هدف از این تحقیق مقایسة تغییر کاربری اراضی مرتعی به دیم‌زار در دو شهرستان رابر و ارزوئیه در یک دوره 15 ساله است. روند تغییرات کاربری محدودة مطالعاتی (ده سرد و کوه سفید) با استفاده از تصاویر لندست ETM (سال 2000) و OLI (سال 2014) در محیط نرم افزار ENVI®5 با روش طبقه بندی نظارت شده پردازش گردید. در نهایت نقشه طبقه بندی کاربری شامل کاربری مرتع، کشاورزی، اراضی بایر و باغ در منطقه شناسایی شد. دقت نقشه های تولیدی با ضریب کاپا محاسبه شد. برای این منظور از تصاویر نرم افزار گوگل ارتس و بازدید میدانی در تهیه نقاط تعلیمی استفاده شد. در نهایت ماتریس دقت برای هر نقشه تشکیل ‌گردید. برای پی بردن به تغییرات هر یک از کاربری‌ها به سایر کاربری‌ها از روش جدول متعامد (Crosstab) استفاده شد. نتایج تغییرات کاربری اراضی در دو منطقه نشان داد که کاربری اراضی مرتع بیش‌ترین تبدیل و تغییر را داشته است، درصد تغییرات در آبخیز ده سرد 77% و در آبخیز کوه سفید 73% بود. صحت نقشه های طبقه بندی برای هر دو زیر حوزه 98% بدست آمد. نتایج این تحقیق نشان داد که گسترش فعالیت‌های زراعی بر روی اکوسیستم‌های مرتعی موجب تبدیل مراتع به زمین‌های کم بازده می‌شود. نتیجه مطالعه همچنین نشان داد که در منطقه کوه سفید و ده سرد به ترتیب 9% و 20% تغییرات در زمین های کم بازده می باشد. تفاصيل المقالة

شتاب در روند تغییرات اقلیمی باعث دگرگونی سریع وضعیت اکوسیستم های مرتعی شده است که یافتن روش های نوین ارزیابی این تغییرات راهی جهت مدیریت پایدار مراتع محسوب می شود. به منظور بررسی روند تغییرات پوشش گیاهی ناشی از اثرات اقلیمی مراتع البرز مرکزی انتخاب شدند. شاخص نرمال‌شده تفاضل پوشش گیاهی (NDVI) با استفاده از تصاویر ماهواره ای لندست، سنجنده +TM، ETMو OLI برای سال های 1366 تا 1395 (30 سال) استخراج گردید. با استفاده از شاخص بارش استاندارد شده (SPI) روند خشکسالی مورد بررسی قرار گرفت. جهت پیش بینی تغییرات آتی پوشش گیاهی مراتع از مدل زنجیره مارکوف استفاده شد. نتایج نشان داد که شاخص (NDVI) از سال های گذشته تا حال نوسان داشته است به طوریکه ضمن افزایش موقتی تغییرات در بعضی سال ها 1366 (0.86)، 1381 (0.87)، 1384 (0.87) و 1394 (0.86)؛ اما روند تغییرات کلی به صورت کاهش در میزان این شاخص در سال های 1374 (0.53)، 1376 (0.65)، 1379 (0.62) و 1387 (0.61) به خصوص برای طبقات متوسط تا خیلی فقیر بوده است. همبستگی بالا (5/91%) بین شاخص SPI و NDVI نشان می دهد که تقریباً در تمامی سال های کاهش پوشش گیاهی، خشکسالی شدید تا متوسط رخ داده است. همچنین مدل پیش بینی مارکوف تغییرات کاهشی شدیدی در میزان شاخص پوشش گیاهی برای سال های 2031 و 2045 پیش بینی می کند. بنابراین مدیریت مراتع باید به گونه ای پیش برود که با روند افزایش تدریجی دما و تأثیرات منفی آن بر پوشش گیاهی، از طریق تنظیم ظرفیت چرایی و نیز جایگزینی دام های با عملکرد بالا و تقویت گونه های گیاهی مقاوم به خشکی نسبت به شرایط آینده آمادگی یابند. تفاصيل المقالة

