مجله مرتع
سال چهارم شماره 3 (پیاپی 15، پاییز 1389)

More than 27 sheep breeds graze on Iran's rangelands. For estimation of grazing capacity in each region it is necessary to determine size and body weight, animal unit equivalent (AUE) and daily requirement for each breed. In this research, animal unit equivalent (AUE) and daily requirement energy for Kordi Khorasan breed was investigated. For this purpose, two herds of Kordi breed were selected. In each herd, 15 three years old ewes, 15 four years old ewes, 5 three years old rams, 5 four years old rams, 10 three month old lambs and 10 six month old lambs were selected. They were weighed three times including; in winter rangeland, when grazing from pasture and house keeping feeding period. According to the results; animal unit weight for herds (three and four years old ewe) was weight 45/9±0.76 kg. Therefore, animal unit equivalent (AUE) for rams, ewes and lambs were 1.42, 0.89 and 0.53 respectively. Two seasons grazing, two herds, two sexes two age and alternate affects herds*season grazing, herd*sex, season grazing* sex and sex*age were significant differed on average animal weight. According to MAFF equation, 1984; daily metabolizable energy requirement for maintenance condition by considering condition of rangelands and distances from watering points and plant density in lowland and highland rangelands was calculated 8.95 Mj (including that multiplied by 1.4). Dry matter requirement based on forage quality in lowland rangelands was calculated 1.47 kg. This amount based on 2 percentage of body weight (Holchek,s equation), is 0.92 kg that the different between amount, show that considering of forage quality for determinate of animal requirement is important.

Karkas hunting prohibited region has 92100 ha area and is located at the central part of Isfahan province. This area is a part of arid and semi-arid ecosystem of Iran. The aim of this study was to investigate the relationships of dominant species of Karkas region with environmental factors including physiographic and climatic factors. Primarily, the vegetation types were distinguished at the filed with physiognomic-floristic-ecologic methods. The species data were gathered with stratified random sampling method using 10m×10m quadrats with recording percentage of the species cover, litter, bare soil and gravel within each quadrat. The physiographic factors including elevation and slope in addition to climatic parameters such as temperature and amount of precipitation were studied. Using Canonical Correspondence Analysis (CCA) Species relations with the environmental factors was studied. The results of study confirmed the drastic effect of environmental factors on dominant species establishment in Karkas region. It was shown that environmental factors interactions was the main factor on species establishment. The results of PCA showed that the most important climatic characteristic on the distribution and establishment of dominant species are precipitation and temperature, while elevation was the most important characteristic of physiography. Results revealed that increase in elevation leads to occurrence of cushion species. In general it could be concluded that in addition to the studied parameters, some other environmental factors play role in plants distribution of Karkas region.

Autecological study of Vicia villosa was performed in Kohgiluyeh and Boyerahmad province from 2002 to 2004. At first, geographical distribution of V. villosa was determined on province map. Then three habitats namely Firooz Abad, Maleh Shureh and Dali Beigi were selected as study areas. Climatic, topographic and edaphic properties of mentioned areas were studied. Seed properties, root structure and different animals preference for grazing from V. villosa was evaluated. Phenological studies were done for two years. Results showed that this species distributes in elevation ranging from 900-2500 m asl. Its habitat climate is semi arid and temperate to cold Mediterranean with annual mean precipitation and temperature of 870 mm and 14.8 Co, respectively. There is no limitation in view point of slope aspect while suitable slope for its occurrence ranges from 5-15%. Germination percentage was obtained 11%. Vertical and horizontal root depths were recorded 150 and 75 cm, respectively. Exploitation by goat was more than sheep and cow. Vegetative growth initiates in March and seed falling occurs in July.

