Revista Brasileira de Ciência do Solo
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/9883
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Item Nitrate reductase and glutamine synthetase activity in coffee leaves during fruit development(Sociedade Brasileira de Ciência do Solo, 2009-03) Reis, Andre Rodrigues; Favarin, José Laércio; Gallo, Luiz Antônio; Malavolta, Eurípedes; Moraes, Milton Ferreira; Lavres Junior, JoséNitrate reductase is the first enzyme in the pathway of nitrate reduction by plants, followed by glutamine synthetase, which incorporates ammonia to glutamine. The purpose of this study was to evaluate the nitrate reductase and glutamine synthetase activity, total soluble protein content, N and Ni content in coffee leaves during fruit development under field conditions to establish new informations to help assess the N nutritional status and fertilizer management. The experimental design was in randomized complete blocks, arranged in a 3 x 6 factorial design, with five replications. The treatments consisted of 3 N rates (0 - control, 150 and 300 kg ha -1 ) and six evaluation periods (January, February, March, April, May, and June) in six-year-old coffee (Coffea arabica L.) plants of Catuaí Vermelho IAC 44 cv. The nitrate reductase and glutamine synthetase activities, leaf soluble protein, and N concentrations increased linearly with the N rates. During fruit development, the enzyme activity, leaf soluble protein and N content decreased, due to the leaf senescence process caused by nutrient mobilization to other organs, e.g, to the berries. Leaf Ni increased during fruit development. Beans and raisin-fruits of plants well-supplied with N had higher Ni contents. Enzyme activities, total leaf N and leaf soluble protein, evaluated during the green fruit stage in March, were significantly correlated with coffee yield. These variables can therefore be useful for an early assessment of the coffee N nutritional status as well as coffee yield and N fertilization management.Item Teor de zinco no café como variável da disponibilidade no solo e extrator(Sociedade Brasileira de Ciência do Solo, 2007-09) Favarin, José Laércio; Vitti, Godofredo Cesar; Dourado Neto, Durval; Favarin Junior, José Laércio; Salgado, Paula RodriguesNo Brasil são cultivadas duas espécies de café: Coffea arabica L. e Coffea canephora Pierre. As pesquisas com adubação com Zn têm sido feitas, principalmente, com cultivares arábica. Esta pesquisa foi realizada com objetivo de obter a relação entre os teores de Zn disponível pelos extratores DTPA e Mehlich-1 em plantas de C. arabica cv. Mundo Novo IAC 379-19 (MN) e C. canephora cv. Apoatã IAC 2258 (AP), bem como em plantas enxertadas (MN/AP). Os tratamentos foram obtidos pelo fatorial 3 x 3, entre materiais genéticos (MN, AP e MN/AP) e doses de Zn (0, 10 e 20 mg dm -3 ). O teor de Zn na planta, em relação à disponibilidade do nutriente no solo, independentemente dos extratores, varia com a espécie e a combinação entre espécies e a enxertia. Os extratores DTPA e Mehlich-1 apresentaram eficiência semelhante para determinar o teor de Zn disponível no solo, independentemente da espécie (C. arabica e C. canephora). A absorção máxima de Zn ocorreu com teor disponível de 5,6 mg dm -3 (DTPA) e 6,6 mg dm -3 (Mehlich-1) para a cultivar Mundo Novo (C. arabica). Para a espécie C. canephora cv. Apoatã e nas plantas enxertadas (MN/AP), não foi estabelecida a máxima absorção de Zn, independentemente dos extratores, nas doses utilizadas no experimento.Item Fertilizer 15N balance in a coffee cropping system: a case study in Brazil(Sociedade Brasileira de Ciência do Solo, 2008-07) Fenilli, Tatiele Anete Bergamo; Reichardt, Klaus; Favarin, José Laércio; Bacchi, Osny Oliveira Santos; Silva, Adriana Lúcia; Timm, Luis CarlosKnowledge about the fate of fertilizer nitrogen in agricultural systems is essential for the improvement of management practices in order to maximize nitrogen (N) recovery by the crop and reduce N losses from the system to a minimum. This study involves fertilizer management practices using the 15 N isotope label applied in a single rate to determine the fertilizer-N balance in a particular soil-coffee-atmosphere system and to deepen the understanding of N plant dynamics. Five replicates consisting of plots of about 120 plants each were randomly defined within a 0.2 ha coffee plantation planted in 2001, in Piracicaba, SP, Brazil. Nine plants of each plot were separated in sub-plots for the 15 N balance studies and treated with N rates of 280 and 350 kg ha -1 during 2003/2004 and 2004/ 2005, respectively, both of them as ammonium sulfate enriched to a 15 N abundance of 2.072 atom %. Plant shoots were considered as separate parts: the orthotropic central branch, productive branches, leaves of productive branches, vegetative branches, leaves of vegetative branches and fruit. Litter, consisting of dead leaves accumulated below the plant canopy, was measured by the difference between leaves at harvest and at the beginning of the following flowering. Roots and soil were sampled down to a depth of 1.0 at intervals of 0.2 m. Samples from the isotopic sub-plots were used to evaluate total N and 15 N, and plants outside sub-plots were used to evaluate dry matter. Volatilization losses of NH 3 were estimated using special collectors. Leaching of fertilizer-N was estimated from deep drainage water fluxes and 15 N concentrations of the soil solution at 1 m soil depth. At the end of the 2-year evaluation, the recovery of 15 N applied as ammonium sulfate was 19.1 % in aerial plant parts, 9.4 % in the roots, 23.8 % in the litter, 26.3 % in the fruit and 12.6 % remaining in the 0–1.0 m soil profile. Annual leaching and volatilization losses were very small (2.0 % and 0.9 %, respectively). After two years, only 6.2 % N were missing in the balance (100 %) which can be attributed to other non-estimated compartments and experimental errors. Results show that an enrichment of only 2 % atom 15 N allows the study of the partition of fertilizer-N in a perennial crop such as coffee during a period of two years.