Final Report Summary - EUPHOROS (Efficient use of input in protected horticulture)
Thanks to protected cultivation we are eating high-quality and healthy vegetables and enjoying beautiful ornamentals year-round, all at an affordable price and the high productivity of protected horticulture is contributing to the economy of whole regions, in Europe and farther. However, concentrations of such an intensive type of agriculture may affect the natural environment, in terms of resource depletion and pollution. The Seventh Framework Programme (FP7) project EUPHOROS has investigated means for reducing the environmental impact of protected cultivation that would not worsen the financial performance, while accounting for the diversity of production systems in Europe.
A lifecycle analysis (LCA)-based environmental study of the current situation was used to identify the most critical elements of the production process, in various climate and market conditions throughout Europe. This was coupled to a complete financial assessment in order to uncover the potential for cost savings, so that suitable technologies could be developed to address the locally relevant bottlenecks and then be evaluated in practice. Results showed that the largest contributor by far to environmental impact of heated greenhouses is the burning of fossil energy for heating, which is also the largest single term in the production costs.
Reduction of heating requirement and application of renewable energy for heating is therefore the way to improve environmental and economic performance of heated greenhouses. We have tested a highly insulated double cover, coated to match photosynthetically active range (PAR) transmittance of single glass and to reduce losses of thermal radiation, coupled to innovative management of humidity. In spite of halving heating requirement in Holland, without any reduction in production, it would not be economic at present. A light-scattering glass cover, also coated to match PAR transmittance of standard glass was shown to reduce somewhat the requirement for artificial light of rose production in Holland, without any detrimental effect on production and its quality.
The potential for reduction of environmental impact, coupled to financial gain for the grower, in unheated greenhouses is more wide-ranging: better management to boost production, smart irrigation to decrease waste of fertilisers, better design and management, to increase lifespan and decrease waste of structures and equipment. The cheapest way to increase production (up to 40 %) in unheated greenhouses in the Mediterranean is through improved design and management of ventilation. Carbon dioxide supply could be a good second. Despite the potential for improvement of the properties of the plastic cover (which is undoubted), the prototypes that we investigated did not improve productivity. The main conclusion was that improvements must be sought that do not reduce transmittance in the PAR, also for the Mediterranean region. Improved climate management through heat storage and release, coupled to carbon dioxide (CO2) supply, increases production but not enough to be presently economic. We have shown that use of fertilisers can be reduced by up to 40 % (and water use by some 25 %) through application of closed irrigation cycles, which may be also economic.
Regarding crop protection, we showed that, although ultraviolet (UV) transmittance of the cover may reduce pest and disease (P&D) pressure, a good climate management is the main factor. For instance, in Almeria the risk and speed of disease development could be better controlled in the novel, semi-closed greenhouse prototype than in the traditional greenhouses. Altogether, this project demonstrates that technology can help minimise the input of valuable resources while at the same time maximising output in terms of productivity.
The results of the project have been compiled into public available web-tools which make it possible to calculate the environmental footprint of one's farm, and of possible improvements:
- to assess the financial consequence of modification to one's farm;
- to evaluate the effect of possible improvements of the opening area on the ventilation rate of the greenhouse; and
- to provide support for the management of closed-loop fertirrigation systems. The tools and the main project results are available from the project website (see http://www.euphoros.wur.nl online) that will be maintained after the life of the project.
Project context and objectives:
Project context
Protected cultivations are expanding in many part of the world, particularly in otherwise marginal agricultural land. Thanks to protected cultivation we are eating high-quality and healthy vegetables and enjoying beautiful ornamentals year-round, all at an affordable price. Protected cultivation is contributing to the economic development of formerly marginal agricultural land around the shores of the Mediterranean and farther. This is explained by the high productivity and high efficiency of use of most resources (particularly water). Nevertheless, there are drawbacks to such an intensive agriculture: for instance, the high spatial intensity of application of water, fertilisers and pesticides results in emissions: N-leaching can be some 2 g NO3 per kg tomato. Even un-heated greenhouse production has a Global Warming Potential equivalent to some 240 g CO2 per kg tomato (deliverable 5). In addition, off-season production and production outside the natural habitat of a crop requires application of fossil fuels, with hugely increased CO2 emissions as a consequence.
Project objectives
Eleven institutions from seven European countries have been cooperating in this project to decrease the need for resources in protected cultivation, while improving - or at least maintaining-the financial balance sheet of the grower. The greenhouse of the future can fulfil the need for safe use of resources (energy, water, pesticides) through modification of greenhouse design and management:
- Reduction of the need for resources: mainly through smart greenhouse design. Coatings and additives can be used to improve the performance of greenhouse covers in terms of light transmission vs. thermal insulation, optimal utilisation of sun energy through efficient energy storage, reduction of the impact of pests and diseases through the spectral properties of the cover.
- Reduction of waste: through better management of the production processes, improve management of irrigation, fertilisation and substrate waste, automatic detection of greenhouse dysfunctions.
- Increased productivity through decision support for management of ventilation, heating and carbon dioxide supply, early detection of stress (biotic / abiotic) and response management.
Description of the work performed and the main results achieved
An environmental study of the current situation was used to identify the most critical elements of the production process, in various climatic and market conditions throughout Europe. This was coupled to a complete financial assessment that uncovered significant potential for cost savings in operating costs (for example, by reducing fertiliser requirements), so that suitable technologies could be developed to address the locally relevant bottlenecks and then be evaluated in practice. Results showed the largest potential for reduction of environmental impact coupled to financial gain for the grower to be: energy consumption (or application of renewable energy) in heated greenhouses; and better management of ventilation, greenhouse climate, fertilisers and substrates in unheated ones.
With respect to improved greenhouse climate, a prototype was developed and tested in Almeria, Spain, that stores waste heat when cooling the greenhouse in the summertime and vice versa in the winter. The potential for energy storage can be increased by a smart design and management of ventilation, and several configurations of ventilators' area and position were evaluated and an innovative configuration proposed. In Holland an innovative greenhouse was built, that couples extremely high insulation, to an improved management of humidity, resulting in a reduction of some 55 % in energy consumption. The potential of solar and wind power to replace fossil fuels was also evaluated, but the poor match in time between potential production and need for energy, ensures that the best perspective for renewables is through grid connection.
New additives for plastic covers were developed and tested that may improve temperature management under high radiation and glass panel coatings were modified to optimise the trade-off between light absorption, diffusion and insulation. On the other hand, it was shown that, although UV transmittance of the cover may reduce pest disease pressure, a good climate management is the main factor. We developed a decision support for monitoring and management of greenhouse conditions (temperature, relative humidity, ventilation and CO2 supply) that improves productivity of resources and may help reducing problems with fungi, thanks to a model to identify periods of high-risk and the likely success of biological control programs. We have shown, for instance, that in Almeria the risk and speed of disease development could be better controlled in the novel, semi-closed greenhouse prototype than in the traditional greenhouses, especially in the spring and autumn. In addition, an 'electronic nose' was tested and modified, that could prove useful in the early detection of pests and disease, although it is still far from practical application.
It was demonstrated to what extent water and fertilisers use and emissions can be curbed by recycling irrigation water, though care must be taken to avoid the build-up of salts to levels that can reduce yield. In addition, with an eye to the full lifecycle of the greenhouse, the reuse of spent materials such as perlite was investigated and viable options were identified.
Results made available through public web-tools
The results of the project have been compiled into public available web-tools whose expected users are professionals, companies and scientists. The tools make it possible to calculate the environmental footprint of one's farm, and of possible improvements:
- to assess the financial consequence of modification to one's farm;
- to evaluate the effect of possible modifications of the opening area on the ventilation rate of the greenhouse; and
- to provide support for the management of closed-loop fert-irrigation systems.
The tools and the main project results are available from the project website (see http://www.euphoros.wur.nl online) that will be maintained after the life of the project and has been widely publicised in workshops, press releases and articles in trade magazines.
The greenhouse of the future will have nearly zero environmental impact. This project demonstrates that technology can help minimise the requirement for valuable resources while at the same time maximising productivity. This will help ensure that green greenhouses are a sound investment in these troubling financial times. In particular we have shown that it is possible to develop a sustainable greenhouse system that:
- may hugely reduce the need for fossil energy and minimise carbon footprint of equipment;
- has no waste of water nor emission of fertilisers and full recycling of the substrate;
- has minimal need of plant protective chemicals (PPCs), yet has high productivity and resource use efficiency.
Project results:
WP1: Environmental and economic assessment
This WP has dealt with the environmental and economic sustainability of the greenhouse production system in Europe. In order to ensure application of the results, the work focused on the balance between the environment and economy, quantifying the reduction of resource input and carbon footprint delivered by each component of this project, together with the financial / economic consequences. With this purpose, the objectives of WP1 were:
1. environmental analysis of the current situation of greenhouse production in European Union (EU) and identification of the major causes of environmental impacts;
2. to assess the environmental impact of the tools (equipment, cultivation system, monitoring and management techniques) developed in this project;
3. to assess economic soundness (profitability) of the tools using a decision support tool;
4. analysis of impact and economic soundness of the combinations of tools that will be implemented at the three test sites;
5. indication of the possible advantages of organising greenhouse enterprises into bigger units (greenhouse clusters) to minimise the environmental impact.
Four European scenarios have been considered:
1. tomato crop in a multi-tunnel greenhouse in Spain;
2. tomato crop in a Venlo type greenhouse in Hungary;
3. tomato crop in a Venlo type greenhouse in the Netherlands; and
4. rose crop in a Venlo type greenhouse in the Netherlands.
Deliverable 5 contains the quantitative analysis of existing greenhouse operations in the four scenarios; such analysis has helped identifying the environmental and economic 'bottlenecks' associated with the different scenarios.
Deliverable 13 analysed a number of options to reduce environmental impacts as well as their economic consequences for each production system under consideration. Alternatives, such as the use of a new greenhouse structure with improved ventilation, new energy saving cultivation methods, as well as new diffusive and anti-reflection (AR) covering materials have been analysed.
Deliverable 20 is a web tool which has been developed for dissemination purposes. The objective was to provide an easy-to-use support tool to perform economic and environmental assessments by a broad range of users. In this sense this web tool has been developed in five languages representatives of the different partners (i.e. Dutch, English, Hungarian Italian, and Spanish).
As a final activity of WP1 the possibility of creating greenhouse clusters for additional environmental impact mitigation has been discussed in deliverable 22.
