Browsing by Author "Martins, A."
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- Decomposição de folhada de quatro espécies florestais no Norte de Portugal: taxa de decomposição e evolução da composição estrutural e do teor em nutrientesPublication . Madeira, Manuel; Martins, A.; Raimundo, F.; Carvalho, L.Decomposition of senescent leaves of Castanea sativa (CS), and needles of Pinus pinaster (PP), Pinus nigra (PN) and Pseu- dotsuga menziesii (PM) was studied during 3.1 to 3.5 years through weight loss and nu- trient concentration evolution, using the litter bag technique, whereas the variation of chemical structural compounds was followed during 391 to 518 days. The highest contents of N were measured in PM and CS (respectively 14.5 and 12.1 g kg-1), which showed lower C/N ratio (39.0, 46.8) than PN and PP (122.2 and 147.7, respectively). Highest contents of Ca (9.1 g kg-1) and of alcohol and water soluble compounds (384 against 95 to 160 g kg-1 to other species) were measured in PM needles, which also showed the lowest contents of holocelulose (253 g kg-1 against about 500 g kg-1 in the other species). The lignin Klason/N ratio decreased according to PP>PN>PM>CS, (71.2, 58.3, 20.5 and 20.3 respectively), and the holocelulose/lignin ratio ranged from 0.9 (PM) to 1.9-2.1 in the other species. Annual decay rates, according to the negative exponential model, were ordered according to CS>PN>PM>PP (respectively -0.35, -0.27, -0.19 and -0.16), but with higher values during the first year for CS (-0.60) and PM (0.31). Soluble compounds and hemicelulose strongly decreased during the decomposition period, while lignin and cellulose amounts showed a low variability, mainly in PP and PM needles. Nutrient amounts decreased during the decomposition process, but remaining quantities for N (41 to 121 %) and P (33 to 104 %) were higher than those estimated for K, Ca and Mg (respectively 17 to 65%, 30 to 60 % and 18 to59%). A strong decreasing of C/N ratio was observed especially for PP and PN, where reached 53.2 and 47.1.
- Effects of soil management practices and irrigation on plant water relations and productivity of chestnut stands under Mediterranean conditionsPublication . Martins, A.; Raimundo, F.; Borges, O.; Linhares, I.; Sousa, V.; Coutinho, J.P.; Gomes-Laranjo, J.; Madeira, ManuelThe effects of different soil management practices and irrigation on plant water relations, physiological response and productivity of chestnut stands in Northeastern Portugal were assessed during four growing seasons (2003 to 2006). Treatments were: conventional soil tillage up to 15–20 cm depth with a tine cultivator thrice a year (CT); no tillage with spontaneous herbaceous vegetation (NV); no tillage with rainfed seeded pasture (NP); and no tillage with irrigated seeded pasture (NIP). Results suggest that soil water availability was the most critical parameter for chestnut productivity over the study period. In all treatments, high predawn leaf water potentials (-0.40 to -0.55 MPa) were observed during the dry seasons of 2003, 2004 and 2006, showing no critical conditions for plant productivity, which is ascribed to water availability in deep soil layers. In contrast, in 2005, an extremely dry year, water potentials decreased and varied from -1.46 to - 1.72 MPa in late summer, showing unfavourable conditions for nut production. Maintenance of spontaneous herbaceous vegetation without irrigation enhanced productivity of chestnut stands as compared with the conventional tillage system and the no tillage system with seeded pasture. Productivity in the soil watering system (NIP treatment) was not significantly different from that observed in the NV treatment. Therefore, studies on the irrigation strategy should be developed, in order to increase its efficiency especially in stands with young trees
- A measure to evaluate the sensitivity to genotype-by-environment interaction in 6 grapevine clonesPublication . Gonçalves, Elsa; Carrasquinho, I.; Martins, A.Background and Aims: The development of an efficient clonal selection process requires 25 the study of genotype-by-environment (G×E) interaction. This work aims to evaluate the 26 variability of the G×E interaction among genotypes and to identify the less sensitive ones. 27 Methods and Results: The approach involves the fitting of mixed models to yield data taking 28 into account the correlation induced by the repeated measurements of the same plot over the 29 years. A measure for comparative evaluation of the G×E interaction among genotypes is 30 proposed (Interaction Sensitivity, IS), based on the variance of the values of the empirical best 31 linear unbiased predictors of G×E interaction effects across environments. In all cases studied 32 significant G×E interaction variability was found, and the proposed measure to rank the 33 sensitivity to G×E interaction varied widely among genotypes. 34 Conclusions: The existence of a common contribution shared by all observations made in the 35 same plot was detected, independently of the lag between years. The proposed measure to 36 rank the sensitivity to G×E interaction permitted identification of stable genotypes. 37 Significance of the Study: This work studied G×E interaction problem in the context of 38 grapevine and proposes a measure for the comparative evaluation of the G×E interaction 39 among genotypes
- New national and regional bryophyte records, 63Publication . Ellis, L. T.; Afonina, O. M.; Czernyadjeva, I. V.; Konoreva, L. A.; Potemkin, A. D.; Kotkova, V. M.; Alataş, M.; Blom, H. H.; Boiko, M.; Cabral, R. A.; Jimenez, S.; Dagnino, D.; Turcato, C.; Minuto, L.; Erzberger, P.; Ezer, T.; Galanina, O. V.; Hodgetts, N.; Ignatov, M. S.; Ignatova, E. A.; Kazanovsky, S. G.; Kiebacher, T.; Köckinger, H.; Korolkova, E. O.; Larraín, J.; Maksimov, A. I.; Maity, D.; Martins, A.; Sim-Sim, M.; Monteiro, F.; Catarino, L.; Medina, R.; Nobis, M.; Nowak, A.; Ochyra, R.; Parnikoza, I.; Ivanets, V.; Plášek, V.; Philippe, M.; Saha, P.; Aziz, Md. N.; Shkurko, A. V.; Ştefănuţ, S.; Suárez, G. M.; Uygur, A.; Erkul, K.; Wierzgoń, M.; Graulich, A.
