فصلنامه تحقیقات مرتع و بیابان ایران
سال بیست و هفتم شماره 2 (پیاپی 79، تابستان 1399)

The Bahadoran Kalmand protected area with an area of 255000 hectares is located at about 30 km Yazd township and in the southeastern township of Mehriz with geographical coordinates of 31° 00′ to 31° 40′ North latitude and 54° 15′ to 55° 20′ East longitude. The vegetation cover was studied using the physiognomic-floristic method. Some soil characteristics were evaluated based on conventional methods and data were analyzed by Principal Component Analysis (PCA) method. The results showed that there was a special relationship between different plant communities and soil characteristics. The most important factors in separating these plant communities were electrical conductivity, acidity, texture, organic carbon, and sodium adsorption ratio. In general, in regard to habitat conditions, each plant community has different ecological needs and tolerance range with environmental factors and soil characteristics.

One of the main goals of rangeland assessment is to obtain the amount of forage production of rangeland species because it plays an essential role in determining rangeland capacity and grazing management. Measuring the amount of production requires a lot of time and costs, so finding cheap, fast and scientific methods to estimate the amount of production can be a great help in assessing vegetation and rangeland management. The purpose of this study was to find a suitable relationship between the percentage of canopy cover of species and plant classes with their production amount. For this purpose, the percentage of canopy cover of the species was examined during a six-year statistical period within 60 plots (1m2) located along six transects (200 m). In addition, each year, the amount of species production in a quarter of the plots (25% of them) that were caged to prevent possible grazing, was measured by clipping. To determine the amount of total forage production, the regression relationship between canopy cover and species production was used and based on the significance of the equation (p≤ 0.05) and coefficient of determination (R²), the best equation was fitted. The results showed that there was a significant correlation (p≤ 0.01) between production as a dependent variable and the percentage of canopy cover of the species as an independent variable. The coefficient of determination for each of the classes I, II and III were 0.77, 0.87 and 0.92, respectively, which provide the most appropriate linear production-canopy relationship for rangeland management.

Important and influential factors on livestock production in arid areas are limited water resources, increasing salinity and lack of food. Halophytes are especially important in saline habitats as alternative forage sources. Forage quality is one of the main factors determining the nutritional requirements of livestock and subsequently the grazing capacity of rangelands. Determination of forage quality of rangeland species is one of the fundamental factors for proper rangeland management. The quality of forage varies in different places and times and different factors affect it. Awareness of forage quality of halophytes at each phenological stage, not only helps beneficiaries in arid and desert areas to select suitable plant species for planting in haloculture programs, but also sets the appropriate time for grazing to achieve greater livestock performance in saline lands. In the present study, the effects of phenological stages on eight forage quality traits were investigated for three halophytes ie., Halocnemum strobilaceum, Nitraria schoberi and Suaeda aegyptiaca. Plant samples were collected in vegetative, flowering, and seeding stages from saline lands in the margin of Houze Sultan, Qom province. Data were analyzed by a factorial experiment in a completely randomized design. Duncan mean comparison test was performed. The results showed that the effects of species and phenological stages on forage quality were significant (p < /em><0.01). In general, the results of this study indicated the superiority of Ha. strobilaceum in terms of nutritional value compared to Ni. schoberi and Su. aegyptiaca, so that it can be considered as a new source of forage in the lands affected by salinity.

