IRANIAN JOURNAL OF RANGE AND DESERT RESEARCH
Year:2017 | Volume:23 | Issue:4 |Papers Count:24

This research was performed to determine the facilitation effect of some species in a degraded rangeland on establishment and primary growth of two important forage spices: Agropyron desertorum (Fisch. ) Schultes and Secale montanum Guss. Acantholimon festucaceum (Jaub & Spach) Boiss, Eryngium bungei Boiss, Noaea mucronata (Forsk. ) Aschers. and Peganum harmala L. were studied as Secale montanum nurse plants and Acanthophyllum bracteatum Boiss., Astragalus arbusculinus Bornm. & Gauba, Ephorbia orientalis L. and Noaea mucronata (Forsk. ) Aschers. were investigated as Agropyron desertorum nurse plants. Seed sowing of the two forage species was carried out in the middle of autumn in the understory of nurse plants and the space between the plants. The soil moisture was measured at two depths of 0-10 and 15-25 cm. After analysis of variance, mean comparisons were made by Duncan's method. According to the results, due to the facilitation effects of Acantholimon festucaceum, Eryngium bungei, Noaea mucronata, and Peganum harmala, the primary growth (height) of Secale montanum seedlings was calculated to be 3. 4, 2. 6, 3. 9 and 2. 2 times higher than the open space treatment, respectively. All species had similar positive effect on the primary growth (height) of Agropyron desertorum; however, Noaea mucronata, with the most positive effect, could increase the establishment rate to 62 %. Considering the importance of facilitation effect of deformed populations of Noaea mucronata in increasing the primary establishment of Agropyron desertorum and primary growth of Secale montanum, the use of Noaea mucronata nurse role in autumn rangeland improvement is recommended to the natural resources offices.

The current research was performed in Homand Absard Research Station to investigate the yield of Vicia villosa under different sowing and establishment methods. Initially, the seeds of this species were collected from similar natural habitats. Afterward, seed characteristics including germination percentage, viability, seed vigor, etc., were examined. The study area is a semi-steppe region with an average rainfall of 333 mm. Two sowing methods including seeding and seeding together with rainfall storage, and spring and autumn sowing dates were considered in a split plot design with three replications. Data analysis was performed with SPSS software, and mean comparisons were done by Duncan's multiple range test. According to the obtained results, no significant differences were obtained for the yield of the seeds cultivated in autumn and spring between two sowing methods at 5% level of probability. However, the interaction between methods and season was significant and higher yield was recorded for the seeding with rainfall storage method in autumn season.

This research was aimed to study the vegetation changes under grazing and non-grazing conditions during five years in order to evaluate vegetation improvement or destruction over time. The study of vegetation changes was carried out inside and outside the exclosure within the sample units. Each sample unit consisted of two parallel transects with 20 quadrates. Within each quadrate, the canopy cover percentage and composition percentage of each species were estimated. The forage yield was measured by clipping and weighing using one-square-meter quadrates. No significant difference was recorded for the canopy cover of inside and outside the exclosure. Statistical analysis was performed in a completely randomized block design and no significant differences were found among the study years. However, significant differences were found for forage yield of inside and outside the exclosure. Therefore, the reduction in forage yield of outside the exclosure is directly related to the intensity of utilization. The life form of species was determined based on Raunkiaer's system Hemicryptophytes was the dominant form in the study area. The results showed that although the exclosure caused to improve rangeland vegetation, the difference between inside and outside the exclosure was not significant. Generally, the results indicated that vegetation changes in the study area were slow and gradual and exclosure could not be considered as an improvement method in short-term. Direct human intervention is required for the restoration of rangelands, located in arid regions.

