فصلنامه تحقیقات مرتع و بیابان ایران
سال بیست و هشتم شماره 1 (پیاپی 82، بهار 1400)

Regardless of rangeland plant production, it is not possible to plan and manage livestock and rangeland. Attention to rangeland forage production is essential for efficient and effective rangeland management. This importance is determined by identifying the relationship between forage production of plants and climatic variables which affect them in the field. For this purpose, the annual forage production values of rangeland index species were measured in Omidabad Eastern site during the years of 1998-2008 for 10 years in the national plan for rangeland assessment of different climatic zones and their re-measurement during the years of 2017-2018 for two years by cutting and weighing in 60 random plots of two square meters along four 300-meter tracts. The amount of rainfall and monthly temperature in this time interval were also calculated using the data of Abadeh meteorological station in all months separately each year. The amount of annual dry forage production of each species as a dependent variable and the amount of rainfall and temperature calculated as independent variables and relationships between them were investigated using a linear multivariate regression program in SPSS software. The results showed that rainfall, winter, and fall temperatures had a significant effect on species production and spring rains as well as the temperature of the growing season, in April and May, alone did not affect the forage production of the species and based on the results research, with the availability of rainfall and temperature data, the annual forage production of the studied species and the annual production of the coming years can be estimated with high accuracy.

Drought and dust are some of the atmospheric hazards that have affected the western and southwestern regions of the country for many years due to various factors. The recent droughts have had a significant impact on the emergence and intensification of dust. Therefore, studies related to it are considered important. In the current study, temporal and spatial fluctuations of meteorological drought and dust in Khuzestan province were examined on a monthly, seasonal and annual time scale. Drought estimation was possible using standard precipitation-evapotranspiration index (SPEI) and estimation of dust occurrence based on phenomenon codes 07 and 09 with a field of view of less than one kilometer. To ensure the adaptation of drought to the abundance of dust, a Pearson correlation was established between the two phenomena. The results of correlation showed a direct and significant relationship between meteorological drought and the number of dusty days in the province. The most correlation is in February, July, June, August, and May. The highest level of significance is attributed to the winter and summer and then spring. Cross-correlation also showed that the events of the dust simultaneously and one month later are more affected by the drought.

Gross primary production is one of the key factors for understanding growing grassland conditions and rangeland monitoring. The present study aims to introduce an improved index based on the primary GDP and NDVI vegetation index of MODIS. In this regard, field operations were carried out in May, simultaneously with the growth of vegetation in the Rasin basin of Kermanshah province. In each of the types, reference areas were determined, and six (100-meter) transects were deployed in each of the representative points. Along each transect, five plots were placed at a distance of 20 meters, and a total of 84 transects and 420 plots were used in the field. Information such as rangeland type and actual fresh forage (AFY, kg/ha) were determined in the Rasin basin. In general, three types were identified in the field. Modified primary GDP data were calculated and validated with the measured data in the Rasin basin of Kermanshah province. The results showed that, in type 1, with R2 equal to 0.77 Ss index of gross primary production of NDVI as an improved index, in type 2, Ss index of primary production of NDVI with R2 0.73, in type 3, Ss index of gross primary production NDVI with R2 equal to 0.71, and finally, for the whole rangeland type, Ss index of gross primary production of NDVI with R2 equal to 0.51 was determined as the improved index. The results also showed that the modified primary GDP data is an acceptable indicator for monitoring grasslands. The accuracy of estimating rangeland production based on the Ss index of gross primary production of NDVI was 80%. The statistical results of comparing the estimated values with field observations indicate the acceptable accuracy of statistical models in estimating production. Also, since MODIS data is available twice a day, the improved index can supply the real need for rangeland monitoring on a regional scale.

Rangelands beneath the forests of Dalab in the northwest of Ilam are grazed from May to November. To investigate the grazing behavior and determine the dependence of livestock on forage resources, three goats and three Kurdish sheep were randomly selected from three herds in the area, and by installing a GPS device on them, information on the distance and movement time of livestock were recorded every month. Maps of geological formation, slope, altitude, land use, and landform were prepared, and monthly GPS information was combined with the maps. The evaluation of forage production was carried out in 27 plots of forest floor and 25 samples of trees and shrubs. The results showed that the goat had an average daily mobility of 7.7 km and a distance of 2.6 km for grazing; but these figures for sheep are 7.8 and 1.9 km, respectively. It was also found that goats were more present in the altitude of 1400 to 1500 m and sheep in the elevation of 1300 to 1400 m. Livestock were more prone to grazing on the forest floor, and they preferred slopes of less than 30%, hill form, and Pabdeh geological formation. Comparison of grazing, moving, and stopping times showed no difference between the types of grazing in terms of grazing behavior, but there were differences between the types of activity (movement, stopping, and grazing) in different months.  Examination of the grazing behavior of the livestock using video recording revealed that the livestock spent about 33 to 36 minutes on grazing, three to five minutes on stopping, and 12 to 14 minutes on grazing without movement.  Finally, it was found that about 50% of the relative forage production was from forest floor grasses, 34% forest trees, and 10% sub-forest farms; therefore, livestock ration dependence on forest floor grasses is about 61 %, forest trees 25 %, and forest floor farms 7 %.