WP2: Energy
The aim of this WP is implements a greenhouse production system that does not rely on fossil fuels, yet is able to deliver the microclimate required for good crop productivity across varied climatic regions as are addressed by this proposal: Mediterranean (Spain), cold temperate (the Netherlands) and continental (Hungary). With this purpose, the objectives of WP2 were to:
1. increase the use of sun energy by improving the properties of the greenhouse cover;
2. study the feasibility of improving passive greenhouse climate through thermal storage;
3. improve the ventilation design and climate management;
4. study the possibilities to incorporate renewable energy.
The first task was to propose technical developments for greenhouse covering materials that allow the maintenance of an optimal microclimate all year round in different climates of Europe, making the best possible profit of the energy from the sun and reducing energy losses from the greenhouse as well. A method has been developed (deliverable 2: Guidelines to determine feasibility of materials / coating combinations) to evaluate the economic performance (saving of energy vs production loss) of glass coatings and / or plastic additives.
It is obvious that there is still an enormous scope for improvement of the thermal and optical properties of the cover materials, both plastic films and glass. Economically feasible technical improvements were investigated by two specialised companies (BASF for plastics, and GROGLASS for glasses). The thermal and spectral properties of the cover material, in combination with local climate data, determine the potential productivity and the distribution of surplus/shortage of energy over the year.
BASF, has developed prototypes near-infrared (NIR) absorbing films. By limiting input of (non-photosynthetic) sun energy in the greenhouse, such films could improve growing conditions, particularly in the summer. These films have been analysed by Wageningen UR, and their optical properties obtained in the UV, PAR and NIR radiation bands. This evaluation allowed BASF to choose the correct loading of NIR absorbing pigments for Almeria. In December 2009 a NIR film together with a reference film (same composition but without NIR absorbing additive) have been produced at Solplast (Spain) following the indications of Experimental Station of the Cajamar Foundation (EEFC) in terms of width and length (deliverable 7). Both films will were tested in two real greenhouse systems at EEFC. The conclusion was that such films could represent an improvement only with negligible loss of PAR which was not presently the case.
GROGLASS developed a glass coatings with optimised performance for the best PAR transmittance (multiangle), solar gain (g-value) and energy saving (U-value) for both single and double glazing. After analysis of different coating stack designs, two of them were chosen for the further development: two and four layer double sided metal oxide coating (vacuum sputtering) on glass. A diffusive glass, with AR coating (to maximise input of PAR) was selected (deliverable 8) for testing in a rose crop in the Netherlands (WP6).
The next task determined the possibilities for technically and economically feasible energy storage systems and the management of those energy storage systems at greenhouses and cluster level both in cold and in warmer climates.
For that:
1. Information was collected on actual energy requirements year round for selected crops / site combinations-tomato and / or rose in Spain, Hungary and the Netherlands).
2. A method was developed to determine the productivity response to frequency, amplitude and efficiency of thermal storage. In the EEFC, and based on the predictions and estimations obtained from the HortiAlmería model, a novel system for cooling / heating semi-closed greenhouses with high efficiency fine wire heat exchangers, based on short term heat storage in a water tank was designed and implemented in a small greenhouse compartment.
3. A deep literature review was done to identify the best technologies for heat storage. The different technologies were grouped in two main categories selecting those more commonly used or most promising for greenhouse use in the future. Besides a rough estimation of the implementation costs associated to each system and scientific results of those most used nowadays was presented.
The poor productivity of Mediterranean greenhouses, is often ascribed to the limited potential for greenhouse climate management in passive greenhouses. However, there is much scope for improving the design and management (particularly the ventilation) of passive greenhouses. Ventilation is necessary for control of temperature and humidity.
However, reducing ventilation as much as possible has the advantages of:
1. improving the natural thermal storage function of the greenhouse;
2. reducing pest pressure; and
3. allowing for carbon dioxide fertilisation.
Our aim was to develop a decision support system (DSS) (deliverable 14) for minimising the necessity of ventilation while improving crop productivity, also through CO2 fertilisation. A method to determine required natural ventilation capacity in view of the local climate conditions and the properties of the cover was developed to assess size and position of the ventilators (windward and leeward) and develop distance indicators for optimal ventilation in presence of neighbouring / greenhouses.
In a greenhouse without carbon fertilisation, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. The ventilation of the greenhouse implies a trade-off between ensuring inflow of carbon dioxide and maintaining an adequate temperature within the house, particularly during sunny but chilly days. Crop production is known to increase both with carbon dioxide concentration and with (average) temperature. Therefore, the management of ventilation in such conditions is looking for 'the lesser of two evils'. We included management of CO2 (with and without artificial supply) in the DSS.
With respect to the application of renewable energy sources to improve climate management, we attempted to match possible renewable energy sources to the greenhouse energy requirement for the same crop / site combinations mentioned above. We considered: solar photovoltaic (PV) and wind energy for their use in Mediterranean greenhouses, PV and wind energy combined with thermal storage and / or solar PV, biomass heat or geothermal energy. The conclusion was that, given the costs of local energy storage, the most economical option is grid connection.
WP3: Water, fertilisers and substrate
Excess irrigation not only wastes water, but usually results also in environmental pollution caused by lixiviation of fertilisers. Closed cycle irrigation systems could solve this problem, but need good management for preventing accumulation of un-used ions. As closed irrigation cycles are most easily implemented in substrates, there is a need for good waste management, to avoid that we solve one pollution problem creating another one.
Accordingly, the objectives of this WP were:
1. An advice system for fertirrigation management of closed growing system in presence of ballast ions. Assessment of quick tests to assist management of fertilisers in such systems.
2. Cost / benefit analysis of the reuse of substrates.
3. To test technical feasibility and evaluate economical recycling options for perlite-based growing substrates.
4. To test technical feasibility and evaluate economical recycling options for rock wool.
Closed-loop soilless culture (hydroponics) is one of the most important components of closed greenhouses. The management of these growing systems implies the control of mineral supply (fertirrigation) as well as the selection and use of growing media, if any, and its disposal or recycling after one or more cultivation cycle. In principle, closed hydroponics should use raw water of excellent quality (with negligible content of ballast ions like Na, Cl), as well as fertilisers of high purity. In some circumstances, especially in the Mediterranean regions, growers do not have access to high-quality (non-saline) irrigation water and, if water desalinisation is not cost-effective (for instance, when low-value vegetables are produced), the application of closed growing technology is more difficult, since ballast ions inevitably accumulate in the plants, in the recycling water and/or in the substrate.
WP3 focused with the aspects inherent to the full closure of the root zone environment, focusing on the conditions that make endless re-use of the drain water currently uneconomical, which is when saline water is the only source for irrigation water. Through fertirrigation guidelines it is possible to prolong the reuse of drain water and minimise emission of polluting chemicals when the water does need to be discarded. UNIPI was responsible for this activity.
A series of experiments (UNIPI) were conducted to investigate the response of tomato and some leafy vegetables grown in closed hydroponics to excess boron in the irrigation water. The severity of B-induced leaf burn in tomato plants was alleviated by the use of saline water. Fruit B content remained well below the level representing a potential risk for the consumers. The response of tomato to B toxicity was not affected by grafting. The experiments with leafy vegetables allow to identify different tolerance of selected species, which are currently used for physiological studies on plant tolerance to B toxicity. The Penman-Monteith (PM) equation and two regression equations for determining the water use of greenhouse gerbera were also calibrated and validated.
We evaluated existing quick tests for nitrate (NO3-), ammonium (NH4+) inorganic phosphate (Pi), potassium (K+), boron (B) and chloride (Cl-) in hydroponic nutrient solutions, soil solutions and soil or substrate water extracts. Only the tests for NO3-, Cl- and Pi were accurate.
Deliverable 15 reports guidelines for best management of growing medium and fertigation (i.e. the application the nutrients with irrigation water) in closed soilless cultivation. Some Excel spreadsheets were attached to the document: NS calculator and crop simulator. Both calculators were incorporated in HydroTools, a DSS for the management of fertigation in greenhouse crops. Other two spreadsheets were prepared as a support to the LCA-WEB calculator and to manage fertigation in soil-bound crops. Mineral wool provides a sort of benchmark for growing media in consideration of their physical and chemical properties (high porosity, for instance) and the standardisation of the products on the market. However, this substrate is generally produced far from where greenhouses are concentrated; therefore, market price is high and, moreover, there is the problem originated by the disposal of exhausted material after a reasonable number of growing cycles. In Mediterranean countries, soilless cultures make a large use of perlite. For instance, in Spain, one of the biggest markets for perlite, 30 000 to 40 000 cubic meters of perlite for soilless cultivations is substituted every year and it is necessary to develop suitable recycling options. The disposal of exhausted perlite seems easier compared to rockwool, since it could be used as soil conditioner. Alternative reuse is the production (close to greenhouse cluster) of blocks for construction industry. PERLITE and TERRA investigated the technical and economic feasibility of perlite and rock-wool recycling. Two procedures were developed and tested to reuse spent perlite (for producing construction block, deliverable 16) and rockwool (TERRA, for producing growing media, deliverable 9).
WP4: PPCs
There are many drivers for improving the design and construction of new greenhouses and the drivers change with region around the EU (WPs 1, 2). EUPHORUS energy and environmental impact evaluations have shown that PPCs make a small contribution in each case. Nevertheless, for a variety of reasons it remains desirable to reduce and substitute PPCs. Indeed, there has been a universal move away from PPCs and into the use of biological control agents (BCA) for crop pests, but crop diseases remain challenging to control without chemicals. Good greenhouse sanitation protocols are important, but PPCs remain necessary as a last line of control for many commercial challenges. With the increasing use of BCAs in protected cropping the grower must now think about climate control not only for maximising plant production (principal driver) and minimising plant disease, but also for maximising the efficacy of BCAs. All three trophic levels will respond to climate variations independently, yet little is known about how the third level, the BCAs, react to the main climate variables of light, temperature and humidity.
The overall objective of this WP was: Overall objective: Minimise the application of PPCs. The specific objectives:
1. evaluate spectral filters for beneficial effects on Oidium and Tetranychus control;
2. evaluate specific P&D epidemiology against minimal ventilation management;
3. model P&D control under energy efficient glass / plastic.
In parallel to WP2 and with BASF, we tested five photoselective plastic coatings for their efficiency in controlling tomato powdery mildew and two-spotted spider mite. Altering the quality of light within the growing environment, especially in the UV region, has been proposed as a means of managing P&D pressures. Five plastics treated with novel coatings supplied by BASF were used as the covers for scaled-down polytunnels. Each was differentially active in the UV region of the light spectrum.
