IRANIAN JOURNAL OF RANGE AND DESERT RESEARCH
Year:2017 | Volume:24 | Issue:3 (68) |Papers Count:22

To investigate the allowable use of Stipa barbata, five sites were selected in the semisteppe rangelands of the country. In the beginning of grazing season, 40 individuals were selected in each site and protected from grazing. Different harvesting treatments were applied including control, 25%, 50%, and 75%. The simulation method was applied to calculate the production and harvestig rate. The mortality, height, and seed production rate of the study species were also evaluated after application of treatments. The data were collected over the years of the research and analyzed in a split plot design based on completely randomized design with SAS and SPSS software. The means of traits were compared with Duncan test. The interaction of treatments was analyzed using the AMMI model with IRRISTAT software. Our results clearly showed that an allowable use of 50% could be recommended as the allowable harvesting rate for Stipa barbata in similar sites.

Vegetation is one of the most important factors affecting the stability of ecosystems. Therefore, detailed information on the environmental factors is essential to control establishment and distribution of plant communities. This study aimed to identify plant communities and investigate the relationships between these communities and soil properties using cluster analysis, detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) in Chamran watershed located in the northeast of Behbahan city in Khuzestan province, Iran. According to field surveys, six homogeneous units were identified and the percentage of species canopy cover were recorded in 10 plots (1×1m) placed in each unit and for floristic studies, plant samples were collected from each plot. In each unit, three soil samples were collected to a depth of 15cm and some physio-chemical analyses were conducted on them. According to cluster analysis results, six plant communities were identified. Floristic studies showed that there were 49 plant genera and 20 plant families so that Astraceae with nine genera was the dominant family and therophytes with 69 species were the dominant life form in the study area. Multivariate analysis (DCA and CCA) indicated that there was a significant relationship between soil factors and plant communities. Results of ANOVA indicated that there were significant differences between soil properties (except clay, pH and K) in identified plant communities. In general, result showed that environmental factors, especially soil, were the key indicators in distribution of plant communities.

This study was aimed to investigte the effects of different harvesting intensities and year on forage production of three range species including Stipa arabica, Oryzopsis holciformis and Poa bulbosa at Koh Panj site in Kerman province during 2007 to 2010. The results were analyzed in a split plot design in time based on a completely randomized design in four replications for each species. The average forage production of Stipa arabica after 50% harvesting showed no significant difference with control treatment and 25% harvesting, indicating that this species tolereate a harvesting intensity of 50% well. However, the average forage production of Stipa 502rabica after 75% harvesting showed a decrease of 29. 1% as compared with control treatment, which was significant statistically. The average forage production of Oryzopsis holciformis and Poa bulbosa after 50% and 75% harvesting showed a decreas of 19. 75% and 33. 55% and 17. 5% and 41. 2%, respectively in comparison to the control treatment, indicating a better response of Stipa arabica to these harvesting intensities. Overall, a harvesting intensity of 50% could be recommended for Stipa arabica and 25% for Oryzopsis holciformis and Poa bulbosa. Our results showed that the growth of the study species in low rainfall years was lower thatn that of high rainfall years. Therefore, the mentioned allowable use for the study species is recommended for normal rainfall conditions. However, in addition to allowable use, range condition and trend as well as soil erodibility should be taken into account.

