in order to study of nitrogen effect on critical period of weed control in sunflower (helianthus annuus l.) in birjand region, a split plot experiment based on randomized complete block design was conducted with 24 treatments and 3 replications in research farm of college of agriculture of birjand university in 2010. the main factor was three levels of nitrogen (0, 100 and 200 kg.ha-1) and the ...

Nearly one quarter of New Zealand’s unique vascular plant flora is threatened, and weed invasion is implicated in the decline of more than half of these threatened species. However, there is little experimental evidence showing that invasive weeds have a direct impact on threatened native plants. This study experimentally tested the hypothesis that competition with invasive weeds threatens the ...

to evaluate the competition effect of velvetleaf on cotton, an experiment was conducted in a completelyrandomized block design with split plot arrangement of treatments with three replications at experimentalstation of gorgan university of agricultural sciences and natural resources during 2011 growingseason. the treatments were three row spacing (20, 40 and 80cm) of cotton (as main plot) and f...

ABSTRACT-Several herbicides are registered for selective weed control in sugar beet; however, no single chemical herbicide can control all weeds in beet fields. Frequently, two or more herbicides may have to be combined sequentially or as tank mixed to achieve adequate broad-spectrum weed control. In order to evaluate the effects of some combinations of broadleaf herbicides on sugar beet yield ...

field experiments were conducted to determine the influence of single and multispecies competition of common cocklebur (xanthium strumarium l.) and jimsonweed (datura stramonium l.) on corn yield and further the competitive abilities of these weeds .common cocklebur and jimsonweed were established at selected densities within 15 cm on either side of the corn row. common cocklebur and jimsonweed...

chickpea (cicer arietinum l.) is a dry pulse crop commonly used from old time. the chickpea yield is lower as compared to maximum potentials of the cultivars. the gap could mainly be attributed to the weed competition in addition to other production constraints. although chickpeas are traditionally grown on residual soil moisture, weeds competition pose major problem in many situations. in orde...

With the increasing pressure on crop production from the evolution of herbicide resistance, farmers are increasingly adopting Integrated Weed Management (IWM) strategies to augment their weed control. These include measures to increase the competitiveness of the crop canopy such as increased sowing rate and the use of more competitive cultivars. While there are data on the relative impact of th...

BACKGROUND The efficacy of pre-emergence herbicides within fields is spatially variable as a consequence of soil heterogeneity. We quantified the effect of soil organic matter on the efficacy of two pre-emergence herbicides, flufenacet and pendimethalin, against Alopecurus myosuroides and investigated the implications of variation in organic matter for weed management using a crop-weed competit...