فصلنامه تحقیقات مرتع و بیابان ایران
سال بیست و هفتم شماره 4 (پیاپی 81، زمستان 1399)

Due to their various roles in the plants’ life, the Arbuscular mycorrhizal fungi (AMF) has been studied from various aspects. In Iran, study on this type of fungi is still at its infancy. Also, the variety of plant species and populations in Iran necessitates a more in-depth analysis compared to other countries in the world. The present study aimed at investigation of the effects of grazing intensity on the diversity and populations of these microorganisms that are symbiotic with the plants and also determining the factors affecting the soil. Three rangelands were considered with three different grazing pressures: no grazing pressure, managed grazing and heavy grazing. Following the sampling of the soil around the rhizosphere of the dominant plant species, the samples were transferred to the laboratory to be analyzed. The results of this study revealed the significant differences in the diversity of AMF species in different sites, and the highest frequency percentage was related to the Septoglomusconstrictum species identified in the heavy grazing region(42.2%).Also, grazing caused changes in the mycorrhizal symbiosis percentage and these factors had a direct correlation, and this could be an evidence of the reduced diversity of AMF, because despite of the existence of spores in the soil, each plant species can only correlate with specific species of AMF. It can be said that appropriate grazing cannot have a negative effect on the population and diversity of AMF, because species diversity indices in a managed grazing region are in a stable state; and, by the proper management of the grazing system and preventing the premature or excessive grazing, its harmful effects can be prevented.

Determining the preference value of rangeland species by grazing livestock is one of the factors in rangeland management. In this study, the preference value of rangeland plants of Polour site in mountainous rangelands of Mazandaran in the months of grazing season (July to September) and different years (2007-2010) was investigated. The species selection index was used to determine the preference value of species. Species Production and consumption inside and outside the exclosure in the months of the grazing season and for four years were collected to calculate the species selection index. Duncan's multiple range test was applied to compare the means of traits. The results show that the species preference index, as well as the species preference index in different months of the grazing season, was significantly different at (p<0.01) Elymus hispidus var hispidus, Arenaria gypsophiloides, Bromus tomentellus, Dactylis glomerata, Festuca ovina, Taraxacum montanum, Tragopogon graminifolius, Falcaria vulgaris were classified in palatable class I. Astragalus aegobromus and Ferula galbaniflua were in palatable class II. Dianthus orientalis, Stipa hohenackeriana, Papaver bracteatum, Thymus pubescens, Verbascum Thapsus, Gagea lutea, Goebelia alopecuroides, and Euphorbia helioscopia were classified in palatable class III. Therefore, in the study of preference value, in addition to the taste of the studied livestock, factors such as the amount of production and the percentage of available plants, the distribution, and the amount of livestock access to them play a role in this area.

In the management of natural resource, recognizing socioeconomic factors affecting land use change is essential for achieving sustainable development and land use planning. In this research, we investigate and determine the socio-economic factors affecting land use changes in the Maraveh Tappeh region of Golestan province. This area has been affected by land use change in recent years. The rangelands and forests have decreased during the study period (1984-2014), and agricultural use with an annual increase of 132 hectares has reached to 10332.97 ha in 2014. This descriptive-analytic research was carried out in 16 villages in the study area with survey sampling method. Data collection was performed by questionnaire and the numbers of questionnaires were determined 310 people. Sampling was done through a Cochran formula and cluster sampling and multi-stage sampling. Cronbach's alpha coefficient was used to determine the reliability of the study and it was found 0.75. In this study, exploratory factor analysis method was used. For the factor analysis, the principal components method was used using rotation varimax. The results of factor analysis showed that socio-economic factors affect on land-use changes in Maraveh Tappeh region and these factors are including: non-economic efficiency of animal husbandry, Low land per capita for each farmer, rural unemployment, low income and high cost of living, increasing input price, the need for housing and the lack of awareness, social reputation and land ownership. These eight factors explained 63.80% of the total variance. Considering researching findings, attention to economic and financial problems and employment condition of village’s resident of Maraveh Tappeh region is essential. Also, husbandry and livestock production management and supply of livestock inputs have been proposed to reduce the land use changes of forests and rangelands and to protect the natural resources.