This study aimed to evaluate the effect of different chemical treatments used for breaking of seed dormancy on soil seed bank properties (density, species richness and seed germination rate). Soil sampling was done in sub-alpine Polur rangelands in 2012 after natural cold stratification. Therefore, 10 (4 m2) plots were systematically established along two transects. Soil samples were then divided into five equal subsamples in the laboratory. Each subsample was treated by one seed dormancy breaking method, i. e. gibberllic acid (GA3: 500 ppm) for 48 hours, H2O2 (1%) for 48 hours, KNO3 (0. 1% and 0. 2%) for 72 hours and without treatment (control). All germinated seeds in the greenhouse were checked and counted for a 3-month period every week. ANOVA was applied to compare seed germination rate among different treatments. General Linear Model was used to evaluate the effect of method, soil depth and the interactions on soil seed bank characteristics. In addition, paired t-test was used to compare the properties of soil seed bank of each treatment between the two depths. The results showed that seed bank density per m2 was highest in the treatment of gibberllic acid in upper soil layer (4827. 2 seeds) compared with H2O2 (1%) for 48 hours (942. 7 seeds), KNO3 of 0. 1% (382. 8), KNO3 of 0. 2% (356. 6) and control (585. 4 seeds). Similarly, in the lower soil depth, the highest seed density was observed in the treatments of gibberllic acid and H2O2 (1%) for 48 hours, respectively. The average seed richness in upper and lower soil depths was highest in the treatments of gibberllic acid (2. 9 and 1. 9) and H2O2 (1%) for 48 hours (2. 6 and 1. 7), respectively (P<0. 05). Seed germination rate was highest in the treatment of gibberllic acid compared with the other treatments (P<0. 05). We concluded that chemical methods such as gibberllic acid could be useful for breaking seed dormancy in the precise studies of the soil seed bank.

Understanding the degradation factors of natural resources and its impact on people's life provides an opportunity for managers to plan an overall strategy for sustainable economic, social and environmental development. The purpose of this study was to investigate the relationship between range condition and number of livestock of Shahsavan tribe in the Sabalan Mountain range. In this regard, four range allotments including Daly Qasem, Laleh Lu, Nabi Chamani and Arkh Bandi was selected and the statistical population was 70 beneficiaries having license grazing, of which 58 samples (people) were selected by Cochran's formula. The research tool was a questionnaire completed through direct interviews with the beneficiaries in the study region. Range condition, calculated by the six-factor method, was the dependent variable in this study. The correlation between range condition and number of livestock was analyzed using Pearson's test in SPSS software. The livestock rate was compared by the Duncan test. The results obtained in this study indicated that there was a significant negative correlation between the range condition and number of livestock in the region. In other words, as the number of livestock increases to achieve higher annual income, range condition decreases. It seems that monitoring programs and proper management as well as implementation of rehabilitation and improvement projects could improve the balance between livestock and rangeland and increase the forage production. It directly and indirectly affects the annual income of beneficiaries and guarantees the ecological balance and social stability of range allotments through prevention of rangeland degradation and sustainable employment.

Ground surface, at the scale of watershed, is considered as a complicated mosaic of capabilities and environmental hazards (the conflict point between society and nature), whose intensity and numerical value of profit and loss for the land use planning and sustainable development can be evaluated using different objective and subjective models. To identify the risk areas, at first, the assessment of current status of the watershed area was considered from the, physical (soil erosion, water quality), ecological (vegetation type and density) and the social- economic (income) points of view. For this purpose, the model of SWAT as well as WQI and NDVI indices were used. The economic status was studied and analyzed using questionnaires.The thresholds level of the mentioned indices was determine. To assess each parameter of erosion, the Skidmore formula was used. The quality of water was assessed using drinking water standards. To evaluate the vegetation cover, the standard of minimum average size of spot was used. The rural poverty line was also used to determine social-economic condition. The risk areas were determined by comparing the value of each parameter with their threshold levels. According to the results, 20% of the study area was above the threshold level of erosion and 15% was below the ecological threshold level. The average annual household income of the villagers was below the poverty line. The results showed that recognizing the risk areas and using risk land-use planning approach could play a more effective role in management activities and decision making. This research can determine the direction of the essential projects in the watershed and leads to more effective executive priorities.

