ABSTRACT:Green manures are an alternative for substituting or supplementing mineral nitrogen fertilizers. The aim of this study was to quantify biological N fixation (BNF) and the N contribution derived from BNF (N-BNF) to N levels in leaves of coffee intercropped with legumes grown on four family farms located in the mountainous region of the Atlantic Forest Biome in the state of Minas Gerais, Brazil. The following green manures were evaluated: pinto peanuts (Arachis pintoi), calopo (Calopogonium mucunoides), crotalaria (Crotalaria spectabilis), Brazilian stylo (Stylosanthes guianensis), pigeon pea (Cajanus cajan), lablab beans (Dolichos lablab), and velvet beans (Stizolobium deeringianum), and spontaneous plants. The experimental design was randomized blocks with a 4 × 8 factorial arrangement (four agricultural properties and eight green manures), and four replications. One hundred grams of fresh matter of each green manure plant were dried in an oven to obtain the dry matter. We then performed chemical and biochemical characterizations and determined the levels of

Avaliaram-se 10 linhagens de pimentão (Capsicum annuum L.) quanto à eficiência nutricional em relação ao P, bem como a dose de P mais adequada para estudos genéticos, e o caráter que mais contribuiu para a divergência genética. O experimento foi conduzido em casa de vegetação, em solo, na Universidade Federal de Viçosa. Os tratamentos foram distribuídos em arranjo fatorial 10 x 5 x 4, constituídos de 10 linhagens, cinco doses de P (0, 250, 500, 750 e 1.000 mg de P/kg de solo) e quatro repetições, em delineamento de blocos casualizados. Em cada dose de P aplicada ao solo foi realizada uma análise multivariada. Constatou-se variabilidade genética entre as linhagens estudadas em todas as doses de P adicionadas ao solo, sendo a dose 250 mg de P/kg de solo a que melhor discriminou as linhagens; portanto, a mais indicada para estudos genéticos. Com essa dosagem, constatou-se que a produção de matéria seca da parte aérea foi o caráter que mais contribuiu para a divergência genética entre as linhagens, podendo ser um parâmetro adequado para seleção em estudos genéticos.

Potassium is a source of non-renewable natural resource, and is used in large quantities in coffee fertilization through basically imported formulations in the form of potassium chloride. An alternative to make production systems more sustainable would be obtaining cultivars more efficient in the use of this nutrient. This study aimed to evaluate the genetic diversity among 20 cultivars of coffee, in conditions of low availability of potassium to identify the best combinations for composing future populations to be used in breeding programs. The experiment was arranged in a randomized block design with three replications of nutrient solution. Agronomic characteristics and efficiencies of rooting, absorption, translocation, biomass production and potassium utilization were evaluated. The clustering analysis was based on the unweighted pair group method with arithmetic mean clustering algorithm (UPGMA) and canonical variables. Variability was observed for most treatments. The multivariate procedures produced similar discrimination of genotypes, with the formation of five groups. Hybridizations between the cultivar Icatu Precoce IAC 3283 with cultivars Catuaí Amarelo IAC 62, Araponga MG1, Caturra Vermelho IAC 477, Catuaí Vermelho IAC 15, Rubi MG 1192 and Catucaí 785/15, and between the cultivar Tupi IAC 1669-33 with cultivars Icatu Vermelho IAC 4045, Acaiá Cerrado MG 1474 and Oeiras MG 6851 are the most promising for obtaining segregating populations or heterotic hybrids in breeding programs aiming more efficiency in potassium utilization.

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Este trabalho teve como objetivo comparar a adaptabilidade e estabilidade de cultivares de café quanto à média de produtividade anual e de biênios, pelo método de EBERHART & RUSSEL (1996), e selecionar cultivares de café para o cultivo orgânico em Minas Gerais. Os experimentos foram conduzidos em três locais, em delineamento de blocos casualizados com trinta genótipos e três repetições. Uma análise se baseou na produtividade média anual de quatro colheitas (2005/2006, 2006/2007, 2007/2008 e 2008/2009) com o total de doze ambientes. A outra análise considerou a média de dois biênios (2005/2006 e 2006/2007; 2007/2008 e 2008/2009) com o total de seis ambientes. A análise em que se considerou a média da produtividade do biênio apresentou redução expressiva do coeficiente de variação ambiental. Por isso, foi possível identificar mais cultivares com adaptabilidade e estabilidade para o cultivo orgânico. Conclui-se que a análise de adaptabilidade e estabilidade com base na produtividade de biênio é mais segura para a seleção de cultivares. Considerando essa premissa, as cultivares 'Catucaí Vermelho 36/6', 'Catuaí Vermelho IAC 15' e 'Siriema 842' são indicadas somente para os ambientes favoráveis. As cultivares 'Sabiá 708', 'IBC Palma 1', 'Catucaí Amarelo 24/137', 'Oeiras MG 6851' e as linhagens H518 e H514 são indicadas para o cultivo orgânico em locais com ambientes similares aos avaliados em Minas Gerais.

