نوع مقاله : مقالات پژوهشی
2 دانشگاه فردوسی مشهد
3 فردوسی مشهد
عنوان مقاله [English]
Introduction: In the whole agro ecosystems, weeds had existence as unwanted plant that control of them is necessary. The competition between weeds and corn for moisture, light, nutrients during the growth season is induced reducing the quality and quantity of corn yield. Although the corn is high and powerful crop but is sensitive to competition with the weed and reduction of yield has been reported over 30%. Since the weeds are adapted to conditions, they are successful to completion and reducing the yield. So weed management is important in corn production. Chemical control has not been the unique and best way to manage the weeds and it reduce the sustainability of agro ecosystems. Although developing the herbicides, reduce the pressures caused by the weeds, but by developing rapidly the weed resistance to herbicides and increasing the environmental concerns and its high cost, today need to new, more immune and sustainable techniques for weed management. The main approach for sustainable weed management in an integrated weed management program is increasing crop competitiveness with weeds to reduce herbicide use. In this regard, the planting date, crop rotation, planting density, intercropping, planting pattern, fertilizer type, rate and application method are some of the most crop management strategies. Among the nutrients necessary for plants, nitrogen is the most nutrient in plant competition. Therefore, its application management plays a key role in reducing weed interference with crops and reduced herbicide use. Foramsulfuron herbicide from ALS inhibitors is a post-emergence sulfonylurea herbicide for the control of grasses and certain broadleaf weeds in maize. Unfortunately, these herbicides are also notorious for their ability to select resistant weed populations. Now, there are more weed species that are resistant to ALS-inhibiting herbicides than to any other herbicide group. In several cropping systems, ALS-inhibiting herbicides were used repeatedly as the primary mechanism of weed control. These herbicides exert strong selection pressure because of their high activity on sensitive biotypes at the rates used and because of their soil residual activity. So, the primary objective of this study was to determine the effect of some crop management strategies including sowing pattern and fertilizer application methods on herbicide optimizing and reducing foramsulfuron dose.
Materials and Methods: In order to evaluate the effects of corn sowing pattern and nitrogen application methods on optimizing and reducing of foramsulfuron dose, a field experiment was conducted as split factorial, based on randomized complete block design with three replications at the Research Station, of Faculty of Agriculture, Ferdowsi University of Mashhad, in 2012. Treatments included, corn sowing methods (single-row with 75 cm distance, twine row as parallel on 75 cm width ridges sides and double row as zigzag on 75 cm width ridges sides) as main plots, factorial of nitrogen application methods (broadcast and band application), nitrogen source for fertilization was urea (400 kg ha-1), and foramsulfuron doses (100, 75, 50 and 0% of recommended dose (2 liter of commercial doses) applied at 4th corn leaf stage as sub plots.Weed density and frequency were recorded 10 days before corn harvesting and total weed biomass, corn biomass and seed yield were recorded at the end of the experiments per 1 m-2. Analysis of variance of data was carried out with SAS software and for means comparisons LSD (p≤0.05) test was used. Also The rectangular hyperbolic equation to describe the relationship between density and weed biomass and biomass and grain yield of maize was used
Results and Discussion: Evaluation of weed flora indicated that 6 weed species (including 5 dicot. and 1 monocot.) including red root pigweed (Amaranthus retroflexus L.), black nightshade (Solanum nigrum L.), lambsquarters (Chenopodium album L.), field bindweed (Convolvolus arvensis L.), purslane (Potulaca oleracea L.) and barnyard (Echino clhloacrussgalli L.) were dominant species, with high evenness in the experimental plots. Amongst the mentioned weed species, the red root pigweed included about 74% of relative frequency and 80% of relative biomass of total weed biomass. Also results showed that the effect of sowing pattern on biomass and density of weeds and corn traits was not significant. However, band application of nitrogen versus broadcast application, increased weed density and biomass per m-2 25 and 10 percent, respectively and in the same way, increased corn height, kernel yield and biomass per m-2 7, 30 and 25 percent, respectively.
Conclusion: It was concluded that by using double row sowing pattern along with band application of nitrogen, we can reduced foramsulfuron dose nearly 50 percent.
ارسال نظر در مورد این مقاله