Microbially healthy water in greenhouse horticulture

Dutch greenhouse horticulture is mostly producing crops in soilless cultivation systems in a growing medium. Production in these production systems is higher than in conventional soil-grown crop production, due to better options for monitoring and control of physical parameters in the root zone environment. Also emissions of plant protection products and nutrients to the environment is much lower in these systems. However, these systems increasingly encounter problems related to microbial water quality.

Within the project 'Microbially healthy water' new methods for measuring and controlling microbial quality and health of the recirculating nutrient solution are developed. These methods will be used to find positive and harmful effects of the microbial composition of the water and the cultivation system on crop health, and to identify possibilities to control the microbial composition by preventive, mitigating or curative measures and apply these in commercial companies. A boundary condition for these methods is zero emission cultivation, towards which Dutch greenhouse industry is moving, at latest in 2027. Knowledge on the influence of micro-organisms on microbial water quality is a crucial step towards robust, zero-emission cultivation systems, in which a stable microbial root zone environment prevents the development of pathogens and thereby the need to use plant protection products. Cultivation systems based on these principles can be applied broadly in the (Dutch) greenhouse sector.

Specific focus will be on control of the composition of the recirculating nutrient solution, to create a robust microbial water quality in the root zone environment (work package 1: KWR, SCFF, Glastuinbouw Nederland, Grodan, Kwekerij Vereijken, Groen Agro Control, Plantenkwekerij Brabant Plant, gewascoƶperatie Gerbera, Gewascoƶperatie Potorchidee), and to control biofilm formation in the irrigation system (work package 2: Wageningen University & Research, KWR, Glastuinbouw Nederland, Microbac, Cindro, Planet Horizons Technologies, Advanced Waste Water Solutions, MVP Starmaker). With developed measures, development and spread of pathogenic micro-organisms can be controlled.