This research was conducted to determine the chemical composition and digestibility of five palatable range species in saline and alkaline rangelands of Golestan province. The study species were: Frankenia hirsuta, Halocnemum strobilaceum, Halostachys caspica, Plantago coronopus and Salsola turcomanic. Plant sampling was performed randomly at vegetative and seed ripening stages. Dry matter (DM), crude protein (CP), acid detergent fiber (ADF), lignin (ADL) and ash were measured by standard methods. Dry matter digestibility (DMD) and organic matter digestibility (OMD) were determined using rumen fluid from buffalo. The study was conducted in a factorial experiment based on completely randomized design with 10 treatments and five replicates. The results showed that phenological stages and species significantly affected most of the forage quality parameters measured. As the plant age increased, the amount of CP, DMD, OMD, DE and ME decreased, while DM, ADF and ADL increased. At both phenological stages, S. turcomanica had the lowest ADF, while the highest was recorded for P. coronopus. The highest and lowest ADL was observed in F. hirsute and S. turcomanica, respectively. Reduction of the crude protein content due to the phenological stage was the highest in F. hirsute and H. caspica and the lowest in S. turcomanica. The highest DMD and OMD at both phonological stages were recorded for S. turcomanica, showing a significant difference with other species. The overall results showed that S. turcomanica had higher forage quality as compared with other species and the forage quality of the study species at vegetative stage was more than that of seeding stage.

Monitoring refers to regular and longtime observations, which helps to early recognition, evaluation and prediction of changes. However, the characters monitored in natural resources science are restricted to vegetation’ s composition and structure, and less attention has been paid to ecosystem function. Landscape Function Analysis (LFA) is a method which uses simple indices for monitoring ecosystems function during the time or space. This paper investigates the effect of grazing intensity (high intensity, moderate intensity and enclosure) and also geographical aspects on ecosystem function of Torogh dam. Based on LFA method, there were four different kinds of patches in studied area namely shrub, grasses, forb and stone; in addition there were four different kinds of inter patches namely bared soil, soil covered with litter, soil covered with stone particles and finally soil covered with stone particles and litter. The results of comparison among three sites showed that all functional parameters (stability, infiltration and nutrient cycle) were reduction by increasing grazing intensity, so that the H value was calculated to be 18. 86, 12. 08 and 17. 17, respectively using Kruskal Wallis method. In addition, comparing different kinds of patches and inter patches showed significant functional differences between them. Therefore, forb and grass patches have the highest functional rank and vice versa for stone and bare soil. The comparison of grouped geographical aspects (northern-western and southern-eastern) shows higher functional degree in all three functional parameters for northern-western group.

Patching pattern of vegetation is known in many parts of the world, especially in arid and semi-arid regions. Studying the effects of patches on surface features such as erosion, sedimentation, runoff, infiltration, etc. is important. The aim of this research was to investigate the effects of different patches on soil surface characteristics in Faraman Rangelands, Kermanshah Province. Eleven soil characteristics were measured in four vegetation patches of shrub, grass, forb, shrub-grass and shrub-forb in five replicates using the Landscape Functional Analysis (LFA). The study parameters were categorized as indicators of stability, infiltration and nutrient cycling was categorized for each patch. Duncan, Dennett and LSD tests were used to show the significant differences between mean values in SPSS software. Results showed that the patch of shrub-grass had maximum value in each of the three indicators of stability, infiltration and nutrient cycling. According to the results, significant differences were found for the stability indicator between shrub-grass and other patches (except shrub). There was a significant difference for infiltration index between shrub-grass patch and other patches and bare soil. Significant difference was also found for the nutrient cycling indicator between the shrub-grass patch and bare soil. Therefore, it is concluded that stability, infiltration and nutrient cycling in shrub-grass patches could be a good indicator for soil conservation in this rangeland. Overall, LFA can be a good way to determine the best type of vegetation patches to increase the sustainability and soil infiltration and thus preventing erosion in different areas.

