Potential of a bioreactor applied to nutrient solutions in a soilless tomato crop

The CTIFL (Carquefou, France) in partnership with the company Divatec, has developed a bioreactor applied to nutrient solutions in a soilless tomato crop. The objectives were to increase the resilience of soilless system against pathogens, to improve fertilization efficiency, and to boost agronomic performance. Inspired by aquaponics cultivation, the principle was to create a nitrifying biofilter promoting the development of potential beneficial plant bacteria. The solution enriched with living organisms was then used to make regular nutrient solutions which were provided daily to the plant by drip irrigation. Plant architecture (plant growth, stem diameter, leaf area index, root density), agronomic parameters and yield were measured in comparison with a conventional irrigation system. Development of Agrobacterium rhizogenes was evaluated at the end of each growing season by a visual inspection of rockwool slabs. Using the bioreactor increased both vegetative and generative vigor as seen on growth (6.4%), stem diameter (7.9%), leaf area index (17.5%), marketable yield (6.4%) and average fruits weight (5.6%). Bioreactor treatment significantly reduced the frequency of presence and heavy roots colonization by Agrobacterium rhizogenes. Results demonstrated that the developed bioreactor had a positive economic and sanitary impact on a soilless tomato crop. This approach opens a new research area on organic nutrition in commercial soilless production.