in order to study the effects of wild mustard density on grain yield and yield components of canola cv. hyola 401 under different rates of nitrogen fertilizer, a field experiment was conducted in 2011-2012. the layout was split-plot in a completely randomized block design and three replications. main-plots included four levels of nitrogen (0, 70, 140 and 210 kg ha-1) and sub-plots consisted of ...

this experiment was conducted to evaluate the effects of different sowing densities and nitrogen fertilizer rates on quantitative and qualitative corn forage yield in an agroforestry system with orange trees. the treatments consisted of 4 nitrogen fertilizer levels of 0, 100, 200, and 300kg n/ha (allocated to main plots) and 4 sowing densities of 80000, 110000, 140000 and 170000 of corn seeds (...

in order to study the competition effects of redroot pigweed (amaranthus retroflexus) and millet (panicum miliaceum) on maize performance under different rates of n fertilizer, a field experiment was conducted in 2009 in the research fields of tarbiat modares university in tehran as a randomized complete block design with factorial arrangement of treatments and three replications. accordingly, ...

introduction integrated weed management is based on combination of several management methods, while reducing the rate of the use of herbicides, will result in efficient management and sustainable weed control. ability of crop tolerance and prevent weed growth are two important traits in weed competition. an appropriate and suitable cultivar, has high yield potential in the presence of weed and...

for determination of economic damage threshold of four wheat (triticum aestivum l.) cultivars in different densities of wild mustard (sinapis arvensis l.), experiments were conducted at agricultural research station gorgan during 2010-2012. the experimental design consisted of four randomized complete blocks in a factorial arrangement. the treatments comprised of factorial combination of wild m...

Pre-dispersal seed predators are often chosen as biocontrol agents because of their high impacts on plant fitness; however, they have a mixed record in realizing decreased plant population growth. Few studies have experimentally removed agents to explore their impact on weed population growth. Here, we used manipulative experiments with invasive yellow starthistle (YST), Centaurea solstitialis,...

The role of common milkweed in the lifecycle of the monarch butterfly has increased interest in the presence of this weed in the north central United States. An initial survey conducted in 1999 found that low densities of common milkweed occurred in approximately 50% of Iowa corn and soybean fields. In 2009, common milkweed was present in only 8% of surveyed fields, and the area within infested...

crop rotation is one of the essential practices in sustainable agricultural systems, be-cause of its effects on soil fertility and other benefits including a reduction in weed compe-tition. a field experiment was conducted at chaparsar rice research station, tonekabon, iran, from 2002 to 2003 to assess the influence of crop rotation, time of planting, and till-age depth on rice (oryza sativa l....

in order to determine the practical method to predict economic production of wheat in competition with feral rye by using regression models, a factorial experiment was carried out based on randomized complete block design with three replications in dargaz. iran. experimental factors were included wheat cultivars (sayson, alvand, chamran and sepahan) and feral rye densities (0, 20, 40, 60 and 80...