In this research, the soil stability, nutrient cycle and soil infiltration parameters were evaluated by LFA method in summer rangeland of Valuyeh Kiyasar in Mazandaran province. Eleven parameters of the soil surface were evaluated on the plant patches in 7 elevation points (with 100-meter interval) from 1600 to 2200 meters a. s. l, in north and south directions. The study was performed on 14 transects with 50 meter length at the dominant slope of the study area. The independent t test was used to compare the soil stability, nutrient cycle and soil infiltration parameters in north and south directions. In addition, the Analysis of Variance and Compare Means test were used to compare these parameters in each elevation point. The results showed that there was a significant difference between north and south directions in terms of soil stability and nutrient cycle parameters (P<0. 01). However, there was no significant difference in infiltration index between two directions. According to the results, infiltration in both north and south directions in different elevation points showed a significant difference at (P<0. 01), so that the elevation point of 2100 in both directions had the highest performance. On the other hand, results indicate the adaptation of the LFA method in this research and other researches, adding the accuracy and speed of this method as compared with other methods.

The aim of this study was to investigate the feasibility of using the framework of grazing gradient for the assessment of rangeland degradation in Northern slopes of Sabalan. In three villages including HeydarAbad, GholiBiglo and ArbabKandi, vegetation and soil samples were taken from a 100-m transect with 1 m2 plots in heavy, medium and light grazing intensity. Analysis of variance and mean comparison results showed that in the GholiBiglo village, changes in the phytomass at the first, second and third distances were 84. 60, 100. 90, 119. 80 kg/ha and canopy covers 33. 10, 35. 90, 43. 20 %, respectively, which had an increasing trend according to the research hypothesis (P<0. 05); however the hypothesis was not confirmed in ArbabKandi and HeydarAbad villages (P>0. 05). In the analysis of mean for three villages, parameters such as species density, stone and gravel, litter, sand, acidity and salinity had notable change trends (P<0. 05); however, other parameters did not confirm the hypothesis (P>0. 05). In ArbabKandi village, species diversity and evenness indices had an increasing trend, but they had no distinguished trend in the GholiBiglo village. In HeydarAbad village, diversity indices had a decreasing trend; however, the evenness indices did not follow a notable trend. Results of multivariate analysis indicated that sites with different grazing conditions cannot be separated. In the north of Sabalan mountain, changes in vegetation and soil factors are not only affected by grazing gradient, however, other factors such as elevation and its dependent variables are the effective factors at different distances from the critical center. According to the species composition and occurred land use change and degradation on these rangelands, and the distribution of critical centers, it is not appropriate to use this framework in the assessment of rangeland degradation.

In the present study, the effects of livestock grazing on rangeland ecosystem structural and functional features of the Khoy mountainous rangeland were investigated. Three sites with light (reference), medium and heavy grazing intensities were selected in Dizaj Batchi rangelands of Khoy, West Azarbaijan Province. In each region, ecological patches of each life form (grass, shrub, forb and mixed as well as interpatches (bare soil)) were selected along 50-m transects using systematic sampling method with five replicates to score 11 soil indicators. Scoring was performed according to the instructions of LFA analysis. Finally, soil stability, infiltration and nutrient cycling were obtained for each patch and interpatches using LFA software. According to the results, the increased grazing intensity caused to change the structural and functional characteristics and the study sites showed significant differences for the study parameters. In other words, increased grazing intensity caused to degradation of ecological patches and increased space between patches. Meanwhile soil surface degradation caused to increased soil erosion and eventually decreased functional features.

Integrating remote sensing techniques (RS) and GIS (GIS) is an important tool to identify sources of sand. This can reduce the time and cost of identifying the location of sand resources. In this study, wind sediment source was identified using the image processing techniques as well as digital data of Landsat 8 and OLI in south Rudbar city. To do so, first the radiometric correction was applied on data and the best band combination was identified by the use of optimal index factor (OIF) techniques, so that the band combination (5, 6, 7) was desirable. Then, the images were classified in three ways including parallelepiped, the minimum distance and maximum likelihood. To assess the accuracy of classification, ground observations were recorded using GPS. Finally, the four criteria including overall accuracy, Kappa coefficient, producers' accuracy and users' accuracy were used to express the accuracy of classification. The results of the three classification methods show that more than 50% of the study area is located in the class of sediment source zones, mainly consisting of agricultural lands, dried-bed rivers and saline lands as well as parabola-shaped surfaces in the playa unit. The results of the accuracy assessment showed that the maximum likelihood algorithm with an overall accuracy of 95. 54 % and Kappa coefficient of 0. 9 were more accurate as compared with other algorithms. To extract the maps of sediment source zones with higher accuracy the use of high spatial resolution images such as Ikonos and Quick Bird is recommended.