با توجه به رشد روزافزون جمعیت در مناطق خشک و نیمه خشک، محدودیت منابع آب رو به افزایش است. از این رو استفاده از آب های غیرمتعارف به عنوان ابزار مهمی در مدیریت منابع آب در مناطق خشک به حساب می آید. در این بین بهره‌گیری از پساب فاضلاب شهری برای آبیاری به صورت توأمان با طرح‌های بیابان‌زدایی از مواردی است که جای بررسی و مطالعه دارد. اثری که این گونه آب ها بر ویژگی‌های فیزیکی و شیمیایی خاک برجا می‌گذارد، اهمیت زیادی دارد. در دهه اخیر روش های هوشمند مصنوعی به خاطر قابلیت شبیه سازی فرآیندها در زمینه های مختلف کاربرد زیادی پیدا کرده اند. برنامه ریزی بیان ژن (GEP) جزء الگوریتم های تکاملی محسوب شده و قادر به بهینه سازی ساختار مدل و مولفه های آن می باشد. در این تحقیق به ارزیابی توانایی و دقت مدل برنامه ریزی بیان ژن(GEP) در شبیه سازی تغییرات میزان سدیم، اسیدیته و هدایت الکتریکی خاک در زمین های تحت آبیاری با پساب و زمین های فاقد آبیاری در دشت قم پرداخته شد. برای مدل سازی تغییرات خصوصیات شیمایی خاک، به صورت تصادفی70 درصد داده های مشاهداتی مربوط به هدایت الکتریکی، اسیدیته و سدیم خاک به منظور تعیین مدل مناسب مورد استفاده قرار گرفته و مابقی داده ها در واسنجی مدل های مورد نظر بهره برده شد و پارامترهای شیمیایی خاک به عنوان متغیر مستقل و تیمار پساب به عنوان تابع انتخاب گردید. نتایج مقایسه ژنی نشان داد که برنامه ریزی بیان ژن، به خوبی روند تغییرات خصوصیات شیمیایی خاک را مدل سازی کرده است و در بهترین حالت اجرای مدل، بالاترین مقدار ضریب تعیین، برای هدایت الکتریکی (97/0 =2R)، اسیدیته (96/0=2R) و سدیم محلول خاک (97/0=2R) محاسبه شد. تفاصيل المقالة

عمق کاشت بدلیل تأثیر زیادی که بر جوانه زنی، سبز شدن و استقرار گیاهچه دارد، در برنامه های اصلاح و احیای مراتع بسیار حائز اهمیت می باشد. اسپرس (Onobrychis) یکی از مهمترین گونه های مرتعی بوده که از نظر علوفه ایی، حفاظتی و یا به عنوان گیاهان جذب کننده زنبور عسل دارای اهمیت بسیار بالایی می باشند. از این رو، در این تحقیق، اثر 4 سطح عمق کاشت (5/0، 5/1، 3، 5/4 سانتی متر) بر جوانه زنی و سبز شدن اسپرس به صورت طرح بلوک های کامل تصادفی در چهار تکرار تحت شرایط گلخانه ای انجام گردید. بذرها در گلدان های پلاستیکی کشت شده و پس از رشد جوانه ها، تعداد آنها شمارش شده و خصوصیات مختلف جوانه زنی (طول ریشه چه، ساقه چه و گیاهچه، بنیه بذر، درصد و سرعت جوانه زنی، وزن تر و خشک ریشه چه و ساقه چه)، اندازه گیری شده و اطلاعات بدست آمده با استفاده از تجزیه واریانس، آزمون دانکن و دانت مورد تجزیه و تحلیل آماری قرار گرفت. نتایج نشان داد که تیمارها بر خصوصیات جوانه زنی و رشد گیاهچه شامل وزن تر ریشه چه و وزن خشک ساقه چه در سطح 5 درصد تاثیر معنی داری دارند و بر درصد جوانه زنی، سرعت جوانه زنی، طول ریشه چه، بنیه بذر، طول گیاهچه، طول ساقه چه در سطح یک درصد تاثیر معنی دار دارند. نتیجه بدست آمده مبین آن است که میان چهار تیمار کاشت، تفاوت معنی داری وجود دارد و عمق کاشت کمتر نسبت به عمق کاشت بیشتر بهتر می باشد. بنابراین توجه به عمق کشت در برنامه های اصلاح و احیای مراتع امری ضروری بوده و می تواند در موفقیت این برنامه ها نقش مهمی داشته باشد. تفاصيل المقالة