Statistically designed experiments allowed WAR to collect detailed datasets for both infections of tomato powdery mildew (Oidium neolycopersicae), infestations of the two-spotted spider mite (Tetranychus urticae) on rose and the efficacy of their respective BCAs. We concluded that UV photoselective plastics should not be chosen on the basis of pest or disease control, at least not at latitudes in northern Europe. In the South the UV irradiance is much greater and more extreme effects on P&D may be seen. However, the coincident reduction in BCA efficacy is still likely to counter some potential benefits. The WAR study does support the utility of B. subtilis as a biological prophylactic. Our experiments only support its use against Oidium, but there are reports of its utility in a range of other leaf infections and there is a good chance that it is beneficial for a range of diseases (deliverable 6).
Venting is used to control heat (and humidity), but it also prevents use of supplementary CO2 to enrich production and allows access for pests and diseases. Reducing ventilation, in semi-closed tunnels for example (see WP2) will affect both temperature and humidity in the growing environment. Whilst the changes may be beneficial for the energy budget, they may have unforeseen and deleterious consequences on P&D pressures, adding requirements for PPCs. One of our tasks recognised the complex cross-talk of variables in protected cropping. Data on the performances of Oidium and Tetranychus, with and without their respective BCAs, has been collected in order to build epidemiological models which will be available to advise, architects, environment engineers and growers about potential P&D performance under new protected cropping designs.
Datasets for prevailing temperature and humidity conditions have been collected from partners in Spain (EEFC), the Netherlands (WUR) and Hungary. For Spain, these span four years from one site, for the Netherlands these two years from twelve sites and for Hungary data is available for one year from one site. Data from sites testing novel greenhouse designs in Spain and the Netherlands have also been included.
A novel image analysis technique for quantifying leaf disease has been developed, tested and validated. Using input from a standard digital camera, disease coverage is automatically calculated per unit leaf area, discriminating areas of sporulation from healthy tissue, leaf veins and hairs. Using this new tool, data from a range of disease epidemiology trials were collected from tomato leaves growing under a regimen of temperatures and humidities. It was clear that Oidium was able to establish and sporulate successfully in the between 15 and 29 degrees Celsius and the prevailing humidity in most commercial greenhouses. However, the data for control using B. subtilis were encouraging. Similar experiments were concluded for the pest T. urticae. In both cases the data were incorporated into novel tri-trophic epidemiological models. The climate models were then combined with the tri-trophic P&D models allowing EUPHORUS to predict P&D pressures in each scenario and the likely effectiveness of BCAs (deliverable 11).
We then parameterised computer models to predict how both the P&D, and each BCA, will perform based on temperature and humidity data. The models parameterised environmental variations by day and by season. Combining climate models with epidemiological models enabled EUPHORUS to evaluate the effectiveness of biological controls throughout a growing year. In the Netherlands, the BCA B. subtilis could provide 15-20 % improved control of tomato powdery mildew across the year, but novel glass made no difference. For Spain the model predicted that tomatoes treated with B. subtilis benefit from a 10 - 25% increase in the time until 50 % disease leaf coverage. The model also shows that the increase in time until 50 % disease leaf coverage (protection) is greater in novel, semi-closed greenhouses than traditional, passively-ventilated greenhouses, especially in the spring and autumn.
At present, such predictions must be restricted to the spread of Oidium and its control by B. subtillis, because the periodic higher humidity may favour development of other tomato diseases. The will be a need to build epidemiological knowledge of other important tomato diseases into the climate scenarios for a more complete picture, but this is outside the scope of this project. Nevertheless, EUPHORUS has delivered new tools for helping design, test and run greenhouses for protected crops in order to reduce dependence on PPCs (deliverable 12).
WP5: Monitoring and management support
The overall objective of this WP was to boost resource use efficiency by ensuring conditions for high productivity; decrease unmarketable losses; increase quality and yield value.
The specific objectives:
1. online monitoring tools for greenhouse performance;
2. online monitoring tools for crop performance;
3. proof of concept of early detection tools for pests and diseases;
4. management support tool that provides the grower with useful information about performance of the greenhouse system and that advises about the controls needed.
For monitoring of the performance of the greenhouse, a soft sensor was developed to estimate continuously the ventilation rate of a greenhouse and the transpiration of the crop. This method makes use of data that are routinely measured by climate control computers, and is suitable for implementation and online application (deliverable 17).
Based on this, a tool was developed for the cost-effective optimisation of additional CO2 supply in greenhouses. The model used in this tool calculates the optimal desired CO2 concentration based on the crop's need for CO2 (uptake due to photosynthesis), the loss of CO2 from the greenhouse by ventilation, the price of the product (e.g. the tomatoes or roses) and the cost of the CO2 to be supplied.
The soft-sensor for monitoring ventilation and transpiration rate of a greenhouse and the tool for cost-effective optimisation of pure CO2 supply in the greenhouse was implemented by HortiMaX in a test greenhouse at EEFC in Almeria (deliverable 23). The results were promising and HortiMaX is planning to install the tool also in Holland, since energy saving and/or application of renewable energy ensures that less CO2 is available as by-product of heating and more and more growers rely on pure CO2 for supply. A follow-up proposal on this topic has been submitted to a EU-FP7 call aimed at small and medium-sized enterprises (SMEs).
With respect to early detection of biotic stress, we have evaluated several imaging and volatile detection technologies which could provide possible early P&D detection. From the point of view of sensitivity, availability, ease of installation, ease of use and cost, volatile sensing techniques offer the most promising approach. A chemical signature sensor (E-nose) and a mobility spectrometer (FAIMS) were chosen for application in laboratory and field tests. Pattern recognition and training were used to discriminate between the complex 'volatile signatures' of plants affected by specific pests and diseases and those of clean plants. For laboratory based experiments the results show that disease could be discriminates as early as four-day post infection. However, for field trials the best results achieved a correct classification for 86 % of samples, although this was based on a relatively small number of samples (between 3 and 15 samples per category). Automatic sampling would be necessary in order to build statistically significant and repeatable datasets. The sensor technologies have shown that they do have the capacity for successful discrimination should the training periods be sufficient. There may need to be sampling protocols in order to minimise interference from background commercial activities and maximise the potential of these technologies. These could be as straightforward as automatic sampling before the start of the day, avoiding areas undergoing harvesting, spraying or clearing operations. It can be concluded that volatile organic compound (VOC) sensing can probably deliver early alert technology in protected cropping environments when coupled to intelligent systems computing. However, at present these remain at the experimental phase of development and none of the techniques investigated can be readily used in industrial greenhouse production. EUPHOROS has provided a prototype system and further development in the next three to five years could readily produce viable commercial systems. In line with this, diagrams or photographs illustrating and promoting the work of the project, as well as relevant contact details or list of partners can be provided without restriction.
More disappointing were the results about early detection of abiotic stress (drought). We tested several methods, based on spectrometry, and none was able to detect stress with an earliness compatible with greenhouse management (which has obviously much stricter requirements than field production). All results about early detection of stress (biotic and abiotic) are reported in deliverable 18.
WP6: Integration and evaluation
The purpose of this WP was to integrate the tools developed in the other WP's in combinations relevant to three local markets and to test the feasibility of each combination. Each of the European countries has its own greenhouse structure and equipment that have evolved locally according to specific circumstances. These can be environmental (climate, water availability and quality, soil structure and quality), cultural (the education level of the grower, the management structure in the greenhouse, the level of environmental friendly conscience of the grower, the traditions that led to the actual cultivation methods), economic (how much can a grower invest in greenhouse structure, equipment and tools, which market do they serve and what does the market expect from the grower). Therefore, the testing in practice and implementation of the tools developed within the development WPs of EUPHOROS, has been addressed from a local point of view. WP6 dealt with implementation of the developed tools in combinations relevant to three local situations. The local situations were: Almería (Spain), Morahalom (Hugary), later replaced by Tuscany (Italy), and Bleiswijk (the Netherlands). Each situation one climate, one culture, one market.
The specific objectives of this WP were to:
1. increase the chance of acceptance through involvement of the end users in an early stage;
2. give feed-back to the developing partners through tests of the tools in three very different climate / market conditions.
These objectives have been achieved through two lines of actions:
(i) involvement of the end users (leading growers and / or growers' organisation, extension services) during the development phase;
(ii) test and evaluation of the most promising combinations of elements at prominent applied research stations in Spain, the Netherlands and Italy.
In the first meeting of the project partners it was decided that tomato would be the working crop for the test and evaluation in Spain and Italy; roses the working crop for the Netherlands. Cut flower cultivation, with roses as the number one cut flower are relevant in surface, economic importance, and in environmental impact. From a total surface cultivated under greenhouses of 10 250 hectares, almost half of it is dedicated to the cultivation of ornamental flowers and plants. Holland has the highest consumption per capita of flowers and plants in the world. Ornamental products, plants and flowers, are also a very important export product in the Dutch economy. It is also a very innovative and mechanised subsector. Within the area dedicated to the ornamental plants, a little bit more than half of it (2430 Ha) is dedicated to the production of cut flowers. In 2011, the rose accounts for 19 % of the total cut flower cultivation surface: after the Crysanthemum, it occupies, the second place in terms of surface and the first one in terms of value: 23 % of the total value of the cut flowers sold by the Dutch Auctions and produced in the Netherlands.
A thorough economic and environmental analysis of the tomato cultivation systems in Hungary and Spain as well as of the rose cultivation in the Netherlands (a reference situation calculated with data from the years 2007 and 2008) was performed at the beginning of EUPHOROS, within WP1. This work helped to decide on which developments to focus (always in close consultation with local stakeholders). The analysis forecasted the potential economic impact of reducing a certain input. It showed that within the cost components of a rose farm in the Netherlands the total costs are mainly determined by: energy and labour. The costs for energy accounts in roses for 36 % of the total costs. This places the input 'energy' as the most important input in which to focus in a project aiming economically viable input reduction. The costs of paid labour accounts for 22 % of the total costs. Therefore, any development able to achieve a reduction in the costs for labour, will contribute to an economically interesting improvement of the production system. The analysis for Spain led the focus towards heat reduction in summer and energy saving options. The costs of fertilisers in Hungary are huge, and as the economic forecast learnt that saving 50 % fertilisers would create a very attractive investment capacity of more than 17 EUR / m2 per year, efforts in this location concentrated in a closed loop circulation; later tested in Tuscany, Italy. Both locations, Hungary and Italy showing great reluctance from growers to adopt this kind of systems due to phytopathologic fears.
