in order to evaluate the effects of cover crops on reduced weed biomass in hybrid sunflower an experiment was carried in the research stations, natural resources medicinal plants (samian_ardabile) with 3 replicates in 1390-1391. the first factor was considered three type of cover crops, winter rye, spring barley, winter wheat with 2 control treatment, second factor was mulch management at two l...

Biodiversity regulates ecosystem functions such as productivity, and experimental studies of species mixtures have revealed selection and complementarity effects driving these responses. However, the impacts of intraspecific genotypic diversity in these studies are unknown, despite it forming a substantial part of the biodiversity. In a glasshouse experiment we constructed plant communities wit...

A major problem in flower bulb cultivation is weed control. Synthetic herbicides are mainly used, although they cause a range of problems, and integrated weed control through application of naturally occurring allelochemicals would be highly desirable. Flower bulb production creates large amounts of leftover biomass. Utilizing this source for weed control may provide new applications of the bul...

Today, planting winter cover crops to reduce herbicide is high considered. The purpose of this study was to examine the effect of barley grass cover crop on control weed of flix weld (Descurainia Sophia). This experiment was conducted at agricultural farm of Rezvan Junior College in kerman provinces (latitude 25 55 / N, longitude 53 26 / E , altitude 1755m) from September 2010 to April 2011. A ...

—Nine-year old artifi cially regenerated red oak (Quercus rubra L.), white oak (Q. alba L.), and shortleaf pine (Pinus echinata Mill.) trees were excavated from plot borders of a U.S. Forest Service long-term soil productivity study in the Carr Creek State Forest near Ellington, MO, to quantify treatment eff ects on aboveand belowground tree biomass. Th e study consists of factorial combination...

BACKGROUND One theoretical explanation for the relatively poor performance of Brassica rapa (weed) x Brassica napus (crop) transgenic hybrids suggests that hybridization imparts a negative genetic load. Consequently, in hybrids genetic load could overshadow any benefits of fitness enhancing transgenes and become the limiting factor in transgenic hybrid persistence. Two types of genetic load wer...

Loblolly pine (Pin1r.s tae(/(i L.) seedlings were grown in co~npetition with native weeds using soil and seed bank collected from recently chopped and burned areas near Appornattox, Virginia. One-year-old seedlings were planted and weeds allowed to germinate from the native seed bank while being exposed to COz (ambient and elevated approximately 700 ppm) and water (water stressed and well water...

The largest known infestation of alligator weed Alternanthera philoxeroides (Mart.) Griseb. in Victoria, Australia, was reported in January 2009 in an urban pond. To determine how long the infestation had been present, high quality digital aerial images (orthophotos) were gathered for the site. Since all infestations are subject to ongoing eradication programs in Victoria, historical orthophoto...

field experiment was conducted to assess the efficacy of wheat residues and different densities of sunflower in weed control during 2007 growing season. the experimental design was a randomized complete block with three replications. the experiment was set up in factorial arrangement, amount of 0, 1250, 2500, 3750, 5000 kg ha-1 of wheat residue and burning of residue (5000 kg ha-1) were the lev...

Martin M. Williams II Corresponding author. U.S. Department of Agriculture—Agricultural Research Service, Invasive Weed Management Research, University of Illinois, 1102 S. Goodwin Ave., Urbana, IL 61801; [email protected] The critical period for weed control (CPWC) identifies the phase of the crop growth cycle when weed interference results in unacceptable yield losses; however, the effect of ...