پوشش گیاهی یکی از معیارهای معرف توان تولید سرزمین به شمار می‌رود. به‌طوری‌که ‌میزان کیفیت و کمیت پوشش گیاهی هر منطقه معیار تعیین توان تولید آن است. در این تحقیق جهت برآورد درصد پوشش و زی‌توده گیاهی منطقه حفاظت‌شده البرز مرکزی (شهرستان کرج) در تیرماه 1395 با استفاده از شاخص‌های گیاهی، از داده‌های رقومی لندست 8 استفاده گردید. جهت بررسی همبستگی بین درصد پوشش و بیوماس گیاهی با داده‌های ماهواره، 27 واحد نمونه برداری در منطقه تعیین و اطلاعات استخراج شد. رابطه درصد پوشش و زی‌توده گیاهی با شاخص های گیاهی از رگرسیون خطی برآورد گردید. نتایج نشان داد از میان شاخص‌های گیاهی انتخابی، شاخص گیاهی نسبت ساده (VR) و شاخص گیاهی بهبودیافته (EVI) دارای بیشترین ضریب تبیین با درصد پوشش گیاهی به ترتیب 0.53 و 0.52 است. بنابراین، این شاخص های گیاهی برای برآورد درصد پوشش گیاهی در سطح اطمینان 5 درصد مناسب هستند. در مرحله اعتبارسنجی میزان ضریب تبیین شاخص پایش محیطی جهانی EVI ،VR، GEMIبا مقدار وزن ‌تر گیاهی به ترتیب 0.43، 0.41 و 0.41 بود. باوجوداین، مقادیر برآوردی در مرحله واسنجی ناموفق بودند. با توجه به نتایج این تحقیق، توصیه می‌گردد جهت تخمین میزان کیفیت و کمیت پوشش گیاهی از شاخص‌هایی استفاده شوند که در آن‌ها نسبت اثر جو و خاک لحاظ شده باشد. Manuscript profile

The information about the forage quality of rangeland species is essential to supply a reasonable diet to livestock and determine thestocking rate and grazing time on rangelands. Salsola turcomanica is one of the important species of semi-arid rangelands in the Western part of Golestan province, Iran. The present study was conducted to provide information about the nutritive value of S.turcomanica at different growth stages in 2019. Plant samples (with three replications) were randomly collected in four growth stages (vegetative stage, early flowering, late flowering and seed maturity) from Gomishan rangelands during the summer and autumn 2019. Seven quality indices, including Acid Detergent Fiber (ADF), Crude Protein (CP), Dry Matter Digestibility (DMD), Metabolizable Energy (ME), Digestible Energy (DE), Total Digestible Nutrient (TDN) and Ash content (Ash) were analyzed. Data analysis was performed using One-way analysis of variance (ANOVA) method and mean comparisons were done by Duncan test. The results demonstrated that there are significant differences among phenological stages for all the traits (p <0.05). The results demonstrated that the content of CP (from 25.66% to 8.33%), DMD (from 84.45% to 56.31%), ME (from 12.35 to 7.57 MJ/Kg), Ash (from 40.03% to 35.60 %), DE (from 36.17 to 24.12 Mcal/Kg) and TDN (from 82.55% to 53.41%) were decreased by the progress of growth stages. Regarding its growth seasons and high values of CP, ME and DMD in all phenological stages, it is suggested that this species can have aprominent place in the grazing livestock diet in semi-arid rangelands. Manuscript profile