Helianthemum lippii and Tavernieracuneifoliais are the most important broadleaf  plants of Hormozgan province, Iran. To investigate the establishment of these species, this study was conducted at the Watershed Management and Natural Resources Station of Dehgin (Hormozgan province) from November 2014 for three years. The three methods of seeding in farrow, pitting, and crescent catchment were studied in a randomized complete block design with three replications in SAS software. The results showed that there was a statistically significant difference between experimental structures, plant species used, and also the interaction of structure and species. A statistically significant difference was recorded for Helianthemum lippii and Taverniera cuneifolia at the level of 5%, for the crescent catchment structures, pitting, and contour-furrow at the level of 1%, and also for the interaction of structure and species at the level of 1%.  The highest percentage of species establishment was in the crescent catchment structure with 27.1% and the lowest was related to the pitting structure with 3.2%. Investigation of the interaction of structure and species in the rate of species establishement in different structures showed that the highest percentage of establishement was related to Taverniera cuneifolia with 31.2% in the crescent-shaped structure, after that, the highest percentage of establishment was related to Helianthemum lippii with 22.9% in the same structure. The lowest establishment was related to the contour-furrow structure with 2.1% for Taverniera cuneifolia and pitting structure with 2.1% for Helianthemum lippii. Based on the results of the present study, it is suggested that to successfully implement rangeland cultivation projects with Lippii Helianthemum and Taverniera cuneifolia in similar climates of Hormozgan province, the mentioned species should be planted in crescent-shaped structures.

Perennial forage grasses are the most important range species in tropical regions. Cenchrus ciliaris is one of the forage perennial grasses with the C4 photosynthesis type, which is specific to tropical regions and has very high adaptability to the rangelands of Khuzestan province. Diversity in such habitats has led to differences in phenotype and yield of ecotype. To implement this project, the habitats were first determined by examining the herbarium addresses and field observations of Cenchrus in Khuzestan province. Subsequently, at the appropriate time, the seeds were harvested from 13 habitats identified in the province and cultivated in the research station Baghmalek and evaluated for three years after the establishment. Results indicated that there was a significant difference between the populations for dry forage yield, plant height, and tiller number. The highest forage yield, the number of tillers, and the height of plant belonged to Cenchrus ciliaris, collected from Shushtar – Cham-Konar with an average of 220 g of dry forage/m2, 130 tillers in the plant, and 55 cm height in the third year after establishment. Among the studied accessions, apparent differences were observed in the vegetative form, so that the population of the Shushtar-Chamknar was erect completely, while, the population of the Behbahan was quite wide on the ground.

Regarding population growth, increasing agricultural land is necessary to provide food and meet existing needs. This issue has led to land degradation because of mismanagement and excessive exploitation. Therefore, much research must be done to determine whether agriculture leads to land degradation or not. Regarding the importance of this issue in arid and semi-arid regions, the Eshtehard region was selected as the study area in this research. Different maps of the area including soil map, altitudes, and land-use were prepared using ArcGIS 9.3 and ENVI software. After visiting the area and determining the main land-uses including rangeland (as control sample), fallow lands, monoculture lands, multicultural lands, and garden lands, soil sampling was carried out in two depths of 0-30 and 30-60 centimeters with three replications for each treatment. Finally, 35 soil samples were transferred to the laboratory, and soil degradation factors such as salinity, sodium, sodium adsorption ratio, and acidity were measured in each soil sample. After determining the normality of the data using the Shapiro test, the study of factors with non-parametric Tukey test showed that there was a significant difference between treatments in the region. Then, a comparison of surface and subsurface layers for each factor was done using a t-test in SPSS software. The results showed that multicultural treatment with the highest score was the most desirable treatment and fallow treatment with the lowest score was the most undesirable treatment, leading to soil degradation in the region.

The effective role of environmental resources in continuing the process of sustainable development and preservation of human life has led to economists focusing on the non-market roles of these resources. Awareness of the amount of benefits which are exited from the society by destroying environmental resources motivates the protection and support of these valuable natural treasures in the society. Awareness of the benefits of environmental resources requires the valuation of these resources. The aim of this study was to evaluate the economic functions of carbon sequestration, oxygen and forage production in Gandomanwetland with an area of 980 hectares with a sustainable management approach. For this purpose, a 200-meter transect was established in the representative areas of three plant types of Juncus inflexsus-Cynodon dactylon, Cyperus longus-Cladium mariscus, and Phragmites australis, and a total of 30 plots of one square meter were randomly placed along the transects. Then, in each plot, in addition to soil sampling, the percentage of canopy cover of all plant species, litter, rocks, and pebbles was estimated. Also, the aerial biomass of the plants was cut at a distance of one centimeter above the soil surface and then collected and dried in 50% of the plots. Plant carbon storage was measured using the electric furnace method and soil organic carbon was measured using the Walkley-Black method. The amount of oxygen production was also calculated based on the amount of plant dry matter. Based on the results of this research, the amount of carbon stored in the plant biomass and soil and the amount of oxygen production were determined separately by plant types. The results indicated that the annual average forage production was 14.8 tons per hectare. Also, the amount of carbon stock and oxygen produced in the whole Gandman wetland was equal to 8.9 and 22.4 tons per hectare per year, respectively. The carbon stored in the wetland soil was estimated at 554.7 tons per hectare. Therefore, the economic value of Gandman wetland per hectare per year for forage production, carbon sequestration, and oxygen production was 72728345, 9 9457140, and 11189600 Rials, respectively. The economic value of carbon stored in the soil of Gandman wetland was 589,424,220 Rials per hectare.

