In strawberry cultivation, soil nematodes, soil-borne fungi, and weeds must be combated. This often presents a problem, not least because of a lack of approved pesticides. Soil steaming offers a solution for this issue. MSD (Möschle, Seifert Dämpftechnik), a company from Durbach, Germany, has developed a revolutionary technology for the cultivation of strawberries in raised beds covered with polythene. In this process, steaming is conducted just before planting.
For raised beds with typical dimensions and a double row of strawberries, 3m long steam hoods are used for each raised bed with a plant spacing of 30cm x 30cm. The steam hoods are fitted with spikes approximately 30cm long which direct the steam into the raised bed, through the polythene film.An MS200 steam generator from MSD is used to produce the steam. It has a maximum output of 250 kg/h with an operating pressure of 0.5 bar and a steam emission temperature of 200C.
The results of this test showed that the spikes and the hot steam did not damage the polythene film on the rows. No heat adhesions could be detected, and the same is true of the areas where the steam hood touched the plastic. There was found to be sufficient heat flow in the raised bed. As expected, the highest temperatures of over 90C were found in the areas immediately surrounding the points of penetration. On the outer surface of the raised row, temperatures of at least 75C could still be found. These temperatures are sufficient to eliminate soil nematodes, soil-borne fungi, and weeds.
Initial mycological test results from the laboratory at the Agricultural Technology Center in Augustenberg show that steaming through the planting holes alone is sufficient to completely kill off all pests. After steaming the affected soil, the presence of no living verticillium fungus could be verified. The temperatures of 70-80C killed it off entirely.This proved that sufficient steam distribution and, consequently, temperature distribution, for sterilisation can be achieved with a 30cm steam spike grid on a ready-to-plant bed that is covered with film. The experiments were conducted in co-operation with the agricultural office of Bruchsal.