جستجوی مقالات مرتبط با کلیدواژه « مدیریت مرتع » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Coping with climate change (CC) is part of the way to face this phenomenon. This depends on the understanding of CC and the degree of adaptability to it.

The research was conducted with the aim of measuring the level of nomads' understanding (NU) of CCe and their adaptation strategies (AS) in the face of CC.

The research was descriptive and the data collection tool was a questionnaire whose items were obtained based on interviews.

NU of the effects of CC is not the same. According to them, CC has had the most obvious impact on vegetation. The priority of AS is also different in the face of CC. A positive relationship was observed between understanding the effects of CC and the degree of adaptability in facing CC. Nomads who had a better understanding of the effects of CC have used livestock management strategies to adapt to it. Age and history of animal husbandry had a positive relationship with the level of understanding of the effects of CC. A negative and significant relationship was also observed between the number of animals and the degree of compatibility.

The NU of CC and its effects on the ecology of the environment is an important starting point in dealing with the negative effects of CC and choosing appropriate strategies to adapt or deal with it. So that the selection of suitable adaptation methods by the nomads reduces the vulnerability of CC on the condition of livestock and rangeland.

The study of vegetation changes under habitat protection conditions has a significant role in rangeland management. The studies confirm that permanent changes in rangelands in terms of plant composition, canopy cover, and forage production are influenced by ecological and management factors. This research was conducted to investigate and monitor the plant vegetation indices of semi-steppe rangelands of central Zagros for five years (2016-2020) at the Zayandehrud watershed management research site (Isfahan province). 

 Vegetation sampling was performed by a systematic random method in each exclosure and grazed site during 2016-2020. Vegetation characteristics, including the percentage of canopy cover of species, the percentage of gravel, bare soil, and litter were determined in each plot. For this purpose, four 100-meter segments were used. Then, ten plots (with 1 x 1-meter dimensions) were established with the same distance. In total, vegetation cover was measured in 80 plots of one square meter in exclosure and grazed sites. To calculate rangeland production, ten samples of each plant species were collected, and their canopy cover percentage was measured. After drying and weighing the samples, by establishing regression equations between the canopy cover percentage and the weight of the dried samples, the amount of production of plant species was determined separately for growth form and palatability class. Rangeland's condition was also evaluated according to the four-factor method and by scoring the factors of soil, vegetation, plant composition and age classes, and plant vigor. After collecting the data in Microsoft Excel, the variance analysis for the vegetation traits was done as a completely random design in a factorial format. This was done through the GLM (General Linear Model) method. Tukey's test investigated vegetation traits mean comparison in MINITAB 16 software. 

The analysis of variance showed a significant difference between vegetation indices, including total canopy cover and production, separately for growth form and palatability class. This was in the exclosure and grazed sites during the assessment period. The average percentage of canopy cover in exclosure sites during different years was 26.7%, 13.7%, 25.84%, 33.74%, and 13.33%. In grazed sites, it was 22.33%, 12.65%, 27.09%, 30.9%, and 11.59%, respectively. Total production at the exclosure site during different years was 624.26, 349.86, 556.79, 894.54, 664.53 kg/ha. Production at the grazed site was 456.45, 243.85, 455.6, 605.47, and 323.44 kg/ha, respectively. The highest values of canopy cover and production belonged to 2019, which was a wet year based on meteorological indices. The lowest canopy cover and production were assigned to 2017 (a drought year). The highest amount of litter was found at the exclosure site. The highest percentage of bare soil and annual plant canopy cover was obtained from the grazed site. The highest percentage of canopy cover and production in the exclosure site belonged to Stipa hohenackeriana. At the grazed site, Hedysarum criniferum and Stipa hohenackeriana accounted for the highest canopy cover and production, respectively. According to the four-factor method, the rangeland condition at the disclosure site was fair in 2016, 2018, and 2019 and poor in 2017 and 2020. At the grazed site, the rangeland condition was fair in 2018 and 2019 and poor in the rest of the years. 

 The comparison of vegetation parameters inside and outside the exclosure shows the good condition of vegetation inside the exclosure. It also shows the effectiveness of the exclosure in rangeland rehabilitation. Balanced livestock grazing on the vegetation caused no significant difference between vegetation characteristics, such as canopy cover in the exclosure and grazed sites. Continuous evaluation and monitoring of rangelands through creating a regular database of vegetation indicators and investigating their changes under different managements. This investigation of their relationship with climatic factors can provide the necessary background for fundamental rangeland planning and management.