This study aimed to investigate the effects of livestock grazing in the way, changing the qualitative and quantitative composition of the plant As well as the different groups of plant species density in the enclosure in Boralan area. The vegetation and soil samples and 360 plots at 18 transect method - systematic random out of the enclosure and enclosure in three annual enclosures took place. The position of each plot were recorded using a Global Positioning System. Tilt maps and directions enclosure was prepared. Using the parameters plots a square meter of canopy cover, density, percentage of dead leaves, rocks and pebbles and bare soil were measured. During the growing season and plant species samples were identified using available resources. Shanon Vynz, Brillouin and uniformity Simpson and Simpson, Camargo, Smith and Wilson nor at the species level using Ecological Methodology software version 6.2, respectively. Compare enclosure vegetation parameters using SPSS software (version 16) and The enclosure and the enclosures were analyzed using multivariate methods. The results showed that the obtained in the studied sites (enclosure) 11 dark, 24 genera and 24 species, is widespread. Inside the enclosure with 24 species, with 17 species richness is more than grazed out. Values ​​of richness, diversity and uniformity within the enclosure is greater than the outside enclosure.

Diaphanoptera khorasanica is Iran's endemic species and vulnerable threat class. In this research, some of the vegetative and environmental characteristics of this species were studied in the Chalpo-e-Ataeiyeh habitat of Razavi khorassan and Hoindeh and Kajdarreh Sarigoul National Park in North Khorasan, Iran. For sampling of D. khorasanica, 45 plots were arranged in a systematic - random method along 9 transects of 100 m for all three habitats. In each plot, the vegetative properties of this species were measured. In each habitat, three soil samples were randomly taken from the depth of 0-20 cm at the under of the plants, and some of their physical and chemical characteristics were measured. Climatic data of 10 years was extracted from synoptic stations of Kashmar and Esfarayn. After data collection, one way ANOVA was used to analyze vegetative and soil characteristics and Duncan's test was used to compare the means. The results showed that there was a significant difference between the three habitats in terms of crown cover and diameter of the thickest stem at 5% level, plant height and leaf length , density and length of the longest stem at 1% level, but the number of seedling and leaf width were not significantly different. Also, there was a significant difference between the habitats for all of soil characteristics (p < 0.01). The most important environmental factors affecting vegetative characteristics were determined using principal components analysis (PCA). The results showed that minimum absolute temperature, average minimum temperature of coldest month, annual rainfall, electrical conductivity, clay and direction of slope had the most effect on these characteristics, respectively. Also among the vegetative characteristics, length of the longest stem, plant height, crown cover, number of plants and diameter of the thickest stem had the most effect on environmental characteristics.

Nine accessions of Elymus libanoticus was planted at Baharestan Agricultural Research Station and evaluated in order to nominate of the best accessions in terms of adaptability and establishment. The experiment started in 2010 and continued to 2015. For each accession adequate seed of different stocks in whole of the province was reaped. In reproduction phase (2010 autumn) and after soil preparation, all accessions were planted on plots with 5*6 m2, with 50cm spacing of planting line and planting points and 3cm of planting depth. At this stage weeding, and three irrigation times were performed. In the summer of 2011 mature seeds of grown accessions harvested and re-cultivation of seeds that were not green in the first stage was carried out. In 2011 and 2012autumn, the accession of each species based on complete randomized block design with 3 replications and 2 meter intervals on 2*4 m2 plots and 4 lines with 4-meter length and 50 cm intervals (In order to elimination of marginal effects) and 3 cm of planting depth planted as rainfed. The measured traits for plant selection were 1) growing 2) flowering 3) seeding 4) Yield 5) canopy cover 6) height and 7) regrowing, all data were statistically compound analyzed by SPSS and averages were compared using Duncan method. Results showed that there were significant differences among the measured traits and accessions (P≤0.05) in all studied years (2012-2015). In terms of measured parameters for all accessions of Elymus libanoticus, Iranshah and Chakhelo accession, respectively showed superiority and minority in the Baharestan research station conditions. In addition to the difference in genotypic power and the amount of precipitation that mentioned in previous studies as the only limiting factors of growth and propagation, Variable factors such as altitude from sea level, depth of soil and geographic direction of collecting areas of different accessions are factors influencing the establishment and adaptation of rangeland species in the site of cultivation and have the most effect on the performance of different accessions. So, it seems that zoning of areas is necessary for seed reproduction in order to improve the rangelands, and the use of extras in each area is necessary for replanting and planting in the same area.

