Icke kemiska metoder för sanering och rengöring

A growing consciousness of health hazards in using and handling chemical substances for commercial horticulture has created a need for non-chemical methods as a means of control and disinfestation. This report is a review of the use and experience of different non-chemical methods. Some new methods which are being developed are microwaves, gamma radiation and ionization. Old methods like the use of steam for disinfection have been improved. They are more energy-efficient and less time-consuming. The possibility of using microwave energy to disinfest growing substrate, both soil and artificial material, is being researched. It is a low-energy and less time-consuming method when it comes to sterilizing soil. Satisfactory results have been documented. The technology has yet to be developed to fit the needs of commercial horticulture. When artificial substrate, rockwool, was treated in a microwave oven it resulted in an unequal distribution of heat in the rockwool and there was a limited temperature range in moistened rockwool. Rockwoll treated with RF-waves was however sufficiently disinfected. The use of steam for sterilizing soil is a well-known method. A new system with negative pressure is beeing developed. This system is more efficient than drain-steaming and steam applied under a plastic cover. Recycled rockwool is satisfactorily sterilized in containers heated by steam in many countries including Holland. The advantage of preventing problems by maintaining highly hygienic standards must not be underestimated. Different methods of cleaning the equipment are available, e.g. steam chambers for cleaning equipment, pot trays, recycled pots etc as well as hot water baths for disinfection of pot trays. Continuous cleaning of greenhouse buildings, coverings and fixtures with high-pressure and hot water is another way to forestall problems. Even the tables should be cleaned with high-pressure when possible. Recirculated drain water and nutrients are a main source of infection. There are different methods to sterilizing the solution, e.g. UV-light, ultra filtration, heating or biological filters