To determine the nutritional value of five halophytes, Aeluropus lagopoides, Atriplex leucoclada, Desmostachya bipinnata, Halopyrum mucronatum, and Halocnemum strobilaceum, this study was conducted in 2016 in Hormozgan province. Plant samples were collected in three phenological stages including vegetative growth, flowering and seeding, and eight forage quality traits (CP, DMD, WSC, ADF, CF, NDF, ME and ash percentage were measured. Data analysis of variance was performed as a factorial experiment in a completely randomized design and the means were compared with Duncan's multiple rsnge test in SPSS software. The results showed that the effect of species for all traits, the effect of phenological growth stages for four traits: (CP), (DMD), (ash), and (ME), and the interaction effect of species and phenological growth stage were significant for all quality indicators except (WSC). The highest forage quality was obtained at vegetative growth stage and Atriplex leucoclada was superior to other halophytes in terms of nutritional value. Therefore, the use of this native species instead of non-native ones of this genus is recommended in rangeland improvement of areas with similar rainfall.

To investigate the effect of biomechanical methods on increasing the vegetation in arid areas, three regions (Ashkezar, Ghahar, and Chahmatk of Ardakan) in Yazd province were selected. Statistical sites were determined within the scope of rainfall storage operations and outside it (control), and at the end of the growing season (May 2018), a survey was conducted. To do this, in each area, 100 plots of 9 square meters (3*3) at a distance of 12 meters from each other and along five transects of 300 meters, which were considered in parallel and at a distance of 100 meters from each other were placed. In each plot, canopy cover percentage and density of different species were measured. Data were compared with a t-test. The results indicate an increase in the canopy within the furrow and crescent. The canopy average in the Ashkezar and Chahmatk of Ardakan rangelands in the rain storage region increased from 2 to 3% compared to the control area. Also, an increase in the density of different species was observed in the precipitation storage area. However, sowing has been done only in the year of rainfall storage. In general, due to vegetation status and plant density by species segregation, performing remedial storage operations along with seeding using Artemisia sieberi and Salsola tomentosa species can be successful for desert rangelands with less than 100 mm of rainfall.

The search for the technical perspectives of the country's natural resources management depicts the important fact that management approaches play a very important role in the protection, rehabilitation, and sustainable use of these resources. In this regard, the present study was conducted to evaluate and compare the ecological indicators of rehabilitated rangelands under two types of ecological-oriented and socio-ecological-oriented management approaches. For this purpose, the international carbon sequestration project and the desertification project of Sarbisheh plain were selected as two projects with socio-ecological-oriented and ecological-oriented management approaches, respectively. Then, in the executive scope of each project, three types of rangeland improvement operations, including plantation, crescent construction, seeding, and sowing were selected, and the percentage of vegetation, the amount of forage production, and carbon sequestrated in the soil were the basis for evaluation and comparison. Vegetation was measured by the linear transect placement method, production amount was measured by the double sampling method, and soil carbon was measured by Wallace and Blake method. The results of the analysis of variance showed that the interaction between the type of management and corrective operations on the value of ecological indexes was a significant difference at (p < /em><0.01). The highest value of indexes was observed in social-ecological-oriented management based on plant operations, and the lowest value was observed in ecological-oriented management under the same activity. The results show that capacity building, institutionalization, and real participation of the local community in all stages of planning, implementation, monitoring, and operation of these areas, in the socio-ecological management approach, bring more success in improving the index of ecological rangelands.

