Possibilities of Microwaves in Soil Disinfestation1

In the search for alternative methods for soil disinfestation, various soil types (sand-loam, loam, clay-loam) with mycelium of Rhizoctonia solani, Fusartum oxysporum f. sp. lycopersici and Trichoderma longibrachiatum and seeds of Lepidium sativum , all present at various depths, were treated with microwaves (2540 MHz, 600 W). High lethality was found to be dependent on the duration of irradiation. The granulometric composition of the soil had a relatively strong effect on killing rate. The reaction to soil moisture content was remarkable, but quite reproducible: two maxima in killing rate could be established, one with extremely dry soil and the other with a relative soil moisture content of 60%. The effect of irradiation on CO₂ production and N-mineralization in the soil was also investigated.