O banco de sementes do solo: uma ferramenta para a avaliação do estado de conservação dos charcos temporários mediterrânicos

Os Charcos temporários mediterrânicos (3170*) são habitats prioritários devido à enorme biodiversidade que albergam e ao grau de ameaça sob o qual que se encontram. A singularidade deste habitat resulta da coexistência de diferentes comunidades de plantas no mesmo espaço mas em períodos de tempo diferentes, o que é viabilizado pela existência de bancos de sementes abundantes e diversificados. A avaliação da composição específica e abundância do banco de sementes do solo permitiu determinar a distribuição espacial das sementes e o potencial de recuperação dos charcos. Com esta avaliação concluiu-se que existe uma maior riqueza específica nas cinturas externa e média dos charcos do que na cintura interna. Concluiu-se também que o conhecimento do banco de sementes dos charcos pode contribuir para a definição de estratégias de gestão/recuperação dos charcos, nomeadamente daqueles que possuem grau de conservação intermédio, funcionando como um valioso instrumento de gestão; The soil seed bank - a tool for assessing the conservation status of Mediterranean temporary ponds Abstract: Mediterranean temporary ponds (3170*) are priority habitats due to the huge biodiversity they shelter and because they are menaced. The uniqueness of this habitat results from the coexistence of different plant communities in the same space at different time periods, what is allowed by the existence of abundant and diversified soil seed banks. The assessment of the specific composition and abundance of soil seed bank, made possible to ascertain the spatial distribution of seeds within ponds and their recovery potential. This assessment showed that there is more specific richness in intermediate and outer belts of ponds than in the inner belt. It also showed how valuable can this information be regarding the design of management or recovery strategies for ponds, particularly for those with intermediate degree of conservation.

Influence of Soil and Irrigation Management on the Quality of Seedless Crimson Table Grapes

The market for table grapes is moving into mass production of specialty seed-less grapes in covered areas, aiming at obtaining premium prices with early or late production of high quality products. Production of quality seedless grapes is not straightforward since it is requires the correct combination of various independent characteristics, such as color, sugars, size and quantity at the right moment for successful harvesting and marketing. The present study was carried out at the two largest Portuguese producers located in Alentejo, and has the objective of studying the effect of irrigation management strategies and two different soils on the various relevant parameters for successful production and marketing. The management strategies were the application of ten day stress at the end of the cycle, in order to promote early maturing of the grapes. Three different timings of the stress were applied. Soil moisture, sap flow, bark thickness, as well as leaf water potential, stomatal conductance and chlorophyll content were measured regularly during the production season. The results indicate that the roots explore a rather large soil volume and the plants can successfully withstand reasonable periods of drought without significant changes to the plant physiology. Additionally late rains can mask the effect of any farmer applied drought and invalidate any farmer induced stress to the plants. Water-logged soils tend to cause early onset of maturity, but cause the ripening stage to extend over a longer period of time, and thus, in effect result in a delay in the harvest date. Topography also has some effect on the ripening, since hot air tends to accumulate under the plastic at the higher areas of the field. This work is funded by PRODER, 4.1, within the scope of project MORECRIMSON

Impacts of crop level, soil and irrigation management in grape berries of cv ‘Trincadeira’ (Vitis vinifera L.)

Berry size and crop yield are widely recognized as important factors that contribute to wine quality. The final berry size indirectly affects the phenolic concentration of the wine due to skin surface-to-berry volume ratio. The effects of different irrigation levels, soil management and plant crop level on growth of ‘Trincadeira’ berries were studied. In order to test the influence of different irrigation levels (rainfed, pre-veraison and post-veraison), different soil management (tillage and natural cover crops) and different plant crop levels (8 and 16 clusters per vine), leaf water potential, skin anthocyanin, polyphenols, berry skin and seed fresh weight were measured in fruits. The segregation of berries into three different berry classes: small, medium and large, allowed to identify different levels of contribution of soil management and irrigation level into berry, skin and seeds ratios. As expected, higher water availability due to irrigation and soil tillage management during berry development induced an increase in berry flesh weight and this was more evident in larger berries; however, berry skin and seed fresh weight remained unchanged. Also, anthocyanins did not show significant differences.