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ABSTRACT Soil attributes can provide indicators for the management and conservation of natural and agrarian ecosystems. This study was carried out before the rupture of the Córrego do Feijão dam and aimed to evaluate and quantify the stocks of carbon, nitrogen and the C/N ratio in soils around the Paraopeba-MG river basin in five regions corresponding to the high, middle, and low river course, considering three usage factors: forest, pasture, and Shrubbery forest, correlating them with the chemical and physical properties of the soil, aiming at the interpretation of past use, to obtain management and conservation strategies for ecosystems. The results indicate a significant variation in carbon and nitrogen stocks with an increase in the 20-40 cm layer. Concerning the type of use, the forest system was the most efficient in accumulating carbon. About to site, the regions of Brumadinho and Fortuna de Minas showed similarities in the incorporation of carbon in the soil, differing from the regions of Jeceaba, Florestal, and Três Marias. There was a close correlation between stocks and the chemical and physical properties of the soil, making it possible to assess the quality of the soils in the study regions in terms of structure and fertility.

Abstract: The objective of this work was to evaluate the agronomic attributes and production efficiency of corn silage and grains in an integrated crop-livestock-forestry (ICLF) system, with intercropping of eucalyptus, corn, and Urochloa cultivars during three crop years. The experimental design was completely randomized, in 2x5x3 split-split plots with four replicates. The plots consisted of corn cropped between eucalyptus rows (ICLF) and in full sun; the subplots, of the forage grasses U. brizantha 'Marandu', U. brizantha 'Xaraés', U. brizantha 'Piatã', U. ruziziensis, and U. decumbens 'Basilisk'; and the split-split plots, of the 2011/2012, 2012/2013, and 2013/2014 crop years. There was no effect of eucalyptus on the silage and grain yields of corn when intercropped with forages in 2011/2012. The production efficiency of silage and grains decreased by 25 and 48%, respectively, in 2012/2013 (12-month-old eucalyptus). There was also a 56% reduction in grain yield in 2013/2014 (24-month-old eucalyptus), compared with full sun. In the year the ICLF system is established, the production efficiency of corn silage and grains is not affected by eucalyptus, but decreases with the development of the trees in the subsequent crop years.

The study was carried out with the aim to evaluate the effect of different special arrangements in forage yield, nutritive value and structure of the understory of signalgrass (Brachiaria decumbens) in silvipastoral system with different regrowth times. The design was in complete randomized block with tree replicates in a factorial scheme with split-plots 2 × 2 × 5 consisting two spatial arrangements [Double lines 9 × (2 × 2m) and simple lines (9 × 2m)] in two sampling places (in the middle of the intercropping and under the three canopy) in the plot and five regrowth times (35, 42, 49, 56 e 63 days) in the split-plot. It was used a silvipastoral system established since June, 2008 in degraded pasture with signalgrass predominance. The pasture was homogenized by grazing at 15 cm from the soil level. Were evaluated the dry matter yield leaf:stem ratio, light interception and leaf area index. In addition were evaluated the nutritive value characteristics dry matter content, neutral and acid detergent fiber, crude protein and lignin. The photosynthetic active radiation was monitored. The use of simple or double lines did not influence the leaf area index, light interception and dry mass yield. The leaf:stem ratio was influenced by the sampling place only in the double line arrangement. The neutral detergent fiber was substantially high in the double line arrangement. Therefore, the use of double lines reduces the photosynthetic active radiation amount incident in the understory, but does not reduce the forage yield in relation to simple line arrangements. These results indicate the use of double lines arrangement may allow the harvest of more threes without reduce the pasture production.

The effect of nitrogen (N) doses on yield of the green maize ears and its production components was evaluated during two years. Five N doses (0, 60, 120, 180 and 240 kg ha-1) applied in topdressing were tested in a randomized block design with four replications. The efficiency of treatments was evaluated by the production and the number of commercial green ears per hectare, weight of husked and unhusked ears, length and diameter of unhusked ears and husked ear/husk ratio. Increases in husked commercial ear yield by N application were found, with maximum production of 13.52 t ha-1 estimated by 157 kg ha-1 N application (first year) and of 14,86 t ha-1 with 177 kg ha-1 N dose (second year). The increases in the production of green ears were not due to increases in the number of ears per area and by length of these. Differently of husked ear/husk ratio, the average weights of the husked and unhusked ears and diameter of unhusked ears were affected by N application. It was proposed a table of recommended N doses based on pre-establishedprices of N and commercial ears.