Livestock grazing significantly influences the structure and dynamics of vegetation in rangelands, prompting the implementation of exclosure operations as a management strategy. Exclosure involves restricting livestock access to rangelands and is recognized as an effective method for rangeland management and improvement. Numerous studies suggest that exclosure operations lead to positive changes in vegetation indicators, including cover structure, production levels, and species diversity. This research aims to investigate changes in vegetation canopy percentage, production rates, and species diversity under exclosure management in the semi-steppe rangelands of Ghalehgharak, Shahrekord.

Sampling locations were selected within the exclosure site (Ghalegharak) and an adjacent grazed site. Plant cover sampling was conducted using a random-systematic method over multiple years (2016 to 2021). Four parallel transects of 100 meters in length were established at each site, with 40 plots of 2 * 2 square meters placed along the transects. Canopy cover percentage was determined using the theoretical estimation method, while biomass was measured through the cutting and weighing method. Species diversity was assessed using Simpson and Shannon-Wiener indices, and species richness was compared using Margalef and Menhinich indices in the Past software. Range condition was determined using modified four-factor and six-factor methods, and trends were evaluated using scale and comparison methods.

Over the five-year study period, the exclosure site exhibited canopy cover percentages ranging from 34.57% to 52.68%, while the grazed site showed variations from 22.15% to 32.76%. Biomass on the exclosure site ranged from 1215 to 1908 kg/ha, whereas the grazed site's production varied from 693 to 1025.6 kg/ha. The rangeland status was determined as moderate for the exclosure site and poor for the grazed site. The trend for the exclosure site was positive, while the grazed site trend was negative. Significant differences were observed between most evaluation indicators for the enclosed and grazed sites, with exclosure enhancing vegetation indices, canopy cover, and biomass. Exclosure significantly increased species diversity and richness, as indicated by Simpson, Shannon-Weiner, Margalef, and Menhinich indices.

The research findings indicate that exclosure positively influences vegetation, biomass, and species diversity in rangelands. Given the declining performance of grazing rangelands in recent years, implementing exclosure operations and strategic livestock grazing management emerges as a favorable approach for pasture improvement and altering current trends.

