بررسی اثر تراکم، پوشش بقایا و سایه اندازی بر رفتار بنه و عملکرد اقتصادی گیاه زعفران (crocus.sativus) (مطالعه موردی: گناباد)

به منظور بررسی اثر تراکم و مدیریت پوشش بر رفتار بنه و عملکرد اقتصادی زعفران در شرایط اقلیمی گناباد، آزمایشی به صورت کرت‌های خرد شده در قالب طرح پایه بلوک‌‍‌های کامل تصادفی با سه تکرار در مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی خراسان رضوی (ایستگاه تحقیقات گناباد) در سال 1397-1400 انجام شد. در این تحقیق تیمار تراکم کاشت در چهار سطح شامل 60، 90، 120 و 150 بنه در مترمربع در کرت اصلی و مدیریت بقایای گیاهی و سایه‌اندازی در چهار سطح شامل حذف بقایای زعفران در پایان فصل رشد (شاهد)، حضور بقایای زعفران در پایان فصل رشد، شاهد + استفاده از کلش جو به میزان 2 تن در هکتار، شاهد + استفاده از سایبان مصنوعی در کرت فرعی قرار داشتند. نتایج این بررسی نشان داد که خصوصیات بنه و گل در هر دو سال مورد بررسی تحت تاثیر افزایش معنی‌دار تراکم قرار گرفت و بیشترین مقدار وزن خشک کلاله در هر دو سال آزمایش به ترتیب با مقادیر 0.86 و 0.32 گرم در مترمربع تحت تراکم 120 بنه در مترمربع حاصل شد؛ البته همزمان با افزایش سن مزرعه، سطوح بالاتر تراکم درصد افزایش کمتری در صفات مورد نظر داشت. از طرف دیگر کاربرد انواع پوشش در تابستان باعث افزایش معنی‌دار همه صفات مورد بررسی در مقایسه با تیمار شاهد (حذف بقایای زعفران) شد. بر اساس نتایج حاصل از این پژوهش، کاربرد کلش جو در سال اول و کاربرد سایبان مصنوعی در سال دوم تحت سطوح تراکم 90 و 120 بنه در مترمربع بیشترین عملکرد کلاله را داشت. با توجه به تاثیر مثبت استفاده از پوشش بر عملکرد اقتصادی زعفران به نظر می رسد که توصیه کاربردی استفاده از انواع پوشش بویژه کلش غلات با توجه به هزینه کمتر آن در مقایسه با سایه‌بان و همچنین دسترسی سهل‌تر برای پوشش مزارع زعفران همزمان با شروع فصل گرما می تواند در جهت پایداری و افزایش عملکرد زعفران مورد توجه باشد.

studying the effect of density and covering on corm behavior and economic yield of saffron (crocus.sativus) (case study: gonabad)

introduction: saffron is a monocotyledonous plant from the iris family that completes its life cycle in one year. during the saffron growth period, flowering is one of the most important stages, which includes a period of high temperature for inoculation and flowering induction and a period of low temperature for flowering emergence given the sensitivity of this plant’s flowering process to temperature changes, it seems that the increase in temperature caused by climate change will affect it, which requires increased preparation and planning to deal with its negative effects. in this regard, this experiment was designed and implemented to investigate the effect of different types of covering under different densities on the economic performance of saffron in the third and fourth year after planting in the gonabad climate condition. materials and methods: in order to investigate the effect of density and summer management covering corm behavior and economic performance of saffron in gonabad climatic conditions, an experiment was conducted in split plots in a randomized complete block design with three replications at the khorasan razavi agricultural and natural resources research and education center (gonabad research station). in this study, planting density treatments were at four levels including 60, 90, 120, and 150 corms per square meter in the main plot and plant residue management and shading at four levels including removal of saffron residues at the end of the growing season (control), presence of saffron residues at the end of the growing season, control + use of barley stubble at the rate of 2 ton/ha, and control + use of artificial shade in the subplot. the dimensions of the subplot were 4×2 and the dimensions of the main plot was 8×4. in order to prevent mixing of other factors, the initial weight of mother corms for planting in all treatments was based on an average of 8-9 grams. before planting, 40 tons per hectare of rotted cow manure was added to the soil. each year, depending on the amount of accumulated rainfall, between 4 and 5 irrigation cycles were performed. during the flower harvest season, to investigate the effect of experimental treatments on saffron flower characteristics, after removing 0.5 m of marginal effect, sampling was performed in each of the subplots to investigate the flower characteristics. also, in both years of the experiment, in order to investigate the effect of experimental treatments on the number and average weight of daughter corms, in the dormancy stage (second half of june 2010 and 2011), and in the quadrats established from the previous stage, all corms were removed from an area of 0.25 square meters of soil, and after counting the number of daughter corms and separating the soil particles, the fresh weight of the corms were measured and recorded. data editing was done by using excel 2010 software and data analysis was done using sas var. 9.4 software. duncan’s test was used at the 5% probability level to compare means. results and discussion: the results of this study were showed that the characteristics of corms and flowers were affected by the increase in density in both years of the study, and the highest amount of stigma dry weight in both years of the experiment were obtained under a density of 120 corms/m2, respectively; however, as the age of the field increased, higher density levels had a lower percentage increase in the desired traits, so that in 2022, stigma yield under a density of 120 corms/m2 did not differ significantly from 90 corms/m2. the application of various types of cover in summer increased all the studied traits compared to the control treatment (removal of saffron residues). based on the results of this experiment, the use of cereal straw in the first year had the highest stigma yield, and in the second year, the artificial shade treatment had the highest stigma yield. also, the study of interaction effects showed that the application of barely stubble (first year) and shading (second year) under density of 90 and 120 corms/m2 increased the dry weight of the stigma compared to other cover management treatments. conclusion: considering the positive effect of using cover on the economic performance of saffron, it seems that the practical recommendation of using various types of cover, especially cereal stubble, considering its lower cost compared to shade and also easier access to cover saffron fields at the beginning of the hot season, can be considered for sustainability and increasing saffron yield.