The experiment was carried out in an area of 8.4 ha of degraded Brachiaria decumbens pasture aiming to evaluate phytosociological parameters. The infestant flora assessment was made on six pasture areas before the establishment of crop-livestock system experiment, at 90, 210 and 330 days after implementation. The inventory square method was used for the phytosociological study, applied through a 0.5 m2 square frame thrown 35 times in each experimental plot. In order to evaluate the species present in the area, the following parameters were determined: frequency, density, abundance, relative frequency, relative density, relative abundance and value of importance of each species (IVI). In the survey accomplished in the pasture area before the experiment implementation, 18 species of 11 botanical families were identified. Poaceae (Gramineae) family presented the greatest number of species, followed by Leguminosae (Fabaceae) – Mimosoideae. At 90, 210 and 330 days after crop-livestock system establishment, 15, 19 and three species belonging to 11, 12 and three botanical families, respectively, were identified. On the maize plots for silage, in all evaluations, the most representative species found on the area was Brachiaria decumbens, with IVI over 100.

Objetivou-se com este trabalho foi avaliar a adaptabilidade e estabilidade de cultivares de alfafa cultivadas em diferentes regiões do Estado de Minas Gerais (Zona da Mata, Zona Metalúrgica e Sul de Minas), quanto à produção de matéria seca de forragem. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições. Foi avaliada a produção de matéria seca de 27 cultivares de alfafa no período de 1995 a 1998. O estudo da adaptabilidade e estabilidade foi realizado por meio das metodologias de Eberhart & Russell (1966) e Lin & Binns (1988). Houve diferenças significativas (P < 0,01) entre as cultivares, os ambientes e a interação cultivar x ambiente, indicando que as cultivares apresentaram desempenho diferenciado diante das variações ambientais. Constatou-se que as cultivares que apresentaram as maiores produções de matéria seca, foram as de maior adaptabilidade e estabilidade pelo método de Lin & Binns. As cultivares Crioula e P-30 são recomendadas para cultivo no Estado de Minas Gerais.The objective of this experiment was to evaluate the adaptability and stability of forage dry matter production of alfalfa cultivars in three different regions in the State of Minas Gerais (Mata, Metalurgica and South). Twenty-seven cultivars of alfalfa were evaluated between 1995 and 1998 using randomized block design with three replications. Adaptability and stability were evaluated using Eberhart & Russel (1966) and Lin & Binns (1988) methodologies. Significant differences (P < .01) among cultivars, environments and the cultivar x environment interactions were observed, showing that cultivars performance is affected by environment. Cultivars with highest dry matter production showed the best adaptability and stability. Cultivars Crioula and P-30 should be recommended to be used in the State of Minas Gerais.

Com o aumento da competitividade do setor produtivo, a pecuária leiteira brasileira busca, de todas as formas, sistemas de produção que obtenham maior produtividade e menor custo. Entre as estratégias adotadas para tal fim, estão a melhoria da qualidade do rebanho e da forragem fornecida aos animais, de modo que estes expressem todo o seu potencial produtivo. A alfafa, conhecida pela excelente qualidade forrageira e boa palatabilidade, surge como boa opção. Entretanto, ainda há muito o que se trabalhar para a obtenção de cultivares melhor adaptadas às condições tropicais. Informações teóricas sobre características de importância forrageira são necessárias para a orientação dos programas de melhoramento. Nesse sentido, o objetivo deste trabalho foi estimar o coeficiente de repetibilidade para a produtividade de matéria seca de alfafa na região Sudeste do Brasil e determinar o número ideal de avaliações para a seleção dos genótipos superiores, por meio de quatro metodologias diferentes. Utilizaram-se dados de produtividade de matéria seca obtidos em quatro ensaios de comparação de cultivares de alfafa, conduzidos em diferentes regiões do Estado de Minas Gerais. Estimou-se o coeficiente de repetibilidade (r), para cada um dos ensaios, por meio dos métodos da análise de variância (Anova), dos componentes principais com base na matriz de covariância (CP-1) e de correlação (CP-2), e pela análise estrutural baseada na matriz de correlação. Observou-se que houve boa concordância entre as diferentes metodologias de estimação do coeficiente de repetibilidade em todos os ensaios. A estimativa média de repetibilidade para produção de matéria seca de alfafa nos quatro ensaios avaliados foi de 0,59, com coeficiente de determinação médio de 0,96. Constatou-se, também, que a realização de apenas quatro cortes, em média, foram suficientes para se conhecer o real valor genotípico das cultivares testadas, com 85% de confiabilidade.

