Background Greenhouse agriculture is a potential adaptation and mitigation strategy to climate change. Growing crops in such a protected environment will enable more adaptation to the predicted increase in frequency of extreme weather. It will also help mitigate the negative effects of wind, drought and severe rainfall. Another advantage of greenhouse horticulture over open field cultivation is that it allows crops to be cultivated in continuous cycles independent of seasons and natural soil conditions. Thus it bypasses the problem of ‘competition for soil’ between energy crops and food crops. Traditional greenhouse agriculture, however, has been very environmentally unfriendly. The major problems are that it has generally required a lot of chemicals, high energy and water (which are directly and indirectly connected to greenhouse gas emissions) and has produced polluting effluents. Objectives The overall purpose of the SUSTGREENHOUSE project was to demonstrate a new sustainable model of greenhouse horticulture that supports the local economy while reducing negative impacts on the environment. It aimed to create a ‘Living Greenhouse’, utilising totally nature-friendly technologies that reduce emissions. The project would develop and demonstrate specific technologies to reduce water input and energy consumption. It would show that greenhouse agriculture can be compatible with nature protection and can be carried out in natural parks and reserves without problems. More specifically, it would show that greenhouse agriculture can result in fewer direct and indirect greenhouse gas emissions, lower water consumption and the emission of fewer polluting nutrients and chemicals into the soil and the air. Expected results of the project included a reduction of CO2 by 10% and of effluent discharge by 20% compared with traditional greenhouse agriculture. The project also aimed to help farmers and students understand the complex relationship between air, water and soil in the greenhouse structure through the development of online monitoring tools, and awareness raising and training activities. It planned to emphasise the responsibilities that agriculture operators have in reducing the global carbon footprint. Results The SUSTGREENHOUSE project demonstrated the feasibility of improving the environmental performance of greenhouses in the Fondi area of the Italian region of Lazio without affecting the quality and quantity of production. It also showed that economic savings are possible. Two demonstration greenhouses were established inside the Special Protected Area of the Fondi Lake and comparisons were made over a three-year period. One followed traditional practices – in order to serve as a control – and the other one utilised the best commercial technologies to reduce emissions. The innovations implemented in this greenhouse included: Rationalisation of the defrosting irrigation system (dynamic sprinklers); Use of a thermal screen; Mixing organic matter (compost) and zeolites to the soil; Use of fungi (mycorrhiza association); Introduction of irrigation and fertilising systems (precision farming).The thermal screen consists of a perforated aluminium layer on a natural cotton support. It runs on a rail allowing it to be drawn up under the ceiling of the greenhouse when it is too cold or there is too much sunshine. In this way during the night the infra-red rays of the crops are reflected downward and direct contact with the cold air is avoided. The thermal screens and dynamic sprinklers tools were implemented to protect greenhouse crops from the low winter temperatures, as an alternative to the conventional defrosting systems. The compost of organic waste serves as a very good natural fertiliser that also improves the soil texture, while the zeolites are minerals with a regular porous crystalline structure that contains much empty space, allowing them to behave like sponges. The zeolites thus capture water and other elements and release them to the roots of the plants slowly. Mycorrhiza associations are structures formed by the union (symbiosis) between fungi in the soil and the young roots of the plants. The crop plantlets were added so that the mushrooms live close to their roots helping them to absorb water and food more easily. They are also able to develop greater resistance to root diseases. The growing substrates enhance soil fertility and biodiversity, increase root adsorption, reduce chemical nutrients and irrigation water, and increase CO2 adsorption and sink. The project also demonstrated precision farming techniques for fertilisation and irrigation. Precision farming utilises provisional and/or diagnostic tools based on the effective needs of the plants in order to optimise irrigation and fertilising and to reduce waste and the use of water and nutrients. Typical local crops were grown over three years in the two greenhouses. Four crops were grown, alternating courgette and tomato, and utilising a demonstration split-plot scheme with 36 random blocks divided in three trials and four under-trials repetitions. The production samples and the recorded environmental data were analysed, and economic and environmental balances were calculated. A global LCA assessment was carried out in order to verify the results obtained with the sustainable greenhouse model. For the first time in Italy a LCA study was conducted on a crop raised in a greenhouse. It required a specific inventory of all the parameters to be taken in consideration. The project’s approach was shown to offer many advantages over conventional greenhouses. Thermal screens were already widely installed in nurseries and flower greenhouses, but they are not used in Mediterranean protected horticulture because of their high price. The trials gave evidence that their economical benefits would recoup investment costs in a few years. Thanks to the thermal screen, the sustainable greenhouse offered a dryer climate with fewer diseases, needing only eight chemical treatments (1.9 Kg x 1000 m2). By contrast, plants grown in the conventional greenhouse were attacked by fungi and 11 chemical treatments (5.3 Kg x 1000 m2) were required. The defrosting system, operated alongside the thermal screen, significantly reduced the amount of water required for anti-frost irrigation. Savings of up to 86% were demonstrated as irrigation requirements are lower in the innovation greenhouse. Through precision agriculture, irrigation and nitrogen fertilisation were made more efficient by basing them on the actual requirements of the plants. Overall, water consumption in irrigation was shown to be able to decrease by 19-25% thanks to 36 soil moisture sensors placed near the roots and on a fine tuned calculation of the specific irrigation needs of each crop. Furthermore, nitrogen fertilisation could be cut by 29% by adjusting it on the basis of weekly monitoring of the exchange of gas fluxes, oxygen and carbon dioxide, of the system ‘plantsoil’, thanks to dynamic detection of the leaf gas exchange, the fluorescence, the soil respiration, and therefore the photosynthetic activity. The project also demonstrated that production can be increased by 5-6%, with savings in expenditures ranging from 0 to 4% and without affecting the quality of the production. Such an increase can be accompanied moreover by a strong reduction in environmental impacts, mostly in soil enriched with compost and mycorrhizas (except for acidification of water and eutrophication). Life Cycle Analysis highlighted that soil enriched with compost and mycorrhizas not only performed best, but also resulted in the largest decrease the GHG emissions. Indicators show CO2 emissions are reduced by 57% and ozone depletion is reduced by 68%. The beneficiary involved local stakeholders in the Steering Committee of the project. It hoped that the regional services that provide technical assistance to farmers would disseminate the methods and techniques of the project. Moreover, the success of the crop trials was assessed using environmental monitoring equipment that was connected to the internet allowing results to be displayed in real time online that both the project team and the public could follow. Further information on the project can be found in the project's layman report (see "Read more" section).