Production of forage protein is limited in arid and semi-arid environments. Grasslegume intercropping could be a viable option to obtain forage with higher protein content. To study the best composition of mixed cropping of alfalfa (Medicago sativa) and three grass species (Agropyron elongatum, Agropyron desertrum and Festuca arundinacea) on vegetative characteristics and forage yield, a two-year experiment was conducted during 2009 and 2010 in Sisab station of the Natural Resources Research Station of North Khorasan province. The experimental design was a split plot based on randomized complete block design with three replications. The main factors were mixcropping ratios and sub-factors were two methods of mixed cropping (including mixed and intercropping). Vegetative traits, forage yield, and land equivalency ratio (LER) were determined during the experiment. Data were analyzed by SAS software and means comparisons were made by Duncan's test. Results of analysis of variance showed that the effect of mixed cropping on growth characteristics of alfalfa and grass species was significant. The higher values of the leaf to stem ratio (81. 66%) was obtained from mixed cropping of alfalfa 25% + Festuca 75% treatment. The effects of sowing pattern (mixed and row intercropping) on vegetative traits were not significant. The effects of mixed cropping on the yield and LER of both alfalfa and grass forage were significant. The highest amount of dry matter production with average values of 2317 kgh-1 was obtained in mixed cropping of alfalfa 25% + Agropyron elongatum 75%. The highest LER (1. 53) was related to the treatment of Festuca 25% + 75% alfalfa in intercropping patterns, representing 53% improvement in land use compared with monocultures of each of species.

In order to study of forage yield and quality traits, 19 populations of Elymus hispidus were sown under irrigation condition using a randomized complete block design (RCBD) during 2006-2009 in Hosein Abad, Shiraz, Iran. Data were collected and analyzed for spike emergence date, dry matter (DM) yield, plant height, stem number, leaf to stem ratio (LSR), and five quality traits as: dry matter digestibility (DMD), water soluble carbohydrate (WSC), crude protein (CP), acid detergent fiber (ADF) and total ash for three years. The results showed significant difference among populations for all traits except total ash. The populations T24, Feriden, Saghez-Ghameshloo, Asadabad and Pashelki-Eghlid with average values of 5458, 5307, 5114, 4696 and 4565 kg/ha had higher annual DM yield. Results of correlation showed positive correlation between stem number with both DM yield and plant height. The correlation between CP/WSC and between DMD /ADF were negatively significant. Using principal component analysis, the first three components determined 67% of the total variation. The spike emergence date, plant height, and DM yield in the first component and CP, WSC and leaf to stem ratio in the second components were the important traits. The 19 genotypes were grouped into three clusters based on Ward cluster analysis method. In terms of forage quantity and quality, Feriden and Ghameshloo (Saghez) populations had higher values as compared with other populations; therefore, these two accessions are recommended for semi-steppe rangelands of Fars province.

Developing countries are looking for modern technology with the use of supplements to increase the production efficiency by reducing drought stress and water saving. In this study, the effects of Abyar supplement on the shoot and root length, and shoot and root dry weight was measured. The Abyar supplement was performed for Atriplex canesence at three concentrations (1/10000, 1/6000, 1/2000) and three irrigation periods (every day, every three days, every six days). The results showed that Abyar supplement at a concentration of 1/10000 was the best treatment in increasing the shoot and root length. The Abyar supplement at concentrations of 1/10000, 1/6000 and 1/2000 with a daily irrigation period had the highest effect on increased root length. There was just a significant difference between the treatments of 1/10000 and 1/2000 at 5% probability level. According to the results of Tukey test, the highest rate of growth was recorded for the Abyar supplement at a concentration of 1/10000 with an irrigation period of every day and every six days and Abyar supplement at a concentration of 1/6000 in three periods (every day, every three and six days). In all treatments, the root weight decreased by increasing plant irrigation period. This supplement leads to the better growth of Atriplex canesence by increasing plant resistance to drought stress and more moisture retention in the plant organs.

Image classification is always one of the most important issues in remote sensing, and the obtained information from image classification is widely used in this field and other applications like urban planning, natural resource management, agriculture, etc. Since the main purpose of processing satellite images is preparing subjective and practical maps, choosing a suitable classification algorithm has an essential role. This paper studies the efficacy of Support Vector Machines (SVM) algorithm regarding satellite image classifications and compares it to artificial neural network algorithm. SVM is a group of classified and observed mechanical learning algorithms, used in remote sensing. In this study, SVM algorithms were employed for land use classification of Meymeh area using ETM+ landsat data. The classification via SVM was automatically performed by three types of linear Kernel, polynomial, and radial basis. Besides, the performance of this method was compared to that of artificial neural network classification method. Results showed that the average overall accuracy and Kappa coefficient of SVM algorithms, including linear Kernel, polynomial and radial basis, were respectively 9 percent and 12 percent more efficient than artificial neural network classification. Consequently, this study substantiates the efficiency and sufficiency of SVM algorithms in classification of remote sensing images.