The Landscape Function Analysis (LFA) is a new method for rangelands analysis based on ecosystem performance indices. Determining the validity and accuracy of evaluation methods to achieve better and more accurate results as well as determining their efficiency in different regions is of great importance. The purpose of this study was to determine the validity and efficiency of LFA method in winter rangelands of Gonbadekavoos city in Golestan province. For this purpose, after identification of patches and inter– patches, the LFA indices (infiltration, stability, soil nutrient cycling), were determined in the field using 11 soil surface parameters with 10 replications. The rate of soil infiltration was determined using a single metal ring in the field, while the soil stability and organic carbon were determined by wet sieving and Walky-Black methods, respectively. The level of compliance of indices provided by the LFA method from field and laboratory measurements was considered as the basis for the validity of these indices. The results demonstrated that stability and soil nutrient cycling indices (R= 0/551 and R= 0. 485), had fair validity (R= 0. 4 – 0. 6) and their use in rangeland management of the study area is recommended. Soil infiltration index (R= 0. 219) had a low validity (R= 0. 2 – 0. 4), therefore, its application in rangeland management of the study area is not recommended.

Studying the phenological stages is one the important factors affecting the time of livestock entry to and exit from rangelands. In addition, the best time for seed collection, nutritional value and range management depend on studying the phenological stages. In this study, phenological stages of 10 range species in Saraliabad-e-Gorgan region were investigated for four years (2007-2010). The longitudinal growth and phenological stages of the study species including vegetative, flowering and seeding stages as well as plant dormancy period and autumn regrowth were recorded. The results of phenology showed that in early June most grasses were at the heading stage and most forbs were at the flowering stage. Therefore, range readiness for livestock entry to the rangeland is in early June with the difference that in wet years, it will be 10 days and one to two weeks later in plain and mountainous areas, respectively. Among the study grasses, Agropyrum intermedium and Agropyrum trichophorum, and among the forbs Medicago sativa reached the flowering stage and seed formation later. The best time to collect the seeds of most grasses is in the middle of July, except A. intermedium and A. trichophorum, which is in mid-September. Early June was the best time to collect the seeds of forbs like Trifolium repens and Medicago lupulina. For Centaurea zuvandica and Medicago sativa mid-July and late July were the best times for seed collection, respectively.

The quantity and quality of drinking water in rangelands are one of the important factors in determining rangeland suitability for livestock grazing. Improper water quality will have adverse effects on livestock health and productivity. This research was aimed to determine the quality of drinking water for livestock in the winter rangelands of Khalilabad. The map of drinking water quality for goats was produced using fuzzy method in GIS software. After sampling of livestock drinking places, TDS, EC, Mg2+ and Na+ were measured. Inverse Distance Weighting (IDW) was used to prepare the zoning map for each factor. The results of this zonation showed that drinking water quality in the region ranged between 2 to 84. 94 mg / l for sodium, 216. 03 to 875. 72 mg / l for Mg, 2016. 37 to 12597. 4 for EC, and 245. 59 – 5909. 19 mg / l for TDS. Fuzzy method was also used to homogenize the water quality zoning maps. The results showed that 71 % of area had a median drinking water quality for goats and 17% of the area had no quality for drinking water. Generally, the north and northwest of the region had good drinking water quality for goats.

