این پژوهش به مطالعه تاثیر روش و زمان مناسب کشت در تولید بذر و علوفه گونه گون علوفه ای (Astragalus brachyodantus) در مراتع طبیعی مشکین شهر از سال های 1391 تا 1394 پرداخت. آزمایش کشت در قالب طرح بلوک های کامل تصادفی با سه تکرار به صورت کرت های خرد شده انجام شد که فاکتور A در آن مربوط به زمان کاشت (در دو سطح کشت پاییزه و بهاره) و فاکتور B مربوط به روش کشت (در دو سطح بذرپاشی و کشت ردیفی و کشت به صورت دیم در عرصه طبیعی) بود. عملکرد علوفه و بذر پس از سبز شدن و استقرار نهال ها اندازه گیری شد. تجزیه و تحلیل داده ها با استفاده از نرم‌افزار SAS و مقایسه میانگین به روش دانکن در سطح 5 درصد انجام شد. نتایج نشان داد اختلاف معنی داری در سطح 1 درصد در عملکرد تولید علوفه و عملکرد بذر بین زمان کشت وجود دارد. مقایسه میانگین عملکرد در صفات مذکور نشان داد که کشت پاییزه بهتر از کشت بهاره بوده است. در روش های کشت فقط در صفت عملکرد بذر اختلاف معنی داری در سطح 5 درصد مشاهده گردید. نتایج بر اساس مقایسه میانگین در عملکرد بذر نشان داد که بیشترین مقدار بذر مربوط به کشت ردیفی در سال دوم بوده است. بنابراین پیشنهاد می شود کشت برای حصول نتیجه بهتر در ارتفاعات کمتر از 1500 متر از سطح دریا ترجیحا در پاییز انجام شود. همچنین کشت ردیفی با عمق 5/2 تا 3 سانتی متر جهت صرفه جویی در مقدار بذر و پراکنش یکنواخت قابل توصیه است. تفاصيل المقالة

One of the fundamental difficulties in Iranian rangelands is the existence of wide area of poor condition rangelands that their grazing capability is low due to continuous livestock grazing pressure. Astragalus flexilipes is one of the palatable plant species of rangelands in Iran, while its distribution is being decreased due to improper grazing. The aim of this study was to evaluation the sowing season and cultivation methods of Astragalus flexilipes in dryland farming using split plot design based on completely randomized block with three replications in Meleh-Kabud, Gahvareh, Kermanshah, Iran over two years of 2016-17. The first factor was sowing seasons (spring and autumn) and the second one was cultivation methods (row sowing and scatter sowing). Data were collected for seedling emergence, survivor rate and growth condition in the second year. Result showed significant effect of cultivation method on seedling emergence and survival rate and significant effect of sowing date on growth condition (P<0.01). The sowing date by cultivation method interaction was significant for seedling emergence and survival rate (p<0.05). The highest values of the latter traits were obtained in spring season coupled with row cultivation method. In autumn sowing the highest growth scores of 3.74 and 3.15 (out of 5) for row sowing and scatter sowing, respectively. It was concluded that the highest establishment was achieved in spring cultivation, but the vigorous plants was observed in the autumn cultivation. Thus, early spring cultivation of Astragalus flexilipes using row-sowing method was recommended for rehabilitation of the poor condition rangeland in similar climate area having relatively lower temperature. تفاصيل المقالة

About 9% (349000 ha) of Khuzestan plain is the source of dust and it has seven dust hot spots. In this research, we investigated vegetation types, the floristic composition, life-form spectrum, and the phytogeography of the area during 2016–2020 by collecting vascular plants to provide an annotated checklist of the plants in Khuzestan province, Iran. In a period of five years, we focused on the vegetation of the septet areas as the source of dust and dune. A primary vegetation map was extracted from Google Earth images based on the texture, tone, and pattern, last vegetation map, and map of dust hot spots. To prepare vegetation types, they were checked in the field. The floristic composition, life-form spectrum, and the phytogeography of the area during five years were obtained by collecting vascular plants to provide a checklist of the sources of dust and dune. The 80 sample vegetation data from selected sites were analyzed using multivariate analysis methods. So, for assessing the relationship between plant species variation and environmental variation, the Canonical Correspondence Analysis (CCA) was used. The data of (80 samples of 8 species) and their soil factors (11 factors) were analysed using Rstudio software. The result showed that dust sources No. 1 and 2 had been covered by 24 vegetation types, and the speciesSeidlitzia rosmarinus,Halocnemum strobilaceumandTamarix passerinoides were regarded as dominant. The dust source No. 3 was covered by 22 vegetation types and the speciesHalocnemum strobilaceum,Aeluropus lagopoides,Seidlitzia rosmarinusandCornulaca monacantha regarded as dominant have been located in the east of Ahvaz. The dust source No. 4 had covered 39 vegetation types and dominant species wereAeluropus lagopoides,Halocnemum strobilaceum,Atriplex leucoclada,Salsolaspp.Seidlitzia rosmarinusandTamarixspp. in small rain reservoir. The dust sources No. 5, 6, 7 (with 249000 ha) were the major part of dust storm sources in Khuzestan, covered by 28 vegetation types. The CCA species-environment biplot showed that CaCO3, EC, Na, SAR, ESP, OC, and CaMg from 11 soil factors were the key factors affecting vegetation in dust sources at our study site. تفاصيل المقالة