Seeding is an important methods of range improvement practice in the world. Optimum seed quantity is a challenging issue worthwhile to be studied. These studies are looking for a balance between the amount of seed and quantity of forge they can attain. The principle goal of this study is to searchfor appropriate amount of seed to produce satisfactory amount of forage and seed through cultivation of Agropyron elongatum and Agropyron desertorum. Factorial random design total black was used for the experiment with four frequencies. Two species: A. elongatum, A. desertorum and three level of seed amounts (2.5, 3, 3.5kg/ha) were used for the study for two years. Rows were 5×3m distanced 1 meter from each other. Seeds were cultivated on rows on every 50cm. Results showed that A. elongatum, seed and forage production were significantly in consistent with the increases seeding intensity from 2.5 to 3 and 3.5 kg/ha. This suggests that usage of more seeds, i.e. more than 3.5 kg/ha may increase the forage and seed production. In A. desertorum level of 3 and 3.5kg seeds per hectare doesn’t show a significant effect on seed and forage production. For levels of 2.5 and 3kg seeding per hectare the result showed significant effect on seed and forage production. Hence, 3kg seed per hectare for this species can be an optimum amount for an acceptable function in terms of seed and forage production.

Seed priming could be as a way to improve seed germination behavior under moisture stress conditions. This experiment was carried out to determine priming effects on seed germination of tall wheat grass (Agropyron elongatum) under control and drought stress (Ψ=-0/8 bar) conditions. Two 3-replicated factorial experiments based on CRD design were carried out in 2009. In control experiment, seeds were primed in -4, -8, -12, -16, -20, -23, and -25 bar polyethylene glycol (PEG) and urea as well as distilled water (hydropriming) for 8, 12, 16, 20 and 24 hours at 25°C. Seed priming increased germination percentage, germination speed, seedling length, seedling dry weight, root/shoot ratio while decreased mean germination time. In this study, increasing priming duration and osmotic potential of priming solution had negative effects on measured characteristics. The most promising control seed treatments including urea and PEG with -4 and -8 bar as well as hydropriming for 12 and 24 hours were advanced to drought stress experiment. Also, it was shown that priming with urea had better results compared toother treatments. It is concluded that seed priming treatments with fertilizers may serve as an appropriate treatment for advancing germination under optimum and drought stress conditions.

More than 53 percent of Iran area is covered by rangelands. The economy of noticeable number of families depends on rangeland ecosystems. Therefore, the participation of ranchers in rangeland improvement and reclamation projects is needed. The purpose of this study was to analyze and determine the effective social factors on ranchers participation in range management plans in Ghaemshahr county using χ2 correlation test and Logit regression. In this study factors such as age, job, education, land ownership and knowledge about range management plans were used. Based on simple randomized sampling, 50 ranchers from 29 traditional (common) units were selected from summer and winter rangelands of Ghaemshahr county. The findings of this research showed that among understudy social factors degree of knowledge of ranchers about range management plans was the most graceful one to absorb their participation in mentioned plans. Results revealed that 1 percent increase in degree of knowledge leads to 3.04 percent increase in ranchers participation. In other words, ranchers participation would increase by 0.58 units if their knowledge about range management plans increases. It was cleared that age had a significant negative effect on ranchers participation. Despite their high experience in range management, this may be is due to their physical disability for participation

Land degradation, soil erosion and sediment yield are important problems in developing countries. Towards this, different managerial treatments are being used to alleviate consequent impacts. How even, evaluated of effectiveness of study treatments in controlling after said resultants has been take in to account. The result study was therefore formulated to study the role of free grazing and short term exclosure treatments on sediment yield in a part of Kodir summer rangeland located in south eastern of Nowshahr, central Alborz highlands, as a representative for Iranian Northern summer rangelands. The sediment yield was measured in 0.25 m2- square plots by applying rainfall simulators with 1.6 mm.min-1 intensity. The results were them compared on storm basis with the help of ANOVA and Tukey test. The results of the study verified the significant difference (p< 0.005) in mean values of sediment yield and concentration. The results also revealed that the rate of sediment yield and concentration in free grazing was almost 1.62 times more than these reported for short term exclosure treatment.