To ensure that the combinations of elements to be tested in the greenhouse conditions at each site were tuned with the expectations of the local growers, at each site feed-back sessions were conducted with groups of relevant stakeholders and potential users. These sessions lead to a plan of tool combinations to implement in trials at each location (deliverable 4). These trials were conducted in 2010 and 2011. In Almería, with a tomato crop, a greenhouse film cover (BASF) with a NIR absorbing coating was evaluated. NIR-absorption lead to a decrease in production equal to the loss in light transmission. New developments should focus on NIR reflection, coupled to high PAR transmittance. A thermal day storage system (EEFC) allowed to heat the greenhouse at night with the heat collected during the day, potentially saving in heating costs, although economically unfeasible at the present market and energy price conditions. The evaluated smart-dust climate measurement system (Hortimax) and a CO2 optimising software (WUR and Hortimax) are ready for exploitation. In Bleiswijk (the Netherlands), with a rose crop, two of the tested developments are ready to be implemented in practice: a cover of Diffuse glass with a AR coating (GroGlass) that lead to a production increase of 5.2 % more stems, and a Rockwool plug-slab combination that decrease the substrate volume by 20 %. Further development (more speed and autonomy), is needed for the electronic nose as an early warning device for pests and diseases. A transpiration model to adjust irrigation will need further adjustments and validation in practice. The two developments tested in Tuscany with a tomato crop (a closed-loop fertigation system and quick test for monitoring nutrients) are ready to be implemented. The results served to give feed-back to the developing partners and firms, for their subsequent development (deliverable 19).
WP7: Dissemination
The lasting contribution to the exploitation of the results of the project is the web page (see http://www.euphoros.wur.nl online) and particularly the web-tools available there (deliverable 20), whose expected users are professionals, companies and scientists. The tools make it possible to calculate:
1. the environmental footprint of one's farm, and of possible improvements;
2. to assess the financial consequence of modification to one's farm;
3. to evaluate the effect of possible modifications of the opening area on the ventilation rate of the greenhouse;
4. provide support for the management of closed-loop fertirrigation systems.
The results of the project have been given wide international resonance through massive participation in two symposia of the International Society of Horticultural Science, whose proceedings are available on the site of the ISHS (deliverable 27). In addition, a number of local thematic workshop have been organised in Britain, Hungary, Italy, the Netherlands, and Spain (deliverable 25), where also a course for professionals was organised (deliverable 26). The results of the project and the web tools have also been widely publicised in papers, symposia, press releases and trade magazines.
Potential impact:
Each of the tested developments had an impact as they all contributed to knowledge development about the tool, the conditions in which to use it, and the performance in semi-commercial conditions. Developments that are not economically feasible now, can become of importance if the conditions in which they are not economically feasible at this moment in the tested location, change. Such is the case, for instance, of the heat day-storage tower in Almería, that despite the great potential savings in energy, it is too expensive to run with the actual energy prices. However, this tool can become economically interesting if the price of the energy source becomes higher than the installation and running costs of the heat storage system. Similarly, the Venlow energy saving greenhouse tested in the Netherlands, is not presently economical, in spite of the huge reduction in energy requirement. It may well be with higher energy prices in the future.
Developments that are not ready to implement but still have a great potential in labour savings are for instance the pest-detection methods. Growers and developers have become aware of the existence of e-technologies that in a nearby future can help them with these labour-intensive activities. In the next years, we can expect quick developments in this field. The tests in Almeria with novel plastic additives have shown that manipulation of radiation by means of additives is not an easy task: it will require some further development in order to allow maximal PAR transmission, but block, reflect and absorb other wavelengths.
On the other hand, quite a few project results are ready for exploitation / implementation:
- Online monitoring and CO2 fertilisation of greenhouses: an economically feasible and impact reducing development.
- The proof-of-principle of the implementation of the monitoring module in the Multima climate computer of Hortimax was positive. Hortimax is willing to develop further the system and implement it in its advanced line of greenhouse computers. A proposal in this direction has been submitted to a EU-FP7 call aimed at exploitation of project results by SMEs.
Computational fluid dynamic (CFD)-aided ventilation design: an economically feasible and impact reducing development. The performance of the prototype greenhouse with improved ventilation design in Almeria made clear that there is a huge potential for increasing productivity of Mediterranean greenhouses (some 40 %) simply by better design and management of ventilation. There is a need for developing CFD-based indicators for assisted greenhouse design. IRTA has cooperated with an Italian greenhouse builder to submit a proposal in this direction to a EU-FP7 call aimed at exploitation of project results by SMEs.
Diffuse glass with AR coating in rose cultivation: an economically feasible and impact reducing development
With the obtained increase in flower yield of 5.2 % more stems of equal to slightly better quality, the examined glass (tempered, by GroGlass double-sided AR coated Vetrasol 503) can be economically feasible (Ruijs et al., 2011), as it has been calculated that 1.5 % more production already can finance the extra investment costs necessary for this type of glass with a payback period of 4 year (calculations based on price estimates by one supplier). Despite the fact that for the production of the diffuse glass with AR coating requires extra electricity, the environmental analysis (Torellas et al., 2011) has shown that with the obtained yield increase (5 %) the development had an obvious benefit, reducing environmental impacts of the production system. In terms of environmental impact this increase in yield compensated the extra energy required for the production of diffuse glass compared to standard glass. Environmental impacts were reduced around 4.6 % to all considered impact categories.
Diffuse glass has a broad impact in Dutch horticulture, beyond rose cultivation
The use of diffuse glass in horticulture has started to be a reality in practice. Parallel to the Euphoros trial, a rose trial was conducted (contract research) for another glass supplier with a Diffuse cover with AR coating on one side only. Results were very similar to the ones obtained in the Euphoros implementation trial. Short after the start of the implementation trial Euphoros in roses, trials started with tomato, where different haze factors were tested. The results show a higher impact from diffuse glass on tomato production (up to 11 % extra production) with the same energy input, probably due to the fact that no shadow screens need to be used in summer and no artificial light was used in the winter, giving the properties of the cover really a chance to influence the cultivation. In 2012, trials with cucumber followed, and showed even more spectacular results than with tomato: 10 % more production with the same energy input in only three (winter!) months. Altogether, a huge potential lies in front of these developments, growers have a great interest and follow the developments around new glasshouse covering materials. A few greenhouses have already been built with these materials. In the coming years new developments can be expected in these field.
Rockwool plugs and smaller slabs reduce substrate volume but have little economic or environmental impact in rose cultivation
The rose plants (Rosa hybrida cultivar 'Red Naomi'!) for the main EUPHOROS trial in Bleiswijk were propagated by cuttings using the Synchronisation Method (Van Telgen et al., 2003) of Wageningen UR Glasshouse Horticulture in Rockwool plugs (Grodan). Once the plantlets were rooted they were planted in SPU (single production units) The reference situation consists of +/- 4 rockwool blocks for propagation wich are placed at planting on top of the substrate slab (100 x 12 x 7.5 cm) with rockwool (Grodan). The used system saves 20 % substrate compared to the reference. The reduced size of the units allowed also extended propagation of the plants and transport of the productive plants to the experimental compartments, instead of planting small plants directly on the slab. The economic evaluation (Ruijs et al., 2011) showed that the reduction of substrate volume with SPU results in a saving of 0.10-0.16 EUR / m2 depending on the SPU option. A sensitivity analysis of the substrate price points out that the savings (difference in yearly costs between the option and the standard cultivation system) are not very much affected, because of the four year cultivation period. The environmental impact analysis (Torrellas et al., 2011) confirms that lower use of substrate volume produced significant reductions in auxiliary equipment (20.6 % in cumulative energy demand) but had a small effect in the total production system (4.8 %). This kind of results would make difficult to convince growers to implement an alternative that gives little environmental improvements in the production system and on the other hand requires extra effort in agricultural practices. However, substrate volume reduction must be equally encouraged to move to more environmental friendly practices.
Closed loop fertirrigation saves water, pesticides and avoids emissions to the environment. Recirculation of nutritive solutions is common practice in The Netherlands, where environmental regulations have made it compulsory since many years. However, in countries like Hungary, Italy and Spain, despite the high cost of fertilisers and the scarcity of water of good quality, growers are very reluctant to use such a system, mainly, as they say, by fear for root borne diseases to spread with the re-use of the leached water. The trials in Tuscany performed by the University of Pisa, UNIPI have shown that 100 % recirculation is possible in tomato cultivation in Italy without any decrease in production nor in fruit quality. A reduction of the water consumption of 25 % was achieved; 11 to 40 % less fertilisers were wasted, delivering a payback time of about two years for the installation. To meet the doubts of the growers, the researchers showed that by means of a simple disinfection system it is possible to reduce the risk for diseases. However, the disinfection equipment together with the analysis for monitoring the diseases increased the required investment for the installation of such a system. Provided the monitoring tools ensured a 100 % closure of the system, they would provide a saving of only EUR 0.12 / m2 year, requiring a pay-back time of the system of over 8 years. These economic results make it difficult to convince growers to switch to these systems. Great efforts have been done by the researchers to disseminate these results.
Conclusion and recommendations
Altogether, we have shown quite a few input reducing options that have good prospects from environmental and economic point of view. The challenge and objective should be to encourage and stimulate growers in all European greenhouse production areas to invest in input and/or emission reducing options to save the environment / planet and to improve the competitiveness of the European greenhouse industry in the global competition.
Although research and demonstration projects have shown the advantages of those options still great efforts have to be done to awaken and to support growers in their transition to a sustainable greenhouse production.
Education, courses and small-scale experiments should be initiated to help and to convince growers in adapting the new and innovative options in their own practice or situation.
It is also recommendable to focus the awakening and knowledge transfer on suppliers of structures, climate systems and irrigations systems in order to stimulate the knowledge flow from research to practice. After all, suppliers and their salesmen have intensive contacts with the end users (growers).
The results and prospects have been shown for the pilot crops tomato (Spain, Hungary, Italy and the Netherlands) and rose (the Netherlands). It would be recommended to shift the attention in research and extension service also to other crops in greenhouse vegetables, cut flowers and potted plants in all European greenhouse areas.
The web tool for the environmental and economic assessment of performances of input / emission reducing options is particularly interesting for advisors, extension service and education. The model (although much simplified) gives insight in the relations between input and output in terms of environmental and economic impact and gives leads / clues to improve the environmental and economic profile of the greenhouse production system in all European countries.
