Browsing by Author "Rosa, A."
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- Cultura em substratos orgânicos de GerberasPublication . Rosa, A.; Lima Costa, Maria Emília; Monteiro, Ileana Pardal; Reis, M.; Cabral Silva, R.; Caço, J.; Osório, JúlioO cultivo sem solo de Gerbera (Gerbera jamesonii) tem-se revelado uma técnica adequada, permitindo ultrapassar alguns dos problemas surgidos na cultura tradicional, em solo. No âmbito do Projecto Agro no197 “Cultura sem solo com reutilização do efluente, em estufa com controle ambiental melhorado”, desenvolvido pela Direcçao Regional de Agricultura do Algarve, pelo Cento de Hidroponia e Utilidades Hortofrutícolas e pela Universidade do Algarve testou-se o cultivo de gerbera em substratos alternativos, no Centro de Experimentação Hortofrutícola do Patacão. Cultivaram-se quatro cultivares de gerbera: Monika, Junkfrau, Venice e Lady, em substratos preparados à base de resíduos orgânicos: casca de pinho e bagaço de uva, durante dois anos consecutivos. Os resultados obtidos sugerem que os substratos testados apresentam características adequadas à cultura da gerbera, tendo-se obtido as produções mais elevadas com o bagaço de uva compostado e a casca de pinho não compostada. Das cv. em estudo, no 1o ano a Venice apresentou o maior número de flores comercializáveis, seguida da Lady com mais flores na classe Extra. No 2o ano, a produção foi mais equilibrada entre as cultivares, sendo de registar o aumento da produção em duas cv., Junkfrau e Monica.
- Export of dissolved and suspended matter from the main estuaries in South Portugal during winter conditionsPublication . Correia, C.; Torres, A. F.; Rosa, A.; Cravo, Alexandra; Jacob, J.; de Oliveira Junior, L.; Garel, ErwanEstuaries are essential drivers of primary productivity in coastal waters through the export of dissolved and suspended material. This study aims at quantifying this fertilization process at the two main estuaries in South Portugal, where typical low river discharge conditions occur in winter due to strong flow regulation by upstream dams and seldom-local rain events. Data were collected across the channel of the lower Arade (10/01/2018) and Guadiana (04/02/2019) estuaries during a semi-diurnal tidal cycle with intermediate tidal ranges (1.5 m and 2.2 m, respectively). Current velocity records were completed with hourly water quality measurements (temperature, salinity, pH, dissolved oxygen, suspended solids, chlorophyll a and nutrients) for determination of the along channel fluxes and residual mass transport of dissolved and suspended matter across the channel sections. The results show that the two estuaries were characterized by distinct water circulation patterns and tidal properties (e.g., standing wave at the Arade, mixed wave at the Guadiana). The concentration of dissolved and particulate matter displayed a general similar anti-phase pattern of variations with tidal height at both sites. The corresponding fluxes were generally strongest during the ebb phase. Thus, the residual mass transport was seaward, indicating that both estuaries contribute to fertilize adjacent coastal waters by exporting nutrients (order of kg), chlorophyll a (order of kg) and suspended solids (up to tons). Moreover, transport differences at both estuaries reflect specific discharge flow and environmental conditions as well as contamination sources close to the study areas. In particular, the signatures of a discharge event from a water treatment plant at the Arade and of coastal upwelling at the Guadiana were identified.
- Grape marc and pine bark composts in soilless culturePublication . Reis, Mário; Inácio, H.; Rosa, A.; Caço, J.; Monteiro, A.Grape marc and pine bark were composted in windrows for a period of three months, supplied with 1kg of nitrogen (urea) m-3 . Grape marc compost (GMC) and pine bark compost (PBC) had, respectively, 84.3 and 85.0% v/v total pore space, 10.3 and 1.2 % v/v easily available water, 59% and 32.0% v/v air capacity, 53.0 and 25.9 % v/v total water content. Rockwool (Grodan®) has higher total pore space (96.7% v/v) and total water content (81.8% v/v) but lower air capacity (14.9% v/v). Rockwool, GMC and PBC were compared as plant substrates for growing a greenhouse tomato crop. Plants of tomato 'Sinatra' (Sluis & Groot, Holland) were grown on 15 L rockwool slabs and on 30 L bags of compost, in a heated plastic greenhouse, from December to June. A nutrient solution with the same chemical composition was used for the three substrates, varying the composition according to plant development. The irrigation period was pre-set and the irrigation frequency was controlled by solar radiation. Fruits were collected twice a week, from March to June, weighted and selected. There were no significant differences in yield and fruit quality between substrates. Commercial yield on GMC was 16.6 kg m-2 , on PBC 15.5 kg m-2 and on RW 16.2 kg m-2 . Temperature in composts showed a higher resistance to daily variation. We observed a good root development after the crop, specially in GMC. Positive changes in the physical properties of composts occurred during the growing period, particularly the increase in water content of GMC and in aeration capacity of PBC, indicating a potential re-using the composts, which was lately confirmed by growing a second and third tomato crop, on GMC (open and closed systems1) and on PBC (open system2).
- Grape marc compost as an alternative growing media for greenhouse tomatoPublication . Reis, Mário; Inácio, H.; Rosa, A.; Caço, J.; Monteiro, A.The present work compares grape marc compost (GMC) with rockwool (RW) as a substrate for greenhouse tomato production in open and closed systems. GMC exhibited a high total pore space (84.3 v/v) and air capacity (59.0% v/v) but a low easily available water (1.2% v/v). Most of the total water content (25.9% v/v) of GMC was retained under a tension above 100 cm of water column (23.7% v/v). Rockwool (Grodan) has a higher total pore space (96.7%) and total water retention (81.8%), most of it (77.8%) retained between 10 and 100 cm of water column, but a lower air capacity (14.9%). Tomato 'Sinatra' (Sluis & Groot, Holland) was grown on 15 L rockwool slabs and on 30 L compost bags, in a heated plastic greenhouse, from November to June, in two consecutive years. In the first year (1997/98) tomato production was compared on RW (open and closed systems) and on GMC (open system). No significant differences were observed in commercial yield on RW (15.6 kg m-2 and 16.2 kg m-2, respectively in closed and open system) and on GMC (16.6 kg m-2, open system). In the second year (1998/99) RW and GMC were used on a closed system and tomato yield was compared using new substrates (1st crop) and substrate from the previous year (2nd crop). Commercial yield reached the standard of the region and no significant differences in between RW and GMC, and between 1st crop substrate (new substrate) and 2nd crop substrate (reused substrate). The results show that grape marc compost can be used as a rockwool substitute for greenhouse tomato production in open and in closed systems.