Soil erosion is influenced by erosivity and erodibility factors and regional modeling of erodibility could be a criterion for estimating soil loss and land degradation. This research was aimed to modeling the erodibility in the Khoyobanabank region using physical soil components and land and vegetation physiognomy through statistical analysis methods. For this purpose, first, 33 soil samples were taken along three transects from playa to the mountain units at a depth of 0 to 50 centimeters. Then through laboratory analysis, the content of sand, clay, silt, carbon and organic matter were measured and erodibility (K) and soil erosion index (SEI) were calculated. In addition, physiognomic parameters such as slope, elevation and slope direction, as well as vegetation cover, were estimated at these points. Finally, the relationship between the above components was determined by simple and multivariate regression, and the most suitable relations were selected. Modeling results show maximum linear relationship between SEI and silt, clay and sand as well as between K and sand, clay and silt. Multiple regression results indicate the most significant relationship between SEI and K with soil physical parameters and land and vegetation physiognomy (P<0. 01). These results could provide the possibility of quick and relatively accurate estimation of erodibility in the form of calculating SEI and K through physical soil components and land and vegetation physiognomy using one-way and multivariate statistical models. Obviously, in the case of achieving the mentioned components, soil erodibility could be estimated in Khobibanbak Basin using linear and nonlinear models.

To evaluate the effects of harvesting on Dactylis glomerata, a half-hectare rangeland was excluded from grazing in Zaradwan paddock before vegetative growing season in 2005. In this research exclosure, 40 individuals of this species were completely randomly selected and each 10 individuals were assigned to harvesting treatments at 0, 20-40, 40-60, and 60-80%. Harvesting treatments were applied three times with a month interval during 2005-2008 and the harvested yield was dried and weighted. Thus, the yield of all plants (except control group) was harvested totally at the end of growing season. In the fifth year of study, without applying harvesting treatments, and at the end of growing season, the features including mortality, height, yield and number of reproductive stems were measured and then all roots were taken out of the soil to measure the reserves of soluble carbohydrates and nitrogen compounds. The crude protein was also measured as an indicator of the forage quality. An unbalanced completely randomized design was used to analyze the data. After five years, only one mortality was observed among the 40 study species. The results indicated that D. glomerata was intensively affected by different harvesting intensities, so that this treatment caused decrease of height, aboveground and belowground dry matter. Harvesting treatments had no significant effects on soluble carbohydrates and nitrogen compounds of the study species. In general, the forage quality of the treatments was not affected by the harvesting intensities.

In order to evaluate the forage yield in sorghum (Sorghum bicolor)-kochia (Bassia indica) intercropping, a two-year field study was conducted as a split plot based on randomized completed design with three replications. The treatments included three levels of salt stress: 2, 7 and 14 dS m-1 in the main plots and five planting systems: sole sorghum, ⅔ sorghum, ½ sorghum, ⅓ sorghum and sole Kochia in the sub plots. The results showed that salt stress although reduced the growth and forage yield of both species, Kochia had lower yield reduction, so that 7 dS m-1 salinity had no-significant effect on height and dry forage of Kochia. Furthermore, 14 dS m-1 salinity level decreased height, dry and fresh forage by 52. 1%, 44. 9% and 62. 4% in sorghum and by 15. 5%, 38. 7% and 23. 3% in Kochia, respectively. This salinity level also reduced relative yield (RY) of sorghum by 9%, while had not significant effect on RY of Kochia. Kochia in all salinity levels showed less response to intercropping, so that in all treatments and for all traits there was no significant difference between ⅓ and ½ sorghum intercropping with sole crop. In this respect, ⅓ sorghum in all salinity levels and ½ sorghum in 14 dS m-1 had a RY more than 1. Sorghum was affected by competition, so that fresh and dry weight of sorghum was not significantly reduced only in ⅓ sorghum than sole crop. Intercropping as ⅔ sorghum especially in high salinity was a severe inhibitor for sorghum. Sorghum RY was more than 1 only in ⅔ sorghum under moderate salinity. The results indicated that the optimum intercropping for each species not only had no significant on forage yield, but also modulated the negative effect of salinity on both species. Achieving a conclusive result for deciding about intercropping in saline conditions needs more research.