گونه خارشتر (Alhagi camelorum) متعلق به خانواده پروانه‌آسا (Papilionaceae) و بقولات است و جزو گونه‌هـای مهـم و غالـب درمنـاطق شور استان گلستان محسوب می‌شود که از جهـت تولید علوفه، حفاظت خاک و ارزش دارویی اهمیت دارد. در طبیعت درصد جوانه‌زنـی بـذر ایـن گیـاه کـم اسـت. هـدف ایـن تحقیق، بررسی اثر تیمار‌های مختلف اسید‌ سولفوریک آب‌جوش، خراش‌دهی و شاهد در شکست خواب و جوانه‌زنی بذر خارشتر است. بـذور ایـن گونه از رویشگاه طبیعی آن در آق‌قلا، اسـتان گلسـتان جمع‌آوری شـد. تاثیر تیمار‌های مختلف مختلف اسید سولفوریک (15 دقیقه، 20 دقیقه و 25 دقیقه)، آب‌جوش 100 درجه (2دقیقه و چهار دقیقه)، خراش‌دهی و شاهد هر کدام با 4 تکرار روی این گونه بررسی شد. نتایج نشان داد که تیمار اسید سولفوریک 15 دقیقه بیشترین تاثیر را (89 درصد) بر جوانه‌زنی خارشتر داشته است. در سایر تیمارها به ترتیب اسید سولفوریک 25 دقیقه با 86 درصد، اسید سولفوریک 20 دقیقه با 75 درصد، آب‌جوش 2 دقیقه با 67 درصد ، آب‌جوش 4 دقیقه با 36 درصد، خراش‌دهی با 20 درصد و شاهد با 6درصد بر جوانه‌زنی گیاه خارشتر تاثیر داشته‌اند. همچنین نتایج این تحقیق نشان داد که عمق 2 سانتی‌متر، مناسب‌ترین عمق جهت کشت این گونه است. در تمامی پارامترهای اندازه‌گیری شده کمترین میزان در تیمار شاهد به‌دست آمد. تفاصيل المقالة

Rangeland degradation is one of the global concerns affecting the pastoralists and those who suffer from its negative environmental consequences. Grazing exclosure has been extensively used among the techniques implemented by the government to protect the fertility of threatened rangelands. The impact of exclosure has been a controversial issue; therefore, it is important to understand its effectiveness in restoring the degraded rangeland ecosystems. The goal of the present study was to evaluate the changes in some physico-chemical properties of soils following the grazing exclusion as compared to the adjacent grazed areas in three winter rangelands in Golestan province, Iran in 2011-2012. In each rangeland, ten soil samples were taken at the depth of 0–20 cm. Then in the laboratory, some soil properties such as soil texture, bulk density, porosity, saturated humidity, pH, EC, OM, total N, lime content, the amount of exchangeable Na+, K+, Mg++ and Ca++ were measured. Data of exclusion and grazed areas were analyzed using the independent T test in SPSS18 software. The results demonstrated that the establishment of exclosure had positive significant effects on the soil physico-chemical properties in Gomishan and Inchehbroun rangelands. So, a significant increase in the mean value of porosity, saturated humidity, OM and total nitrogen (p<0.05) as well as the significant decrease in bulk density and lime content (p<0.05) was observed in these rangelands. According to the results, the application of exclosure is recommended in Gomishan and Inchehbroun rangelands. تفاصيل المقالة

