a field experiment was conducted to investigate the spatial distribution of weeds at the sari agricultural sciences and natural resources university in 2011. field was divided into 42 grids (1.5×1.5 feet) then all samples were taken from grids intersection points before corn planting, after harvesting and ear emergence stage. weed maps and semi variance analysis carried out using rw99 and gs+ s...

a field experiment was conducted to investigate the spatial distribution of nutsedge (cyperus spp) during rice growing season using geostatic in 2011 at sari agricultural sciences and natural resources university. at the first field was divided into 36 grids (2.5×2.5 meter) after the final preparation. grid intersection points were determined and marked. all samples were taken from these points...

in the absence of herbicides, cover crops play an important role for weed management in organic than in conventional farming. therefore, in order to evaluate the effects of cover crop management and plant density of buckwheat (fagopyrum esculentum) as cover crop on weed suppression, a field experiment was conducted at the research farm of university of zanjan, during the growing season of 2011....

a field experiment was conducted to study the spatial relationships between weed seed bank and population and their distribution models in sugar beet crop (beta vulgaris) in 2009 at motahari  agricultural research station of karaj. sampling from seed bank before sugar beet drilling and weed population in three stages during the growing season were done using square (50*50 cm) and rectangle (25*...

abstract field experiment was conducted to evaluate the effects of sowing date, crop density, and weed interference on yield and yield components of chickpea in lorestan province during 2005-06. the experimental was a randomized complete block design by factorial arrangement with 4 replications. the experiment had 3 factors: sowing date at 2 levels (autumn, and winter), crop density at 3 levels...

in order to investigate the effect of crop rotation on relation of seed bank with nightshade (solanum nigrum l.) weed seedling population during the growth season of corn, a field experiment was carried out in dasht-naz crop company in sari, during 2012. at the first, farm was divided into 2×2 m networks and the cross points was signed and all sampling were taken from those points. sampling of ...

prediction of weed emergence timing would help minimize crop yield loss and reducing herbicide use by optimization of the timing of weed control. therefore, seedling emergence evaluation was conducted in different irrigation levels (40, 60, 80, 100 percent of crop water requirement and furrow irrigation) to develop a thermal time seedling emergence model for amaranthus retroflexus l. in sunflow...

evaluation of weed population and their interference on lentil varieties at different sowing date was investigated in a field experiment in khorramabad during 2005-06 growing season. the experimental design was a randomized complete block in factorial arrangement with 4 replications. the experiment had 3 factors including: planting date at three levels (autumn, winter, and spring) weed interfer...