LONG-TERM INFLUENCE OF TILLING ON SPROUTI NG DENSITY OF ADVENTITIOUS PLANTS WITHOUT WEED MANAGEMENT

The sprouting of weeds was followed over a 9-year period (1977-1978 to 1985 - 1986) in a triennial rotation alternating between two spring c ultures (barley-pea) and one winter culture (wheat) grown on two agric ultural plots. The plots, one superficially worked while the other til led, did not undergo any weeding treatment. A simultaneous increase in sprouting was observed in both plots at the beginning of the second r otation. However, this increase was greater on the superficially worke d plot. The modifications within the adventitious community are qualit ative in the first rotation, but become essentially quantitative at th e beginning of the second rotation. Some species increase in density ( Alopecurus myosuroides, Avena fatua, Galium aparine, Fallopia convolvu lus, Sinapis arvensis, Thlaspi arvense) while others decrease (Amarant hus retroflexus, Kickxia spuria, Stellaria media).