IntroductionRangeland provides numerous ecosystem goods and services. Most rangeland management decisions focus on forage production, and this can lead to the loss of other rangeland ecosystem services. One of those services is carbon sequestration, the removal of carbon dioxide from the Earth's atmosphere and its storage in the ground. Rangeland, which covers approximately half of terrestrial ecosystems, is one of the most important sinks for atmospheric carbon dioxide. Photosynthesis, respiration and decomposition are the main processes in the ecosystem that determine how carbon is stored in the soil. Anthropogenic activities like livestock grazing can significantly alter soil carbon storage. Unfortunately, human activities have resulted in lower soil carbon and increased global climate change. Livestock grazing is one of the most significant factors affecting the structure and functioning of ecosystems. Grazing livestock can affect the amount of carbon in the soil through reduced vegetation cover, altered species composition, soil degradation, urination and defecation. On the other hand, changes in the quantity and quality of forage production by livestock grazing have a strong effect on the welfare of the beneficiaries. Consequently, knowledge of the relationship between forage production and other ecosystem goods and services such as soil carbon is essential to the sustainability of ecosystems. It is important to study the quantity and quality changes in rangeland production in relation to different livestock grazing intensities on soil carbon. However, this information can assist range managers in providing techniques to promote soil carbon storage. The purpose of the study is 1) to determine annual forage production in rangelands at different grazing intensities, 2) to study the quality of rangeland forages produced, 3) to assess soil carbon content at different grazing intensities, and 4) to assess the relationship between rangeland production and soil carbon content at different grazing intensities. Material and MethodsA rangeland adjacent to Khabr National Park in Kerman province was selected as the study area. The study area is shrub- dominated species Artemisia aucheri Boiss. Three sites with different grazing intensities (for example, exclosure, high grazing and moderate grazing) were sampled. At each site, three 100m transects with 50m intervals were set up. Ten quadrats were randomly assigned to each transect. For each quadrat, the species met were recorded and their number of individuals and the amount of forage produced were measured. The annual forage production (forage quantity) was measured using the clip and weigh method. To determine forage quality, crude protein, acid detergent fibre (ADF), dry matter digestion and metabolizable energy were estimated for each species. Additionally, a soil sample was taken from each of the quadrats. The samples were air-dried and sieved with a 2 mm sieve. The organic carbon of the soil samples was determined through wet oxidation with Walkley-Black chromic acid. Then, the species importance index (IVI) was estimated using relative frequency (Fr), relative density (Dr) and relative dominance (Dor). One-way ANOVA and LSD were used to compare different grazing intensities in terms of soil carbon, annual production, crude protein, ADF and metabolizable energy. Pearson's correlation was used to examine the relationship between soil carbon and annual production with the qualitative attributes of production, ie. The primary component analysis (PCA) was used to identify the most important species in terms of production at the three sites with different grazing intensities (exclosure, high grazing and moderate grazing). Principal Component Analysis (PCA) was used to identify the most important species in terms of production at the three sites with differing grazing intensities (exclosure, high grazing and moderate grazing). Results and DiscussionThe quantity and quality of forage has been reduced in the livestock grazing sites. The study area has a long history of cattle grazing, which has significantly altered the composition of the vegetation. About 26% of the exclosure site species had been removed from the plant composition of medium pasture sites, most of which are appetizing species. Although the amount of organic carbon in the soil increased at the exclosure site, it was not significantly different from grazing sites. Therefore, despite the improvement in forage quality and quantity, soil organic carbon had shown a lower reaction to the exclosure. Due to the presence of acceptable species, there was a positive relationship between forage quantity and quality at the exclosure site. Although A. aucheri was still dominant shrub species in the site with medium grazing intensity, there was no significant relationship between forage quantity and quality due to the decrease of palatable species. With the increase in the number of non-platable species in the high grazing site, there was a significant negative relationship between forage quantity and quality. There was a positive and meaningful relationship between soil carbon and the amount and quality of forage at the exclos site. The relationship between soil carbon and forage quantity and quality was not significant on grazing sites because of a change in plant composition. In the sites under grazing, palatable forbs such as Tragopogon jesdianus Boiss. and Lathyrus annuus L. were not observed and perennial grasses were significantly reduced. It should be noted that forage production of forbs has not changed much on the site with average grazing compared to the exclosure site. Perennials, especially woody plants, were severely reduced at the site with high grazing intensity. There were no bushes observed at that location. Annual grasses had increased in the site with heavy browsing. As perennials decrease, space and resources become available for the invasion of annual plants, especially annual grasses. Therefore, Bromus tectorum L. had the highest forage production in the   high grazing area. In terms of crude protein, the high grazing area had low quality forage. Since livestock grazing and subsequent changes in plant composition do not greatly impact soil carbon, livestock management can contribute to the improvement of plant composition and forage production at this site. Taking into account the impact of grassland management on other ecosystem functions, it is suggested to explore the relationship between the amount of production and other functions of quality rangeland ecosystems in order to sustainably manage rangeland ecosystems.

Fire is the fastest cause of extensive changes in vegetation. The purpose of this research is to examine some of these changes. SO, after determining key area of four 200m transects and a distance of 100 m from each other, 10 plots 1m2 fixed on each of them, formed sample units in each field. This site burned in 2011 and 2013, in 2018 and 2019, random-systematic statistical collection was carried out in it. Results showed, in fire treatment the dominance of production and cover is with invader plants. Production of this class 52.05 and 209.1gr/m2 has been preserved in burnt area compared to control. Also, annual grasses have significant average difference in terms of production and canopy compared to other species. However, annual forbs had 1.5 times more production in fire than control. Although the amount of production in burnt area is more than control but, it doesnt mean an increase in the amount of allowable forage. The plant type in the burned fundamental change compared to the control by replacing annuals instead of permanent species. As result production, density and canopy cover of different palatability classes and growing forms also found fundamental changes. Fire is cause of changing in rangeland condition from excellent to average, the trend is positive in both treatments. The management of burnt fields is very specialized, and according to the existing conditions, it is strongly not recommended to create a fire either intentionally or accidentally in this area is vegetation zone form of Iran.