- Produção de castanha e de folhada e concentração de nutrientes nas folhas de soutos submetidos a diferentes sistemas de mobilização do soloPublication . Madeira, Manuel; Raimundo, F.; Pires, A.L.; Fonseca, S.; Martins, A.The effects of several soil management systems on litterfall production (leaves, burs, chestnuts and inflorescences) and leaf nutrient concentration were studied in a 50 year-old chestnut grove, located in North-east Portugal. The experimental trial was installed in the beginning of 1996 and it was monitored for eight years. The treatments were: chisel plow (average depth 15 cm), which corresponds to the traditional tillage (MT); disc harrowing tillage, up to 7 cm depth (GD); rainfed seeded pasture, with leguminous and grasses species (PS); and no-tillage with spontaneous herbaceous vegetation (NM). Results, between 1999 and 2004, showed that the average production of litterfall (leaves, burs, chestnuts and inflorescences), was greatest in NM treatment (755 g m-2), followed by the PS (729 g m-2), GD (708 g m-2) and MT (627 g m-2) treatment, although the differences were not significant. During that period, the burs (36.7%) made the greatest contribution to total litterfall, followed by the leaves (32.5%), chestnuts (24.7%) and inflorescences (6.1%). The chestnut production was significantly lower in the MT (133 g m-2) treatment than in the NM (193 g m-2) and PS (191 g m-2). The N, P and Mg content in leaves were significantly lower in MT treatment than in the others; the K content was significantly lower in MT and PS treatments than in GD; the Ca concentration was significantly lower in MT treatment than in GD and PS. Management practices alternatives to the traditional soil tillage revealed to be more appropriated to enhance productivity of chestnut groves and to reduce production costs.
- Relatório técnico sobre o Programa de Monitorização dos Ecossistemas Terrestre e Estuarino na Envolvente à CTRSU da S. João da TalhaPublication . Brotas, Vanda; Sim-Sim, Manuela; Gordo, Leonel; Bloisé, C.; Garcia, César; Martins, A.; Neves, Ana; Tracana, A.A poluição atmosférica é considerada um grave problema de saúde pública e admite-se que um terço dos moradores das cidades Europeias esteja exposto a concentrações excessivas de matérias poluentes. A monitorização ambiental desempenha assim um papel fundamental para o acompanhamento e deteção de possíveis alterações ambientais em complemento com os métodos convencionais. Embora muitos países tenham realizado progressos para reduzir a poluição, em muitas regiões as concentrações ainda estão acima dos limites legais e recomendados para proteger a saúde dos cidadãos europeus sendo de extrema importância que se efetue a caracterização e monitorização ambiental, nomeadamente em locais com forte pressão humana e industrial. Na região envolvente à CTRSU de São João da Talha estabeleceu-se desde 1998 um programa de monitorização, pouco habitual a nível nacional e mesmo internacional, que permitiu avaliar os efeitos da poluição sobre os ecossistemas, usando diferentes grupos de organismos terrestes e aquáticos. O primeiro ano de monitorização teve como principal objetivo a criação de valores de referência, correspondendo ao ano anterior à construção da CTRSU; todos os dados obtidos posteriormente foram comparados com os valores de referência. Tem-se hoje em dia uma série temporal de dados desde 1998, que constitui um valioso património sobre o conhecimento dos ecossistemas terrestre e estuarino na área circundante à CTRSU e a sua relação com uma zona fortemente industrializada onde habitam milhares de cidadãos. Estas bases de dados (registo fotográfico, espécies, habitats, poluentes) são de grande importância técnica e científica sendo fundamental dar continuidade a estudos como o “Programa de Monitorização dos Ecossistemas Terrestre e Estuarino na Envolvente à CTRSU de S. João da Talha”.