Interrelationships among oilseed rape (Brassica napus L.) grain yield and weed growth under different nitrogen levels

Document Type : Full Article


1 Department of Agroecology, College of Agriculture and Natural Resources of Darab, Shiraz University, I. R. Iran

2 Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, I. R. Iran


Management of nitrogen fertilization in crops is one of the most important components of integrated weed management. A two-year field experiment was conducted to determine the direct effects of wild mustard aboveground biomass and N content of wild mustard on oilseed rape yield. A set of factorial treatments was arranged in a randomized complete block design with four replications. Treatments were various wild mustard densities (0, 10, 20, 30, and 40 plant m-2) and nitrogen (N) rates (0, 50, 100, 150, and 200 kg N ha-1). Increased wild mustard densities from 10 wild mustard m-2 caused a decrease of 27 % in oilseed rape N content of shoot. Increase in nitrogen fertilizer caused an increase in N content of oilseed rape shoot up to 150 kg N ha-1, but no significant difference was found between 150 (0.88 %) and 200 (0.89%) kg N ha-1. Correlation analysis showed that there was a negative significant correlation between oilseed rape grain yield and weed biomass (r=-0.60, p≤0.05) and weed nitrogen content (r=-0.81, p≤0.01). Path analysis showed a highly negative significant direct effect (direct path: -0.88, p≤0.01) between weed biomass and oilseed rape grain yield.  Correlation and path analyses indicated that the main factor which could cause oilseed rape yield loss was weed biomass and the second factor was N content in wild mustard.


Main Subjects

Article Title [Persian]

روابط متقابل بین عملکرد کلزا و رشد علف هرز در سطوح مختلف کود نیتروژن

Authors [Persian]

  • حسین غدیری 2
  • محسن عدا‌لت 2
2 دانشگاه شیراز
Abstract [Persian]

چکیده- مدیریت کود دهی نیتروژن در گیاهان زراعی یکی از مهم‌ترین اجزای مدیریت تلفیقی علف های هرز می باشد. آزمایش مزرعه‌ای دو ساله‌ برای بررسی اثرات مستقیم زیست توده و محتوای نیتروژن خردل وحشی بر عملکرد و اجزای عملکرد کلزا اجرا گردید. آزمایش به صورت فاکتوریل در قالب طرح بلوک های کامل تصادفی با 4 تکرار انجام شد. تیمارهای آزمایش شامل تراکم های مختلف علف هرز خردل وحشی (صفر، 10، 20، 30 و 40 بوته در متر مربع) و سطوح مختلف نیتروژن (صفر، 50، 100، 150 و 200 کیلوگرم در هکتار) بودند. افزایش تراکم خردل وحشی از 20 بوته در متر مربع باعث کاهش 27 درصدی در محتوای نیتروژن شاخساره کلزا شد. افزایش کود نیتروژن تا سطح 150 کیلوگرم در هکتار باعث افزایش محتوای شاخساره کلزا شد ولی بین تیمار 150 کیلوگرم نیتروژن (88/. درصد) و200  کیلوگرم نیتروژن (89/0 درصد) تفاوت معنی داری وجود نداشت. نتایج تجزیه همبستگی نشان داد یک رابطه مستقیم منفی شدید بین عملکرد دانه کلزا و زیست توده خردل وحشی  و همچنین محتوای نیتروژن علف هرز وجود داشت. تجزیه مسیر نیز نشان داد یک رابطه مستقیم و منفی شدید بین زیست توده علف هرز و عملکرد کلزا وجود داشت. نتایج تجزیه همبستگی و تجزیه مسیر نشان داد عامل اصلی کاهش عملکرد کلزا زیست توده علف هرز و عامل دوم محتوای نیتروژن در خردل وحشی بود.

Keywords [Persian]

  • واژه های کلیدی:
  • گیاهان روغنی
  • تجزیه مسیر
  • رقابت
  • علف هرز
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