Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resista...

to evaluate the role of effective factors on competition of two wheat cultivars against two species of narrow leaf and broad leaf weeds this study was conducted as two separated experiments based on a randomized complete block design with 3 replications at agricultural faculty of bu-ali sina university, in 2008-2009. in both experiments, alvand and sayson cultivars were planted with densities o...

Weeds represent a global agronomic problem that threatens the productivity of cultivated crops. Weeds compete with cultivated crops for the available moisture, nutrients and light. Consequently, weeds significantly reduce either crop yield or quality. Control of weeds is essential to maintaining the production of economic crops. Weed control may be achieved either through manual eradication or ...

Numerous plant species are considered weeds in agronomic cropping systems. Weeds have many attributes undesirable to crop producers, not the least being the ability to reduce crop yields through competition for resources such as sunlight, water, nutrients, and space. Weeds also may harbor insects and provide a host for certain plant pathogens. Some weed species, such as wild garlic and eastern ...

BACKGROUND: Application of plant mulches plays a significant role in development and expansion of sustainable farming systems. OBJECTIVES: Assessment effect of chemical and non-chemical weeds management methods on weeds density and biomass and the properties of soil, including microbial biomass carbon (MBC) and soil organic carbon (SOC) in potato cultivation. ...

introduction amount and vertical distribution of leaf area are essential for estimating interception and utilization of solar radiation of crop canopies and, consequently dry matter accumulation (valentinuz & tollenaar, 2006). vertical distribution of leaf area is leaf areas per horizontal layers, based on height (boedhram et al., 2001). above-ground biomass is one of the central traits in func...

abstract water is the most common carier used to dilute herbicides and their application. researches had shown that water quality is an important factor in some herbicide efficacy. in order to study the effect of water hardness on 2,4-d efficacy, an experiment was carried out under controlled conditions in 2010 at the college of agriculture, ferdowsi university of mashhad. experimental treatmen...

Weeds can cause great economic and ecological harm to ecosystems. Despite their importance, comparisons of the taxonomy and traits of successful weeds often focus on a few specific comparisons - for example, introduced versus native weeds. We used publicly available inventories of US plant species to make comprehensive comparisons of the factors that underlie weediness. We quantitatively examin...