Forage quality information could help managers of rangelands to select appropriate grazing method to achieve higher animal performance without damage to ecosystem. The aim of this study was to investigate the nutritional value of Thymus kotschyanus, Artemisia melanolepis and A. austriaca in different altitudes and phenological stages in 2016. According to the presense of the selected species, three rangeland sites in the southeast of Sabalan near Alvares ski resort including 2200-2400, 2600-2800, and 3000-3200 meters above sea level were selected. At each site 50 samples from each species were taken at three phenological stages. The nutritional value of the species was determined by measuring the percentage of dry matter, ash, organic matter, protein, fat, Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), macro elements (nitrogen, phosphorus, potassium, calcium, and sodium) and micro elements (iron, zinc, copper and manganese) and the results were analyzed in a completely randomized design using ANOVA. Duncan's multiple range test was used to compare the means. Considernig the difference in altitude in the habitat of T. kotschyanus and A. melanolepis, the effect of altitude factor on the studied traits in these two species was solely evaluated by independent t-test and the results showed that, altitude changes had no effect on the nutritional value and macro and micro elements of T. kotschyanus and A. melanolepis. The difference between phenological stages in species was significant. The highest and lowest percentage of organic matter were in seedling and growth stages for A. austriaca (94.43%) and A. melanolepis (91.49%), respectively. As phenological stages pass, there was a significant decrease in the percentage of fat, protein and ash in all three species (p < 0.05). The highest crude protein was observed in A. melanolepis at vegetative stage (17%) and the lowest in A. austriaca at seedling stage (7.5%). With the development of growth stages organic and dry matter, NDF and ADF were increased in the species. Phosphorus, potassium, nitrogen and sodium in the species were decreased significantly as phenological stages progress (p < 0.05). The highest phosphorus was recorded at vegetative stage in A. austriaca (0.34%) and the lowest (0.12%) in T. kotschyanus at the seedling stage. Overall, A. austriaca, A. melanolepis and T. kotschyanus have high nutritional value and suitable minerals, which can be used as substitute forage when other forage species are reduced in a given rangeland.

Carbon sequestration in soil and plant tissues is an effective way for climate change mitigation in the world. In this study, the effect of biomechanical operations (gabions which planted by Agropyrum elongatum) on carbon sequestration were examined in the rangelands of Kardeh basin, Mashhad and compared with natural rangelands and non- established waterways. In each treatment, Sampling from soil in two depths, above-below biomass of dominant species and litter were done by a systematic - randomly method and analyzed for carbon stocks. Carbon sequestration in biomechanical treatment during 1996- 2014 has been calculated by subtracting carbon stocks in this treatment and non- established waterways. Generally, total carbon stocks in biomechanical operation (above- below biomass, litter and soil up to 50 cm depth) is 16.23 ton/ha and carbon sequestration in this treatment during these years is 5.69 ton/ha. Also, carbon stocks in natural rangelands and non- established waterways is 54.07 and 10.61 ton/ha respectively. Overall, implementation of biomechanical practices in Kardeh basin in addition to soil conservation and restoration of vegetation,has improved the economic value of eroded lands in terms of carbon stocks and sequestration.

The persent study was designed to investigate the effect of canopy cover of three woody species, Amygdalus scoparia, Daphne mezereum, Ebenus stellata on the composition and density of soil seed bank under their canopies. Fifteen individuals were selected from each of the woody species in Chenarnaz rangelands, Yazd provimce, Iran in autumn, 2018. then the soil samples were taken from under the canopies of woody species with a control treatment outside the canopy from a depth of 0-5 cm with an auger, 5 cm in diameter. The density and composition of soil seed banks in samples were measured through germination method in the greenhouse. The results of one-way ANOVA showed significant differences of total seed bank densities under A. scoparia (with average 1133.17 seed per m2), D. mezereum (with average 823.10 seed per m2), E. stellata (with average 793.21 seed per m2). In addition, total soil seed bank density was significantly higher than the outside of canpies (with average 134.48 seed per m2). Hemi-cryptophyte was the most frequent in the soil seed bank. The results of this research showed the positive effect of the canopy of woody species in increasing of density of soil seed bank in which A. scoparia showed a great impact on soil seed bank characteristics.

