Journal of Rangeland Science
Volume:5 Issue: 1, Winter 2015

Annually, 200 ha of Agh Ghala rangelands in Golestan, Iran are under Alkaligrass Puccinella distans's cultivation but the failure in the identification of appropriate sites for seed sowing may result in high costs of cultivation. The current study aims to reduce such costs through the examination of apt sites to grow P. distans in northern rangelands of Agh Ghala Golestan, Iran. Because of the same topography and climate of the study area and Gomishan rangeland in closure where the plant grows and seeds are collected, a map of photomorphic units was first prepared using satellite images of Landsat 5 (28.05.2011) and Google Earth. Then, some soil physical and chemical properties including texture, EC, pH and organic matter were measured in three photomorphic units. In each photmorphic unit, three transects (length of 150 m and intervals of 50 m) were set up. Along each transect, three soil samples at the depth of 0–10 cm (9 samples in each photomorphic unit) were taken and transferred to the laboratory. In order to verify the suitability of the predicted photomorphic unit, the seeds had been sown in the above mentioned key area of each photomorphic unit and P. distans cover percent was estimated. Data were analyzed and means comparison was done between the units using Tukey method. Incorporating all the obtained data led to predict the location of appropriate photomorphic unit for the seed sowing of this plant. Despite the initial prediction of suitable seeding location (photomorphic unit 3), results indicated that the photomorphic unit 1 was the most successful area which had a lower depth of underground water table and higher EC and vegetation cover percent as compared to two other units. Based on the findings of current study, it is recommended that seeding operation should be concentrated on photomorphic unit 1.

Rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. Investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. Accordingly, data collection and measurements for evaluating vegetation dynamics in rangeland ecosystems of Zharf region in Khorasan province, Iran were conducted from 2009 to 2013. Vegetation variables were measured by the means of 3 transects with the length of 500m and sampling plots. Meanwhile, at the location of each plot, soil moisture content was measured at two depths of 0-15 and 15-30 cm using a Time-Domain Reflectometer (TDR) instrument. At the same locations, soil samples from topsoil layer (up to 15 cm depth) were collected to measure organic carbon. Results showed that at a four-year period, depending on inter-annual changes in rainfall and other climatic parameters and under local management practices, more or less changes occurred in some major vegetation factors such as species and total canopy cover. Changes were more prominent in canopy cover of annual plants, perennial forbs and to some extent in perennial grasses. Changes in soil organic carbon showed a very slow trend. Based on soil texture and variations of seasonal and annual rainfall, soil moisture caused variations in vegetation factors. In the study site, considering the relative stability of soil cover by stones, gravels and plant litter, total soil cover changes were a function of changes in total canopy cover of plants. The results of this study could be considered for proper adjustment of rangeland management in Zharf region.

Annually, 200 ha of Agh Ghala rangelands in Golestan, Iran are under Alkaligrass Puccinella distans''s cultivation but the failure in the identification of appropriate sites for seed sowing may result in high costs of cultivation. The current study aims to reduce such costs through the examination of apt sites to grow P. distans in northern rangelands of Agh Ghala Golestan, Iran. Because of the same topography and climate of the study area and Gomishan rangeland in closure where the plant grows and seeds are collected, a map of photomorphic units was first prepared using satellite images of Landsat 5 (28.05.2011) and Google Earth. Then, some soil physical and chemical properties including texture, EC, pH and organic matter were measured in three photomorphic units. In each photmorphic unit, three transects (length of 150 m and intervals of 50 m) were set up. Along each transect, three soil samples at the depth of 0–10 cm (9 samples in each photomorphic unit) were taken and transferred to the laboratory. In order to verify the suitability of the predicted photomorphic unit, the seeds had been sown in the above mentioned key area of each photomorphic unit and P. distans cover percent was estimated. Data were analyzed and means comparison was done between the units using Tukey method. Incorporating all the obtained data led to predict the location of appropriate photomorphic unit for the seed sowing of this plant. Despite the initial prediction of suitable seeding location (photomorphic unit 3), results indicated that the photomorphic unit 1 was the most successful area which had a lower depth of underground water table and higher EC and vegetation cover percent as compared to two other units. Based on the findings of current study, it is recommended that seeding operation should be concentrated on photomorphic unit 1.

Recent attitude of vegetation assessors is using of new ecologic approaches to evaluate and analyse the complex rangeland ecosystems. Plant diversity is the most important indices to assess the ecological changes of rangelands. In order to survey of plant indices of rangelands, two exclosure areas (long-term and mid-term) and a grazing area in rangelands of Javaherdeh (Ramsar, Iran) were selected. Quadrate size and number were respectively obtained by minimal area and statistical formula methods. The diversity, richness, and evenness indices in each quadrate were calculated. For comparing of these indices, one way ANOVA and Duncan test method were used. Results showed that the higher values of diversity and richness indices were obtained in the long term exclosure and the lower values of evenness index were obtained in the grazed area. The SHE analysis clarifies that the highest species richness and diversity was obtained in lower plots number in the long-term exclosure areas and reversely it needs more plots for assessment of grazed area. Along with time elapsing, the long-term exclosure and grazing area had higher and lower evenness, respectively. The mid-term exclosure, however, needs also long time to reach the maximum species richness and diversity. Hence, in order to achieve the ecologic management of the rangeland ecosystems, knowing of bio-indicators and their components analysis (SHE) can draw future trend of the ecosystem and bring out data to program it.