One of the effective ways for reducing atmospheric CO2 is carbon sequestration by plants and soils. Rangelands with an expanded area have a great potential for Carbon (C) Stocks. In this study, C stocks in three treatments including natural rangelands (NR), Pit- seeding by Agropyrum elongatum (PS) and abandoned dry farming (ADF) were examined in Kardeh basin Mashhad, Iran in 2013. In each treatment, ten transects and in each transect, ten plots were established. Percentages of vegetation cover, litter, rock and soil were recorded in each plot. Aerial and root biomasses of dominant species were sampled by the clipping and weighing method. Litters in each plot were collected and weighed, too. Carbon content of biomass and litter were measured by combustion method using Electric Combustion Furnace. Ten soil samples were taken along each transect at two depths of 0-25 and 25-50 cm. The soil organic carbon percent was determined by the Walkley–Black method. Data analysis was performed by one-way analysis of variance (ANOVA) and means were compared using Duncan test. Results showed significant differences between treatments for total C stocks (soil+biomass+litter). NR and ADF management with the average values of 535.32 and 177.14 (t.ha-1) had the highest and lowest C stocks, respectively. Among the components of the ecosystem, soil had a main role in C sequestration followed by above biomass, roots and litters. PS management had the highest C stocks in plant biomass and litter but its soil C stocks were significantly lower than NR. Perennial grasses, bushes and perennial forbs were dominant in PS and NR management that play the most important role in plant C stocks. In conclusion, proper management of natural rangelands and more attention to vegetation and soil conservation may lead to store a considerable amount of C stocks in these lands. تفاصيل المقالة

Exclusion and not using of rangeland in the long term affects the composition and homogeneity of vegetation and consequently leads to the improvement of plants status. In this study, the characteristics and structural changes of the rangeland of Gonbad, Hamadan province, Iran, in 2014 (after 20 years of enclosure) were evaluated using Braun-Blanquet plot, Phytosociology and multivariate analysis by the software PC-Ord5. According to clustering diagram and Indicator Species Analysis, it was found that the studied region had 10 vegetation types and 17 Indicator Species. Detrended Correspondence Analysis (DCA) showed that in the first axis the variables: stone and gravel percentage, Electrical Conductivity (EC), clay, and organic carbon were important and in the second axis canopy cover of grasses, total canopy cover, and pH were important. Principal Component Analysis (PCA) confirmed the relationship between plant communities and environmental factors in the enclosure region. It was found that there are correlations between the echo logical units and the factors: stone and gravel (0.25), clay (-0.26), sand (0.28), silt (0.38), slope (-0.36), total neutralizing value (0.34), and plant species indicators that resulted to the separation of the units. The results showed that in the long-term enclosure, plant communities tend towards a uniform and homogeneous composition and consequently led to the improvement of the rangeland vegetation conditions. Therefore the density, composition and the class I plant species have increased. تفاصيل المقالة