In mountainous regions, the amount of time that the land is exposed to the sun is one of the factors that influence the productive potential of legumes. The aim of our study was to evaluate, for two different terrain aspects under sun exposure faces, the production of green and dry matter, as well as the nutrient accumulation in the aerial part of legumes and the coffee productivity. The northwestfacing terrain is at 950 m altitude, the average annual temperature is 18.0 °C, the average rainfall is 1320 mm and the average daily solar exposure is 9.1 h. The south-facing terrain is at 690 m altitude, the average annual temperature is 14.0 °C, the average rainfall is 1277 mm and the average daily solar exposure is 6.8 h.The main soil of both terrains are a clayey dystrophic Red-Yellow Oxisol. The experimental design was inrandomized blocks with a 2 x 8 factorial scheme (two different terrain aspects and 8 types of green manure), and four replications were performed.On the northwest-facing terrain, D. lablab, C. spectabilis, and S. deeringianum had the highest amount of dry matter (3.31, 2.98, and 2.85 Mg ha-1 , respectively) and nitrogen accumulation (111.54, 91.83, and 91.51 kg ha-1 , respectively).The most promising legumes on the south-facing terrain (lower altitude, lower temperature, and lower incidence of light) for dry matter productions were C.

ABSTRACT:The evaluation of the decomposition of plant residues added to the soil for green manures allows better understanding of the nutrient supply for coffee. The aim of this study was to determine the decomposition constant (κ), the halflifetime (t 1/2 ) and the nutrient release from legumes and spontaneous plant under two environmental conditions of sun-exposure in the Zona da Mata of Minas Gerais state. The experimental unit located in Araponga has northwest sun-exposure face and the experimental unit located in Pedra Dourada has the south sun-exposure face. The experimental design was a randomized block in a 2 x 8 x 6 factorial (two environments facing sun-exposure, 8 green manures and 6 residue decomposition assessment times), with four replicates. The results showed that κ and t 1/2 of the evaluated green manures did not differ between the northwestern face (highest altitude, temperature and incident light) and the south face (lower altitude, temperature and incident light). The κ difference obtained between all green manures was due to its chemical and biochemical composition. At the end of the evaluation period of 240 days an average of 62,3 and 63,1% N; 99,4 and 99,5% P and 92,8 and 93,3% K were released from the green manures of the northwest and south faces respectively. The most promising legume in the total nutrients release on the northwest face was D. lablab with 74,6; 10,9 and 69,0 kg ha -1 of N, P and K, respectively. To the south face the most promising legume was C. spectabilis with 69,1; 10,4 and 47,9 kg ha -1 of N, P and K, respectively.Index Term: Nutrient cycling, plant residues, polyphenols, ratio C/N, plant coffee. LIBERAÇÃO DE NUTRIENTES DE ADUBOS VERDES SOBRE DIFERENTES FACES DE EXPOSIÇÃO SOLAR RESUMO:A avaliação da decomposição dos resíduos vegetais adicionados ao solo por adubos verdes permite melhor compreensão do fornecimento de nutrientes para o cafeeiro. O objetivo foi determinar a constante de decomposição (κ), o tempo de meia vida (t 1/2 ) e a liberação de nutrientes de leguminosas sob duas condições ambientais de face de exposição solar na Zona da Mata de Minas Gerais. A unidade experimental localizada em Araponga possui face de exposição solar noroeste, já a unidade experimental localizada em Pedra Dourada possui face de exposição solar sul. O delineamento experimental foi em blocos casualizados, em fatorial 2 x 8 x 6 (dois ambientes sob face de exposição solar, 8 adubos verdes e 6 tempos de avaliações da decomposição dos resíduos), com 4 repetições. Os resultados mostraram que a κ e t 1/2 dos adubos verdes não diferiram entre a face noroeste (maior altitude, temperatura e incidência de luz) e a face sul (menor altitude, temperatura e incidência de luz). A diferença obtida na κ entre os adubos verdes deve-se a sua composição química e bioquímica.Ao final de 240 dias de decomposição foi liberado em média para o cafeeiro 62,3 e 63,1% do N; 99,4 e 99,5 % do P e 92,8 e 93,3% do K no ambiente sob face noroeste e sob face sul, respectivamente. A leguminosa mais promissora na lib...

Abstract:This study aimed to identify promising arabica coffee genotypes for organic systems. The experiments were arranged in a randomized block design, with 30 genotypes and three replications. The adaptability and stability analysis was carried out using the modified centroid method, considering the mean yield of two biennia