enrichment of the substrate composition with fine charcoal for seedling production of these trees is interesting for increasing soil porosity, water retention and the proliferation of beneficial microorganisms. Experiments were carried out to analyze the effect of substrate enrichment with charcoal on the quality of Clitoria fairchildiana, Enterolobium schomburgkii and Inga edulis seedlings. The treatments consisted of a 3:2:0.5 (v:v) mixture of clay soil, sand and bovine manure and a 3:2 (v:v) mixture of clay soil and sand combined with charcoal rates of 0, 10, 19 and 29%. After mixing the components, substrate samples were collected and chemically analyzed. The experiment was arranged in a completely randomized design with 5 treatments and 10 replications. The seedlings were inoculated with homologues rhizobia and growth controlled monthly. The plants were collected to determine the number of nodules and dry biomass of roots, shoots and nodules. Seedling growth was similar on substrates containing charcoal or manure, except for E. schomburkii, which increased by more than 100% on the charcoal-containing substrates. The number and dry biomass of nodules in the charcoal-containing substrates was up to 100% and 300% higher than in the manure-containing treatment, respectively. The results indicated that the substitution of manure by charcoal favors the seedling quality of the studied species.

RESUMO Neste estudo avaliou-se a fertilidade do solo, a biomassa e atividade microbiológica do solo sob coberturas florestais de Eucalyptus grandis, Eucalyptus pilularis, Eucalyptus cloeziana e Corymbia maculata; Pinus caribaea var. hondurensis, com 40 anos de idade, e um fragmento de Floresta Estacional Semidecidual, localizados no campus da Universidade Federal de Lavras. Em amostras de solo coletadas na camada de 0-5 cm foram determinados parâmetros de fertilidade, a respiração basal e o carbono de biomassa microbiana. Os resultados mostraram que as espécies E. grandis e E. cloeziana mantiveram teores de carbono de biomassa microbiana mais elevados dentre os ecossistemas avaliados e iguais àqueles observados sob a floresta nativa. Em contraste, o solo sob pinus apresentou os menores índices microbiológicos. Sob C. maculata e E. pilularis os teores foram intermediários para este parâmetro. A respiração basal de todos os ecossistemas foi igual. O nível de fertilidade foi extremanente baixo sob todos os tipos de cobertura vegetal avaliados.

ABSTRACT This study evaluated the soil fertility, biomass and microbial activity of the soil under forest cover of Eucalyptus grandis, Eucalyptus pilularis, Eucalyptus cloeziana and Corymbia maculata; Pinus Caribbean var. hondurensis, 40 years old, and a fragment of Semideciduous Forest, located on the campus of the Federal University of Lavras. In soil samples collected in the 0-5 cm layer were determined fertility parameters, basal respiration and microbial biomass carbon. The results showed that for the species E. grandis and E. cloeziana the carbon of biomass microbial content was higher than for any other ecosystem evaluated, and equal to those observed under native forest. In contrast, the ground under Pinus had the lowest microbiological indexes. Under C. maculata and E. pilularis the contents were intermediate for this parameter. The basal respiration of all ecosystems was equal. The fertility level was very low in all types of evaluated vegetation.