There are many remediating methods for the polluted soils but only phytoremediation is a cost effective, environmental friendly, aesthetically pleasing approach that is most suitable for many countries. The purpose of this study was to investigate the potential of native plants for phytoremediation of contaminated soils with lead, zinc, cadmium and nickel in the rangelands around National Lead & Zinc Factory, Zanjan, Iran. Sampling was done at 11 sites on May, 2014 and plant samples were collected from 14 native plant species. Three soil samples were taken at each site. Soil samples were taken from the rooting zone. Extraction of Pb, Zn, Cd and Ni from plants was done by acid digestion. Plant samples were digested in the di-acid mixture (3:1) of nitric acid (HNO3) and perchloric acid (HClO) and soil samples were digested with 4M HNO3 acid. Metals of Pb, Zn, Cd and Ni were extracted from plant and soil samples were determined using Inductively Coupled plasma Optical Emission Spectroscopy “ICP-OES”. In general, the results showed that no hyperaccumulators of Pb and Zn were identified in the area. All plants were classified as low lead accumulators, excluder and moderate accumulators, low zinc accumulators or excluders; though Pb and Zn concentrations in the plants were higher than standard range. Standard range of lead and zinc in rangeland plants is 0.2-20 and 1-400 mgkg-1, respectively whereas the species of Brassica juncea and Scariola orientalis were classified as Cd hyperaccumulators and Scariola orientalis and Echium amoenum were classified as Ni hyperaccumulators. The normal value of Cd and Ni in these plants were 0.1-2.4 and 0.02-5.0 mgkg-1, respectively. Thus, these native plants had an implication of carrying out phytoremediation in the rangeland soils around National Iranian Lead & Zinc Factory, Zanjan. تفاصيل المقالة

Species diversity, richness and biomasses (aboveground biomass) and their relationships are the key variables of ecosystems. This study was conducted to determine the relationship of Species Diversity (SD) and Species Richness (SR) with Above-Ground Biomass (AGB) at a local scale at 5 different habitats (shrubland, forbland, grassland, shrub-forbland and forb-shrubland) in Zagros mountains in west of Iran (2015). For each habitat, 50 plots (2m2) were determined. SD was estimated by Shannon–Wiener’s index, SR was defined as the number of species per plot and AGB was detected per unit of area (gm-2). Results indicated that all of relationship patterns existed in these habitats. The unimodal relationship was found in shrub-forbland and forb-shrubland whereas the relationship of SD/SR vs.AGB in shrubland was linear and negative, and in forbland and grassland, it was positive. There were many complex and variable mechanisms dealing with the SD/SR vs. AGB relationship. The unimodal relationship indicates that SR and SD peaked at intermediate levels of AGB, and it is an inherent attribute of the spatially heterogeneous habitats affected by life forms, micro-sites, facilitation and competition. The positive linear was related to positive response of SD, SR and AGB to environmental factors or because of any reason (grazing, disturbance level…), the AGB may not reach to the highest possible level; thus, it may only show a positive relationship. When SD and AGB are affected in the opposite directions by environmental factors such as soil fertility, negative patterns may be caused. The negative pattern represents short gradients indicating a similar species composition among plots. Greater R2 in SD vs. AGB than SR vs. AGB at all habitats showed that evenness and richness (components of SD) are more important than just SR; thus, SD vs. AGB relationship is better and more reliable to predict the variations (SD and AGB). تفاصيل المقالة

As far as Iran is concerned in arid and semi-arid region and amount of water is limited, improvement of water consuming is very important. One of the ways for storing water is to use superabsorbent polymer. So, this research compared normal and deficit irrigation methods by considering the effects of stockosorb (0.1% and 0.3% by volume) and zeolite (10 weight% and 15 weight%) in two sandy soils (70% and 80%) on soil physicochemical characteristics (EC, pH, field capacity, available water, wilting point, bulk density, practical density, porosity, nitrogen, phosphorus and potassium) and plant morphological traits (plant height, basal area, large and small diameter of canopy) of Atriplex lentiformis (Torr.) S.Wats. The research was carried out in the field of desert research centre in Semnan Province in 2013. A split factorial experiment based on a randomized complete block design with four replications was used. Data were analyzed using SPSS16 software. The result showed that superabsorbent had a significant effect on plant height, large and small diameter of canopy. Also, superabsorbent had a significant effect on EC, pH, field capacity, available water, bulk density, porosity, K. However, they had no significant effect on wilting point, soil particle density, P and N. Also, the result of economical investigation of stockosorb and zeolite showed that using 10 wt% zeolite, 15 wt% zeolite and 0.1% stockosorb with normal irrigation is economical. تفاصيل المقالة

