integrated sandwich steaming The partial integrated sandwich steaming is an advanced combined method for steaming merely the areas which shall be planted and purposely leaving out those areas which shall not be used. In order to avoid risk of re-infection of steamed areas with pest from unsteamed areas, beneficial organisms can directly be injected into the hygenized soil via a soil activator (e.g. special compost). The partial sandwich steaming unlocks further potential savings in the steaming process. Container / Stack steaming Stack steaming is used when thermically treating compost and substrates such as turf. Depending on the amount, the material to be steamed is piled up to 70 cm height in steaming boxes or in small dump trailers. Steam is evenly injected via manifolds. For huge amounts, steaming containers and soil boxes are used which are equipped with suction systems to improve steaming results. Midget amounts can be steamed in special small steaming devices. The amount of soil steamed should be tuned in a way that steaming time amounts to at most 1.5 h in order to avoid large quantities of condensed water in the bottom layers of the soil. In light substrates, such as turf, the performance per hour is significantly higher. History Modern soil steam sterilization was first discovered in 1888 (by Frank in Germany) and was first commercially used in the United States (by Rudd) in 1893 (Baker 1962). Since then, a wide variety of steam machines have been built to disinfest both commercial greenhouse and nursery field soils (Grossman and Liebman 1995). In the 1950s, for example, steam sterilization technologies expanded from disinfestation of potting soil and greenhouse mixes to commercial production of steam rakes and tractor-drawn steam blades for fumigating small acres of cut flowers and other high-value field crops (Langedijk 1959). Today, even more effective steam technologies are being developed. Application of hot steam In horticulture as well as nurseries for sterilization of substrates and top soil In agriculture for sterilization and treatment of food waste for pig fattening and heating of molasses In mushroom cultivation for pasteurization of growing rooms, sterilization of top soil and combined application as heating In wineries as combination boiler for sterilization and cleaning of storage tanks, tempering of mash and for warm water generation. References Further reading (1997): STEAM - The Hottest Alternative to Methyl Bromide. American Nurseryman, August 15, 1997, 37–43 (1995): Agricultiural Production Without Methyl Bromide