Journal of Rangeland

---

This study aimed to evaluate the effects of various grazing intensities including non-grazing (as control site), moderate grazing and heavy grazing on aboveground and belowground biomass of Bromus tomentellus in Bijar protected area- Kordestan province. Regression techniques were used to assess the relationships of aboveground and belowground biomass of the species, and one-way ANOVA and Duncan's test were used to compare all the treatments. According to the results, there was a linear relationship between aboveground and underground biomass in the different treatments. Increasing grazing intensity leads to a significant reduction in aboveground, belowground and total biomass of the plant species. The species biomass in moderatly and heavily grazed sites declined 37% and 80% respectively in compare with the control. ‏‏‏‏‏‏The average  total biomass in the control, moderately and heavily grazed sites were estimated 839, 488.75 and 132.88 kg/ha respectively. The relative contribution of aboveground and belowground biomass of the species were decreased and increased respectively as the grazing intensities were increased. The relative contribution of aboveground biomass in the control, moderately and heavily grazed sites were 54.97%, 61.42% and 64.34% respectively. The relative contribution of belowground biomass in the control, moderately and heavily grazed sites were 45.03%, 38.58% and 35.66% respectively. The results of this study highlight the importance of controlling the grazing intensities to prevent soil erosion and losing the valuable plant species.

---

This study was conducted to investigate whether different livestock grazing intensities and exclusion could affect rangeland total carbon (C) storage in the Bijar protected area, Kurdistan. Carbon storage in above- and below-ground of samples collected from 1 m² plots established along the 50 meters transects were measured. The results showed that the plant community composition has been gradually changed from perennial grasses ( Festuca ovina and Bromus tomentellus ) in  exclusion to F. ovine and annual species ( Vaccaria pyramidata) in low grazing pressure and  Artemisia sieberi and Aegilops sp in heavily grazed sites.  The biomass C storage was also decreased significantly under livestock grazing conditions (P< 0.05). The total biomass C storages in moderate and heavy livestock grazing pressure were decreased by 45/6 and 75/5 percent compared to exclusion area. Result showed that  organic carbon in grazing exclusion area was 189.1 ton/ha, in low grazing area  107.4 ton/ha and in heavily grazed sites 46.4 ton/ha. We also found that more than 98 % of total C sequestration occurred in soil organic carbon content. The carbon content in below ground biomass was also greater than above ground biomass.  Our results also suggest that 43-year continuous moderate and heavy livestock grazing result to 1.9 and 3.3 ton/ha decrease in organic carbon content per year.

---

Grazing of livestock is the most effective factor in changing plant traits in rangelands, which in turn affects the ecosystem functionality. The characteristics change of the Artemisia fragrans species in mountainous Artemisia shrublands for their different grazing intensity effect (light, medium and heavy) were investigates in this study. For the aim of the study, three rangelands under different grazing intensities were selected. Vegetation measurements were done within 60 one square meter plots, located alongside of transects of 200 meters long. Then 40 plants of different sizes were selected and measured. To compare the mean of measured characteristics, one-way ANOVA and Duncan's multiple range tests were used. The results showed a significant difference between above ground biomass, average diameter of crown, height, crown surface and plant volume within the selected sites. Under-ground biomass, collar diameter and collar surface in different locations were not significantly different. The highest and lowest mean of air biomass per plants in two places with light and heavy grazing intensity were 17.9 and 12.4 grams respectively. The highest mean ground water biomass (19.9 grams per base) and the lowest value (16.5 grams per basin) belonged to light and heavy grazing sites, respectively. Trend of changes was negative from heavy to light grazing intensity. In general, the effect of grazing intensity on diameter and collar surfaces change was less than the height, average diameter of crown and crown cover. The result of this study could be used in risk management of rangelands.

---

This study aimed to investigate the restoration of land abandoned for different period of time. The land has been managed under free grazing and control systems. Research questions are: whether land abandonment restores bio-chemical properties of the soil and second whether grazing managements interacts with land abandonment to form a direct soil restoration. Several lands with different abandoned histories including >5, 5-15, 15-30, and longer than 30 years of abandonment and  a control (undisturbed rangeland) were selected in two grazing management systems, low intensity (protect areas) and free grazing management. Several soil infiltration variables such as saturated hydraulic conductivity (Kfs), absorption ratio, capillary length and biological parameters such as carbon mineralization, microbial biomass, basal respiration, etc. were analysed in order to compare them among different land abounded histories in both land with low and free grazing management.  The results showed that there were no significant differences in Kfs among the treatments but the land abounded more than 30 years history.  Moreover, basal respiration significantly decreased with increasing the age of abandonment and became relatively similar to control. Carbon mineralization in land abandonment of protected areas became more rapidly similar to control compared to free grazing management. The results indicate that soil succession in land abundant of free ranging areas with high grazing intensity proceed less rapidly toward climax, however, in protected areas with low grazing intensity, soil relatively resorted and became similar to neighbouring rangelands after 30 years.