Regardless the crop production, range and livestock management is unlikely to be possible. Considering the range production is essential for efficient and effective range management. This study aims to investigate the relationship between the rate of forage production and the effects of climate variables. For this purpose, forage yield of four range species including Artemisia sieberi, Scariola orientalis, Stipa atriseta, and Stachys inflate regarded as indices species was recorded in Bidalam rangeland, Fars province, Iran in a 10-year period (1998 to 2007) and then, the study continued for another two years (from 2016 to 2017). Forage yield was collected through cutting and weighing method in 60 random 2m2 plots along four 300 m transects during 12 years. Climatic parameters such as rainfall, temperature, relative humidity and sunshine periods were obtained from Abadeh weather station and used for estimation of forage yield in different growth periods of the year. The annual dry matter production of each species and sum of all species were used as dependent variables and climatic parameters were considered as independent ones using multivariate linear regression. The results showed that previous rainfall (rainy of growing season plus last year) had the highest effect on annual forage production of rangelands (R2=0.88). It was concluded that using regression analysis between annual rainfall and forage production in some indices species, the rangeland production of coming years could be estimated with high accuracy. تفاصيل المقالة

Adaptation of plants under drought and salinity stress depends directly on the type of soil texture. Therefore, in this research, the morpho-physiological variations of Stachys multicaulis,an Iranian wild endemic plant species, were investigated in different soil textures under drought and salinity stress. For this purpose, plants were cultivated in three different light, medium and heavy soil textures under pot condition (outside the greenhouse near the plant original habitat) in 2016. Then, a set of drought stress (3 day intervals of irrigation; 3 to 15 days) and salinity stress (0, 5, 10, 15, 20 and 25 ds/m- NaCl) was used in two separate factorialexperiments based on a completely randomized design with four replications. The results showed that both drought and salinity had significant effects on morpho-physiological properties of S. multicaulis (p<0.01) based on type of soil texture. All of traits had higher performance in heavy soil texture except trichome length. For 15 day interval of irrigation, higher values of plant biomass, plant greenness, leaf length/width ratio, leaf angle, and node distance as 8.25g, 28.1%, 4.17, 55°, 1.5cm respectively were obtained in heavy soil texture. Similarly, for salinity of 25 ds/m, higher values of same traits as 7.7g, 25%, 3.9, 50°, and 1.4cm, respectively were obtained in heavy soil texture. Both drought and salinity stress had no significant effect (p<0.01) on leaves trichome number, trichome length, floret number per plant and branch number per plant in all three soil textures. The morphological variations of the plant occurred with greater intensity in salinity stress and it was concluded that plant tolerance to salinity was lower than drought. تفاصيل المقالة

This study was performed to evaluate the forage nutritive value of Cymbopogon olivieri before and after conducting the essential oil extraction in rangelands of Khuzestan province, Iran. In this study, the aerial parts of Cymbopogon olivieri were collected in flowering stage from 10 natural regions located in Khuzestan province in 2016. Regions included ChalGandali, TalkhabKalat, Bardmar, Morad Abad, Tembi, Dezful, Andika, Lali, Shoushtar, and Izeh. Essential oil composition was analyzed by GC/MS. The forage quality traits including Crude Protein (CP), Dry Matter Digestibility (DMD), Water Soluble Carbohydrates (WSC), Crude Fiber (CF), Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), and total Ash were measured. After normalizing the gathered data, the means of the traits were compared by Duncan’s multiple range test (p <0.05) in SAS software. The 21 components were identified in the essential oil of the plant species. The result showed that the highest mean values of CP, DMD, WSC, CF, ADF, NDF, and total Ash were obtained as 4.83%, 48.03%, 14.9%, 76.63%, 50.12%, 84.59%, and 3.98%, respectively. The result showed that phenological stage had significant effects on forage quality. The higher amount of NDF (77.01), ADF (40.54), and CF (63.64) were observed after essential oil extraction stage, but the higher amount of CP (3.31), WSC (11.99), and DMD (46.03) were observed before essential oil extraction. In this study the range of changes for CP ranged from 1.26 to 5.06, DMD between 45.89 to 49.27, WSC between 7.27 to 11.53, ADF 40.40 to 45.5, total Ash ranged between 3.14 to 4.94, CF ranged from 58.6 to 65.82 and NDF was in the range of 63.49 to 70.72. So, it was concluded that since the essential oil extraction led to decreasing of forage quality have more benefit for dairy and meat production. تفاصيل المقالة