Salsola laricina is one of the main elements of vegetation communities in the steppe rangelands of the dryland region, which protects it from disturbances and provides conditions that can preserve its ability to rehabilitate after chest, is one of the basic requirements of rangeland management in such fields. Therefore, in the present study, the variability of structural and functional traits and morphological characteristics and seed germination were tested under supportive grazing. For this purpose, by establishing a sampling system inside and outside of the 10 year old Khoshkerood detention, the vegetation cover and structural and functional traits of Salsola laricina species, such as crown cover, density and forage production in the field were measured. Seed of healthy and healthy rootstocks, morphological characteristics and seed germination, such as; 1000 seed weight, germination percentage, germination rate, root length, stem, seedling, and finally vigor index (straw) Seed) was measured in laboratory conditions. The results showed that the values of structural and functional traits, inside the enclosure, are more than outside the enclosure. In this regard, the percentage of crown cover, density, and amount of production of Salsola laricina species were respectively in the enclosure relative to the outcrop, 5.46 and 3.6%, 21600 and 17000 bases per hectare and 161.4 and 12.71 kg respectively hectare. The average of morphological and germination characteristics of the seeds collected from the intruder was also greater than the outside grazing. So that the highest index of seed vigor as a sum of outcomes of morphological and germinating properties in inoculated and outcroped seeds is 389.88 and 1037.37, respectively. The increase of these values in the enclosure relative to the outcrop; indicates the effect of supportive grazing on the improvement of structural and functional characteristics and the morphological and seed germination characteristics of rangeland species in vulnerable ecosystems in arid areas.

Owing to premium properties such a transformation of forage with low quantity and quality into high quality dairy and meat products, compromising with arid and semi-arid rangeland and resistance against diseases, camel has basic function in extensive grazing systems. These properties have made camel herding as one of the strategies in sustainable development in natural resources management and sustainable livelihood of local communities. Nevertheless, camel herding is facing various challenges in Iran. This study aimed to strategic analysis of camel herding systems from Kalkooyi nomads and rangeland experts’ viewpoints in Qom Province. In this order, strength, weakness, opportunity and threat factors were identified using semi-structured interview. Then, weighting factors was done through designing and completing questionnaire based on two stakeholders. Data analysis was done using SWOT framework in Microsoft Office Excel. Result showed that the most important internal factors affecting camel herding in strength criteria was positive attitude and the interest and motivation towards camel herding among Kalkooyi nomads and in weakness criteria was shortage in suitable water sources for livestock drinking from both nomads and experts’ viewpoints. Also, between external factors as opportunity criteria, positive attitude of community members towards camel and its products and in threat criteria lack of comprehensive planning and roadmap for camel herding were the most important factors. Strategic position of camel herding was determined as offensive (SO) from nomads’ viewpoint with weights of 3.502 and 3.407, respectively. This position was determined as competitive (WO) from experts’ view point with weights of 2.073 and 2.517, respectively. Since both stakeholders assigned high weights to opportunity factors, the ultimate emphasis is on providing the condition for using opportunities of camel herding as well as strengthening the strengths and reducing the weaknesses. The result of this study helps executive managers and policy makers to plan and adjust camel herding roadmap with providing more information.

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.

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.

The main objective of this research was to evaluate vegetation changes and soil indicators in the Kalat Sadat Sabzevar area under rangeland management practices. Vegetation factors including plant species production, vegetation cover, cover percentage, litter percentage, plant species density, and rangeland condition and trend were measured at the exclosure site and adjacent control site. The assessment was conducted using a random-systematic method with a sufficient number of samples and appropriate distribution of samples at the time of rangeland readiness. The rangeland trend was determined on the basis of two methods, and rangeland condition was determined based on the four-factor method. Soil sampling was carried out at a depth of 20 cm. A total of 12 soil samples were taken from the first, second and third transects (exclosure site), as well as fourth, fifth and sixth (control site). Data were analyzed by the independent t-test using SPSS software. According to the obtained results, the highest canopy cover percentage in terms of palatability belonged to class II plants (19.37), and in terms of vegetative form belonged to the perennial plants (16.2). Also, the largest share of production in the exclosure site and grazing site was related to shrubs and perennial grasses, respectively. The results showed that clay, silt, lime, organic carbon, nitrogen and electrical conductivity were significantly different at 5% level between the exclosure and grazing sites, but there was no significant difference between acidity and phosphorous. Therefore, exclosure could be recommended as an improvement practice to be carried out in more areas of the region.

