Allelopathic effects of Chenopodium album L. and Chenopodium polyspermum L. on another weed and two crop species

Chenopodium album L. and Chenopodium polyspermum L. are cosmopolitan weeds that often cause serious crop yield losses. Although it is well known that both species compete strongly with crops, nothing has been published on their relative allelopathic potentials. Experiments for assessing the allelopathic effects of C. album and C. polyspermum on three indicator species were conducted under controlled conditions. The indicator species were sunflower (Helianthus annuus L. cv. SO 222), tomato (Lycopersicon esculentum Mill cv. Heinz 1370) and the cosmopolitan weed Indian goosegrass (Eleusine indica subsp. indica (L.) Gaertn.). Top growth of mature C. album and C. polyspermum plants was freeze-dried, milled to a coarse powder and gamma-irradiated. Steam-sterilized soil was mixed with the powdered material to reach a concentration of 1% for each donor species. The control treatments consisted of an untreated soil and the same soil containing 1% extracted material of the donor species. Only sunflower and tomato s...