Global warming due to increasing concentrations of greenhouse gases, especially carbon dioxide, has led to drastic climate change in recent decades. This has intensified the process of degradation of natural resources, soil and water, especially in arid and semi-arid regions. One of the most important tools for adapting or modifying the consequences of this crisis is the sequestration and storage of carbon by natural ecosystems with the help of efficient management tools such as rangeland and watershed management. This study was conducted to evaluate and quantify carbon storage in various types of biological remediation and rehabilitation operations, including pit-seeding and exclosure in the Gavdareh watershed of Kurdistan province. Sampling was performed in soil and plant units using a systematic random sampling method of aerial parts, roots, litter, and soil. Samples were analyzed in vitro. The results of the statistical analysis of the data indicated that the amount of vegetation carbon storage in the experimental treatments had a significant difference (p≤ 0.05). The least significant difference in this level of probability is 334.35 kg/ha (p≤ 0.05), and also the results of comparing the mean yield of these treatments showed that the amount of carbon storage in the exclosure was higher than other treatments, and compared to the experimental control in the upper and higher class. The average total carbon stored per unit area was 8809 kg/ha, 67% of which was related to carbon storage in the soil. In general, it is concluded that biological remediation operations, especially exclosure, have a high capacity for carbon storage, and the soil is the most important carbon reservoir in this operation.

Nowadays, the adverse effects of climate change and its damaging effects have become an environmental, social and economic problem. Assessing the vulnerability of local communities to climate change as an important step in identifying effective mechanisms and prioritizing management will be enhancing flexibility and increasing adaptability. This research is field-survey research, performed by using field observation and completing a vulnerability questionnaire to climate change in three villages of Aghabarar, Seyyed Ayaz, and Seyyed Ahmad in Qasrshirin city. The study was based on the vulnerability indexes such as exposure, sensitivity, and adaptation capacity. Questionnaires were completed among the target groups, which were finally analyzed using statistical tests such as the analysis of variance, Fisher, and Levin. The results showed that the components of exposure, sensitivity, and economy in Qasr Shirin city were vulnerable. Also, there was no significant difference between the three villages in a dry climate, and the vulnerability of Aghabarar village was 3.43, Seyyed Ahmad village was 3.30, and Seyyed Ayaz village with a value of 3.13 was higher than the average value of vulnerability. Also, Seyyed Ahmad village had the highest level of environmental vulnerability in the face of climate change with a value of 4.1. The vulnerability of exposure components and sensitivity is due to climatic events, geographical location, and dependence of local communities on natural resources and climate. Also, the high vulnerability of the economic component is due to the poverty and lack of physical capital of the communities. The vulnerability of the three components of exposure, susceptibility, and economics has caused the vulnerability of the communities studied. These factors affect the compatibility of local communities and countries, their willingness, or ability to adapt. The government with local involvement can effectively respond to the negative effects of climate change as well.