The EUPHOROS research project has proven that environmental friendly greenhouse productions systems can go hand in hand with economic viability. This offers great perspectives for greenhouse production in the future in Europe and worldwide.
Project website: http://www.euphoros.wur.nl
A lifecycle analysis (LCA)-based environmental study of the current situation was used to identify the most critical elements of the production process, in various climate and market conditions throughout Europe. This was coupled to a complete financial assessment in order to uncover the potential for cost savings, so that suitable technologies could be developed to address the locally relevant bottlenecks and then be evaluated in practice. Results showed that the largest contributor by far to environmental impact of heated greenhouses is the burning of fossil energy for heating, which is also the largest single term in the production costs.
Reduction of heating requirement and application of renewable energy for heating is therefore the way to improve environmental and economic performance of heated greenhouses. We have tested a highly insulated double cover, coated to match photosynthetically active range (PAR) transmittance of single glass and to reduce losses of thermal radiation, coupled to innovative management of humidity. In spite of halving heating requirement in Holland, without any reduction in production, it would not be economic at present. A light-scattering glass cover, also coated to match PAR transmittance of standard glass was shown to reduce somewhat the requirement for artificial light of rose production in Holland, without any detrimental effect on production and its quality.
The potential for reduction of environmental impact, coupled to financial gain for the grower, in unheated greenhouses is more wide-ranging: better management to boost production, smart irrigation to decrease waste of fertilisers, better design and management, to increase lifespan and decrease waste of structures and equipment. The cheapest way to increase production (up to 40 %) in unheated greenhouses in the Mediterranean is through improved design and management of ventilation. Carbon dioxide supply could be a good second. Despite the potential for improvement of the properties of the plastic cover (which is undoubted), the prototypes that we investigated did not improve productivity. The main conclusion was that improvements must be sought that do not reduce transmittance in the PAR, also for the Mediterranean region. Improved climate management through heat storage and release, coupled to carbon dioxide (CO2) supply, increases production but not enough to be presently economic. We have shown that use of fertilisers can be reduced by up to 40 % (and water use by some 25 %) through application of closed irrigation cycles, which may be also economic.
Regarding crop protection, we showed that, although ultraviolet (UV) transmittance of the cover may reduce pest and disease (P&D) pressure, a good climate management is the main factor. For instance, in Almeria the risk and speed of disease development could be better controlled in the novel, semi-closed greenhouse prototype than in the traditional greenhouses. Altogether, this project demonstrates that technology can help minimise the input of valuable resources while at the same time maximising output in terms of productivity.
The results of the project have been compiled into public available web-tools which make it possible to calculate the environmental footprint of one's farm, and of possible improvements:
- to assess the financial consequence of modification to one's farm;
- to evaluate the effect of possible improvements of the opening area on the ventilation rate of the greenhouse; and
- to provide support for the management of closed-loop fertirrigation systems. The tools and the main project results are available from the project website (see http://www.euphoros.wur.nl online) that will be maintained after the life of the project.
Project context and objectives:
Project context
Protected cultivations are expanding in many part of the world, particularly in otherwise marginal agricultural land. Thanks to protected cultivation we are eating high-quality and healthy vegetables and enjoying beautiful ornamentals year-round, all at an affordable price. Protected cultivation is contributing to the economic development of formerly marginal agricultural land around the shores of the Mediterranean and farther. This is explained by the high productivity and high efficiency of use of most resources (particularly water). Nevertheless, there are drawbacks to such an intensive agriculture: for instance, the high spatial intensity of application of water, fertilisers and pesticides results in emissions: N-leaching can be some 2 g NO3 per kg tomato. Even un-heated greenhouse production has a Global Warming Potential equivalent to some 240 g CO2 per kg tomato (deliverable 5). In addition, off-season production and production outside the natural habitat of a crop requires application of fossil fuels, with hugely increased CO2 emissions as a consequence.
Project objectives
Eleven institutions from seven European countries have been cooperating in this project to decrease the need for resources in protected cultivation, while improving - or at least maintaining-the financial balance sheet of the grower. The greenhouse of the future can fulfil the need for safe use of resources (energy, water, pesticides) through modification of greenhouse design and management:
- Reduction of the need for resources: mainly through smart greenhouse design. Coatings and additives can be used to improve the performance of greenhouse covers in terms of light transmission vs. thermal insulation, optimal utilisation of sun energy through efficient energy storage, reduction of the impact of pests and diseases through the spectral properties of the cover.
- Reduction of waste: through better management of the production processes, improve management of irrigation, fertilisation and substrate waste, automatic detection of greenhouse dysfunctions.
- Increased productivity through decision support for management of ventilation, heating and carbon dioxide supply, early detection of stress (biotic / abiotic) and response management.
Description of the work performed and the main results achieved
An environmental study of the current situation was used to identify the most critical elements of the production process, in various climatic and market conditions throughout Europe. This was coupled to a complete financial assessment that uncovered significant potential for cost savings in operating costs (for example, by reducing fertiliser requirements), so that suitable technologies could be developed to address the locally relevant bottlenecks and then be evaluated in practice. Results showed the largest potential for reduction of environmental impact coupled to financial gain for the grower to be: energy consumption (or application of renewable energy) in heated greenhouses; and better management of ventilation, greenhouse climate, fertilisers and substrates in unheated ones.
With respect to improved greenhouse climate, a prototype was developed and tested in Almeria, Spain, that stores waste heat when cooling the greenhouse in the summertime and vice versa in the winter. The potential for energy storage can be increased by a smart design and management of ventilation, and several configurations of ventilators' area and position were evaluated and an innovative configuration proposed. In Holland an innovative greenhouse was built, that couples extremely high insulation, to an improved management of humidity, resulting in a reduction of some 55 % in energy consumption. The potential of solar and wind power to replace fossil fuels was also evaluated, but the poor match in time between potential production and need for energy, ensures that the best perspective for renewables is through grid connection.
New additives for plastic covers were developed and tested that may improve temperature management under high radiation and glass panel coatings were modified to optimise the trade-off between light absorption, diffusion and insulation. On the other hand, it was shown that, although UV transmittance of the cover may reduce pest disease pressure, a good climate management is the main factor. We developed a decision support for monitoring and management of greenhouse conditions (temperature, relative humidity, ventilation and CO2 supply) that improves productivity of resources and may help reducing problems with fungi, thanks to a model to identify periods of high-risk and the likely success of biological control programs. We have shown, for instance, that in Almeria the risk and speed of disease development could be better controlled in the novel, semi-closed greenhouse prototype than in the traditional greenhouses, especially in the spring and autumn. In addition, an 'electronic nose' was tested and modified, that could prove useful in the early detection of pests and disease, although it is still far from practical application.
It was demonstrated to what extent water and fertilisers use and emissions can be curbed by recycling irrigation water, though care must be taken to avoid the build-up of salts to levels that can reduce yield. In addition, with an eye to the full lifecycle of the greenhouse, the reuse of spent materials such as perlite was investigated and viable options were identified.
Results made available through public web-tools
The results of the project have been compiled into public available web-tools whose expected users are professionals, companies and scientists. The tools make it possible to calculate the environmental footprint of one's farm, and of possible improvements:
- to assess the financial consequence of modification to one's farm;
- to evaluate the effect of possible modifications of the opening area on the ventilation rate of the greenhouse; and
- to provide support for the management of closed-loop fert-irrigation systems.
The tools and the main project results are available from the project website (see http://www.euphoros.wur.nl online) that will be maintained after the life of the project and has been widely publicised in workshops, press releases and articles in trade magazines.
The greenhouse of the future will have nearly zero environmental impact. This project demonstrates that technology can help minimise the requirement for valuable resources while at the same time maximising productivity. This will help ensure that green greenhouses are a sound investment in these troubling financial times. In particular we have shown that it is possible to develop a sustainable greenhouse system that:
- may hugely reduce the need for fossil energy and minimise carbon footprint of equipment;
- has no waste of water nor emission of fertilisers and full recycling of the substrate;
- has minimal need of plant protective chemicals (PPCs), yet has high productivity and resource use efficiency.
Project results:
WP1: Environmental and economic assessment
This WP has dealt with the environmental and economic sustainability of the greenhouse production system in Europe. In order to ensure application of the results, the work focused on the balance between the environment and economy, quantifying the reduction of resource input and carbon footprint delivered by each component of this project, together with the financial / economic consequences. With this purpose, the objectives of WP1 were:
1. environmental analysis of the current situation of greenhouse production in European Union (EU) and identification of the major causes of environmental impacts;
2. to assess the environmental impact of the tools (equipment, cultivation system, monitoring and management techniques) developed in this project;
3. to assess economic soundness (profitability) of the tools using a decision support tool;
4. analysis of impact and economic soundness of the combinations of tools that will be implemented at the three test sites;
5. indication of the possible advantages of organising greenhouse enterprises into bigger units (greenhouse clusters) to minimise the environmental impact.
Four European scenarios have been considered:
1. tomato crop in a multi-tunnel greenhouse in Spain;
2. tomato crop in a Venlo type greenhouse in Hungary;
3. tomato crop in a Venlo type greenhouse in the Netherlands; and
4. rose crop in a Venlo type greenhouse in the Netherlands.
Deliverable 5 contains the quantitative analysis of existing greenhouse operations in the four scenarios; such analysis has helped identifying the environmental and economic 'bottlenecks' associated with the different scenarios.
Deliverable 13 analysed a number of options to reduce environmental impacts as well as their economic consequences for each production system under consideration. Alternatives, such as the use of a new greenhouse structure with improved ventilation, new energy saving cultivation methods, as well as new diffusive and anti-reflection (AR) covering materials have been analysed.
Deliverable 20 is a web tool which has been developed for dissemination purposes. The objective was to provide an easy-to-use support tool to perform economic and environmental assessments by a broad range of users. In this sense this web tool has been developed in five languages representatives of the different partners (i.e. Dutch, English, Hungarian Italian, and Spanish).
As a final activity of WP1 the possibility of creating greenhouse clusters for additional environmental impact mitigation has been discussed in deliverable 22.
WP2: Energy
The aim of this WP is implements a greenhouse production system that does not rely on fossil fuels, yet is able to deliver the microclimate required for good crop productivity across varied climatic regions as are addressed by this proposal: Mediterranean (Spain), cold temperate (the Netherlands) and continental (Hungary). With this purpose, the objectives of WP2 were to:
1. increase the use of sun energy by improving the properties of the greenhouse cover;
2. study the feasibility of improving passive greenhouse climate through thermal storage;
3. improve the ventilation design and climate management;
4. study the possibilities to incorporate renewable energy.