One of the major challenges in semi-arid regions of Iran is to supply the adequate forage for livestock and meanwhile prevent the destruction of rangelands due to overgrazing. Therefore, this study aimed to compare three cropping systems of barley using Salsola turcomanica (ST), and Chrysopogon zizanioides (CZ) in three treatments of barley+ST, barley+ST+CZ and mono-culture of barley. Two-year field trials data were collected from November 2018 to October 2020 in two experimental sites using a Randomized Complete Block Design (RCBD) with four replications. The results of analysis of variance over two years indicated that the effects of year, location, and year by location interaction were significant (p<0.01) for all of barley’s yield components. Mixed cropping of barley with other species had no negative effect on barley traits such as grain yield, straw yield and harvest index. In addition, the mixed cropping of barley+ST and barley+ST+CZ in the first year produced 2.5 t/ha more forage yield than that mono-culture of barley. This was due to high production of Salsola (ST), in mixed cropping. In both years, yield of Salsola production was about 25% of whole produced biomass. Drastic reduction in rainfall in the second year reduced the obtained yield; so, there was no significant difference among three cropping systems in the second year. However, cropping systems of barley+ST and barley+ST+CZ produced about 1 t/ha more forage than that for the mono-culture of barley. Mixed cropping of barley +ST+CZ did not affect yield components of barley. Mixed cropping of barley with Salsola turcomanica could guarantee soil cover throughout the year and is recommended for forage production in rangeland in Iran. Manuscript profile

Salsola turcomanica (Litv) is a widespread wild plant species in Middle Eastern arid and semi-arid areas and is a relatively palatable halophyte species that has low establishment rate in the field. In winter 2017, in order to optimize the germination indices, its seeds were treated by scarification, stratification, scarification after stratification, gibberellic acid, potassium nitrate and hot water. Then, in separate trials, the effects of six levels of drought stress (0, -2, -4, -6, -8, -10 Bar) and salinity (0, 5, 10, 15, 20, and 25 ds/m) were assessed under laboratory conditions as well as the effect of four sowing depths (0, 0.5, 1, and 1.5 cm) investigated on seedling emergence under greenhouse conditions. All four experiments were carried out using completely randomized designs with four replications. A significant decrease was observed in the seed germination indices by increasing drought and salinity stress levels (p<0.05). This species had moderate to low germination percent under -2 bar drought stress and 15 ds/m salinity. Based on the obtained result, the scarification was the best treatment of seed germination, so the seeds of S. turcomanica were scarificated and sown (100 kg/ha) in the field at the end of autumn 2018. According to the results, the highest seed emergence was observed at the shallow depth sowing and resulted in 28.7% vegetation cover and 176.44 (g/m2) dry matter production at the end of growing season. So, it was concluded that for dry land farming system, cultivation of this species in winter rangelands can reduce wind erosion during its growth period in summer and provide a considerable quantity of forage. Based on the results of this research, cultivation of this species can be recommended to rangeland improvement or ley-farming projects. Manuscript profile

Most of rangeland soils are limited in their ability to supply adequate nutrients to plants. Soil conditioners have been shown to alter soil fertility and plant characteristics. This investigation aimed to evaluate the influence of two soil conditioner on nutrition value of N. schoberi and A. podolobus. For this, two separate experiments for each species were carried out in greenhouse using completely randomized design with three replications during 2018 and 2019. Treatments were four levels of wheat straw Biochar (WSB), as well as, lignite at rates of 0, 1.25%. 2.5% and 3.75% w/w added to clay loam soil. In the end of vegetative stage and before flowering, plant samples were taken and their Crude protein (CP) and Acid detergent fiber (ADF) content were measured and then Dry matter digestibility (DMD) and Metabolizable energy (ME) were calculated. Data were analyzed by One-way analysis of variance (ANOVA) and the means were compared using Duncan's test. The results demonstrated that WSB addition had no effect on nutrition value of both species. By application of Lignite, CP content of N. schoberi enhanced up to 44.45%, than that for control. The effect of lignite addition on nutrition value traits was high for N. schoberi. But this material had no effect on A. podolobus quality traits. Based on our findings, application of Lignite at 3.75 (w/w) recommended to improve soils of rangeland for cultivation of N. schoberi in dry-lands plantation projects or the conversion of dry lands to arable pastures. Manuscript profile