This study investigates and analyzes the decades of change in climatic zones in Karkheh, Karoun, and Zohreh - Jarahi watersheds. For this purpose, the database of temperatures and precipitation networks during the period 1976-2015, with a spatial resolution of 15 x 15 km, formatted in the conical Lambert image system, was used. In fact, because these two elements are the most important climatic drivers in the study area and the changes of other elements in these two elements are more visible, they have been used to study and analyze the climate change zone. After establishing the database, cluster analysis was used to identify climatic regions, and the audit analysis was used to validate it. Cluster analysis was performed on 52 indices of temperature and precipitation (monthly and annual average, coefficient of variation of temperature, and precipitation monthly and annual changes) during different periods, and climatic zones and their changes were analyzed. Based on the results, three climatic zones including humid and moderate zone, hot and dry zone, and very hot and dry zone were identified in the study area. The results showed that in recent periods, the humid area, in addition to having spatial displacement, its area reduced so that in the fifth period, the area reached less than five percent. Also, the hot and dry zone, stretched as a strip from the northwest to the southwest of the study area, had less spatial displacement, unlike the humid area, while its area increased in recent periods. On the other hand, the area of the very hot and dry zone has increased towards recent periods. Spatial and temporal increase of hot and dry climates and very hot and dry climates and decrease of the humid zone has been able to lead to the development and intensification of dust source, especially downstream of the studied watersheds.

Assessing the potential habitat and studying the geographical distribution of species is a key issue in many ecological studies, environmental protection, wildlife, and assessing the trend of changes at various scales. Therefore, in the present study, modeling of potential habitat of Ferula ovina in the present and future years was performed using a generalized incremental model in Fereydunshahr region. The results showed that in 2030 and 2080, in exchange for all climatic factors remaining constant, except the average annual temperature, the probability of surviving the Ferula species has increased; in other words, the probability of its occurrence increases. The habitat area in the class where the species is most likely to be present is currently about 12,970 hectares in Fereydunshahr, Isfahan, which in 2030 and 2080 will be reached about 27157.3 and 31036.9 hectares, respectively. This indicates that the increase in the average annual temperature in 2030 and 2080 compared to now will have a positive effect on the presence of the species in the habitats studied. Because according to the results obtained in response curves, by increasing annual temperature, the probability of the presence of Ferula species increases. The results of this research can be used to improve and rehabilitate the vegetation of areas with similar conditions, which is one of the important achievements of this research.

Diversification of used species in sand stabilization and desertification can help sustain these ecosystems. Most species used in sand stabilization require initial support to adapt to new conditions over time. One of the most important of these supports is irrigation in the early years of planting. In this study, the yield and water use efficiency of (Ammodendron persicum) in lysimetric conditions under the influence of different levels of irrigation were considered. Different irrigation levels consisted of 75, 50, and 25 percent irrigation and field capacity (control), applied in a completely randomized design with four replications. Evapotranspiration rates in control, 75, 50, and 25% under-irrigation treatments were 60, 47, 37, and 26 liters, respectively. By calculating water use efficiency based on the amount of dry matter produced per liter of transpiration water, it was found that there was a significant difference between different treatments. The highest water use efficiency with 2.07 g of dry matter for per liter of transpiration was related to 50% irrigation treatment. As the water consumption decreased, the root to aerial part ratio increased, so that it showed a significant difference in different treatments. The root to aerial part ratio in the control was 0.84 and in the 75% under-irrigation treatment was 1.51. The results of this study showed that Ammodendron persicum in the early stages of establishment due to low growth rate had low water requirements and improved its water use efficiency through various mechanisms such as root development. Due to the low growth, water loss through evaporation in early stages of establishment was high, and to improve irrigation efficiency, appropriate methods to reduce evaporation and maintain soil moisture are recommended.

