crop rotation effect on spatial dynamic of fumaria vaillantti and polygonum aviculare

to evaluate the effect of crop rotation on spatial dynamic of fumaria vaillantti and polygonum aviculare a study was conducted at the three farms with different rotation in the astan ghods razavi filed that located at 10 kilometers southeast of mashhad, iran. the rotations were alfalfa- fallow- wheat, canola- fallow- wheat, and wheat- fallow- wheat. at the crosses of 7×7 m quadrangular grids network, discrete systematic sampling was performed using 0.5×0.5m quadrates at three stages including before chemical control, after chemical control, and before harvesting and density of weed species were recorded separately. in each three rotations fumaria vaillantti and polygonum aviculare were part of dominant species at second and third sampling stages, but at the first sampling stage dominant species were different. polygonum aviculare was became dominant species at the third sampling stage, mean while, the importance of fumaria vaillantti were reduce. bing winter fumaria vaillantti and summer polygonum aviculare can be the cause of this phenomenon .variogram parameters survey show that the minimum and maximum of nugget effects for studied species was 0.17 and 1.001 respectively. the range of weeds in field varied between 2.8 – 93.5m. nugget effect and range were downside at each three rotations and at during of first and second sampling, while nugget effect and range variations of fumaria vaillantti were different depend on rotation type. the distribution maps of studied weed were drawn after applying varigram parameters in kriging method that showed patchy and plow directed distribution. our results showed that crop rotation and cultural operation effects dynamism of the weeds, that knowledge of these effects can be an opportunity for more effective weed control.