Published online by Cambridge University Press: 12 June 2017
A curved-linear Fresnel lens was investigated to test the effect of concentrated solar radiation on surface and buried weed seed. The lens produced a line focus 1 by 150 cm with a mean temperature of 309 C. A 20-s exposure to seed on the soil surface was 100% lethal to green foxtail, kochia, common lambsquarters, common purslane, and wild buckwheat. In a separate study, emergence from kochia and yellow foxtail seed was reduced 100% at 10 mm soil depth after 15 min in soil of 35 and 93 g/kg moisture and 20 to 40% at 178 g/kg moisture content. Concentrated solar radiation from a Fresnel lens has the greatest potential for affecting weed seed on the soil surface. A series of Fresnel lenses and/or larger lenses may be required for many practical field applications.