Seed germination is usually the most critical factor in determining the success or failure of plant establishment. The most important environmental factors affecting germination, establishment, and growth of plants are temperature and humidity, which have significant effects on germination characteristics such as germination percentage and rate. For this purpose, to determine the cardinal temperatures of seed germination in Ziziphus spina-christi, in vitro experiment, the germination characteristics of the seeds of this plant at different temperatures were evaluated in a completely randomized design with four replications. Germination response was assessed at the constant temperatures of 5, 10, 15, 20, 25, 30, 35, 40, and 45°C. The cardinal temperatures for the germination of Ziziphus spina-christi seeds were fitted using germination rate and by three models including the beta, segmented, and dent-like models. To select the superior model and measure the accuracy of the model in describing the germination rate of Ziziphus spina-christi seeds for temperature, the statistics of root mean square (RMSE) and coefficient of determination (R2) were used. Accordingly, a higher R2 and a lower RMSE represent a closer correlation of the model with reality.  Based on the results, these statistics were better for the segmented model than the other models, so that they were 0.0004 and 98% for this model, respectively. Therefore, based on the segmented model, which was known as the superior model, the basal temperature, the optimum and maximum germination rate of this plant were calculated to be 8.6, 34.3 and 49 ° C, respectively. Then, the response of germination and seedling growth of Ziziphus was explored in another experiment to different levels of salinity and drought stresses at the optimum temperature.  In this experiment, the seed germination was studied at four levels of salinity and drought stresses with osmotic potentials of 0, -2, -4, -6, -8, and -10 bars. The results of this experiment showed that salinity and drought stress reduced the germination percentage and rate of Ziziphus spina-christi seeds. Germination percentage for control was 97% while in -10 bar salinity and drought stress was 16% and 0, respectively. In addition, compared to drought, seed germination showed more sensitivity to salinity stress.

To replace oil mulches, this study examined the effect of degradable non-oil mulch under the brand name Nucleus (MA-19). This research assumed that the application of the mentioned mulch in biological stabilization projects has no adverse effects on seed germination and seedling growth. The effect of mulch was studied on the establishment of Haloxylon persicum and Nitraria schoberii in a pot experiment in weather conditions of Research Institute of Forests and Rangeland in Tehran, Iran in 2017-2019. Before the experiment, the seed germination test was made to ensure seeds which having standard germination. After determining the germination percentage of seeds (85-90%), seeds were planted in the greenhouse. Then, the soil surface of the pots was sprayed with mulch for comparison with the control. On the other hand, in potting experiments, which were in the form of planting seedlings, after placing the seedlings in the pot, the soil surface was sprayed with the mentioned mulch. The irrigation of the pots was uniform and equal to the field capacity of the soil and based on the soil moisture curve, which was done only once a month, depending on the weather conditions and temperature. Statistical test and comparison of means according to t-test results showed that mulch treatment did not have any negative effects on germination, viability, height, and diameter of seedlings, and in this regard, used mulch behaves as a control treatment (without mulch).

Rangelands are composed of different plant species with different vegetative characteristics that have a certain grazing value. Hence, the grazing livestock also shows a special grazing behavior according to it. Without knowing these behaviors, planning and managing rangelands and livestock is not possible. This research was carried out on camel herds in the rangelands of the Tabas desert from 2015 to 2017. Parameters such as grazing time, rest time, livestock movement time, distance traveled, and livestock movement speed were examined by GPS. The results showed that in spring, summer, fall, and winter, grazing time, livestock movement time, distance traveled, livestock movement speed at (p < /em><0.01), and rest time at (p < /em><0.05) were significantly different. The highest grazing time (342 minutes), rest time (119 minutes), and distance traveled (21.66 km) by camels in the studied rangelands were in summer and the lowest in winter. The highest speed (2.12 km/h) and travel time (359 minutes) were in spring and the lowest in winter. Therefore, knowing the mentioned parameters will help the rangeland management in determining the appropriate time for the camel to move in the rangeland and will increase the livestock performance.

In the program of increasing forage production, it is necessary to collect information about the establishment of forage plants. In this regard, the native population's seeds of sainfoin (Onobrychis altissima.) were collected to study different rangeland cultivation methods from the rangeland areas of Baladeh Noor watershed in Mazandaran province in 2013 and at the research station of Poshtkooh with an average 320 mm of rainfall in a cold semi-arid climate. The cultivation were in two forms: seeding and seed scattering treatments, which were performed on spring and fall sowing in the form of split plots based on the randomized complete block design in three replications. The main treatment of the experiment was date of rangeland cultivation and the sub-plot was (seeding and seed scattering). Factors studied included plant height, canopy cover, seed production, plant production, and establishment percentage. The results show a significant difference between sowing and in spring and fall for the studied factors (plant height, canopy, production, seed and species production. Seeding method in fall had the highest values of the studied factors. Therefore, it is possible to improve the rangelands of similar climatic zones with sainfoin by sowing to increase forage production and direct grazing.

