the effect of nitrogen (n) levels on n uptake by high weed densities at early growth stages of corn (zea mays l., cv. double cross 370) was investigated for two years (2008-2009) at the agricultural research station of shiraz university. the experiment was arranged in a split-plot arrangement in the randomized complete blocks design with three replications. two levels of weed control (weedy and...

Gene flow exposed by genetically engineered crops Gene flow is the transfer of genes between populations of the same or related species. The exchange between crop cultivars of genes selected by traditional breeding that confer characteristics such as shorter stems, higher yield, or increased seed quality will attract little attention. In the same way, crop-weed hybrids having acquired traits su...

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...

Sunflower has historically been an important crop in Central Queensland. In recent years the sunflower area in Central Queensland has been reduced due to low and variable prices and increased competition from alternate summer crops. Issues of tall persistent stubble that provides little ground cover and a lack of in-crop weed control options have also contributed to declining popularity of sunf...

In order to determine the responses of morphological characteristics, yield and yield components of rapeseed (Brassica napus L.) to plant density and weed interference duration, a factorial experiment was conducted using a randomized complete block design with 3 replications at the Rice Research Institute of Iran (RRII) in Rasht, in the 2008 growing season. The factors comprised plant density a...

introduction the lentil or masoor (lens culinaris l.) is a brushy annual plant of the legume family, grown for its lens-shaped seeds. lentil has been one of the first crops domesticated in the near east. with 26% protein, lentil is the vegetable with the highest level of protein other than soybeans, and it is an important part of people’s diet in many parts of the world. it is reported that the...

The critical period for weed control (CPWC) is the period in the crop growth cycle during which weeds must be controlled to prevent unacceptable yield losses. Field studies were conducted in 2005 and 2006 in the University of Birjand at the south east of Iran to determine CPWC of corn using a randomized complete block design with 14 treatments and four replications. The treatments consisted of ...

Thirty-five percent of global production from crops including at least 800 cultivated plants depend on animal pollination. The transformation of agriculture in the past half-century has triggered a decline in bees and other insect pollinators. In North America, losses of bee colonies have accelerated since 2004, leaving the continent with fewer managed pollinators than at any time in the past 5...

Managing production environments in ways that promote weed community diversity may enhance both crop production and the development of a more sustainable agriculture. This study analyzed data of productivity of maize (corn) and soybean in plots in the Main Cropping System Experiment (MCSE) at the W. K. Kellogg Biological Station Long-Term Ecological Research (KBS-LTER) in Michigan, USA, from 19...