In rangeland management, the ecological needs and response of plants to the environment is studied by investigating the relationship among measurements of plants and environmental factors. The aim of this study was to investigate the relationship between plant density, vegetation cover and biomass of Salsola turcomanica with the soil physico-chemical properties. For this purpose, in three areas (area with high, medium and low coverage of S.turcomanica), three transects of 100 m length were located at a distance of 100 m from each other. In each transect, 10 plots (2m2) were systematically established. Then vegetation cover and the density of individual plants were recorded. Biomass was estimated via cutting and weighing method. Soil samples were systematically taken from center of each plot at the depth of 0-20cm. Some soil physical and chemical properties such as soil texture, bulk density, pH, EC, organic carbon, Absorbable P, exchangeable K and Na were measured. Data were analyzed by one-way analysis of variance and mean comparisons were made using the Tukey test. The relationships among plant measurements and soil properties were investigated using multiple regression analysis. The results demonstrated that soil acidity had the most influence on the vegetation cover of S.turcomanica, likewise soil acidity and soil exchangeable sodium content had the most influence on its biomass. Among the exchangeable cations, Ca had the highest value and Na had the lowest one. This plant grows in saline and alkaline soils with low organic matter. Considering its long growth period and adaptation of this species to harsh environmental conditions, its use in rangeland improvement operations is recommended. تفاصيل المقالة

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. تفاصيل المقالة

In recent years, rangelands have been regarded as potential carbon sinks. One of the most widely suggested options to sequester more C in rangelands is the restoration of the degraded rangelands through grazing the exclusion. In present study, the effects of exclusion on the carbon sequestration of Gomishan rangelands were investigated. Three transects were established in a key area inside and outside the exclosure. In each transect, ten plots were established systematically and in each plot, the number of plant individuals for each plant species was recorded and used to estimate the density of each species per unit area. In order to estimate the plant biomass, a few individuals of each species were sampled by the clipping and weighing method. The carbon content of aerial and root biomass were obtained by the combustion of 10 g of oven-dried samples. Five soil samples at the depths of 0–10 and 10–20 cm were taken along each transect and then, transported to the laboratory. The soil organic carbon percent was determined by the Walkley–Black method. Plant data analysis was performed by one way analysis of variance (ANOVA) and Tukey test. The rate of soil carbon sequestration inside and outside the exclosure was compared using the independent T test at significance level of 1%. Finally, the economic benefit of sequestrated carbon was estimated. The results revealed that the response of plant and soil carbon storage to the exclosure in Gomishan rangelands was positive and there was a significant difference between exclosure and grazing areas for the stored carbon of plant biomass and soil. After a 20 year exclosure, the value of carbon sequestration per hectare in Gomishan rangelands was estimated as 14743 $/h. It can be argued that the education and extension of carbon sequestration in Iran will offer new incentives to restore the degraded rangelands. تفاصيل المقالة

Abstract. Information on forage quality in phenological stage could help range managers to choose suitable grazing method to achieve higher animal performance without detriment to vegetation. Vetiver grass (Vetiveria zizanioides) is a non-native perennial grass that was introduced to the Iran in 2008. This plant is a multi use species that could be considered from different viewpoints. Thus, its forage quality in three phenological stages (vegetative, flowering and maturity) was investigated. Samples of each stage were collected and analyzed for 7 quality traits such as Crude Protein (CP), Acid Detergent Fiber (ADF), Dry Matter Digestibility (DMD), Metabolizable Energy (ME), Digestible Energy (DE), Ash content (Ash) and Total Digestible Nutrient (TDN). Data were statically analyzed using One-way analysis of variance (ANOVA) and mean comparisons were done by Duncan method. The results indicate that there was a significant difference among phenological stages for all the traits (p<0.01). As the plant age increased, the quality values including CP (from 8.89% to 5.25%), DMD (34.79% to 31.63%), ME (3.91 to 3.38 MJ/Kg), Ash (6.7% to 5.5 %,), DE (1.71 to 1.64 Mcals/Kg) and TDN (23.07% to 20.79%) were decreased while ADF was increased (from 63.72% to 65.7%). This led to the reduction of Vetiver grass forage quality. Because of lower values of CP, ME and DMD (except vegetative stage) and higher values of ADF, it was suggested that this species had no prominent place in the ruminants' diet. However, it played important roles in soil conservation and it may be complementary to the native vegetation because it is available at different times of the year considering its phenology and growth season. تفاصيل المقالة