Uhf Electromagnetic Energy for Weed Control in Vegetables

Abstract

UHF energies (45 to 730 j/cm 2 , 2450 MHz) were applied to irrigated and non-irrigated soils in the field just before planting of cantaloupe ( Cucumis melo L., var. reticulatus Naudin) and onion ( Allium cepa L.) to study the influence of UHF energy on plant growth. London rocket ( Sisymbrium irio L.) and sunflower ( Helianthus annuus L.) were controlled with 180 j/cm 2 of UHF energy applied after seed had imbibed water from soil. These species and ridgeseed spurge ( Euphorbia glyptosperma Engelm.), redroot pigweed ( Amaranthus retroflexus L.), common purslane ( Portulaca oleracea L.), and Japanese millet [ Echinochloa frumentacea (Roxb.) Link.] were controlled with 360 j/cm 2 (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/cm 2 . Soil temperature after UHF treatment increased with increasing UHF energy levels and decreasing soil moisture and depth.