In water efficiency studies, the values of runoff, evapotranspiration and range production are the main variables. Rangelands of Golestan province, Iran, have a high potential of run-off due to the geographical location, climate, and destruction of these resources as well as drastic land use change from forests and rangelands to agricultural lands. Therefore, in the present study, in order to determine the best management of rangelands, we developed a rangeland improvement model using the Soil and Water Assessment Tool (SWAT) in the Gorganrud Watershed, Golestan Iran. Calibration and validation of model was performed using Sequential Uncertainty Fitting Program (SUFI-2) in the eco-hydrological model SWAT. For this purpose, the SWAT was calibrated and validated for a 31-year period of discharge and 5-year period of range production and then the model was executed for different scenarios of rangeland management. The results showed that the model performance was satisfactory for predicting discharge. The values of Nash-Sutcliffe coefficient were calculated to be 0.72, 0.71 and 0.64 in calibration period and 0.59, 0.48 and 0.53 in validation period for Basirabad, Tilabad and Haji Ghoshan stations, respectively. As well, four range improvement scenarios (mechanical, biological, biomechanical and livestock grazing management) were defined in this study. On average, by applying mechanical, biological, biomechanical, and grazing management scenarios evapotranspiration was increased to 2.3%, 12.8%, 15.5% and 2.8%, respectively, in comparison with actual evapotranspiration. According to the obtained results, the biomechanical scenario was identified as the best one in increasing evapotranspiration in poor and moderate rangelands.

This study was conducted with two aims, including the study of various rangeland managing effects on soil carbon sequestration and another purpose was studying of difference between the used methods of reporting the amount of soil carbon. Different approaches to calculation and presentation of carbon include using carbon concentration parameter (gr C/kg soil)؛ Carbon mass parameter based on constant depth (ton C/ ha) and carbon mass based on equivalent depth (ton C/ha). However some scientific reasons show, the approach of carbon mass based on equivalent depth; due to fluctuation of calculation depth effect on the role of bulk density changes that by applied its role can estimate the actual soil carbon in an equivalent depth. By soil sampling from shallow depth in five kinds of rangeland utilization and management (including of pen area, rural, enclosure, key area (moderate grazing) and watering place); the amount of carbon was calculated according to the above-mentioned methods then statistical analysis was used. The results of means comparison showed that base on first methods home range, enclosure and key area with the amount of 37. 80, 27. 30 and 22. 92 gr c/ kg soil have the highest carbon while conflicting results were obtained base on equivalent soil mass. To resolve this prevalent inconsistency in numerous studies, equivalent soil mass were calculated and its result showed that pen site have the highest carbon mass 108. 64 ton per hectare in equivalent depth. Overall results in this study area, the conventional methods that are used for calculating organic matter Due to the unequal soil masses are not accurately expressing about differences in soil mass. For the evaluation of reliable storage of soil organic matter and nutrients; comparison soil masses should be equivalent. However, the validity of these findings is recommended to be tested in other sites for achieving practical results.

Rangelands can play key role to supply the main part of food needs of human. In this regard, considering to optimum efficiency is very important. Nowadays, decision making is very momentous; many of decisions are made on multi criterion and multi criterion decision making methods have special position. In this study multi criteria decision making has used and analytical hierarchy process (AHP) selected to identify the most preferred utilization system in the rangelands of Guilan Province according to economic, social and ecological criterion. In this study by means of pair wise comparison among criterion and sub-criterion and using Super Decision software, Guilan provinces’ experts comments, evaluated preference and priority of strategies. Results are integrated and final preference of procedures has been obtained. In Guilan province results showed that private utilization system with overall priority 0.541 had the best preference utilization system and government utilization system with overall priority 0.317 was at the second priority and finally, traditional system had the last priority with overall priority 0.222.