---

The aim of this study was to evaluate the effect of 35 years of spate irrigation on total biomass (TB) and carbon stock (CS) of dominant species of rangeland plants in Kowsar station located in Gareh Bygone Plain, Fasa, Iran . Samples of Heliantemum lippii, Dendrostellera lessertii and Artemisia sieberi were taken from two sites, irrigated through flood spreading and without flood spreading as the control in autumn 2018. The TB and CS of the plant samples were measured. The obtained data were analyzed using randomized complete block design and the means were compared with Duncan test at P<0.05. The results showed that the effect of spate irrigation, plant species and their interactions on TB and CS was significant at P<0.01. The comparison of the means showed that the reaction of the H. lippii was very high compared to the flood spreading, so that the TB of this species increased from 671.63 to 2013.94 and its CS from 381.90 to 1106.20 Kg/ha, respectively, i.e. 2.00 and 1.90 fold. In the case of D. lessertii, the TB and CS increased 40.00 and 38.64%, respectively. A. sieberi showed a slight negative reaction to flood spreading, so that its TB decreased from 1005.25 in non-flood conditions to 780.9 99 Kg/ha with spate irrigation. The A. sieberi showed a slight negative reaction to flood spreading, so that its TB and CS decreased from 1005.25 and 547.10 in control to 780.99 and 429.30 Kg/ha in flood spreading stripes, respectively. Although, this decreases were not significant at the P<0.05. With respect to the vastness of rangelands in our country, it is possible to store large amounts of carbon dioxide present in the atmosphere (entry the international arena of carbon trade) and reduce the effects of climate change through the flood spreading.

---

Mycorrhiza is a symbiosis between plants and some soil-borne fungi which plays a crucial role in sustainable crop production, soil fertility and rangeland restoration. Due to such roles in plant growth, health improvement and soil aggregation enhancement, arbuscular mycorrhiza (AM) is becoming a tool in agricultural and environmental practices. To examine the potential impact of AM in rangeland restoration, the symbiosis effect of two AM species on some morphological and physiological characteristics of Agropyron elongatum was analyzed. The experiment was performed under greenhouse condition at Malayer University in a completely randomized design with two treatments and twenty replications. The morphological characteristics of plants i.e. stem length, wet and dry weight of aerial parts and also physiological characteristics, including photosynthetic pigments content, total phenol content and content of nitrogen, potassium and phosphorus elements were measured. The results showed that both species of AM, especially R. intraradices, are highly competent to improve the morphological and physiological characteristics of A. elongatum. In other words, F. mosseae, enhanced morphological traits i.e. stem length, wet and dry weight of aerial parts in inoculated plants up to 318, 240 and 220 percent, respectively. Also, the aforementioned fungus, improved the content of phenol, nitrogen, potassium, phosphorus, chlorophyll a, chlorophyll b, total chlorophyll and carotene, up to 134, 131, 162, 181, 172, 178, 174 and 175 percent, respectively. On the other hand, R. intraradices promoted, stem length, wet and dry weight of aerial parts almost 474, 325 and 317 percent respectively. The incremental effects of R. intraradices on the content of phenol, nitrogen, potassium, phosphorus, chlorophyll a, chlorophyll b, total chlorophyll and carotene were about 153, 172, 163, 244, 337, 251, 246 and 250 percent. Therefore, R. intraradices, as a better partner for symbiosis with tall wheatgrass, is recommended for restoration of degraded pastures.

---

Salicornia europaea is succulent annual halophyte. It has a variety of uses, such as: eatablility, oil extraction, cosmetic applications, fodder feeding and finally its seed as the poultry nutrition additive. The content of oil and fatty acid profile of the plant was tested through samples taken in 1*1 m² plots at the seed ripening stage (September). Soxhlet method was used to extract the samples oil, and the obtained oil was analyzed by using gas chromatography method. Results showed that the amount of oil content ranged from 18to 4/5 % for dry weight of seeds, leaves and steams. Gas chromatography analysis identified 5 types of acid: Palmitic, Stearic, Lauric, Myristic and Palmitoleic of saturated fatty acids. There were seven types of essential acids:  oleic, linoleic, linolenic, α-linolenic and isomer trans-Linoleic acid. Arachidic and Palmitoleic acid polyunsaturated fatty acids were found in the extracted oil. Palmitic acid among the saturated fatty acids and linoleic acid among the polyunsaturated fatty acids was predominant. Results show that seeds are suitable for eating as the oil and biomass for its omega3. In order to determine the percentage of lignocellulosic compounds as the raw material of biofuel, sampling was taken in three stages of vegetative growth (May), flowering (August) and seeding (Mehr) in the same plots of one square meters.  Salicornia europaea has the potential as bio-ethanol crops. 28-30% cellulose, 7-8% hemi-cellulose, and 6-8 % lignin biomass of good quality for produce bio- ethanol in all growth stage.