The dust phenomenon is of particular importance because of its close association with public health. Many researchers are looking for ways to reduce the harmful effects of this phenomenon. To this end, having information about the nature of the spatial and temporal pattern of this phenomenon is of particular importance to all researchers. Dust is one of the natural hazards of the central Iranian plateau. In this study, statistical analysis was performed on a yearly and monthly basis in the period 2006 to 2018 using codes 06 and 07 obtained from 50 synoptic stations located in the study area. Also the spatial pattern of dust days with horizontal views less than 1000 m, 1000 to 1500 m and 1500 to 3000 m in the study area was plotted. The results also showed that Tabas synoptic stations with 661 days, Arak with 528 days and Zahedan with 511 days with 1500 to 3000 m horizontal view were more important in the study period. Also, the results of seasonal survey of dust days in the statistical period showed that spring with more than 42% had the highest occurrence of dust. The results showed that in the horizontal view of less than 1000 m, Zahedan station with 113 days and Tabas station with 91 days of dust had higher frequency. Meanwhile, Zahedan and Shahreza stations with 91 and 55 days of dust with a horizontal view of 1000 to 1500 meters also had the highest frequency of dust days in the study area. Monthly statistical analysis revealed that most of the dust events were recorded in June and May. The results of spatial variation of dust days showed that there is no regular spatial pattern due to the extent of the area but in general in all three classes of horizontal view the focus of this phenomenon is most of the southeastern part of the study area.

A number of factors cause negative changes in the quality and quantity of rangelands, which leads to downward sloping and severe soil degradation, vegetation cover, and ultimately decrease the income of stakeholders. Stakeholders and ranchers have an indigenous managerial experience at their rangelands because of their dependence on rangelands. The purpose of this study was to investigate the effective indices of rangelands downstream from the viewpoint of stakeholders in northeastern Golestan province. This research was a descriptive- applied one in terms of purpose, and it was surveyed by random stratified sampling method among the stakeholders in the study area. Questionnaires were used to collect data. The validity of the research instrument was evaluated using the experts' viewpoints and its reliability was evaluated based on Cronbach's alpha coefficient for the main variables of the study. The statistical population of the study consisted of 461 stakeholders in two rural and nomadic farming systems that 182 of them were selected by Cochran formula as sample size. The results showed that the downward trend of rangelands is more often detected by stakeholders with livestock indices than by vegetation and soil indices. According to the findings of the study, there was a positive and significant relationship between age and past livestock variables with stakeholder's view of rangeland's downward signs at 99 and 95% confidence level. According to the research findings, there was a positive and significant relationship between age variables and stakeholder's pastoral background with their view of detecting the downward trend of rangelands at 99 and 95% confidence level. Also, the results obtained from comparing the stakeholder's views in the two rural and nomadic systems showed that the nomadic stakeholder were more familiar with the indicators of the downward trend of the rangelands to rural stakeholder.

Mining has increased dramatically in recent years and, destroys natural resources and the environment. This study was carried out to investigate the effect of mining activities on diversity, richness, evenness and structure of vegetation cover in rangelands around copper mine of Dareh Zereshk located in Yazd province. Three sampling sites (0-200), (200-500) and (500-1000) meters far from the mine were selected for the study. Then, on each site, 3 transects of 200 m with 50 m apart, Were affected Perpendicular to the slope direction. In each plot, canopy cover percentage and density of plant species of existing species was recorded. The results of variance analysis for different indicators of species diversity, richness and evenness showed that all indicators had significant differences in the three study areas (p <0.05). So that the richness and diversity indices increased with distance from the mine and instead the evenness index was higher near the mine. Also, increasing the distance from the mine significantly increased the percentage of canopy cover of Asteraceae, Fabaceae, Poaceae, Chenopodiaceae and Lamiaceae(p <0.05). In addition, some structure of vegetation cover such as geophyte, chamophyte, hemicryptophyte, shrubs, grasses and perennials were significantly reduced near the mine. In general, the results showed that mining operations had a significant effect on the structure of vegetation in the area and reduced plant diversity. Therefore, it is necessary to pay attention to the pasture damage in the rangeland.