Environmental factors including rainfall are the factors affecting palatability of plants and consequently the preference value for animals. In this study, the preference value of plants was determined in Sarakhs (winter rangeland at North-East of Khorassan province) by timing method during 2007 to 2010 for the two first months of growing season (March and April). The results showed that Artemisia diffiusa, Carex physioides and Poa bulbosa were grazed in all four years by livestock, indicating that these species were more palatable. The preference value of the species differed between drought and normal years. According to the obtained results, a high correlation was found between the grazing time of Poa bulbosa and pervious rainfalls. Also, a significant relationship was found between the grazing time of Carex physioides in March and the rainfall of autumn, January and total rainfall of February and March. A significant correlation was also found between the grazing time of Artemisia diffusa in March, and the rainfall of January, total rainfall of autumn and December, and total rainfall of autumn, January, and February. This research was aimed to determine the seasonal and annual forage preference value with regard to the rainfall fluctuations in Sarakhs rangelands.

Plant growth-promoting rhizobacteria are a subset of bacteria, accumulating on the root and rhizosphere. One of the seed priming methods is the use of microorganisms in seed inoculation, known as biopriming. The use of these microorganisms in seed inoculation leads to increased plant performance, especially if the microorganisms are symbiotic in the root zone of the plants. This study was aimed to investigate the effects of biopriming with Azospirillum and Azotobacter on drought resistance in fescue under greenhouse conditions. Osmotic potential at four levels was applied on the Fescue seeds using polyethylene glycol for 2 and 4 days as priming treatment along with inoculation with rhizobacteria. Drought stress was applied during the plant growth based on field capacity at four levels. The results showed that biopriming treatments caused improved performance and increased drought resistance compared to the control. The study showed that both Azospirillum and Azotobacter increased the performance significantly compared to the control. Generally, Azotobacter showed relatively better performance than Azospirillum. However, the Azotobacter treatments at 2 and 0. 5 MPa for 2 days can be considered as a superior treatment in fescue as compared with other treatments.

Seasonal variation in seed bank impacts vegetation dynamic. The purpose of this study was to determine the changes of soil seed bank during the growing season. This study was carried out in a summer grassland in the northern slopes of Alborz Mountain, SorkhAbad, Savadkoh in Mazandaran province, Iran. Sampling was done in March, May, August and October 2010 from two soil depths (0-5 and 5-10 cm). Seed bank composition and size were determined by seed germination of soil samples in glasshouse for 11 months. In this study, 76 species were identified in the soil seed bank during the growing season. In all months, seed density was greater in the upper soil layer than that in lower soil depth. The seed bank in summer (August) and autumn (October) had the maximum seed density. Significant temporal changes were found in the seed bank of 21 species. The seed bank of Thlaspi sp., Stellaria media, Fumaria sp., Poa bulbosa, Alyssum sp., Thlaspi hastulatum, Hieracium sp. and Myosotis silvatica significantly increased during growing season while a significant reduction was found in the seed bank of Sonchus oleraceus, Cynodon dactylon, Carex sp., Potentilla canescense, Digitaria sanguinalis, Taraxacum montanum, and Dactylis glomerata. For some species such as Medicago lupulina, Agropyron repens, Veronica persica, Stachys byzantine, Tragopogon sp., and Bromus sp. soil seed banks showed a peak and then significantly declined.

Range suitability assessment for different objectives is along with management principles and guarantees sustainable development. A considerable area of Golestan Province plains is covered with halophytes, grazed by different livestock including sheep. A study was done to assess the suitability of saline winter rangelands with dominant species of Halocnemum strobilaceum and Aleuropus lagopoides for sheep grazing. The F. A. O method in GIS environment was used in this research for Gomishan Plain, Golestan province, Iran. In the method, three criteria of vegetation, water and soil erodibility were used as the sub-models and constituted the final model components. For vegetation sub-model, vegetation types, cover percentage, forage production, range condition and trend and range capacity were determined. Distance from water resources, water quantity and quality were determined for water sub-model. For the soil erodiblity sub-model evaluated by the EPM model, slope, rock and soil sensitivity to erosion were determined. The final model of range suitability for sheep grazing revealed that 38. 69 and 61. 31 percent of the region were classified as low suitability and no suitability, respectively. Among all factors determined in sub-models, the distance from water resource was the most limiting factor for sheep grazing and forage production was the most reducing factor of range suitability. Finally, utilization of rangelands in the region could be improved by reducing grazing intensity and implementing range restoration practices.

