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Torres, Maria Odete

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0000-0002-4905-710X

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2014 - 20163
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  • A preliminary spatial-temporal study of some soil characteristics in the calcareous massif of Sicó, Portugal
    Publication . Torres, Maria Odete; Neves, Manuela
    The mountainous massif of Sicó, in the centre of Portugal, is an extensive area composed of calcareous Jurassic formations. Hillside calcareous soils, with high pH, present chemical restrictions to support plant growth and are subjected to important erosion processes leading to their degradation if not protected by vegetation. In a first year of study some soil physicochemical characteristics have been measured in some geo-referenced locations of a larger design experiment and an exploratory spatial analysis has been performed. The objective of this study was to present some suggestions in order to give sustainable phosphorus fertiliser recommendations aiming to establish pastures in these soils and thus support traditional livestock activity. Ten years apart, those soil characteristics have been measured again in the same locations and comparisions have been made. The objective was to understand the variability of the soil properties under study in order to better adequate the fertiliser soil management regarding the area restoration
    2016Journal article Open access Show more
  • Underestimated role of legume roots for soil N fertility
    Publication . Carranca, Corina; Torres, Maria Odete; Madeira, Manuel
    Nitrogen (N) is a major fertilizing element for plants. The distribution of N in legumes is influencing the efficiency of the next crop. Nitrogen storage in legumes is actually estimated by N fixation in shoots, whereas there is little knowledge on the contribution of roots and nodules to legume N and soil N. Here, we studied the contribution of roots and nodules of grain and pasture legumes to plant N and soil N in Mediterranean fields. Experiments were run under rainfed conditions for a 2-year period in three regions of Portugal. Entire plants including top plant and visible roots and nodules were sampled at the end of the growing seasons for grain legumes, sweet and yellow lupine, and over two harvests in case of pastures. N2 fixation was measured for grain legumes and pasture legumes using 15N tracing. Our results show that aboveground N concentration did not vary among legumes, but differed in the belowground tissues. Field studies show that 7–11%of total legume N was associated with roots and nodules. Data also show an allocation of 11– 14 kg N fixed t−1 belowground dry matter in indeterminate legumes, which represents half the amount of total aboveground plant. This finding demonstrates that investigation relying only on shoot Nunderestimates the role of legumes for soil N fertility
    2015Journal article Open access Show more
  • Infestantes de Pastagens. Plantas tóxicas e agressivas
    Publication . Vasconcelos, Teresa; Monteiro, Ana; Torres, Maria Odete; Sá, Gizela; Forte, Paulo
    As características mediterrâneas de Portugal permitem que a produção animal possa ser feita à custa da vegetação de incultos, pousios, matas, restolhos, pastagens naturais e seminaturais, a que se junta geralmente palha, feno e por vezes silagem. Todavia, pastagens degradadas tornam-se pouco produtivas o que dificulta a intensificação do uso das pastagem e a busca de uma pecuária mais produtiva. As infestantes, também designadas por ervas daninhas, são dos principais fatores que contribuem para a baixa produtividade das pastagens. Assim, a gestão das infestantes é um problema com que se depara constantemente qualquer agricultor, principalmente se os animais são criados e mantidos quase que exclusivamente em pastoreio. O problema das infestantes está diretamente ligado à grande capacidade que estas têm em competir com gramíneas e leguminosas espontâneas ou cultivadas de elevado valor nutricional. Por exemplo, as sementes das infestantes podem germinar ao longo do ano, dificultando o controlo por apresentarem uma sucessão de gerações durante o ano. Além disso, uma vez germinadas, as suas plântulas apresentam, quase sempre, um crescimento mais rápido do que as das espécies pratenses, desenvolvendo em particular o sistema radicular. Isto proporciona-lhe maior facilidade para captar água e nutrientes durante os períodos críticos e aumentar a sua área foliar rapidamente. Acrescenta-se ainda que diversas espécies de infestantes produzem sementes com dormência, o que lhes confere uma capacidade germinativa durante vários de anos. A facilidade que as infestantes têm em se adaptar às mais diferentes condições edafoclimáticas (solo, clima, etc.) também facilita a sua competição com as espécies pratenses
    2014Book Restricted access Show more