Rangelands are one of the most vulnerable resources in Iran which have been invaded in various ways since the nationalization. Land reform law and its enacting clauses are among the main reasons for condescension of the national lands. The purpose of this study is to investigate the land use changes based on documents available in the records of implementation of natural resource regulations, land affairs, the situation at that time and the current situation. This research is of quantitative and practical type and its statistical population consisted of six registration plaques of Bileh Savar city of Ardabil province. Possibility of access to the registration files of these plaques and their proximity to each other were the reasons for choosing this area. After receiving the information, the maps were investigated in the Arc GIS environment. The overlap extent of all maps was examined using the Kappa coefficient in Idrisi Selva environment. Using aerial photographs of 1962 as well as the current situation using Google Earth satellite images (2015), all areas of national lands and exceptions in different periods were compared. To perform this comparison, a pair T test was applied. The results showed that there was a significant difference between the area of national lands and exceptions at the time of implementing natural resource regulations and aerial photographs of the same period. While the land affairs documents at the same period did not have significant difference from aerial photographs. In addition, the implementation of various land assignment laws until 2015 has led to the assignment of more than 90% of national lands in this region. At the time of the nationalization of the rangelands, by plowing most of the national lands, the beneficiaries were trying to change the national lands to agricultural lands. Recognition of the waste land and formerly-utilized land was another reason for difference in statistics of these two offices. It is proposed to protect the national lands by fully implementing the cadaster system and adopting laws against land grabbers.

Dust phenomenon is one of the natural disasters that is considered as a serious environmental hazard, especially in arid and semi-arid regions due to the great damage it causes every year. The present study aimed to investigate the relationship between 14 climatic variables with the maximum monthly aerosol optical depth (AOD) due to the dust events in Hormozgan province. First, by coding in the Google Earth Engine (GEE) environment, a satellite image was retrieved from the MODIS aerosol products for each day, and while preparing the AOD time series, the average maximum monthly dust values for a 17-year period (2000-2017) was extracted. Also, monthly climate and water balance products of University of Idaho including actual and reference evapotranspiration, minimum and maximum temperature, precipitation accumulation, soil moisture, Palmer drought severity index, climate water deficit, downward surface shortwave radiation, vapor pressure, vapor pressure deficit, and wind speed, as well as land surface temperature (LST) and vegetation index (EVI) were extracted and, while sampling these images, the relationship between the average maximum monthly dust values with them were computed using the ordinary least squares (OLS) and geographic weighted regression (GWR) methods. Then, the global Moran's I statistics was employed to analyze the spatial autocorrelation and distribution of dust over the province. The results showed that the GWR model with the root mean square error of 0.14, the sum of residual squares of 11.3, the coefficient of determination of 0.82, and the corrected Akaike information criterion of -570.19, performed better than the OLS method. The evaluation of the coefficients of the GWR model showed that the variables of vegetation cover, soil moisture and precipitation had the greatest effect on the amount of dust, respectively. Also from the perspective of spatial autocorrelation, a cluster pattern was observed for dust distribution over the province.

In order to determine the appropriate season and method of rangeland planting of Onobrychis chorassanica Bunge., and providing conditions for increasing forage production of degraded rangelands in arid and semi-arid climates, two separate experiments were carried out in split plots in a randomized complete block design with four replications during the years 2013 to 2017 in Golestan preserved summer rangeland of Mashhad on the northern slope of the Binalood Mountains. The treatments were rangeland planting seasons (autumn and spring) and planting methods (seeding in pitting and in shallow grooves). In the first experiment, the mean comparisons of the combined analysis for two years showed that the emergence and seedlings establishments were 57.7% and 26.1%, in 2014-2015 growth season, respectively, were significantly higher than the 2013-2014 (21.5% and 10.4%). Results also indicated that the emergence and seedlings establishment percentage (58.8% and 26.8%) in the autumn season showed significant differences with spring (20.4% and 9.7%). Mean comparisons of rangeland planting methods had no significant difference in both growing seasons. The results of the second experiment showed that the seedlings establishment percentage (22.1%) in the 2nd year of establishment was significantly lower than (26.1%) comparing with the first year. Although establishment percentage in autumn season was increased by 2.7 times compared with spring season, but planting dates had no significant effect on leaves, stem and fruit dry matter yield. The planting method with pitting led to a significant increase in leaves, stem, fruit and total areal biomass yield with 2.2, 4.8, 4.2 and 11.2 gr plant -1, respectively, by 58, 33, 14 and 26%, compared to shallow groove planting method. The results of this study showed that autumn rangeland season is preferable to spring but seeding in shallow grooves compared to pitting is not significantly different in increasing the percentage of emergence and seedling establishment. However, seeding in pitting leads to improved forage and seed yield and ultimately production stability.