استفاده از کود نیتروژن و تراکم بوته باقلا در تناوب به عنوان منابع تامین نیتروژن در تولید پایدار ذرت علوفه‌ای

گنجاندن حبوبات در سیستم‌های زراعی برای مدیریت پایدار سیستم‌های کشاورزی و کاهش نیاز به مصرف کود نیتروژن در تولید ذرت ضروری است. از این رو آزمایشی با هدف بررسی تاثیر تراکم های مختلف باقلا (20، 35، 40 و 80 بوته) در تناوب با ذرت علوفه ای و کاربرد سطوح مختلف نیتروژن بر پایه اوره (صفر، 100، 200 و 300 کیلوگرم در هکتار) بر خصوصیات علوفه ذرت مورد ارزیابی قرار گرفت. همچنین یک سطح نکاشت از باقلا به منظور بررسی اثر تراکم های بوته باقلا بر خصوصیات ذرت علوفه ای در نظر گرفته شد. نتایج تجزیه مرکب نشان داد که تراکم باقلا بر عملکرد دانه، تعداد و وزن خشک گره در ریشه، وزن خشک ریشه، ارتفاع بوته، شاخص کلروفیل و شاخص باروری در باقلا معنی دار بود. بر اساس نتایج مقایسات میانگین تراکم 80 بوته باقلا با میانگین 376.5 گرم در مترمربع دارای بیشترین عملکرد دانه بود. بیشترین شاخص کلروفیل نیز در تراکم 80 بوته باقلا با میانگین 35.8 مشاهده شد و تراکم 80 و 40 بوته باقلا به ترتیب با میانگین 1676.8 و 1565.1 دارای بیشترین شاخص باروری بودند. اثر متقابل تراکم باقلا و کود نیتروژن بر تعداد برگ در بوته، ارتفاع بوته، شاخص کلروفیل، کارآیی جذب نیتروژن و عملکرد خشک علوفه در ذرت علوفه ای معنی دار شد. بر اساس مقایسات میانگین، تراکم 40 بوته باقلا+200 کیلوگرم نیتروژن در هکتار دارای بیشترین عملکرد خشک علوفه ذرت (2.3 کیلوگرم در مترمربع) ، بیشترین ارتفاع بوته (175.8 سانتی متر) و بیشترین شاخص کلروفیل (46.2) بود. تراکم 35بوته باقلا+300 کیلوگرم نیتروژن در هکتار با میانگین 16.3 درصد نیز دارای بیشترین شاخص برداشت پروتئین در ذرت علوفه ای بود. همچنین نتایج نشان داد که بیشترین میزان کارآیی جذب نیتروژن ذرت از تراکم های 25، 35 و 40بوته باقلا در شرایط عدم مصرف کود به دست آمد. به طور کلی نتایج نشان داد که قرارگیری باقلا در تناوب به همراه استفاده از کود نیتروژن باعث بهبود عملکرد و صفات کمی در ذرت علوفه ای شد.

nitrogen fertilizer and faba bean density as sources of nitrogen supply in sustainable production of forage corn

introduction some studies have reported that application of chemical fertilizers, especially nitrogen, is one of the most appropriate methods to increase crop production and maintain food security in the world. however, it should also be noted that the improper use of nitrogen fertilizers can disrupt natural ecosystems. alternative methods can be used to prevent this, such as the use of plants with biological nitrogen fixation (e.g., legumes). faba bean is one of the most important varieties of this family (fabaceae) and contains 24-30% protein and 51-68% carbohydrates. this plant is one of the most important spices of the genus (vicia) and has a high yield compared to other legumes. due to its environmental, economic and agroecological performance, faba bean can improve the sustainability of agricultural ecosystems. corn (zea mays l.) is one of the most important annual cereals. however, maize cultivation is not economical because it requires nitrogen fertilizer, and improper use of nitrogen also increases ecosystem instability. incorporating legumes into cropping systems is critical for sustainable management of agricultural systems and reducing nitrogen fertilizer requirements for corn production. materials and methods a two-year experiment was conducted in 2018-2019 as a factorial experiment based on a randomized complete block design with three replications at the research farm of the faculty of agriculture and natural resources, university of mohaghegh ardabili, ardabil, iran. the experimental treatments were different plant densities of faba bean (25, 35, 40 and 80 plants m-2) and different nitrogen fertilizer rates (0, 100, 200 and 300 kg ha-1) of forage corn. in this experiment, the faba bean variety shadan was planted and manually harvested at the physiological maturity stage. the corn variety was a single cross hybrid 201, which was planted at a density of 80000 plants ha-1 in the rows with faba bean residues. at the v5 stage of corn, n fertilizer (as urea) was applied in 3 stages. three corn plants were harvested at the milk stage and then oven dried at 70°c for 72 h and weighed. traits studied in this experiment included chlorophyll index, plant height, root nodule dry weight, root dry weight, number of root nodules, and grain yield in faba bean, and chlorophyll index, protein harvest index, plant height, number of leaves per plant, physiological nitrogen efficiency, nitrogen uptake efficiency, and dry matter yield in forage corn. statistical analysis of data was performed using sas 9.4 software, and significant differences between treatment means were tested using the duncan's multiple range test at p< 0.05. results and discussion faba bean the highest grain yield (g m-2), plant height (cm) and chlorophyll index of faba bean were obtained at the density of 80 plant m-2. at the densities of 25 and 35 plants m-2, the number of root nodules and the dry weight of root nodules (g) were the highest. as plant density increased, root dry weight (g m-2) also increased, so that the density of 80 plants m-2 had the highest root dry weight per m2. the highest fertility rate was observed at the densities of 80 and 40 plants m-2. corn our results showed that the interaction between faba bean density and n fertilizer had effects on plant height, chlorophyll index, protein harvest index, physiological nitrogen efficiency, nitrogen uptake efficiency, and dry forage yield. the results of the mean comparisons showed that the highest dry forage yield was obtained at the density of 40 faba bean plants+200 kg n ha-1 an increase of 155% over the control treatment. the highest number of leaves was observed in the treatments at the density of 40 faba bean plants+100 kg n ha-1, at the density of 40 faba bean plants+200 kg n ha-1 and at the density of 35 faba bean plants+200 kg n ha-1. the density of 40 plant of faba bean+100 kg n ha-1 and the density of 40 plant of faba bean+200 kg n ha-1 had the highest plant height.