management of nitrogen fertilization in crops is one of the most important components of integrated weed management. a two-year field experiment was conducted to determine the direct effects of wild mustard aboveground biomass and n content of wild mustard on oilseed rape yield. a set of factorial treatments was arranged in a randomized complete block design with four replications. treatments w...

Good management models for postemergence weed control require good estimates of which weed density produces an economic threshold yield. Because intraweed competition increases if weeds are aggregated, weed spatial pattern may be an important factor for inclusion in management models. Mathematical models of weed–crop competition have demonstrated that this may be the case, but the small number ...

Effect of weed competition periods on weeds and yield of black seed was studied through field experiments conducted at Agronomic Research Area, University of Agriculture, Faisalabad during winter 2006-07 and 2007-08. Weeds were allowed to compete with the crop for 40, 50, 60, 70, 80 days after sowing and throughout the growth season along with a weed free treatment. The data on weed density and...

One of the most important stress factors in maize (Zea mays L.) fields is weed competition, which reduces the crop yield. Weeds chiefly interfere with maize and establish considerable competition for light, water and nutrients. To avoid these harmful effects, there are different agronomic measures and factors among which, the most relevant are the interactions between crop and weed, weed manage...

in order to evaluate competition among some weed species and canola, a field experiment in astan ghods razavi's field in mashhad was done on 2007-2008. thirty 50×50 cm quadrates were used in two times (stem and flower production) to measure the canola dry weight, leaf area index and canola and weeds density with destruction and thirty similar quadrates were used for counting weed species a...