Semi-arid mountainous areas are of special importance in terms of ecological function i.e. vegetation dynamics and its evaluation under environmental- managerial factors is a necessity for their sustainable use. Due to the highly variable environmental characteristics in these areas, proper land management and utilization can severely affect the Range Condition (RC). Here, the relationship between topography, soil characteristics and management (RC) under grazing] was investigated through multivariate analysis in mountain areas of Golestan’s Chahar Bagh, northeastern Iran in 2019. The RCs were assessed by scoring vegetation and soil characteristics in areas under livestock grazing areas. The preliminary findings of this research showed that environmental factors i.e. clay, P, EC, slope, aspect, Soil Moisture (SM) and K had the most effect on the formation of five different vegetation types (Cum.% of Var.=80.4%). The results showed that RC changes had more significant relationships with managerial factor/grazing than environmental factors. In general, the effect of environmental and management factors and their common effect in changing RC were equal to 1.84%, 74.1 and 21.04%, respectively. The change of soil physical properties was more than soil chemical properties under RC changes. Factors of Organic Matter (OM), Bulk Density (BD), porosity and SM showed significant changes under excellent, good, fair, poor and very poor conditions (P<0.05). In general, excellent and good rangelands were related to more OM and porosity and less slope and K. Moreover, poor/very poor rangelands were related to more SM, BD, P and slope. Overall, managing grazing can significantly decline/improve RC in mountainous area. تفاصيل المقالة

Economic, social, and ecological factors in rangelands affect range management. By integrating and studying these factors, a more appropriate method can be applied to assess the sustainability of rangelands. In the present study, Analytical Hierarchy Process (AHP) as well as the experiences and views of rangeland exploiters and nomadic and natural resources experts in Kerman province were used to compare and prioritize the economic, social, and ecological factors affecting sustainable range management in semi-arid rangelands of Kerman province in 2017. Then, the means comparisons were made between priorities of rangeland exploiters and experts. Using AHP weight data, our results showed that ecological capital had the most impact of 0.71 and 0.61 from the viewpoints of rangeland exploiters and experts, on sustainable range management in the study area, and the two other factors including economic ones with 0.17 and 0.19 and social ones with 0.09 and 0.19 capital were ranked, respectively. Furthermore, according to the results of comparing the views of rangeland exploiters and experts, significant differences were found between the views of the two mentioned groups for 14 indicators including plant species diversity, soil erosion, groundwater, unity and solidarity at the range allotment level, trusting the experts and promoters, the presence of people in decision making and planning, the presence and role of women in livestock and non-livestock products, living cost, and livestock number. Overall, the results indicate the inconsistency between the views of these two groups. Therefore, prior to policy making for sustainable range management, more consistency is required between the views of rangeland exploiters and experts in each of the related organizations for greater participation of range managers. تفاصيل المقالة