The aim of this study was to evaluate the biological and mechanical methods of priming on improving germination characteristics and growth of Haloxylon ammodendron seedlings. Cultivation was performed in two parts of seedling tray and Petri dish in a completely randomized design in the Plant Physiology Laboratory of Semnan University. The biological treatments were Pseudomonas fluorescens, Azotobacter chroococcum, Bacillus megaterium, Azospirillum lipoferum, and Flavobacterium F-40. Ultrasonic device with 24 kHz wavelength application for 5 minutes was considered as mechanical priming treatment. Traits related to seed and seedling germination were measured. Result of analysis of variance in laboratory (Petri dish) showed significant differences for radicle length, ratio of  radicle  length to plumule  length, seedling growth, radicle and plumule fresh weight, and plumule dry weight (p<0.01). In the seedling tray, the effect of treatments was significant in radicle and plumule length, ratio of  radicle  length to plumule  length, radicle and plumule fresh weight, plumule dry weight, leaf freash and dry weight and leaf areas (p<0.01). Based on the results obtained from the comparison of means, ultrasonic treatment caused an increase (33%) in fresh weight of Haloxylon ammodendron radicle compared with the control in the seedling tray test. Azotobacter significantly increased radicle length (19%), ratio of  radicle  length to plumule  length (13%), seedling growth (10%), radicle fresh weight (23%), fresh weight (18%) and dry weight (18%) of plumule as compare to control in petri dish. In addition, Azotobacter increased radicle length (16%), ratio of  radicle  length to plumule  length (60%), leaf fresh weight (26%) and dry weight (68%), leaf area (172%) compare with the control in the seedling tray. Flavobacterium was able to increase the plumule length (21%) of Haloxylon ammodendron compared to the control in the seedling tray experiment. Azospirillum increased plumule fresh (65%) and dry weight (156%) of the plant in the seedling tray compared to the control. In general, according to the present results, the use of Azotobacter, Flavobacterium and Azospirillum bacteria was evaluated as a positive bio-priming treatment and can be used for propagation and production of Haloxylon ammodendron seedlings.

This study was conducted in the central plateau of Iran to examine the income, cost, and profitability of conventional systems, in which camel is common during the years 2015 to 2017. For this purpose, by selecting 28 conventional systems with an average of 126 camels, the amount of income and cost per camel during the regular period of each year (spring) was completed and calculated by the operators with a questionnaire. The type of research is practical, and the statistical population included 28 camel herders. Random sampling was performed. Variables included income factors and camel costs. Using the analysis of engineering economics, the current value of income (PV income) and the present value of costs (PV cost) were calculated for the studied years, and then the net present value (NPV) and the benefit-to-cost ratio (BCR) was calculated with Excel software. The results showed that in all conventional systems, the net present value was positive, and the benefit-to-cost ratio was greater than one (BCR≥1). The highest gross income in each of the conventional systems was related to the sale of live camels (male camels, 6-month-old camels, elimination camels) and the highest cost was related to camel driver’s wages and the purchase of manual forage. However, by calculating gross income from expenses, the amount of profitability was determined, so it is suggested that due to the appropriate profitability of this profession, the relevant agencies have a plan to expand the cultivation of this industry along with the tourism industry and considering that forage of these habitats will not be able to supply the nutritional needs of camels in traditional areas, and the continuation of this situation will endanger the vegetation; therefore, it should be done with caution.

The purpose of this study was to investigate the characteristics of wind regime and sand transport potential in the Sarakhs Erg, located in the north-eastern corner of Iran. Accordingly, using the data of wind speed and direction (1978-2016) of the Sarakhs synoptic station, the potential of sand transport (DP), Resultant Drift Potential (RDP), Resultant Direction Drift (RDD), and the ratio of RDP/DP were calculated using Fryberger-Dean (1979) method. Also, the characteristics of erosive winds and temporal changes were investigated based on sand transport (DP) potential. The results showed that the dominant wind direction and the sandy wind were northwest. Agricultural lands, especially in the fall season, as well as the sediments of the Tajan Border River, were the sources of wind sediments. In general, wind energy in the Sarakhs region based on the sand transport (DP) potential is put in the low class (DP=193 v.u) with the highest and the lowest in July and November, respectively. On the other hand, sand discharge capacity based on the average sand carrying potential (DP = 193 v.u) for this range was estimated to be about 13.51 m3 in width. Field studies and satellite images showed that sand and nebka zones were two main forms of wind sediments in Sarakhs Erg sediments.