This study was aimed to determine the variation of species diversity, richness and evenness of plant species under various managements (different range conditions) in five vegetation types. After determining vegetation types, range condition was measured applying the method of society for range management (SRM). In order to assess species diversity, richness and evenness, canopy cover percentage and species density were determined along transects within plots. Species diversity was determined using Simpson index, Shannon-wiener function and Hill index(N1 and N2) and species richness was determined by Margalef, Minhinnick, Bootstrap and Jack-Knife methods and species evenness was measured using Simpson, Camargo, Smith-Wilson and Nay revised index. Mean comparison test (non-paired t-student test) was used to determine the relationship between species diversity, richness and species evenness under different conditions. The results showed that in various managements with changes in range condition, a trend of regular changes could be observed between vegetation cover and range condition. In other words, the value of estimated indices of species diversity and evenness was higher in good range condition as compared to the fair and poor range condition; however, the maximum value of species richness was related to good, fair, and poor conditions, respectively. Results of mean comparisons showed a significant difference between good and poor condition for most of the indices used in species diversity, richness and evenness, while there was no significant difference between good and moderate condition.

Study on plant vegetation changes has many applications for range improvement and range management. Plant vegetation percentage, production and composition were studied over fouryears in a17-year exclusion area and a grazing area in Golestan Research Station in Mashhad City. Soil organic matter content of both areas was measured at 0-30 cm soil depth. Plant composition was determined by identifying the perennial species. Vegetation percentage and plant production were estimated using quadrate and clipping method, respectively. In general, plant vegetation percentage and plant production were higher in exclusion area as compared with grazing area; however, this increase was not statistically significant in some years. Plant vegetation composition also showed some differences, but the changes seemed to be low during the exclusion period. Organic matter percentage was calculated to be 0.57 and 0.54 for exclusion and grazing areas, respectively. In conclusion, in the areas with similar climatic condition, range exclusion will not result in large changes in plant composition and vegetation percentage for fodder production or creating green space.

Sagebrush rangelands in Iran with 39.71 million hectares include more than 46% of the total rangelands, and are recognized as an important and dominant rangeland species in Iran Turan flora. These lands are often associated with grazing of livestock and wildlife. To determine how to better manage this important resource, a rangeland-livestock model was tested in the Hablerud river basin located in Tehran and Semnan Provinces of Iran using the Soil and Water Assessment Tool (SWAT). With regard to climate variation, this watershed consists of three ecological zones: semi-steppe, steppe, and desert. Calibration and validation of model were tested with the Sequential Uncertainty Fitting Program (SUFI-2). Results showed that observed data of forage production were inside or quite close to the predicted bands in three zones. Also, based on the model results, simulated forage production varied from 0.35 to 0.5, 0.15 to 0.26, and 0.033 and 0.1 ton ha-1 in semi-steppe, steppe, and desert, respectively. Sensitive analysis showed that whatever we move from semi steppe to desert, the number of sensitive parameters increases and water and soil parameters becomes more sensitive in forage production.

To evaluate the vegetative and productive characteristics and forage consumption by livestock at different stages of Bromus tomentellus phonology, this experiment was carried out during five years in Urmia-Garebagh rangelands. Thus starting the grazing season and livestock entering, any remaining amount of forage grazing was harvested until a month intervals, and consumption rate was determined by subtraction between harvested forage and fenced plot forage. Finally, in order to study the effect of harvest months on the production and consumption of species under investigation in the study area, data were analyzed. ANOVA combined data showed that overall because of hot weather in 87 and 89 the second and fourth year was highest production years and sixth month of forage production (biomass) was the lowest production through the months, but the second month has highest consumption of the grazing season.

Importance of production information in range management has caused researchers be seeking to find suitable methods for yield estimation. As clipping and weighing method has been recognized as a time consuming, high cost and destructive method, researches have been conducted on indirect methods. Estimating yield from cover data can be considered as an important method. In the present study, relationship between cover and yield was determined at first. Then investigation was done to find how cover data can be used to estimate production using a double sampling procedure or pooled equation. Research was carried out in two rangelands of Manuka (a semi-arid rangeland) and Conservation (as an arid area). Double sampling was formed by clipping and weighing method as direct sampling and foliage or canopy cover measurement as indirect sampling for each group of species. The number of paired of direct and indirect sampling based on time consumption and accuracy were 4, 6, 8, 12, 16, 20, 24, 28, 32, 36 and 40. SPSS was used for data analysis. Data were collected during 2 or 3 years in different seasonal conditions of fair, poor and good. The results showed the possibility of estimating range production from cover measurement using equation based 8 to 12 paired direct and indirect sampling. Correlation between cover and yield was higher for all collected data in both rangelands of Manuka and Conservation. According to the results, cover data can be used in both models of double sampling or pooled equation for accurate yield estimation.