Identification of habitats and suitable environmental conditions for the presence of various animal and plant species is one of the key issues in ecology and environment modeling. In Iran, Gymnocarpus decander species is the main and most abundant plant of the Baluchi flora, especially in the rangeland areas. Due to its high resistance to harsh environmental conditions and salinity, this species can be useful for rangeland reclamation and restoration. In order to assess potential habitats of G. decander in Sistan and Baluchestan province, Iran, this research was conducted in May 2020 using multivariate statistical methods including factor analysis, clustering and logistic regression. To do so, the map of real habitats ofG. decander, was modeled using altitude and 62 climatic variables which were prepared using 24 meteorological stations across the province and neighboring. Climatic variables were reduced to 5 factors using PCA, including temperature, precipitation, radiation, dust and maximum temperature, which accounted for 88.3% of the climate change in the studied region. According to the regression models, the precipitation, temperature and altitude variables were the most significant independent variables (p <0.05) which influence the potential habitats ofG. decanderin the study area. Also, the study area was divided into 5 groups (G1:G5). The results suggest that models are more accurate in homogeneous groups than in the whole region. The Kappa coefficient and perdition accuracy had the highest and lowest values for G1 (68% and 88%) and G5 (19% and 59%), respectively. The results also showed that currently, 48.2% of the studied region has actual habitats. While the modeling results based on the model of the whole region showed that the potential habitat area of this species was 52.3% and based on the grouping models, it was 53.7%. Therefore, based on differences between actual data and modeling result, 4.8% of potential habitats have noG. decander. Also, results indicate that the G4 region with altitude range between 800-1250 m, growth season mean temperature was about 16 °C and annual precipitation about 170 mm was the main habitat forG. decanderin Sistan and Baluchestan. According to the results of this study, G. decander is an endangered species and it is necessary to plan long-term management to preserve and restore its habitats in the arid regions of southeastern Iran. تفاصيل المقالة

Plant life and food production for human closely depend on fertile and healthy soil. Knowledge about qualitative properties of soil and its potential production can contribute us in the plantation, fertilization, utilization and land management. In addition, Rangelands cover a very large portion of the earth's surface and play an important role in food security and other ecosystem services. Therefore, the present study has been conducted in order to evaluate soil quality according to minimum data set in Karvan rangeland which is located in the west of Isfahan province, Iran. For this aim, three vegetation types including Scariola orientalis-Astragalus gossypinus (Sc.or-As.go), Psathyrostachys fragile-Astragalus gossypinus (Psa.fr-As.go) and Cousinia bachtiarica-Astragalus gossypinus (Cu.ba-As.go)were selected in the study area. Then, four transects were established by a random systematic sampling; bias was placed to the general and lateral slope at the each vegetation type. The soil samples were taken at the start and end of each transect from two different depths (0-20 and 20-75 cm). Soil samples were analyzed and the physicochemical factors such as texture (silt, clay and sand), pH, Nitrogen (N), Phosphorus (P), potassium (K), Organic Carbon (OC) and Organic Matter (OM) were measured. Then, Soil Quality (SQ) indices were calculated using Bajracharya formula. The results showed that soil of the study area had a poor quality and also, there was different soil qualities regarding three vegetation types. It was found that OC (or OM) and N had maximum limitations on soil of Karvan region and caused low SQ indices. Also, pH only without any limitations was put in the highest rank for SQ measuring. تفاصيل المقالة

The aim of this research was to investigate the effect of index species, Astragalusammodendron on the associated plants of Agropyron tauri and Bromus tomentellus fromdifferent aspects in Shazand rangeland in southwest of Markazi province. The effects ofspecies density and distribution pattern and then index species on the soil properties werestudied. Based on the randomized – systematic method, 4 transects with a length of 50 m wereestablished. To find the relationships between index and associated plants, 30 points wererandomly chosen along the transects and the number of species was counted from these pointsto a 50 cm distance in different aspects. Along the transects, the distribution pattern of indexplants and their presence and absence were determined. To find the effects of index species onsoil properties, soil samples were taken and soil properties were determined in laboratory.Data were analyzed using SPSS software. The results showed that Astragalus ammodendrondensity with Agropyron tauri and Bromus tomentellus were similar to the east and westaspects and near distances. Astragalus ammodendron distribution pattern was randomizedwith a tendency toward the clumped pattern. The effect of Astragalus ammodendron on thesoil characteristics was not significant except for the north aspect. Generally, it is concludedthat the effect of Astragalus ammodendron (index species) on Agropyron tauri and Bromustomentellus densities was not significant. تفاصيل المقالة

