Background Conventional agricultural practices in EU Member States currently results in a fertiliser consumption of 2 000-2 500 kg/ha/yr. Such amounts have considerable negative consequences for soil and water pollution in Europe. Recent studies suggest that adding carbon dioxide (CO2) and oxygen to water used for irrigation - a system known as fertigation - increases both yield and crop quality, while reducing soil and groundwater pollution. Though first studies have proven highly promising, fertirrigation has not yet been tested on a large scale. Objectives The project aimed to demonstrate the technical and economic viability of fertigation, as well as several other new agricultural techniques. Applied to large-scale intensive crops, this approach would aim to reduce soil and ground-water pollution. The fertigation technology would be applied in the greenhouses of six cut-flower producers. The project planned to optimise the technique and develop a standard procedure for its widespread implementation. Results The FERTIGREEN project demonstrated the technical viability of the new gas system and the potential improvement that it may represent for the whole horticulture sector, both economically and environmentally. The demonstration was based on two developments: gas system injection in greenhouses and data modelling for fertigation process control. All activities were completed successfully: design of field testing and data acquisition protocol, installation of the gas technology in six greenhouses and subsequent development of a computer model. Actions also included an analysis of the technical and economical viability of the system. The project also demonstrated that: Applying CO2 to irrigation water avoids the use of nitric acid for pH control, with related positive effects, especially for health and safety and reduction in groundwater pollution. Better flower yields and quality can be obtained using the project methodology, a result that is encouraging for the further application of this system. The main problem to solve in this production sector is the control of the quantity of water and fertiliser applied to each crop, causing, in most cases, over irrigation. Increased resistance of crops to fungi and bacteria is possible, and the need to reduce the amount of added chemical products.The technologies developed by the project are directly transferable and could be reproduced and applied to most crops in the EU, especially fruit and vegetables where intensive production methods are used (for example, tomatoes, peppers and strawberries). The developed gas, sensor and data collection system are easy to install and implement, they require relatively low investment costs, and can be adapted to any type of current installation. The technical results, however, could not be entirely validated: the expected benefits of the fertigation system, especially the reduction of nitrate contamination and increase in crop yield and quality, require further validation. The main reason for the limited success of the project was the high variability in the field data, due to the fact that it was a demonstration project. Tests performed in real conditions on intensive cultures would obviously lead to different results Further research into the use of gas into irrigation water for intensive crops is needed in order to define precisely and quantify the real benefits of this technology, since the effect of the gas use was masked by the excess amount of irrigation water. A positive outcome, however, was the raising of awareness of the importance of adequate and efficient water and fertiliser management. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).