1کارشناسیارشد فیزیولوژی گیاهان زراعی، گروه زراعت، دانشگاه علوم کشاورزی و منابع طبیعی، ساری، ایران
2عضو هیئت علمی گروه زراعت، دانشگاه علوم کشاورزی و منابع طبیعی ساری
3استادیار معاونت موسسه تحقیقات برنج کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، آمل، ایران
4دکتری زراعت، دانشگاه علوم کشاورزی و منابع طبیعی ساری
چکیده
بهمنظور دستیابی به تراکم مطلوب و مصرف بهینه کود نیتروژن در لاین امیدبخش 965، آزمایشی بهصورت کرتهای خردشده در قالب طرح پایه بلوکهای کامل تصادفی و سه تکرار اجرا شد. کود نیتروژن بهعنوان عامل اصلی در چهار مقدار شاهد (صفر)، 92، 115 و 138 کیلوگرم در هکتار نیتروژن خالص از منبع اوره و فاصله کاشت بهعنوان عامل فرعی در سه سطح 20×20، 25×25 (نشاکاری با دست) و 16×30 سانتیمتر (نشاکاری ماشینی) در نظر گرفته شدند. نتایج نشان داد با افزایش مقادیر نیتروژن در گیاه برنج در مرحله آبستنی، ارتفاع بوته و شاخص سطح برگ از یک تا 35 درصد نسبت به شاهد بیشتر بود. بیشترین شاخص سطح برگ در فواصل کاشت 20×20 و 16×30 سانتیمتر بهترتیب با 50/8 و 14/9 درصد اختلاف نسبت به فاصله کاشت 25×25 سانتیمتر و بیشترین وزن خشک اندام هوایی با 34/7 درصد و مقدار کلروفیل b و a+b بهترتیب با 2/9 و 2/2 برابر افزایش نسبت به مقدار صفر نیتروژن در مقدار کودی 138 کیلوگرم نیتروژن خالص و فاصله کاشت 20×20 سانتیمتر بهدست آمد. بیشترین عملکرد شلتوک (10309 و 10998 کیلوگرم در هکتار) و کارایی زراعی نیتروژن (29/8 کیلوگرم بر کیلوگرم) بدون اختلاف معنیدار در مقادیر کودی (115 و 138 کیلوگرم در هکتار نیتروژن خالص) بهترتیب در فواصل کاشت20×20 و 16×30 سانتیمتر مشاهده شد. در مجموع، برای دستیابی به عملکرد بهینه در کشت لاین امیدبخش 965 برنج دو مقدار 138 و 115 کیلوگرم نیتروژن در هکتار بهترتیب برای فاصله کاشت 16×30 سانتیمتر (نشاکاری ماشینی) و فاصله کاشت 20×20 سانتیمتر (نشاکاری با دست) توصیه میشود.
Response of agronomical characteristics of rice (Oryza sativa L. ‘promising line of 965’) to nitrogen and mechanized and hand transplanting spaces
نویسندگان [English]
Mohammad Ali Shabantabar Azizi1؛ Hemmatollah Pirdashti2؛ Hoda Abadian3؛ Mehranoosh Emamian Tabarestani4
1MSc. of Crop Physiology, Department of Agronomy, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
2Scientific Member, Department of Agronomy Sari Agricultural Sciences and Natural Resources University
3Assistant Professor, Deputy of Rice Research Institute of Iran (RRII), Agricultural Research, Education and Extension Organization, (AREEO), Amol, Iran
4Ph.D. of Agronomy, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
چکیده [English]
Introduction: In the last 50 years, global rice yield has continuously increased partly because of the increase in fertilizer use especially those containing the nitrogen (N) nutrient. Unfortunately, a large proportion of N is lost through surface run-off; nitrate leaching in groundwater; volatilization to the atmosphere, thus increasing greenhouse gas emissions; or denitrification by different microorganisms. In addition to N, planting space (PS) is another key factor in determining crop yield. It is well known that the panicle number per unit area (PN) plays an important role in determining yield and increasing the tiller number (TN) may be a feasible way to offset paddy yield (PY) losses (Liu et al., 2017). On the other hand, a high PN could lead to a yield reduction because of an excessive TN, increased ineffective tiller percentage, high spikelet sterility, and a reduced number of grains per panicle (Kabir et al., 2008). Therefore, the present study was designed and conducted to determine the best amount of N fertilizer and PS to optimize yield and yield components of the rice promising line of 965.
Materials & Methods: The experiment was laid out as a split-plot arrangement based on a randomized complete block design and three replications in the Rice Research Institute of Iran– Deputy of Mazandaran (Amol) in the cropping year of 2022. The main plots were pure N fertilizer with four amounts (0, 92, 115, and 138 kgN.ha-1 from the source of urea fertilizer and subplots were PS with three levels of 20×20, 25×25 (transplanting by hand), and 30×16 cm (Mechanized transplanting). The traits measured in this study included plant height (PH), shoot dry weight (SDW), Leaf area index (LAI), chlorophyll a (chl a), b (chl b), fertile tiller number per hill (FT), filled and unfilled grains number (FG and UG), thousand grain weight (TGW), biologic and paddy yield (BY and PY), harvest index (HI) and nitrogen agronomic efficiency (NAE). Data were analyzed using SAS software and the means were compared with the LSD test.
Results & Discussion: The results showed that with the increase amounts of N in the booting stage of rice plant, the PH and LAI markedly was higher from 1 to 35% than non-application of N. Also, the maximum LAI belonged to 20×20 and 30×16 cm of PS with 50.8 and 14.9% difference compared to 25×25 cm of PS, respectively. The highest SDW was obtained at 138 kgN.ha-1 and 20 ×20 cm PS with 34.7% and the highest amount of chl b and chl a+b belonged to 138 kgN.ha-1 amount of nitrogen fertilizer and 20×20 cm with 2.9 and 2.2 times increase compared to the zero amount of N at the same PS, respectively. The highest PY (10309 and 10998 kg.ha-1) and NAE (about 29.8 kg.kg-1) without significant difference in fertilizer amounts (115 and 138 kg N.ha-1) were recorded at 20×20 and 30×16 cm of PS, respectively. In total, two amounts of 138 kgN.ha-1 for 30×16 cm (Mechanized transplanting) and 115 kgN.ha-1 for 20×20 cm (transplanting by hand) are recommended to achieve the highest PY from rice promising line of 965 cultivation. Similarly, Moosavi et al. (2015) indicated that N application in the Khazar cultivar is associated with increased durability and development of leaf surface, photosynthetic activity, and plant growth rate, which leads to increased PY.
Conclusion: With the increase of N fertilizer amounts, the number of FG, TGW, and HI markedly increased. In total, two amounts of 138 and 115 kgN.ha-1 are recommended at the PS of 20×20 (hand transplanting) and 30×16 cm (mechanized transplanting) to achieve optimal yield of the promising rice line 965, respectively.