بوته‌زارها با کارکردهای اکولوژیکی متنوع، سطح وسیعی از زمین‌های خشک و نیمه‌خشک را پوشانده‌اند. ارزیابی تغییرات خصوصیات خاک در بوته‌زارها می‌تواند در شناخت وضعیت تغذیه‌ای و روابط اکولوژیکی این بیوم¬ها به منظور اهداف مدیریتی سرزمین مؤثر واقع گردد. در این تحقیق تغییرات مکانی خصوصیات حاصلخیزی خاک بر اساس ساختار لکه و فضاهای باز بین لکه‌ای در بوته‌زارهای خالص شامل تیپ Artemisia sieberi، Scariola orientalis و Astragalus myriacanthus واقع در اراضی خشک فلات مرکزی ایران موردمطالعه قرار گرفت. ارزیابی‌ خصوصیات حاصلخیزی خاک و کیفیت خاک با انتخاب فضای باز مرجع بین لکه¬ها و ثبت خصوصیات مورفولوژیکی لکه برای مطالعه ارتباطات اکولوژیکی آنها موردبررسی قرار گرفت. بر اساس نتایج خصوصیات ماده الی، ازت، فسفر و شاخص کیفیت خاک (SQI)، در بین تیپ بوته‌زارها، و هم در فضای بین لکه¬ای در هر تیپ تغییرات معنی‌دار را نشان داد (P<0.01). بالاترین مقدار شاخص کیفیت خاک مربوط به زیر تاج پوشش در تیپ A. myriacanthus و برابر با 87/0 بود و کمترین مقدار نیز مربوط به نقطه مرکزی فضای خالی در تیپ A. sieberi و معادل 22/0 بود. خصوصیات عملکردی بوته‌ها مانند زیست‌توده، ارتفاع و تاج پوشش با توزیع فضایی عناصر و فاکتورهای حاصلخیزی خاک در فضای بدون پوشش بیشترین ارتباط را نشان داد (P<0.05). تفاصيل المقالة

چکیده در این پژوهش اثر بازدارندگی اکالیپتوس و عمق کشت بر جوانه زنی و رشد اسپرس در قالب آزمایش فاکتوریل براساس طرح پایه کاملأ تصادفی با چهار تکرار و دو فاکتور مورد بررسی قرار گرفت. فاکتور اول دگرآسیبی در پنج سطح 0، 005/0، 01/0، 02/0 و 03/0% وزنی پودر برگ اکالیپتوس در 1000 گرم خاک و فاکتور دوم عمق کاشت در چهار سطح 5/0 (شاهد)، 5/1، 3 و 5/4 سانتی متر بود. اثر دگرآسیبی، عمق کشت و اثر متقابل آنها بر تمامی صفات به استثنای طول ریشه چه معنی دار بود. اثر دگرآسیب بر وزن خشک اندام هوایی بیشتر از سایر صفات بود. همچنین افزایش عمق کشت منجر به کاهش طول ریشه چه و ساقه چه و سایر صفات رویشی مورد اندازه گیری شد. در مجموع، افزایش میزان دگرآسیبی اکالیپتوس و عمق کشت بر مؤلفه های رشد اسپرس تأثیر منفی داشتند و زمانی که این دو عامل هم زمان لحاظ شدند، تأثیر نامطلوب آنها بیش از زمانی بود که بطور مستقل در نظر گرفته شدند. بنابراین در نظر گرفتن اثرات متقابل آللوپاتی و عمق کشت می تواند نقش تعیین کننده ای در بهینه سازی تولید اسپرس در اراضی دارای اکالیپتوس داشته باشد. تفاصيل المقالة