Identification of effective environmental factors in distribution and establishment of plant species plays an important role in rangeland ecosystems management. The purpose of this study was investigation of reasons for plant species distribution and relationship between index species in Khorramabad rangelands and physical and chemical properties of soil. At preliminary inspection, vegetation types were separated and the key area of each type was recognized. Four vegetation types were identified as follows: Agropyron libanoticum-Acantholimon bromifolium، Hordeum glaucum-Taeniatherum crinitum، Astragalus adscendens-Agropyron trichophorum andAstragalus adscendens-Daphne mucronata. The size and number of sampling plots were calculated to be 4 square meters with minimal area method, and 160 based on the statistical formula, respectively. Sampling method in each vegetation type was randomize-systematic, so that, in each plot, vegetation factors were measured, then at the beginning and end of each transect a profile was dug and some physical and chemical properties of soil were measured. Vegetation ordination was done by CCA method and results showed that organic matter, nitrogen, phosphorus, potassium and pH were the most important factors affecting Daphne mucronata distribution. The distribution of Agropyron libanoticum and Acantholimon bromifolium were affected by potassium, soil texture, and EC. As well, soil texture and lime had a decisive role in distribution of Taeniatherum crinitum, Hordeum glaucum, Astragalus adscendens and Agropyron trichophorum.

Rangelands cover about half of Iran’ s territory with unique ecological characteristics. Understanding these characteristics is an essential need for any management in these arenas. In this regard, the present study was carried out to evaluate the intensity of grazing on vegetative and reproductive characteristics of Bromus tomentellus, as a key species in the rangelands of Gavanban in Kermanshah province during four years. At first, a reference area of one hectare was selected and fenced. Simulation method was used in this study. Treatments included four harvesting intensities of 25, 50 and 75% and control on Bromus tomentellus. In each treatment, 40 individuals of species were selected. The effect of exploitation on phenological characteristics such as height, number of flowering stems, vigor, vitality, collar area, forage production and other characteristics were evaluated. All data were analyzed using combined analysis of variance in a completely randomized design. Results showed that production of Bromus tomentellus did not differ statistically in response to different harvesting intensities, and up to 75 percent of the species could be harvested; however, in some cases, morphological traits were affected, leading to decreased number of flowering stems, and increased collar diameter over the years. Also, it did not have any significant effect on height and vitality. In other words, the regeneration of species harvested decreased (due to reduction in the number of flowering stems). However, 75% harvesting intensity caused increased collar area.

Understanding the forage quality of native species is important to identify the valuable species for range improvement and reclamation as well as determining the appropriate grazing time and rangeland grazing capacity. In the present study, plant sampling was performed for Astragalus cyclophyllon and Hedysarum criniferum at three phenological stages (vegetative growth, flowering and seeding) in Chadegan-Isfahan. The samples collected were dried, grounded and analyzed to determine the forage quality. Data were analyzed in a factorial experiment based on a completely randomized design with two treatments and three replications. According to the results, the chemical composition and forage quality of the study species varied significantly (p<0/05). The Crude Protein (CP), Dry Matter Digestibility (DMD) and Metabolism Energy (ME) contents in both species showed a decreasing trend with the development of phenological stages. H. criniferum had higher contents of CP, DMD and ME as compared with A. cyclophyllon in all the growth stages. Our results clearly showed that the study species could be classified as desirable species because of their high nutrition values. Conservation of the species such as these two legumes with a low distribution and high nutrition values as compared with alfalfa is critically important. Therefore, domestication of these two species is highly recommended to supply a part of forage for livestock.

In arid and desert regions, wind has an important role in soil erosion. The amount of wind energy and its direction variability have significant control on the morphology and maintenance of aeolian land forms. This research was aimed to analyze the erosive winds and investigate the discharge and sediment transport in the study area. For this research, anemometric data of a duration period of 20 years (1994-2013) were analyzed. Wind rose and sand rose are one of the best methods to determine the wind erodibility. The results obtained from the analysis of wind rose data indicated that the direction of prevailing wind in the study area was NE, W and E. The results of sand rose for a wind speed threshold of 12 knots showed that the drift direction was from south – west towards north – east. The maximum and minimum amount of total sand drift potential was 105. 3 and 594. 7 in vector units, related to Kashan and Ardestan stations, respectively.