The first task was to propose technical developments for greenhouse covering materials that allow the maintenance of an optimal microclimate all year round in different climates of Europe, making the best possible profit of the energy from the sun and reducing energy losses from the greenhouse as well. A method has been developed (deliverable 2: Guidelines to determine feasibility of materials / coating combinations) to evaluate the economic performance (saving of energy vs production loss) of glass coatings and / or plastic additives.
It is obvious that there is still an enormous scope for improvement of the thermal and optical properties of the cover materials, both plastic films and glass. Economically feasible technical improvements were investigated by two specialised companies (BASF for plastics, and GROGLASS for glasses). The thermal and spectral properties of the cover material, in combination with local climate data, determine the potential productivity and the distribution of surplus/shortage of energy over the year.
BASF, has developed prototypes near-infrared (NIR) absorbing films. By limiting input of (non-photosynthetic) sun energy in the greenhouse, such films could improve growing conditions, particularly in the summer. These films have been analysed by Wageningen UR, and their optical properties obtained in the UV, PAR and NIR radiation bands. This evaluation allowed BASF to choose the correct loading of NIR absorbing pigments for Almeria. In December 2009 a NIR film together with a reference film (same composition but without NIR absorbing additive) have been produced at Solplast (Spain) following the indications of Experimental Station of the Cajamar Foundation (EEFC) in terms of width and length (deliverable 7). Both films will were tested in two real greenhouse systems at EEFC. The conclusion was that such films could represent an improvement only with negligible loss of PAR which was not presently the case.
GROGLASS developed a glass coatings with optimised performance for the best PAR transmittance (multiangle), solar gain (g-value) and energy saving (U-value) for both single and double glazing. After analysis of different coating stack designs, two of them were chosen for the further development: two and four layer double sided metal oxide coating (vacuum sputtering) on glass. A diffusive glass, with AR coating (to maximise input of PAR) was selected (deliverable 8) for testing in a rose crop in the Netherlands (WP6).
The next task determined the possibilities for technically and economically feasible energy storage systems and the management of those energy storage systems at greenhouses and cluster level both in cold and in warmer climates.
For that:
1. Information was collected on actual energy requirements year round for selected crops / site combinations-tomato and / or rose in Spain, Hungary and the Netherlands).
2. A method was developed to determine the productivity response to frequency, amplitude and efficiency of thermal storage. In the EEFC, and based on the predictions and estimations obtained from the HortiAlmería model, a novel system for cooling / heating semi-closed greenhouses with high efficiency fine wire heat exchangers, based on short term heat storage in a water tank was designed and implemented in a small greenhouse compartment.
3. A deep literature review was done to identify the best technologies for heat storage. The different technologies were grouped in two main categories selecting those more commonly used or most promising for greenhouse use in the future. Besides a rough estimation of the implementation costs associated to each system and scientific results of those most used nowadays was presented.
The poor productivity of Mediterranean greenhouses, is often ascribed to the limited potential for greenhouse climate management in passive greenhouses. However, there is much scope for improving the design and management (particularly the ventilation) of passive greenhouses. Ventilation is necessary for control of temperature and humidity.
However, reducing ventilation as much as possible has the advantages of:
1. improving the natural thermal storage function of the greenhouse;
2. reducing pest pressure; and
3. allowing for carbon dioxide fertilisation.
Our aim was to develop a decision support system (DSS) (deliverable 14) for minimising the necessity of ventilation while improving crop productivity, also through CO2 fertilisation. A method to determine required natural ventilation capacity in view of the local climate conditions and the properties of the cover was developed to assess size and position of the ventilators (windward and leeward) and develop distance indicators for optimal ventilation in presence of neighbouring / greenhouses.
In a greenhouse without carbon fertilisation, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. The ventilation of the greenhouse implies a trade-off between ensuring inflow of carbon dioxide and maintaining an adequate temperature within the house, particularly during sunny but chilly days. Crop production is known to increase both with carbon dioxide concentration and with (average) temperature. Therefore, the management of ventilation in such conditions is looking for 'the lesser of two evils'. We included management of CO2 (with and without artificial supply) in the DSS.
With respect to the application of renewable energy sources to improve climate management, we attempted to match possible renewable energy sources to the greenhouse energy requirement for the same crop / site combinations mentioned above. We considered: solar photovoltaic (PV) and wind energy for their use in Mediterranean greenhouses, PV and wind energy combined with thermal storage and / or solar PV, biomass heat or geothermal energy. The conclusion was that, given the costs of local energy storage, the most economical option is grid connection.
WP3: Water, fertilisers and substrate
Excess irrigation not only wastes water, but usually results also in environmental pollution caused by lixiviation of fertilisers. Closed cycle irrigation systems could solve this problem, but need good management for preventing accumulation of un-used ions. As closed irrigation cycles are most easily implemented in substrates, there is a need for good waste management, to avoid that we solve one pollution problem creating another one.
Accordingly, the objectives of this WP were:
1. An advice system for fertirrigation management of closed growing system in presence of ballast ions. Assessment of quick tests to assist management of fertilisers in such systems.
2. Cost / benefit analysis of the reuse of substrates.
3. To test technical feasibility and evaluate economical recycling options for perlite-based growing substrates.
4. To test technical feasibility and evaluate economical recycling options for rock wool.
Closed-loop soilless culture (hydroponics) is one of the most important components of closed greenhouses. The management of these growing systems implies the control of mineral supply (fertirrigation) as well as the selection and use of growing media, if any, and its disposal or recycling after one or more cultivation cycle. In principle, closed hydroponics should use raw water of excellent quality (with negligible content of ballast ions like Na, Cl), as well as fertilisers of high purity. In some circumstances, especially in the Mediterranean regions, growers do not have access to high-quality (non-saline) irrigation water and, if water desalinisation is not cost-effective (for instance, when low-value vegetables are produced), the application of closed growing technology is more difficult, since ballast ions inevitably accumulate in the plants, in the recycling water and/or in the substrate.
WP3 focused with the aspects inherent to the full closure of the root zone environment, focusing on the conditions that make endless re-use of the drain water currently uneconomical, which is when saline water is the only source for irrigation water. Through fertirrigation guidelines it is possible to prolong the reuse of drain water and minimise emission of polluting chemicals when the water does need to be discarded. UNIPI was responsible for this activity.
A series of experiments (UNIPI) were conducted to investigate the response of tomato and some leafy vegetables grown in closed hydroponics to excess boron in the irrigation water. The severity of B-induced leaf burn in tomato plants was alleviated by the use of saline water. Fruit B content remained well below the level representing a potential risk for the consumers. The response of tomato to B toxicity was not affected by grafting. The experiments with leafy vegetables allow to identify different tolerance of selected species, which are currently used for physiological studies on plant tolerance to B toxicity. The Penman-Monteith (PM) equation and two regression equations for determining the water use of greenhouse gerbera were also calibrated and validated.
We evaluated existing quick tests for nitrate (NO3-), ammonium (NH4+) inorganic phosphate (Pi), potassium (K+), boron (B) and chloride (Cl-) in hydroponic nutrient solutions, soil solutions and soil or substrate water extracts. Only the tests for NO3-, Cl- and Pi were accurate.
Deliverable 15 reports guidelines for best management of growing medium and fertigation (i.e. the application the nutrients with irrigation water) in closed soilless cultivation. Some Excel spreadsheets were attached to the document: NS calculator and crop simulator. Both calculators were incorporated in HydroTools, a DSS for the management of fertigation in greenhouse crops. Other two spreadsheets were prepared as a support to the LCA-WEB calculator and to manage fertigation in soil-bound crops. Mineral wool provides a sort of benchmark for growing media in consideration of their physical and chemical properties (high porosity, for instance) and the standardisation of the products on the market. However, this substrate is generally produced far from where greenhouses are concentrated; therefore, market price is high and, moreover, there is the problem originated by the disposal of exhausted material after a reasonable number of growing cycles. In Mediterranean countries, soilless cultures make a large use of perlite. For instance, in Spain, one of the biggest markets for perlite, 30 000 to 40 000 cubic meters of perlite for soilless cultivations is substituted every year and it is necessary to develop suitable recycling options. The disposal of exhausted perlite seems easier compared to rockwool, since it could be used as soil conditioner. Alternative reuse is the production (close to greenhouse cluster) of blocks for construction industry. PERLITE and TERRA investigated the technical and economic feasibility of perlite and rock-wool recycling. Two procedures were developed and tested to reuse spent perlite (for producing construction block, deliverable 16) and rockwool (TERRA, for producing growing media, deliverable 9).
WP4: PPCs
There are many drivers for improving the design and construction of new greenhouses and the drivers change with region around the EU (WPs 1, 2). EUPHORUS energy and environmental impact evaluations have shown that PPCs make a small contribution in each case. Nevertheless, for a variety of reasons it remains desirable to reduce and substitute PPCs. Indeed, there has been a universal move away from PPCs and into the use of biological control agents (BCA) for crop pests, but crop diseases remain challenging to control without chemicals. Good greenhouse sanitation protocols are important, but PPCs remain necessary as a last line of control for many commercial challenges. With the increasing use of BCAs in protected cropping the grower must now think about climate control not only for maximising plant production (principal driver) and minimising plant disease, but also for maximising the efficacy of BCAs. All three trophic levels will respond to climate variations independently, yet little is known about how the third level, the BCAs, react to the main climate variables of light, temperature and humidity.
The overall objective of this WP was: Overall objective: Minimise the application of PPCs. The specific objectives:
1. evaluate spectral filters for beneficial effects on Oidium and Tetranychus control;
2. evaluate specific P&D epidemiology against minimal ventilation management;
3. model P&D control under energy efficient glass / plastic.
In parallel to WP2 and with BASF, we tested five photoselective plastic coatings for their efficiency in controlling tomato powdery mildew and two-spotted spider mite. Altering the quality of light within the growing environment, especially in the UV region, has been proposed as a means of managing P&D pressures. Five plastics treated with novel coatings supplied by BASF were used as the covers for scaled-down polytunnels. Each was differentially active in the UV region of the light spectrum.
