POSSIBILITIES IN MICROWAVE APPLICATION FOR GROWING SUBSTRATE DISINFESTATION

Microwave application for agricultural or horticultural purposes is useful with regard to environmental care when compared to the use of pesticides and low energy cost when compared to steam treatment.

The experimental work consists of depth penetration studies of 2450 ± 20 MHz waves measured by means of biological test material (i.e. : Rhizoctonia solani, Fusarium oxysporum f.sp. lycopersici, Verticillium sp., Pyrenochaeta sp. Trichoderma longibrachiatum and Lepidium sativum seeds), temperature measurements and heating of moistened rockwool for recycling as growing support.

Although the experimental microwave source was of weak effective power (600 W), changes in CO₂-production and nitrogen mineralization by soils have been stated due to exposure periods of several minutes.
Fungal growth and seed germination were inhibited depending on soil type, exposure period, depth and soil moisture content.
An experiment with Pyrenochaeta infested soil showed reduced brown root rot symptoms on tomato plants after microwave application.
Nematode counts from soil also showed complete control after a few minutes of exposure to microwaves from the same source.

The safety aspects and mobile character of practical applications are discussed as well as the need for further research, e.g. on pulsed microwaves with the aim to obtain eventual non-thermal effects, and on frequencies other than 2450 MHz; i.e. 915 MHz, the latter allowing better penetration in soil.

II International Symposium on Soil Disinfestation

E. Van Wambeke, J. Wijsmans, P. d’Hertefelt

https://doi.org/10.17660/ActaHortic.1984.152.22