O objetivo deste trabalho foi avaliar o potencial forrageiro de cultivares de alfafa na região de Cerrado do Estado de Minas Gerais. Odelineamento experimental foi o de blocos ao acaso, com três repetições. Durante os períodos de seca e das águas, foram observadas diferenças significativas entre as cultivares quanto ao potencial de produção de forragem, teor de proteína bruta, relação folha/caule e tolerância a pragas e doenças. As cultivares Crioula e P 30 destacam-se das demais em relação ao potencial produtivo e resistência a pragas e doenças e são recomendadas para a região dos Cerrados da Zona Metalúrgica de Minas Gerais.The objective of this work was to evaluate the yields of alfalfa cultivars in the Cerrado region of Minas Gerais State, Brazil. A randomized block design with three replications was used. During the dry and rainy season, significant differences were observed among cultivars for forage production, crude protein content, leaf:stem ratio, insect and disease resistance. The Crioula and P 30 cultivars had the best performance for forage production and resistance to insects and diseases. These cultivars are recommended for forage production in the Cerrado region of the Metallurgic Zone of Minas Gerais State.

RESUMO A matéria orgânica humificada apresenta bioatividade semelhante à das auxinas. Contudo, são necessárias informações sobre a capacidade de estímulo vegetal das substâncias húmicas extraídas de solos manejados com sistemas integrando lavoura, pecuárias e florestas. O objetivo deste trabalho foi avaliar o desempenho inicial do milho em resposta à aplicação de concentrações de substâncias húmicas isoladas em solos manejados com sistema de integração lavoura, pecuária e florestas, aplicadas por via da semente. Sementes de milho variedade AG 1051 foram tratadas por 16 horas, em soluções contendo 0, 10, 20, 30, 40 e 80 mmol L-1 de carbono na forma de substâncias húmicas. Em seguida, foram plantadas em vasos de 1 dm3, com solo corrigido e fertilizado, em casa de vegetação. Foram avaliadas características de crescimento da parte aérea e do sistema radicular. Observou-se que as substâncias húmicas extraídas de solos submetidos a integração lavoura, pecuária e florestas apresentaram efeitos positivos no desempenho inicial do milho, incrementando o acúmulo de matéria seca das plantas, em comparação com o efeito das substâncias extraídas de solos do controle, na área degradada inicial (133%), do cerrado (29%), bem como do eucalipto (30%) e da pastagem plantada solteira (56%).

ABSTRACT The objective of this study is to evaluate the forage mass, chemical composition, mineral content, and mineral absorption in signal grass (Urochloa decumbens) grown with different eucalypt clones in an integrated crop-livestock-forest (iCLF) system. The split-split-plot scheme included three replicates arranged in a completely randomized block design. The eucalyptus clones GG 100 and I 144 (Eucalyptus grandis × Eucalyptus urophylla) and VM 58 (Eucalyptus grandis × Eucalyptus camaldulensis) were distributed in the plots. The split plots corresponded to the growth ages of signal grass (10, 17, 24, 31, 38, 45, and 52 days after corn harvest for silage). The split-split plots corresponded to two sampling sites: center of the inter-row and soil under the Eucalyptus canopy. The Eucalyptus clones did not affect the forage mass of the grass. Forage mass was increased linearly as the grass matured and was more readily available in the center of the inter-row than under the tree canopy. The grass grown with clone I 144 presented better chemical composition, with higher levels of crude protein and phosphorus and lower levels of neutral detergent fiber. The Eucalyptus clones did not significantly affect mineral absorption. However, the Eucalyptus clones, grass age, and sampling sites significantly changed potassium absorption. It is concluded that the forage mass of signal grass is suitable for use in grazing at 38 to 52 days after corn harvest in the iCLF system in the autumn season in the Midwest region of Minas Gerais, without compromising the chemical composition of the grass.