Uhf Electromagnetic Energy for Weed Control in Vegetables

Abstract

UHF energies (45 to 730 j/cm2, 2450 MHz) were applied to irrigated and non-irrigated soils in the field just before planting of cantaloupe (Cucumis meloL., var.reticulatusNaudin) and onion (Allium cepaL.) to study the influence of UHF energy on plant growth. London rocket (Sisymbrium irioL.) and sunflower (Helianthus annuusL.) were controlled with 180 j/cm2of UHF energy applied after seed had imbibed water from soil. These species and ridgeseed spurge (Euphorbia glyptospermaEngelm.), redroot pigweed (Amaranthus retroflexusL.), common purslane (Portulaca oleraceaL.), and Japanese millet [Echinochloa frumentacea(Roxb.) Link.] were controlled with 360 j/cm2(0.0048 kmph) regardless of seed or soil moisture. London rocket and sunflower were not controlled by several soil-incorporated herbicides. UHF energy had no deleterious effects on the growth of cantaloupe or onion and tended to increase the yields above those of the hand-weeded vegetables. Phytotoxic UHF radiation penetrated 7.5 and 10 cm in irrigated and non-irrigated soil, respectively, at 360 j/cm2. Soil temperature after UHF treatment increased with increasing UHF energy levels and decreasing soil moisture and depth.