Germination Inhibition of Undesirable Seed in the Soil using Microwave Radiation

Research was carried out to determine the effects of thermal treatment with microwaves on the germination of weed seeds in different growing conditions. Firstly, the elimination of weed seeds buried in the ground at several depths was evaluated using a waveguide designed to obtain a wide superficial distribution of the irradiated energy. Secondly, flowerpots and trays being treated with soils or substrata that will subsequently be employed for ornamental plant cultivation were considered. A modular prototype oven that can be placed in an automatic sowing line was tested to disinfect seedbed trays for horticultural plants. To inhibit germination of buried seeds in fields requires greater exposure times or power, a minimum of 21 MJ m−2. However, germination inhibition in flowerpots was achieved with short exposure energies, of between 60 and 80 MJ m−3, since the use of microwave radiation was viable for this application. The modular oven offers a practical application for seed elimination in the soils or substrata placed in sowing trays for either horticultural nurseries or ornamental plant nurseries, where the soil can be disinfected in the module introduced in the automatic sowing line.