Dust storms are known as hazardous problems in western part of Iran. Iraq is one of the main sources for dust storm arriving to the western part of Iran. The Radial Basis Function Network model (RBFN) has been used to assess wind erosion hazards in the source area of dust storms over several western Iranian cities. Normalized Difference Salinity Index (NDSI) was used to determine the changes in the source area salinity over the studied years. The RBFN model has been used to assess the wind erosion severity of all land uses in the source area. Generally, NDSI values of all land uses in 2003 were higher than those in 2013. The maximum and minimum mean NDSI values were seen in severely dissected plains and mountainous lands, respectively. The observed differences in the wind erosion hazard maps of 2003, 2005, 2007, 2009, 2011 and 2013 were due to the changes in vegetation percent. Soil salinization caused the source area vegetation degradation and wind erosion exacerbation. So, the occurrences of dust storms in Western parts of Iran have become more frequent. The in situ observations showedthat there were two, five, five, twelve and nine records of pervasive dust storms in western parts of Iran in 2003, 2005, 2007, 2009 and 2011, respectively.

Information on quality characteristics of forage species help the range managers to select a suitable grazing program that minimizes the damages to vegetation. Water Soluble Carbohydrates (WSC) -the main photosynthetic products- are stored in various plant parts and are more likely to be consumed when plants require them. In order to investigate the changes of WSC in distinguishable organs in three phenological stages, samples were taken from Bromus tomentellus and Festuca ovina in three phenological stages (vegetation, flowering and maturity). Samples of roots and aerial parts were taken for both species using a completely randomized factorial arrangement-based design with the phenological stages regarded as the first factor and herbage parts as the second factor with 5 replications. Higher WSC values were observed in the leaves of B. tomentellus (4.6%) and F. ovina (4.5%) in maturity and flowering stages, respectively. Maximum WSC values of roots were obtained in B. tomentellus (3.2%) and F. ovina (3.5%) at vegetation and maturity stages, respectively. It was suggested that range utilization in a phenological stage might be managed in which forage species can withstand the defoliation without severe reserve depletion. Results indicate that except flowering stage in B. tomentellus, WSC was increased with the increase of panicle weight in the maturity stage and there was an inverse relationship between plant components and WSC content percent in the other phenological stages.

The aim of this study was to assess the regional effects of fire on the surface cover and forage production of mountainous rangelands of Delfan County, Lorestan province, Iran. The fire took placed in June 2007 with significant effects on the vegetation characteristics in the study area. Four fire affected sites were selected for sampling and a close area without fire was considered as control. Sampling was carried out using a random systematic method and the size of plots was determined using the minimal area framework. The number of plots was determined using a statistical method. Totally, the data of eight sites including four fire affected sites and four control sites were measured during four consecutive years in early July of each year after fire. In each site, four transects of 50m length were selected in the direction of slope as well as perpendicular to the slope and five plots were established along each transect. The characteristics of canopy cover percent, litter percent, bare soil, density and forage production were recorded and compared to the fire affected and control sites. One-way analysis of variance and Duncan multiple range test were used to compare the mentioned characteristics over years in each region separately. According to the results, forage production, canopy cover percent, the density of grasses and forbs and litter cover percent increased significantly while the density and canopy cover percent of shrub species on the fire affected area has decreased significantly. On the other hand, fire had decreased bare soil cover percent significantly but it had no significant effects on the canopy cover of annual grasses.

Salinity is one of the most brutal environmental stresses that hamper crop productivity worldwide Approximately 10% of the total land surface is salt affected and about 10 million hectare of agricultural land is lost annually due to salinization and water logging. This study was conducted to determine the ion exchanges in Halocnemum strobilaceum and Halostachys caspica in saline conditions. The seeds of plants were sown in the pots in a greenhouse in Research Institute of Forests and Rangelands, Iran. After 5 months, plants were exposed to different salinity levels including 0, 100, 200, 300, 400 and 500 mM of NaCl and Na2SO4 for 45 days and the amounts of Na+, k+, Mg2+ and Ca2+ were measured in stems and roots. Results showed that ion contents were affected by NaCl and Na2SO4 in both species. The minimum and maximum values of Na+ (568 and 1613mg kg-1 DM) were found in the root of H. caspica and shoot of H. strobilaceum, respectively. Ion content was increased with the increase of salinity up to 100 and 200-300 mM in H. strobilaceum and H. caspica, respectively.Also, the ion exchanges were higher in H. strobilaceum than H. caspica. In general, this investigation showed the ion uptake of both species at low salinity but they changed the tolerance mechanism at high salinity. So, Na+ and K+ were translocated from shoot to root while Ca2+ translocation from root to shoot was increased by salinity.