Statistically designed experiments allowed WAR to collect detailed datasets for both infections of tomato powdery mildew (Oidium neolycopersicae), infestations of the two-spotted spider mite (Tetranychus urticae) on rose and the efficacy of their respective BCAs. We concluded that UV photoselective plastics should not be chosen on the basis of pest or disease control, at least not at latitudes in northern Europe. In the South the UV irradiance is much greater and more extreme effects on P&D may be seen. However, the coincident reduction in BCA efficacy is still likely to counter some potential benefits. The WAR study does support the utility of B. subtilis as a biological prophylactic. Our experiments only support its use against Oidium, but there are reports of its utility in a range of other leaf infections and there is a good chance that it is beneficial for a range of diseases (deliverable 6).
Venting is used to control heat (and humidity), but it also prevents use of supplementary CO2 to enrich production and allows access for pests and diseases. Reducing ventilation, in semi-closed tunnels for example (see WP2) will affect both temperature and humidity in the growing environment. Whilst the changes may be beneficial for the energy budget, they may have unforeseen and deleterious consequences on P&D pressures, adding requirements for PPCs. One of our tasks recognised the complex cross-talk of variables in protected cropping. Data on the performances of Oidium and Tetranychus, with and without their respective BCAs, has been collected in order to build epidemiological models which will be available to advise, architects, environment engineers and growers about potential P&D performance under new protected cropping designs.
Datasets for prevailing temperature and humidity conditions have been collected from partners in Spain (EEFC), the Netherlands (WUR) and Hungary. For Spain, these span four years from one site, for the Netherlands these two years from twelve sites and for Hungary data is available for one year from one site. Data from sites testing novel greenhouse designs in Spain and the Netherlands have also been included.
A novel image analysis technique for quantifying leaf disease has been developed, tested and validated. Using input from a standard digital camera, disease coverage is automatically calculated per unit leaf area, discriminating areas of sporulation from healthy tissue, leaf veins and hairs. Using this new tool, data from a range of disease epidemiology trials were collected from tomato leaves growing under a regimen of temperatures and humidities. It was clear that Oidium was able to establish and sporulate successfully in the between 15 and 29 degrees Celsius and the prevailing humidity in most commercial greenhouses. However, the data for control using B. subtilis were encouraging. Similar experiments were concluded for the pest T. urticae. In both cases the data were incorporated into novel tri-trophic epidemiological models. The climate models were then combined with the tri-trophic P&D models allowing EUPHORUS to predict P&D pressures in each scenario and the likely effectiveness of BCAs (deliverable 11).
We then parameterised computer models to predict how both the P&D, and each BCA, will perform based on temperature and humidity data. The models parameterised environmental variations by day and by season. Combining climate models with epidemiological models enabled EUPHORUS to evaluate the effectiveness of biological controls throughout a growing year. In the Netherlands, the BCA B. subtilis could provide 15-20 % improved control of tomato powdery mildew across the year, but novel glass made no difference. For Spain the model predicted that tomatoes treated with B. subtilis benefit from a 10 - 25% increase in the time until 50 % disease leaf coverage. The model also shows that the increase in time until 50 % disease leaf coverage (protection) is greater in novel, semi-closed greenhouses than traditional, passively-ventilated greenhouses, especially in the spring and autumn.
At present, such predictions must be restricted to the spread of Oidium and its control by B. subtillis, because the periodic higher humidity may favour development of other tomato diseases. The will be a need to build epidemiological knowledge of other important tomato diseases into the climate scenarios for a more complete picture, but this is outside the scope of this project. Nevertheless, EUPHORUS has delivered new tools for helping design, test and run greenhouses for protected crops in order to reduce dependence on PPCs (deliverable 12).
WP5: Monitoring and management support
The overall objective of this WP was to boost resource use efficiency by ensuring conditions for high productivity; decrease unmarketable losses; increase quality and yield value.
The specific objectives:
1. online monitoring tools for greenhouse performance;
2. online monitoring tools for crop performance;
3. proof of concept of early detection tools for pests and diseases;
4. management support tool that provides the grower with useful information about performance of the greenhouse system and that advises about the controls needed.
For monitoring of the performance of the greenhouse, a soft sensor was developed to estimate continuously the ventilation rate of a greenhouse and the transpiration of the crop. This method makes use of data that are routinely measured by climate control computers, and is suitable for implementation and online application (deliverable 17).
Based on this, a tool was developed for the cost-effective optimisation of additional CO2 supply in greenhouses. The model used in this tool calculates the optimal desired CO2 concentration based on the crop's need for CO2 (uptake due to photosynthesis), the loss of CO2 from the greenhouse by ventilation, the price of the product (e.g. the tomatoes or roses) and the cost of the CO2 to be supplied.
The soft-sensor for monitoring ventilation and transpiration rate of a greenhouse and the tool for cost-effective optimisation of pure CO2 supply in the greenhouse was implemented by HortiMaX in a test greenhouse at EEFC in Almeria (deliverable 23). The results were promising and HortiMaX is planning to install the tool also in Holland, since energy saving and/or application of renewable energy ensures that less CO2 is available as by-product of heating and more and more growers rely on pure CO2 for supply. A follow-up proposal on this topic has been submitted to a EU-FP7 call aimed at small and medium-sized enterprises (SMEs).
With respect to early detection of biotic stress, we have evaluated several imaging and volatile detection technologies which could provide possible early P&D detection. From the point of view of sensitivity, availability, ease of installation, ease of use and cost, volatile sensing techniques offer the most promising approach. A chemical signature sensor (E-nose) and a mobility spectrometer (FAIMS) were chosen for application in laboratory and field tests. Pattern recognition and training were used to discriminate between the complex 'volatile signatures' of plants affected by specific pests and diseases and those of clean plants. For laboratory based experiments the results show that disease could be discriminates as early as four-day post infection. However, for field trials the best results achieved a correct classification for 86 % of samples, although this was based on a relatively small number of samples (between 3 and 15 samples per category). Automatic sampling would be necessary in order to build statistically significant and repeatable datasets. The sensor technologies have shown that they do have the capacity for successful discrimination should the training periods be sufficient. There may need to be sampling protocols in order to minimise interference from background commercial activities and maximise the potential of these technologies. These could be as straightforward as automatic sampling before the start of the day, avoiding areas undergoing harvesting, spraying or clearing operations. It can be concluded that volatile organic compound (VOC) sensing can probably deliver early alert technology in protected cropping environments when coupled to intelligent systems computing. However, at present these remain at the experimental phase of development and none of the techniques investigated can be readily used in industrial greenhouse production. EUPHOROS has provided a prototype system and further development in the next three to five years could readily produce viable commercial systems. In line with this, diagrams or photographs illustrating and promoting the work of the project, as well as relevant contact details or list of partners can be provided without restriction.
More disappointing were the results about early detection of abiotic stress (drought). We tested several methods, based on spectrometry, and none was able to detect stress with an earliness compatible with greenhouse management (which has obviously much stricter requirements than field production). All results about early detection of stress (biotic and abiotic) are reported in deliverable 18.
WP6: Integration and evaluation
The purpose of this WP was to integrate the tools developed in the other WP's in combinations relevant to three local markets and to test the feasibility of each combination. Each of the European countries has its own greenhouse structure and equipment that have evolved locally according to specific circumstances. These can be environmental (climate, water availability and quality, soil structure and quality), cultural (the education level of the grower, the management structure in the greenhouse, the level of environmental friendly conscience of the grower, the traditions that led to the actual cultivation methods), economic (how much can a grower invest in greenhouse structure, equipment and tools, which market do they serve and what does the market expect from the grower). Therefore, the testing in practice and implementation of the tools developed within the development WPs of EUPHOROS, has been addressed from a local point of view. WP6 dealt with implementation of the developed tools in combinations relevant to three local situations. The local situations were: Almería (Spain), Morahalom (Hugary), later replaced by Tuscany (Italy), and Bleiswijk (the Netherlands). Each situation one climate, one culture, one market.
The specific objectives of this WP were to:
1. increase the chance of acceptance through involvement of the end users in an early stage;
2. give feed-back to the developing partners through tests of the tools in three very different climate / market conditions.
These objectives have been achieved through two lines of actions:
(i) involvement of the end users (leading growers and / or growers' organisation, extension services) during the development phase;
(ii) test and evaluation of the most promising combinations of elements at prominent applied research stations in Spain, the Netherlands and Italy.
In the first meeting of the project partners it was decided that tomato would be the working crop for the test and evaluation in Spain and Italy; roses the working crop for the Netherlands. Cut flower cultivation, with roses as the number one cut flower are relevant in surface, economic importance, and in environmental impact. From a total surface cultivated under greenhouses of 10 250 hectares, almost half of it is dedicated to the cultivation of ornamental flowers and plants. Holland has the highest consumption per capita of flowers and plants in the world. Ornamental products, plants and flowers, are also a very important export product in the Dutch economy. It is also a very innovative and mechanised subsector. Within the area dedicated to the ornamental plants, a little bit more than half of it (2430 Ha) is dedicated to the production of cut flowers. In 2011, the rose accounts for 19 % of the total cut flower cultivation surface: after the Crysanthemum, it occupies, the second place in terms of surface and the first one in terms of value: 23 % of the total value of the cut flowers sold by the Dutch Auctions and produced in the Netherlands.
A thorough economic and environmental analysis of the tomato cultivation systems in Hungary and Spain as well as of the rose cultivation in the Netherlands (a reference situation calculated with data from the years 2007 and 2008) was performed at the beginning of EUPHOROS, within WP1. This work helped to decide on which developments to focus (always in close consultation with local stakeholders). The analysis forecasted the potential economic impact of reducing a certain input. It showed that within the cost components of a rose farm in the Netherlands the total costs are mainly determined by: energy and labour. The costs for energy accounts in roses for 36 % of the total costs. This places the input 'energy' as the most important input in which to focus in a project aiming economically viable input reduction. The costs of paid labour accounts for 22 % of the total costs. Therefore, any development able to achieve a reduction in the costs for labour, will contribute to an economically interesting improvement of the production system. The analysis for Spain led the focus towards heat reduction in summer and energy saving options. The costs of fertilisers in Hungary are huge, and as the economic forecast learnt that saving 50 % fertilisers would create a very attractive investment capacity of more than 17 EUR / m2 per year, efforts in this location concentrated in a closed loop circulation; later tested in Tuscany, Italy. Both locations, Hungary and Italy showing great reluctance from growers to adopt this kind of systems due to phytopathologic fears.
