پديد آورندگان :
اميني، زهره دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه زراعت و اصلاح نباتات , نصيري محلاتي، مهدي دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه زراعت و اصلاح نباتات , بنايان اول، محمد دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه زراعت و اصلاح نباتات , پارسا، مهدي دانشگاه فردوسي مشهد - دانشكده كشاورزي و گروه پژوهشي بقولات پژوهشكده علوم گياهي - گروه زراعت و اصلاح نباتات
كليدواژه :
آبياري تكميلي , برگزدايي , تن خشكي , كود نيتروژن
چكيده فارسي :
به‌منظور بررسي اثر كود نيتروژن، رژيم آبياري و برگزدايي بر عملكرد و اجزاي عملكرد نخود رقم (ILC482)، آزمايشي به‌صورت اسپليت اسپليت پلات با طرح پايه بلوك‌هاي كامل تصادفي در سه تكرار در مزرعه تحقيقاتي دانشگاه فردوسي مشهد در سال زراعي 91-1390 اجرا گرديد. كود نيتروژن شامل سه سطح 30، 75 و 150كيلوگرم در هكتار به‌عنوان عامل اصلي، تيمار آبياري شامل آبياري كامل، آبياري تكميلي در مرحله گلدهي و آبياري تكميلي در مراحل گلدهي و غلاف‌دهي به‌عنوان عامل فرعي و برگزدايي شامل پنج سطح صفر، 25،50، 75 و 100درصد برگزدايي به‌عنوان عامل فرعي-فرعي درنظرگرفته شد. وزن خشك برگ و ساقه، عملكرد دانه در واحد سطح، عملكرد بيولوژيك، تعداد غلاف در بوته، تعداد دانه در بوته و وزن صد‌دانه اندازه‌گيري شدند. نتايج نشان داد تيمار 150كيلوگرم نيتروژن باعث بهبود اكثر صفات فوق (به‌جز شاخص برداشت) شد. اين تيمار با عملكرد 7/135گرم دانه در متر مربع بيشترين ميزان عملكرد و كمترين شاخص برداشت (3/32درصد) را توليد كرد. با افزايش مقدار كود نيتروژن مصرفي، اثرات منفي ناشي از برگزدايي در برخي صفات مانند تعداد دانه، تعداد غلاف و وزن برگ بهبود يافت. آبياري كامل و آبياري تكميلي در مراحل گلدهي و غلاف‌دهي با متوسط عملكرد دانه 146گرم در متر مربع نسبت به آبياري تكميلي در مرحله گلدهي برتري داشتند. آبياري در مراحل گلدهي و غلاف‌دهي بيشترين شاخص برداشت (2/41درصد) را توليد كرد. بيشترين عملكرد بيولوژيك از تيمار‌هاي 150كيلوگرم نيتروژن (4/413گرم در متر مربع) و آبياري كامل (7/415گرم در متر مربع) به‌دست آمد. برگزدايي كامل، عملكرد دانه و عملكرد بيولوژيك را به‌ترتيب 54 و 42درصد نسبت به شاهد كاهش داد. كمترين شاخص برداشت نيز به تيمار برگزدايي كامل تعلق داشت. با مصرف نيتروژن مي‌توان خسارت ناشي از برگزدايي را كاهش داد و همچنين مي‌توان در شرايطي‌كه محدوديت منابع آب وجود دارد، با آبياري تكميلي در مراحل حساس رشدي نسبت به كمبود آب مقابله كرد.
چكيده لاتين :
Introduction
Chickpea (Cicer arietinum L.), an annual with indeterminate growth habit, is one of the most important food legumes. Loss of foliage due to leaf diseases or environmental hazards are prevalent for many crops. Such loss of foliage affects the yield and also the carbohydrate and protein status of leaves and seeds. The source-sink relationship change during growth stages. Few factors including nitrogen fertilizer and water influence this relationship. This experiment was conducted in order to study the effects of nitrogen fertilizer, supplementary irrigation and defoliation on yield and yield components of chickpea.
Materials & Methods
The experiment was conducted as split-split plot based on randomized complete block design with three replications in research farm of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran in 2012. Main plot was nitrogen fertilizer including 30, 75 and 150 kg N/ha and sub-plot was irrigation regimes including full irrigation, supplemental irrigation at flowering and supplemental irrigation at flowering and seed filling stages. Defoliation including 0, 25%, 50%, 75% and 100% was considered as sub-sub plot. Leaf and stem dry weight, seed yield, biological yield, pod number per plant, grain number per plant, 100 grain weight and harvest index were all recorded.
Results & Discussion
The results indicated that all traits excluding harvest index were higher in 150 kg N.ha-1 treatment compared to other levels of nitrogen. Nitrogen rate of 150 kg.ha-1 produced the highest grain yield (135.7 g.m-2). The highest harvest index (40.7%) was obtained at 30 kg.ha-1 N treatment. Full irrigation and supplemental irrigation at flowering and poding stages with average grain yield of 146 g.m-2 were higher than supplemental irrigation at flowering (83 g.m-2). Supplemental irrigation at flowering and poding stages showed the highest harvest index (41.2 %). The highest biological yield was obtained from 150 kg N.ha-1 (413 g.m-2) and full irrigation (415 g.m-2). Nitrogen rate 75 kg.ha-1 at 0% defoliation (control), resulted in the highest seed yield (177 g.m-2). The lowest seed yield (58 g.m-2) was obtained from 75 kg.ha-1 nitrogen treatment and complete defoliation. By increasing of N fertilizer application, the negative effects of defoliation in some traits such as pod number and seed and leaf weight decreased. In 30 and 75 kg.ha-1 nitrogen treatment, 100% defoliation decreased pod number to 50%, but this was 20% in 150 kg.ha-1 nitrogen treatment. Full irrigation with 0% defoliation produced the highest (196 g.m-2) and supplemental irrigation at flowering stage with complete defoliation the lowest (56 g.m-2) grain yield. Defoliation decreased the most of mentioned traits significantly. Complete defoliation decreased grain and biological yield to 46% and 56%, respectively compared to the control. The lowest harvest index (29%) was obtained in complete defoliation. All of traits including pod number, seed number, harvest index and biological yield had
positive and significant correlation with seed yield. Biological yield (83%) had highest correlation with yield.
Conclusion
Generally, defoliation decreased grain yield. However, application of nitrogen fertilizer at low levels could decrease the negative effects of defoliation. High N application improved the ability of plant to compensate the leaves that removed grain yield in treatments of full irrigation and supplementary irrigation at flowering and depoding stages was equivalent, therefore under water deficit condition, supplementary irrigation at flowering and podding stages recommend.