Adverse climate change, drought, and floods have a negative impact on natural resources, crops, and livestock production as the main sources of livelihood for the villagers. Therefore, it is important to study the perception of rural communities about the occurrence of climate change and its relationship with a sustainable livelihood. The present study was conducted for this purpose by descriptive-survey research method. In this study, 297 residents Age 35 years and older in 10 villages of the Oghan watershed in Golestan province were surveyed. The data collection tool of the questionnaire was developed by the researcher; its content validity was confirmed using the opinions of university academics and natural resources experts. The results showed that age, number of livestock, history of animal husbandry, length of stay in the village, and income of individuals with their perception of the symptoms of climate change have a positive and significant relationship. Findings of structural equation model evaluation showed a causal relationship between the perception of the occurrence of climate change symptoms and individuals' livelihood changes so that with increasing awareness of villagers about the occurrence of climate change symptoms, their livelihood is facing more changes.

Monitoring the changes in the rangelands makes it possible to make informed decisions about the application of management and protection plans. The purpose of this research is to monitor the changes from rangelands in the five-year period from 2000 to 2015 using geographic information systems and ENVI software. In this regard, Landsat images were first prepared at the specified times. By using the Minimum Distance, Mahalanobis, Maximum Likelihood, and Decision Tree, three NDVI, EVI, and SAVI indicators were modeled in 2016. Then, the best classification method was obtained by evaluating accuracy by Kappa coefficient and overall accuracy. As a result, other images for the past years were classified by this method and five classes were classified as low-density, semi-collimated, dense, non-covered, and gardens, and agricultural lands according to the subject. Educational points were also selected for both land surveying and ROI. The results showed that the tree of decision-making with the SAVI index yielded the highest accuracy with a precision of 94.73. Thus, although the area of low density and semi-dense pastures in 2005 and dense pastures in 2010 has increased, overall, during the period 2000 to 2015, all three classes of rangelands decreased. The attention and the class of gardens and agricultural lands have increased at a low level. Based on the findings of the study period, the behavior of the indicators is similar. From 2000 to 2010, the indicators were incremental, but in 2015, they decreased. Hence, it can be said that during the destruction of rangelands, the amount of non-covered areas has increased.

Nowadays, water scarcity and desertification are serious problems in many parts of the world, which puts the development of vegetation and the growth of agricultural products at serious risk. Therefore, proper management and application of new methods to increase irrigation efficiency and thus improve the utilization of limited water resources is an inevitable necessity. One of these methods that have been considered recently is the use of various additives such as polymer and natural. This study aimed to investigate the effect of natural and artificial superabsorbents on the performance of Prosopis Juliflora in climatic and edaphic conditions of arid areas of Ilam province, especially in Mohsenab plain of Mehran city, and it is an issue that is less addressed in this region and in general in the field of arid and semi-arid regions. In this regard, the effects of natural additives (Humus and Sawdust) and artificial superabsorbent (Nanohursan polymer) on Prosopis juliflora have been compared by comparing the average of thirtheen vegetative and physiological indexes in a completely randomized block design. The results of this study showed that the effect of superabsorbents (treatments) on all morphological and physiological traits of the studied species except for vegetative traits, stability coefficient, and specific leaf area index was statistically significant at p < /em>< 0.05. Therefore, as a general conclusion, it can be said that the majority of growth characteristics of Prosopis juliflora have improved due to the use of the studied treatments, and therefore, the addition of natural and unnatural additives in this region and similar areas is recommended.

Social network analysis and identification of key actors in social systems is one of the necessary measures for the sustainable management of natural resources. The purpose of the present study is to evaluate the social capital, status, and relationships of actors in the information exchange network and their structural pattern and to identify key actors in the three villages of Estaj, Borzu, and Izi in Sabzevar. For this purpose, first, qualitative studies of survey approach, direct observation method, and target population interview were identified. Based on the results of calculating the intermediate centrality index, the degree of input, output, and proximity in the trust matrix and participation in irrigation in the three villages studied, the role and position of actors were identified, and key actors were identified in these indexes. The results showed key actors have a high social status, authority, and influence and play a role of control and intermediary in the village. As a result, they can as social power and local leaders play a key role in the decision-making and networking processing, coordinating individuals, communicating with others, accessing resources and information, and speeding up their exchange, resolving disputes and conflicts, trust in the network and thus increase social capital. Increasing the amount of social capital as the key management tool will lead to the establishment of sustainable management of natural resources.