---

Background and objectives: Determining the organic carbon content of rangeland vegetation is essential for monitoring rangeland condition and facilitating reclamation efforts. Satellite data provides a valuable tool for conducting extensive vegetation studies. This research aimed to estimate the organic carbon content of vegetation using field assessments and remote sensing indices in the rangelands of Lashgardar protected area, Malayer. Leveraging Landsat time series images, this study utilized Landsat 8 data from the Operational Land Imager (OLI) sensor.
Methodology: Field sampling was conducted in the rangelands of Lashgardar protected area on May 28, 2016. The dominant growth form in these rangelands is herbaceous-shrub, with Asteraceae family species being the most abundant. Forty points were randomly selected as the centers of sampling plots for plant biomass. To account for GPS accuracy error, a factor of twice the pixel size was applied, resulting in the selection of 40 plots measuring 30×30 m2 for field sampling. Subplots measuring 1×1 m2 were utilized to collect composite aboveground biomass samples from the central point and the four corners of each main plot. Samples were processed in the Rangeland Science Laboratory at Malayer University following coding for laboratory procedures. The organic carbon content of vegetation was determined using the loss on ignition (LOI) method after air-drying. Vegetation indices were extracted from Landsat 8 satellite images captured by OLI sensors, including digital bands 1 to 7 with a spatial resolution of 30 meters. Various vegetation indices such as Greenness, RVI, NDVI, IPVI, DVI, WDVI, ARVI, SAVI, TSAVI, BI, OSAVI, GEMI, EVI, LAI, and GARI were derived from Landsat images.
Results: Comparative analysis of estimated organic carbon data with measured organic carbon content revealed that only the Green Atmospherically Resistant Vegetation Index (GARI) could effectively estimate the organic carbon content of vegetation. The best model was achieved using the GARI index for organic carbon estimation, represented as OC = 5.4 + 1.38 GARI, with an explanatory coefficient (R2) of 0.13 and Root Mean Square Error (RMSE) of 0.7. These findings suggest that remote sensing indices can serve as complementary methods in vegetation studies.
Conclusion: The GARI index demonstrated promising results for estimating organic carbon content in vegetation within the study area and is recommended as a suitable indicator for similar areas. However, the efficacy of each index may vary depending on specific area characteristics and vegetation types. It is advisable to conduct time-series studies with larger sample sizes tailored to the unique conditions of the study area to identify the most appropriate indices.
 

---

Background and objectives: Salinity stress poses a significant challenge worldwide, particularly in arid and semi-arid regions, impacting the physiological processes and secondary metabolites of medicinal plants like Mentha suaveolens Ehrh. Distributed in humid rangelands, this species is notably affected by environmental salinity rise and excessive exploitation. Therefore, enhancing or preserving the quality and quantity of its metabolites under natural or cultivated conditions, including irrigation with unconventional saline waters, using modern methods, becomes imperative. Recently, gamma-aminobutyric acid (GABA), a biomolecule known to induce plant tolerance in various physiological processes, has been explored to optimize conditions and enhance plant performance under stress. This study aimed to model and evaluate the effects of GABA concentrations on the secondary metabolites and physiological characteristics of Mentha suaveolens under varying salinity levels.
Methodology: The influence of GABA concentrations ranging from 0 to 2.4 mM on secondary metabolites and physiological traits of apple mint species under salinity levels of 0 to 150 mM NaCl was assessed in a greenhouse at the Faculty of Agriculture, Maragheh University, during the year 1401. At the end of the trial period, parameters such as biomass performance, relative water content of aerial organs, and secondary metabolites including flavonoids, phenols, DPPH radical scavenging activity, proline, malondialdehyde (MDA), carotenoids, chlorophyll, and essential oil content were evaluated. Statistical analysis and Principal Component Analysis (PCA) were performed on the collected data.
Results: Salinity stress led to reductions in root and shoot dry weight, piperitone oxide content, relative water content, chlorophyll content, and PSII maximum quantum yield (Fv/Fm). Conversely, malondialdehyde (MDA), total flavonoids, and DPPH radical scavenging activity increased under salinity. Application of GABA mitigated the negative effects of salinity stress, with the most significant changes observed under higher salinity (150 mM) and GABA (2.4 mM) levels. PCA analysis accounted for 90.58% of changes under different treatments. DPPH activity, piperitone oxide, and essential oil content showed the highest gradients, indicating their sensitivity to salinity levels and GABA application. Notably, NaCl(0)-GABA(0) and NaCl(0)-GABA(2.4) treatments exhibited the most significant combined effects on plant physiological characteristics. Salinity stress had varying effects on phenol and biomass content, while GABA application showed minimal to moderate effects on these parameters. Overall, severe salinity stress (>120 mM NaCl) adversely impacted plant performance and evaluated characteristics.
Conclusion: Salinity stress significantly altered functional characteristics of Mentha suaveolens, inducing metabolic changes to cope with or enhance tolerance to salinity stress. Modeling indicates that optimal GABA application could maintain or improve medicinal performance under moderate salt stress conditions. However, extreme salinity stress (120 to 150 mM) adversely affects plant performance, suggesting limited efficacy of GABA application in such conditions.