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Parra S.,Junta de Andalucia | Hueso J.J.,Estacion Experimental Fundacion Cajamar | Cuevas J.,University of Almeria
Acta Horticulturae | Year: 2013

The European Union, under pressure from the World Trade Organisation to achieve substantial changes, has resolved to modify the Common Agricultural Policy, and progressively liberalize EU market access to non-member states. In this scenario, only the most competitive agents can attain success. Mediterranean fruit crops face these challenges. In this regard, Spain is the second world leading producer of loquat, and accounts for 80% of exports worldwide. Nevertheless, labour cost represents 75% of the total costs for this crop and, in this context, loquat ranks first among horticultural and fruit crops in Spain. To date, this labour cost has been found difficult to reduce (mainly due to the heavy requirements for pruning, fruit thinning and harvesting) - hence increasing orchard density appears to be a promising way to increase loquat profitability. In this study, the profitability of a traditional Spanish orchard, 540 trees per ha, has been compared to that of an ultrahigh density planting (2353 trees per ha). Initial results show that mean yield is greater in an ultrahigh density orchard (31 versus 25 tonnes per hectare), even during the first years of cropping, and that, although both kinds of orchard are profitable (Net Present Value above 240,000 € considering usual parameters), the time required to reach this threshold is 65% less in an ultrahigh density orchard. Sustainability of ultrahigh density orchards is yet to be ascertained, especially regarding orchard longevity. Our results can help to reduce this uncertainty. © 2013 ISHS.

Camacho-Rodriguez J.,University of Almeria | Gonzalez-Cespedes A.M.,Estacion Experimental Fundacion Cajamar | Ceron-Garcia M.C.,University of Almeria | Fernandez-Sevilla J.M.,University of Almeria | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2014

Different pilot-scale outdoor photobioreactors using medium recycling were operated in a greenhouse under different environmental conditions and the growth rates (0.1 to 0.5 day-1) obtained evaluated in order to compare them with traditional systems used in aquaculture. The annualized volumetric growth rate for Nannochloropsis gaditana was 0.26 g l-1 day-1 (peak 0.4 g l-1 day-1) at 0.4 day-1 in a 5-cm wide flat-panel bioreactor (FP-PBR). The biomass productivity achieved in this reactor was 10-fold higher than in traditional reactors, reaching values of 28% and 45% dry weight (d.w.) of lipids and proteins, respectively, with a 4.3% (d.w.) content of eicosapentaenoic acid (EPA). A model for predicting EPA productivity from N. gaditana cultures that takes into account the existence of photolimitation and photoinhibition of growth under outdoor conditions is presented. The effect of temperature and average irradiance on EPA content is also studied. The maximum EPA productivity attained is 30 mg l-1 day-1. © Springer-Verlag 2013.

Acien F.G.,University of Almeria | Fernandez J.M.,University of Almeria | Magan J.J.,Estacion Experimental Fundacion Cajamar | Molina E.,University of Almeria
Biotechnology Advances | Year: 2012

The cost analysis of a real facility for the production of high value microalgae biomass is presented. The facility is based on ten 3m3 tubular photobioreactors operated in continuous mode for 2years, data of Scenedesmus almeriensis productivity but also of nutrients and power consumption from this facility being used. The yield of the facility was close to maximum expected for the location of Almería, the annual production capacity being 3.8t/year (90t/ha·year) and the photosynthetic efficiency being 3.6%. The production cost was 69 €/kg. Economic analysis shows that labor and depreciation are the major factors contributing to this cost. Simplification of the technology and scale-up to a production capacity of 200t/year allows to reduce the production cost up to 12.6 €/kg. Moreover, to reduce the microalgae production cost to approaches the energy or commodities markets it is necessary to reduce the photobioreactor cost (by simplifying its design or materials used), use waste water and flue gases, and reduce the power consumption and labor required for the production step. It can be concluded that although it has been reported that production of biofuels from microalgae is relatively close to being economically feasible, data here reported demonstrated that to achieve it by using the current production technologies, it is necessary to substantially reduce their costs and to operate them near their optimum values. © 2012 Elsevier Inc.

Gonzalez-Lopez C.V.,University of Almeria | Ceron-Garcia M.C.,University of Almeria | Fernandez-Sevilla J.M.,University of Almeria | Gonzalez-Cespedes A.M.,Estacion Experimental Fundacion Cajamar | And 2 more authors.
Bioresource Technology | Year: 2013

Nannochloropsis gaditana is a good producer of proteins and valuable fatty acids for aquaculture. Recycling of culture medium is interesting for microalgae commercial production as it cuts costs and prevents environmental contamination. The recycled medium must be sterilized to prevent the buildup of unwanted metabolites and microorganisms. We tested several sterilization methods: filtration, ozonation, chlorination, addition of hydrogen peroxide and heating. Results showed that the most successful method is ozonation lowering the bacterial load to 1.9103CFUs/mL, which is 1000-fold and 10-fold lower than the supernatant obtained after harvesting and the initial filtered medium, respectively. Continuous cultures of N. gaditana were grown using this recirculated supernatant. A maximum biomass productivity of 0.8g/L/d composed of ~50% proteins and 40% lipids with more than 3%d.w. EPA was obtained making this biomass very interesting for aquaculture. © 2012 Elsevier Ltd.

Sanchez J.A.,University of Almeria | Rodriguez F.,University of Almeria | Guzman J.L.,University of Almeria | Ruiz Arahal M.,University of Seville | Fernandez M.D.,Estacion Experimental Fundacion Cajamar
Acta Horticulturae | Year: 2011

In order to realize an optimal control of greenhouse crop irrigation, it is necessary to determine the transpiration. The micro-lysimeter was a good system to sample the transpiration values online but it is an expensive and a complex option, due to maintenance requirements. As an alternative, the use of transpiration models based on climate variables would be a better choice. In this paper, two transpiration models are shown. First, a grey-box static model based on the Penman-Monteith equation was developed, obtaining good results but also some problems were found: different parameter values for different seasons, bad fixing with the lower and higher leaf area index in the estimated transpiration values, and anticipation with respect to the real transpiration in determinate conditions. On the other hand, black-box dynamic models, obtained with system identification techniques, were developed, obtaining better results and solving the problems found in the grey-box model.

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