Arid land degradation is the biggest environmental challenges in 21st century. Saxaul (Haloxylon spp) is one of the most important species for sand dunes fixation, widely used in reclamation of arid lands. One of the applications of satellite data is to estimate the biomass of plants. In this study, Landsat 8 satellite images were used for mapping the biomass of Haloxylon plants in the South Khorasan province. Then, 11 vvegetation indices (DVI, IPVI, NDVI, PVI, RVI, SAVI, TSAVI, WDVI, Brightness, Wetness, Greenness) were calculated. To determine the correlation between biomass and satellite data, 30 plots of 30*30 m2 were used in the region and vegetation parameters were measured. Principal component analysis and cluster analysis were used to classify the indices. Finally, the effective indices were selected and the regression models were fitted. Results showed that the regression model obtained from the TSAVI index with RMSE of 14. 9 and R2=0. 43 had the best estimation for the above ground biomass of Haloxylon.

Knowledge of species distribution patterns in each area is the basis of vegetation measurement. Determining the species distribution pattern helps us select the appropriate methods for measuring quantitative properties such as species density and abundance. In order to study the distribution pattern of three shrub specie, a part of Kurdistan rangelands was selected as the study area. A random systematic sampling method was used along four transects of 300 meters. The first point on each transect was randomly selected and the rest (14 points) were selected along each of the transects with 20-meter intervals from each other. In each vegetation type, criteria such as density and abundance were measured in plots, and the distance from a random point to the nearest plant and to the nearest neighbors was determined along the transects. In addition, the distribution pattern of Acantholimon bracteatum, Astragalus gossypinus and Acanthophyllum mucronatum was determined using distance indices (Eberhardt, Hopkins, Johnson and Zimmer) and the quadrate indices (Green, Morisitas index, Morisitas standard, and Lioyd). The results of analysis showed that the distance indices had more accuracy than quadrate indices with the same performance.

This research was aimed to study the forage quality of narrow-leaf and broadleaf species, compatible with the warm steppe climate of Khuzestan. The study was conducted during 2011-2012 using a one-way analysis of variance and three replications. In this experiment, 14 common native species in the region from five botanical families were selected. The sampling was done at late flowering stage. Traits such as total dry matter, organic matter, ash, protein, crude fiber, crude energy, soluble carbohydrates and starch were investigated. According to the results, the highest percentage of protein and fiber was measured for the plants from the Leguminous and Poaceae families, respectively. In addition, a significant negative correlation was found between the protein and fiber percentage (r=-0. 565**). Melilotus officinalis, from the leguminous family, had the highest crude energy with no significant difference with some species from the Poaceae family. The highest content of ash and lowest crude energy were recorded for Malva parviflora. Avena ludoviciana and Hordeum murinum from the Poaceae family had the highest and lowest content of soluble carbohydrates, respectively., Generally, planting of the species compatible with the climate of the region could be used both for forage production in rangelands and vegetation restoration in degraded rangelands.

In this study, vegetation of the Bisotun Protected Area with an area of ca. 50, 000 hectares in west of Iran, Kermanshah province, was studied. Samples of vegetation were collected using the Braun-Blanquet method where 66 ré lé ves were taken from different habitats. To express the phytosociological status of the site, data were analyzed by employing Analyse Factorielle des Correspondence (AFC) and Classification Ascendante Hié rarchique (CAH) methods using Anaphyto software. The results of phytosociological data analysis showed that there were 10 associations, three subassociations and two communities in the area as follows: Lonicero nummulariifoliae-Aceretum cinerascentis (pistacietosum khinjuki, vicietosum variabilis, amygdaletosum orientalis), Trigonosciadio tuberosi-Feruletum haussknechtii, Prangetum pabulariae, Ferulago phialocarpae-Cruciatetum persicae, Pimpinello deverroidi-Astragaletum compacti, Astragaletum geminani, Quercetum persicae, Trifolietum scabro-pilularae, Trifolietum scabro-stdellati, Trifolio scabri-Avenetum fatuae, Trifolio scabri-Avenetum ludovicianae, Crataegetum aroniae, Amygdaletum arabicae, Bupleurum kurdicum community and Triticum boeoticum– Festuca ovina community. The establishment of the syntaxa is affected by altitude, exposure, slopes, and edaphic factors.