تاثیر مدیریت تغذیه بر مراحل فنولوژیک، کارآیی مصرف نور و عملکرد نخود زراعی (Cicer Arietinum L.) تحت تاثیر تاریخ کاشت

طول دوره مراحل رشد گیاه، استفاده از تشعشع خورشیدی، آب و مواد غذایی از جمله موارد تعیین‌کننده عملکرد گیاه به‌شمار می‌آیند. از این رو، به‌منظور بررسی مدیریت تغذیه و شرایط آب ‌و هوایی بر مراحل فنولوژیک، کارآیی مصرف نور و عملکرد نخود زراعی (cicer arietinum l.)، آزمایشی به‌صورت فاکتوریل در قالب طرح بلوک‌های کامل تصادفی با سه عامل و سه تکرار در مزرعه دانشکده کشاورزی دانشگاه گنبدکاووس در دو سال زراعی95- 1394 و 96 -1395 انجام شد. دو تاریخ کاشت شامل اواسط دی‌ماه و اواسط بهمن‌ماه، کود زیستی مزورایزوبیوم در دو سطح شامل تلقیح و عدم تلقیح و کود شیمیایی نیتروژن در چهار سطح شامل صفر، 20، 40 و 60‌کیلوگرم نیتروژن در هکتار با منشا اوره، به‌عنوان تیمار مدنظر قرار گرفتند. نتایج نشان داد که تاریخ کاشت عامل اصلی تغییر در مراحل فنولوژیک گیاه در هر دو سال بود. عملکرد دانه در تاریخ کاشت اواسط بهمن‌ماه نسبت به اواسط دی‌ماه به‌ترتیب در سال اول و دوم 17.84 و 23.65‌درصد کاهش یافت. همچنین، بیشترین مقدار این صفت در هر دو سال از مصرف 60‌کیلوگرم نیتروژن در هکتار حاصل شد، ولی با این حال بین 20، 40 و 60‌کیلوگرم نیتروژن در هکتار تفاوت معنی‌داری در هر دو سال وجود نداشت. تلقیح بذر با مزورایزوبیوم در سال اول و دوم به‌ترتیب سبب افزایش 242 و 170‌کیلوگرمی عملکرد دانه در هکتار نسبت به تیمار عدم تلقیح شد. کارآیی مصرف نور نسبتاً پایدار بود و تحت تاثیر معنی‌دار عامل‌ها قرار نگرفت. در مجموع، نتایج نشان داد در بین عوامل مورد بررسی، تاریخ کاشت نقش بیشتری در طول مراحل رشد گیاه، کارآیی مصرف نور و در نهایت عملکرد گیاه داشت.

The effect of nutritional management on phenological stages, radiation use efficiency and seed yield of chickpea (Cicer arietinum L.) under influence of planting date

IntroductionChickpea (Cicer arietinum L.), is a cool season seed legume, serves as an important cheap source of protein and energy in developing countries. Plant phenology is an important aspect of plant adaptation to environmental conditions in order to match maximum the cropping cycle with the seasonal weather pattern (Vadez et al., 2013). Except of drought stress, other environmental factors such as temperature, photoperiod and nutrient deficiencies will affect the plant development stages (Soltani, 2009). The radiation use efficiency (RUE) indicates the amount of dry matter produced gram per unit of absorbed light (MJ) (John et al., 2005). Studies have shown that the supply of nitrogen and the change in planting date will affect on the time of entry into phonological stages and RUE and ultimately seed yield. Regarding the importance of chickpeas as supplier of protein for human and as fixation of nitrogen for plant, this experiment was conducted with the aim of evaluating the contribution of planting date, nitrogen and nitrogen fixation on phonological stages, RUE and seed yield in the climatic conditions of Gonbad Kavous. Materials MethodsThe field experiment was conducted as factorial layout based on a randomized complete block design with three replications at the experimental farm of Gonbad Kavous University during the growing season of 20152016 and 20162017. Nitrogen (none consumption, consumption of 20, 40 and 60 Kg nitrogen ha1), planting dates (early January and early February) and inoculation with Mesorhizobium (inoculation with Mesorhizobium and non inoculation) were considered as treatments. Half of nitrogen was used in planting time and the other half was used during seed filling stage due to the decrease of the symbiotic relationship between bacteria and chickpea. Seeds in inoculation treatments were inoculated with Mesorhizobium, strain SWRI14, which were obtained from the Soil and Fertilizer Research Institute, Tehran. The optical density (OD’s) were adjusted so that the cell concentration was 109 CFU ml1. Plots (1.5 m×6 m) were designed with 5 rows per plot. Between blocks, 1.5 m alley was kept. Seeds were sown on 5 January and 2 February 2016 and 5 January and 4 February 2017. In order to obtain the desired density (33 plants/m2), two seeds were sown per hill and hand thinning (one plant hill–1) was performed when seedlings reached 46 leafstage. Phenological stages (including planting to emergence, planting to flowering and planting to physiological maturity), radiation use efficiency (RUE) and seed yield were studied. Comparison of means was performed by LSD test for 5% probability level by using of SAS statistical software version 9.1.3. Results DiscussionThe results showed that planting date was the main cause of change of phenological stages of the plant in two years. Probably due to the presence of native rhizobium in the soil, nitrogen fertilizer and Mesorhizobium could not play the significant role in phenological stages and temperature and moisture had the main role in entering to the phenological stages. Generally with delay in planting time, the growth period of the plant decreased in both years. The seed yield of planting date in earlyFebruary compared to earlyJanuary in first and second year was decreased by 17.84% and 23.65%, respectively. This could be due to the short growing period of this planting date. The highest amount of this trait was obtained from 60 Kg N ha1 in both years but there were no significant differences between 20, 40 and 60 Kg N ha1 in both years. Seed inoculation with Mesorhizobium in the first and second year increased the seed yield by 242 and 170 Kg compared to noninoculation, respectively. This is justifiable regarding to the role of nitrogen in improving plant growth, yield components and finally increasing of seed yield. The radiation use efficiency was fairly stable and was not affected by factors in both years. It seems that radiation use efficiency is relatively stable in similar environmental conditions. However, some environmental conditions such as drought stress have significant effects on leaf photosynthesis and thus the radiation use efficiency, so that drought stress reduced this efficiency in the second year compared to the first year. ConclusionThe two years results showed that among factors, the role of planting date in chickpea was more than nutrient (nitrogen) and living factors (Mesorhizobium). Different climatic conditions between two years and between planting dates have significant role in the beginning and duration of phonological stages and seed yield. Therefore, considering the climate change and rainfall fluctuations in order to maximize the use of resources and achieving to high yield, it is necessary to select the planting date that provides the appropriate conditions for the plant in each region. Also the application of supplementation of adequate nitrogen for crops can increase seed yield.