Research on substrates: State of the art and need for the coming 10 years

This paper presents the knowledge used today as well as that which may be needed in the near future on the products themselves and on their associated management. The substrate market has considerably developed over the last 20 years. Several factors explain this, including the development of nursery products "ready to plant", mainly grown in containers and the research for precocity and agronomic performance, through the monitoring of most production parameters. These developments were accompanied by intensive research activities, both public and private, dealing with the products, first carried on rockwool and then on peat based mixtures, and with the production features. Important advances were accomplished: i) on the physical properties (management of water and air stock), ii) on the plant nutrition (management of the exchange in the substrate liquid and solid phase and from the substrate to the root system) and requirements, iii) on the substrate biological properties and their role in disease propagation. What are now those needs for the coming 10 years? 1. Products. Environmental constraints will increase, trying to limit the extent of peat use in growing media or to substitute it by industrial by-products. Environmental constraints will also apply for the after use elimination of these substrates. Researches on alternative peat products of organic origin, potentially usable as substrates, therefore appear necessary. 2. Associated management. i. With the help of emerging technologies, it appears possible to move from the management of reserves to that of fluxes (gases, solutes and water). This means having to develop appropriate models and model parameter characterisation procedures to adequately describe fluxes in the substrate-plant-atmosphere continuum (SPAC). ii. Environmental constraints stress the need for more research to reduce water, fertilisers, growth regulators, wetting agents and biocides use and leaching into the environment. iii. Research on peat-free products has to include the biostability of these products and its consequence on chemical, biological and physical properties. iv. The physiology of cultivated plant must be studied, to integrate this knowledge into models of the substrate-plant-atmosphere continuum v. Research results must be integrated for establishing references and norms for commercial purposes.