To ensure that the combinations of elements to be tested in the greenhouse conditions at each site were tuned with the expectations of the local growers, at each site feed-back sessions were conducted with groups of relevant stakeholders and potential users. These sessions lead to a plan of tool combinations to implement in trials at each location (deliverable 4). These trials were conducted in 2010 and 2011. In Almería, with a tomato crop, a greenhouse film cover (BASF) with a NIR absorbing coating was evaluated. NIR-absorption lead to a decrease in production equal to the loss in light transmission. New developments should focus on NIR reflection, coupled to high PAR transmittance. A thermal day storage system (EEFC) allowed to heat the greenhouse at night with the heat collected during the day, potentially saving in heating costs, although economically unfeasible at the present market and energy price conditions. The evaluated smart-dust climate measurement system (Hortimax) and a CO2 optimising software (WUR and Hortimax) are ready for exploitation. In Bleiswijk (the Netherlands), with a rose crop, two of the tested developments are ready to be implemented in practice: a cover of Diffuse glass with a AR coating (GroGlass) that lead to a production increase of 5.2 % more stems, and a Rockwool plug-slab combination that decrease the substrate volume by 20 %. Further development (more speed and autonomy), is needed for the electronic nose as an early warning device for pests and diseases. A transpiration model to adjust irrigation will need further adjustments and validation in practice. The two developments tested in Tuscany with a tomato crop (a closed-loop fertigation system and quick test for monitoring nutrients) are ready to be implemented. The results served to give feed-back to the developing partners and firms, for their subsequent development (deliverable 19).
WP7: Dissemination
The lasting contribution to the exploitation of the results of the project is the web page (see http://www.euphoros.wur.nl online) and particularly the web-tools available there (deliverable 20), whose expected users are professionals, companies and scientists. The tools make it possible to calculate:
1. the environmental footprint of one's farm, and of possible improvements;
2. to assess the financial consequence of modification to one's farm;
3. to evaluate the effect of possible modifications of the opening area on the ventilation rate of the greenhouse;
4. provide support for the management of closed-loop fertirrigation systems.
The results of the project have been given wide international resonance through massive participation in two symposia of the International Society of Horticultural Science, whose proceedings are available on the site of the ISHS (deliverable 27). In addition, a number of local thematic workshop have been organised in Britain, Hungary, Italy, the Netherlands, and Spain (deliverable 25), where also a course for professionals was organised (deliverable 26). The results of the project and the web tools have also been widely publicised in papers, symposia, press releases and trade magazines.
Potential impact:
Each of the tested developments had an impact as they all contributed to knowledge development about the tool, the conditions in which to use it, and the performance in semi-commercial conditions. Developments that are not economically feasible now, can become of importance if the conditions in which they are not economically feasible at this moment in the tested location, change. Such is the case, for instance, of the heat day-storage tower in Almería, that despite the great potential savings in energy, it is too expensive to run with the actual energy prices. However, this tool can become economically interesting if the price of the energy source becomes higher than the installation and running costs of the heat storage system. Similarly, the Venlow energy saving greenhouse tested in the Netherlands, is not presently economical, in spite of the huge reduction in energy requirement. It may well be with higher energy prices in the future.
Developments that are not ready to implement but still have a great potential in labour savings are for instance the pest-detection methods. Growers and developers have become aware of the existence of e-technologies that in a nearby future can help them with these labour-intensive activities. In the next years, we can expect quick developments in this field. The tests in Almeria with novel plastic additives have shown that manipulation of radiation by means of additives is not an easy task: it will require some further development in order to allow maximal PAR transmission, but block, reflect and absorb other wavelengths.
On the other hand, quite a few project results are ready for exploitation / implementation:
- Online monitoring and CO2 fertilisation of greenhouses: an economically feasible and impact reducing development.
- The proof-of-principle of the implementation of the monitoring module in the Multima climate computer of Hortimax was positive. Hortimax is willing to develop further the system and implement it in its advanced line of greenhouse computers. A proposal in this direction has been submitted to a EU-FP7 call aimed at exploitation of project results by SMEs.
Computational fluid dynamic (CFD)-aided ventilation design: an economically feasible and impact reducing development. The performance of the prototype greenhouse with improved ventilation design in Almeria made clear that there is a huge potential for increasing productivity of Mediterranean greenhouses (some 40 %) simply by better design and management of ventilation. There is a need for developing CFD-based indicators for assisted greenhouse design. IRTA has cooperated with an Italian greenhouse builder to submit a proposal in this direction to a EU-FP7 call aimed at exploitation of project results by SMEs.
Diffuse glass with AR coating in rose cultivation: an economically feasible and impact reducing development
With the obtained increase in flower yield of 5.2 % more stems of equal to slightly better quality, the examined glass (tempered, by GroGlass double-sided AR coated Vetrasol 503) can be economically feasible (Ruijs et al., 2011), as it has been calculated that 1.5 % more production already can finance the extra investment costs necessary for this type of glass with a payback period of 4 year (calculations based on price estimates by one supplier). Despite the fact that for the production of the diffuse glass with AR coating requires extra electricity, the environmental analysis (Torellas et al., 2011) has shown that with the obtained yield increase (5 %) the development had an obvious benefit, reducing environmental impacts of the production system. In terms of environmental impact this increase in yield compensated the extra energy required for the production of diffuse glass compared to standard glass. Environmental impacts were reduced around 4.6 % to all considered impact categories.
Diffuse glass has a broad impact in Dutch horticulture, beyond rose cultivation
The use of diffuse glass in horticulture has started to be a reality in practice. Parallel to the Euphoros trial, a rose trial was conducted (contract research) for another glass supplier with a Diffuse cover with AR coating on one side only. Results were very similar to the ones obtained in the Euphoros implementation trial. Short after the start of the implementation trial Euphoros in roses, trials started with tomato, where different haze factors were tested. The results show a higher impact from diffuse glass on tomato production (up to 11 % extra production) with the same energy input, probably due to the fact that no shadow screens need to be used in summer and no artificial light was used in the winter, giving the properties of the cover really a chance to influence the cultivation. In 2012, trials with cucumber followed, and showed even more spectacular results than with tomato: 10 % more production with the same energy input in only three (winter!) months. Altogether, a huge potential lies in front of these developments, growers have a great interest and follow the developments around new glasshouse covering materials. A few greenhouses have already been built with these materials. In the coming years new developments can be expected in these field.
Rockwool plugs and smaller slabs reduce substrate volume but have little economic or environmental impact in rose cultivation
The rose plants (Rosa hybrida cultivar 'Red Naomi'!) for the main EUPHOROS trial in Bleiswijk were propagated by cuttings using the Synchronisation Method (Van Telgen et al., 2003) of Wageningen UR Glasshouse Horticulture in Rockwool plugs (Grodan). Once the plantlets were rooted they were planted in SPU (single production units) The reference situation consists of +/- 4 rockwool blocks for propagation wich are placed at planting on top of the substrate slab (100 x 12 x 7.5 cm) with rockwool (Grodan). The used system saves 20 % substrate compared to the reference. The reduced size of the units allowed also extended propagation of the plants and transport of the productive plants to the experimental compartments, instead of planting small plants directly on the slab. The economic evaluation (Ruijs et al., 2011) showed that the reduction of substrate volume with SPU results in a saving of 0.10-0.16 EUR / m2 depending on the SPU option. A sensitivity analysis of the substrate price points out that the savings (difference in yearly costs between the option and the standard cultivation system) are not very much affected, because of the four year cultivation period. The environmental impact analysis (Torrellas et al., 2011) confirms that lower use of substrate volume produced significant reductions in auxiliary equipment (20.6 % in cumulative energy demand) but had a small effect in the total production system (4.8 %). This kind of results would make difficult to convince growers to implement an alternative that gives little environmental improvements in the production system and on the other hand requires extra effort in agricultural practices. However, substrate volume reduction must be equally encouraged to move to more environmental friendly practices.
Closed loop fertirrigation saves water, pesticides and avoids emissions to the environment. Recirculation of nutritive solutions is common practice in The Netherlands, where environmental regulations have made it compulsory since many years. However, in countries like Hungary, Italy and Spain, despite the high cost of fertilisers and the scarcity of water of good quality, growers are very reluctant to use such a system, mainly, as they say, by fear for root borne diseases to spread with the re-use of the leached water. The trials in Tuscany performed by the University of Pisa, UNIPI have shown that 100 % recirculation is possible in tomato cultivation in Italy without any decrease in production nor in fruit quality. A reduction of the water consumption of 25 % was achieved; 11 to 40 % less fertilisers were wasted, delivering a payback time of about two years for the installation. To meet the doubts of the growers, the researchers showed that by means of a simple disinfection system it is possible to reduce the risk for diseases. However, the disinfection equipment together with the analysis for monitoring the diseases increased the required investment for the installation of such a system. Provided the monitoring tools ensured a 100 % closure of the system, they would provide a saving of only EUR 0.12 / m2 year, requiring a pay-back time of the system of over 8 years. These economic results make it difficult to convince growers to switch to these systems. Great efforts have been done by the researchers to disseminate these results.
Conclusion and recommendations
Altogether, we have shown quite a few input reducing options that have good prospects from environmental and economic point of view. The challenge and objective should be to encourage and stimulate growers in all European greenhouse production areas to invest in input and/or emission reducing options to save the environment / planet and to improve the competitiveness of the European greenhouse industry in the global competition.
Although research and demonstration projects have shown the advantages of those options still great efforts have to be done to awaken and to support growers in their transition to a sustainable greenhouse production.
Education, courses and small-scale experiments should be initiated to help and to convince growers in adapting the new and innovative options in their own practice or situation.
It is also recommendable to focus the awakening and knowledge transfer on suppliers of structures, climate systems and irrigations systems in order to stimulate the knowledge flow from research to practice. After all, suppliers and their salesmen have intensive contacts with the end users (growers).
The results and prospects have been shown for the pilot crops tomato (Spain, Hungary, Italy and the Netherlands) and rose (the Netherlands). It would be recommended to shift the attention in research and extension service also to other crops in greenhouse vegetables, cut flowers and potted plants in all European greenhouse areas.
The web tool for the environmental and economic assessment of performances of input / emission reducing options is particularly interesting for advisors, extension service and education. The model (although much simplified) gives insight in the relations between input and output in terms of environmental and economic impact and gives leads / clues to improve the environmental and economic profile of the greenhouse production system in all European countries.
The EUPHOROS research project has proven that environmental friendly greenhouse productions systems can go hand in hand with economic viability. This offers great perspectives for greenhouse production in the future in Europe and worldwide.
Project website: http://www.euphoros.wur.nl
