The allelopathic effects of fresh and dry residual extract of Wild mustard (Sinapis arvensis) and Canada Thistle (Cirsium arvense) on germination and nutrient uptake of canola (Brassica napus)

Allelopathic phenomenon is an interference method of weed on crops that can help to know crop-weed interaction. This experiment was conducted to evaluation of Sinapis arvensis and Cirsium arvense allelopathic effects on canola germination and nutrient uptake in 2007 at greenhouse of University of Mohaghegh Ardabili. Treatments were differential concentrates (0, 2.5, 5, 10, 20 and 40%) of fresh and dry residual extract of Sinapis arvensis and Cirsium arvense. The experiment was laid out as factorial in completely randomized design. Analyses shown that fresh and dry extract of two weeds reduced germination of canola in compared with control 1.5 to 2.5 times. Also fresh and dry extract of weeds reduced canola dry aboveground mass. Nitrogen and P uptake reduced under fresh extract, while dry extract of Sinapis arvensis increased p uptake in canola more than 4 times. Fresh and dry extract of Sinapis arvensis and Cirsium arvense increased canola K concentrate. The experiment results show that in addition to competing weeds, through release of chemicals can be also inhibit on growth and physiological processes of crop.