تاثیر زهکشی لانه ‌موشی و کود نیتروژن بر عملکرد و اجزاء عملکرد کلزا به ‌عنوان گیاه کشت دوم اراضی شالیزاری در منطقه رشت

به‌ منظور بررسی اثر سامانه زهکشی لانه‌ موشی و مدیریت کود نیتروژن بر عملکرد و اجزاء عملکرد کلزا، آزمایشی به‎صورت فاکتوریل در قالب طرح بلوک‎های کامل تصادفی در سه تکرار در مزرعه تحقیقاتی دانشکده علوم کشاورزی دانشگاه گیلان در سال زراعی 1402-1401 به‎مرحله اجرا گذاشته شد. کرت‎های اصلی تیمار زهکشی شامل: بدون زهکشی (d0، شاهد)، زهکشی لانه‎موشی بدون گراول (d1) و زهکشی لانه‎موشی با گراول (d2) و کرت‌های فرعی تیمار کود نیتروژن از منبع اوره شامل: 180 کیلوگرم در هکتار (n1) و 240 کیلوگرم در هکتار (n2) بودند. گیاه کلزا (brassica napus) رقم دلگان به‌عنوان گیاه کشت دوم بعد از برداشت برنج انتخاب شد. نتایج تجزیه آماری داده‎ها نشان داد که اثر تیمار زهکشی بر وزن دانه در شاخه فرعی و درصد پروتئین (0.05≥p) و بر وزن دانه در شاخه اصلی، وزن دانه در بوته و عملکرد دانه (0.01≥p)، و اثر تیمار کود بر تعداد دانه در غلاف شاخه فرعی و تعداد دانه در هر غلاف (0.05≥p) و اثر متقابل آن‌ها بر وزن دانه در شاخه اصلی، وزن دانه در بوته و عملکرد دانه )0.05≥p) معنی‌دار بود. بیشترین عملکرد دانه با 3579.48 کیلوگرم بر هکتار در تیمار d1n2 بدست آمد که در مقایسه با تیمار بدون زهکشی و زهکشی با گراول با همان سطح کود نیتروژن به‌ترتیب 13.63 و 2.31 درصد بیشتر بود. از آنجا که گیاه کلزا از نظر عملکرد و درصد روغن اهمیت دارد و بین تیمارهای زهکشی و کود نیتروژن از نظر میانگین درصد روغن اختلاف معنی‌داری وجود نداشت، بنابراین می‌توان از دیدگاه عملکرد گیاه، تیمار زهکشی لانه‌موشی بدون گراول با سطح کود 240 کیلوگرم بر هکتار را به‌عنوان گزینه مناسب برای کشت گیاه کلزا بعد از برداشت برنج معرفی کرد.

effect of mole drainage and nitrogen fertilizer on the yield and yield components of rapeseed as a second crop of paddy fields in rasht region

many agricultural lands in guilan province of iran, especially paddy fields, remain uncultivated in the second half of the year due to various reasons including heavy rainfall, low soil permeability (stickiness of soil particles) and inefficiency of the existing drains. mole drainage as a low-cost drainage method, proportion for rice cultivation conditions and easier to implement than pipe drainage, can be a suitable solution in the development of second cropping. due to the oil content of 40% of the seed, the rapeseed plant is one of the valuable oil plants and has the ability to be cultivated as a second crop in paddy fields. nitrogen plays a key role in the performance of plants and its deficiency causes limitations in plant production. equipping paddy fields with mole drains along with the application of appropriate level of nitrogen fertilizer can increase the quantitative and qualitative yield of rapeseed as a second crop and contribute to the food security of the country. therefore, the development of the cultivated area of rapeseed in paddy fields after rice harvesting in rasht region, the study of the combined effect of mole drainage and different levels of nitrogen fertilizer on yield and yield components were the aims of this project. materials and methodsin order to investigate the effects of mole drainage and nitrogen fertilizer on the yield and yield components of rapeseed as a second crop in rasht rice fields, a factorial layout based on a randomized complete block design with three replications at the research field of the faculty of agricultural sciences of guilan university was implemented in the crop year of 2022-2023. the factors included mole drainage at three levels (without drainage, without gravel and with gravel) as d0, d1 and d2 respectively, and nitrogen fertilizer as urea source at two levels (180 and 240 kg ha-1) as n1 and n2 respectively. rapeseed plant (brassica napus) of delgan cultivar was selected as the second crop after rice harvest. to carry out the experiment, at first the desired land was blocked and divided into plots, then the underground drains of mole were created without gravel and with gravel with a special blade in the desired plots. to drain the drainage from the mole drains, the polyca pipe was installed at the end of each mole tunnel, then the other side of polyca pipe was connected to the sub-pipe collection and finally led to the main surface drain. this experiment was conducted in 18 plots and each one was 9 × 6 meters. the distance between plots was 1.5 m, between replications was two meters, and the distance between plants was 15 and between rows was 25 cm. to avoid the effectiveness of drainage treatments from undrained treatments, undrained plots were considered at the end of the field. before cultivation, basic chemical fertilizers, 200 kgha-1 of potassium from potassium sulfate source and 200 kgha-1  of phosphorus from ammonium phosphate source were applied. nitrogen fertilizer from urea source was applied at the level of 180 and 240 kgha-1  in equal amount at three stages. just before the harvest stage, to determine the traits of the number of seed in the pods of sub-branches, the number of seed per pod, the weight of seed in sub-branches, the weight of seed in the main branch and the weight of seed per plant, ten plants were randomly selected and harvested manually from the crown area. also, to determine the seed yield, one square meter was randomly selected from each plot, taking into account the borders, and the bushes were manually harvested from the crown area.