Horticulture sans sol : histoire et actualité

Soilless horticulture is a production tool using mineral solution for the plant nutrition with another substrate or support than soil. The apparition of this agrotechnic at the beginning of the twentieth century is linked with the history of the knowledge in plant mineral nutrition. The first conceptual break between plant and soil is the fact of van Helmont at the beginning of the seventeenth century. Nitre as a nutritive principle was experimented by Glauber in the middle of the same century. The questioning of Woodward in 1699 on the role of small terrestrial particles and salts would be answered firstly by de Saussure in 1804 and then by agricultural chemists during the nineteenth century. Sand culture or solution culture transfer from nutrition research laboratory to horticultural production appears in the twenties in the US with carnation, rose or tomato in a favourable scientific environment. In France in 1938, Truffaut introduces the Gericke’s soilless technic. But isolated exemples and whatever the yield increase with soilless cultivation on inactive or active substrates, the professional horticulturists develop effectively this agrotechnic between 1980 and 1990 after a long time of experimentation by research and extension services between 1965 and 1985. Firstly working with recirculated nutritive solution, this development was the fact of light and practical equipments, of the automation but mainly of the leaching of used solutions. Volumes and mineral contents of these leachings has increased considerably during the fifteen past years. Since 1990, the environmental consequences of this habit raise new concerns and new needs in experimenting recirculation technics. But desinfection is a handicap for recirculation. Technical solutions would be acceptable by vegetable and ornemental horticulturists only if there are minimal plant health hazards and economically optimal solutions. Free of the physical and chemical soil limits, soilless technics must face a growing social and environmental pressure. However, adopting;the soilless technics, being aware of the environmental hazards or demonstrating new acceptable solutions, the history of this agrotechnic shows firstly the links between science, application and society and secondly the weight of time in the transfer from the lab to the field.