فصلنامه تحقیقات مرتع و بیابان ایران
سال بیست و یکم شماره 2 (پیاپی 55، تابستان 1393)

Determination of forage quality is one of the fundamental factors for suitable management. There are spatial and temporal variations in quality of rangeland species. In this study، forage quality of five important grasses of Bromus tomentellus، Poa angustifolia، Festuca ovina، Agropyron intermedium and Agropyron trichophorum were measured at three phenological stages (vegetative growth، full flowering and seed ripening) in summer rangelands of Golestan province. For this purpose، five replications were randomly selected from each phenological stage. Quality factors of crude protein، ADF، crude fiber، dry matter digestibility and metabolizable energy were measured using in vitro procedures. The results obtained from chemical analysis were analyzed in a factorial experiment at randomized complete block design with SAS software. Results showed that forage quality differed significantly for differentspecies as well as at different phenological stages (p<0. 05). Among studied species، the highest forage quality was related to Bromus tomentellus while the lowest was related to Agropyron trichophorum. The highest and the lowest forage quality were recorded for vegetative growth and seed ripening stages، respectively.

Forage quality is one of the most important factors in determination of the rangeland grazing capacity and also indicates the sufficiency of nutritive requirements of grazing animals. In this research, the samples of range species (including; Acantholimon festucaceum, Andrachne fruticulosa, Artemisia sieberi, Euphorbia decipiens, Noaea mucronata, Scariola orientalis, Stachys inflate, Stipa Arabica and Stipa barbata) in Maime, which were dominant in region, were collected in three phenological stages (vegetative, flowering and seeding) in three replications, and five individual plants were collected in each replication. Then, plant samples were chemically dissolved to measure the nitrogen (N) and acid detergent fiber (ADF). A split plot in a completely randomized design was used to analyze the data. Results indicated that the mean of effective indices on forage quality had considerable changes in phenological stages and it had significant influence on the forage quality. With progress of growth stages, the amount of crude protein (CP), dray mater digestibility (DMD) and metabolism energy (ME) decreased and the amount of acid detergent fiber (ADF) increased. In addition, results showed that crude protein amounts of all studied species in vegetative and flowering stage swere more than critical level (7%) for need of daily animal requirement and in seeding stage was less than animal requirement. Mean value of dray mater digestibility (DMD) in vegetative stage was more than critical level (50%), and in flowering stage and seeding stage were less than its critical level for need of maintenance. The mean value of metabolism energy in all three phenological stages was less than critical level (8 Mj/Kg/DM) for need of maintenance of single animal unit. This suggests that desirable quality of pasture forage at different grazing times is not same and determination of daily animal unit requirement based on forage quality is needed. In general, the studied ranges are desirable in terms of supplying the required daily crude protein for animal units, grazing in rangelands, but in terms of providing metabolism energy are undesirable.

This research was aimed to investigate the ecological capability of Hesare Hosseini Watershed to determine optimum land uses and improve the current environmental management. Ecological and socio-economic characteristics were first studied and mapped. These maps were digitized in Arc/Info software and then were entered to the Arcview software with other data for creating database. Digital Elevation Model (DEM) was produced in Arcview using topographic map. Based on that, the maps of slope, aspect and elevation were produced. Then, the environmental units map was prepared by overlying the maps of elevation, slope, aspect, soil types and vegetation cover in Arcview. The land capability for different land uses was determined by Iranian ecological model using Structured Query Language (SQL) in Arcview. According to the obtained results, this region has no first and second-class capability for irrigation farming. Overall, 54.51% of the watershed area is suitable for range management, 12.76% for dry farming, 31.1% for conservation and 1.63% for irrigated farming.

Being informed about the sufficiency of forage required for the daily need of the animal unit grazing on the rangeland is of paramount importance in animal and rangeland management. Therefore, in the current study, 32 important plant species grazed by animals on semi steppe rangelands of Karsank in Chaharmahal-o-Bakhtiari were sampled during three growth stages (vegetative growth, flowering and seeding). During each stage, three samples were taken and three plant bases were cut for each sample. Having measured the percentage of nitrogen (N) and acid detergent fiber (ADF) of the studied species, the amount of their crude protein (CP), dry matter digestibility (DMD) and metabolisable energy (ME) were determined to know their critical level for meeting animals’ daily requirements. In order to analyze the data, analysis of variance (ANOVA) was used and to observe the within-groups differences Duncan's test was employed. Results showed that the maximum crude protein (23.87%), dry matter digestibility (74.35%) and metabolisable energy (6.73 Mj/Kg/DM) belonged to Bellevalia glauca. The minimum crude protein (9.81%) belonged to Thymus daenensis and the minimum dry matter digestibility (51.38%) and metabolisable energy (6.73 Mj/Kg/DM) were recorded for Asperula molluginoides. The average crude protein for vegetative, flowering and seeding stages were 20.92, 13.03 and 8.89%, respectively, that at all three growth stages, it was higher than its critical level (7.0%) to meet the daily maintenance requirement of an animal unit. Average dry matter digestibility values for the three phenological stages were 62.48, 55.02 and 46.18%, respectively, that its amount was higher than the critical level (50%) for vegetative and flowering stages and was lower than the critical amount at the seeding stage for meeting the daily maintenance requirements of an animal unit. Metabolisable energy in vegetative, flowering and seeding stages were 8.62, 7.35 and 5.85%, respectively, which were higher than the critical level (8Mj) during the vegetative growth and flowering stages and lower than the same critical level at the seeding stage for meeting the daily maintenance requirements of an animal unit. This is an indicator of the fact that desirability of range forage at different grazing times is not the same and it is necessary to determine the daily requirement of animal unit on the basis of forage quality. In general, the studied rangelands are considered to be desirable in terms of supplying required daily crude protein and metabolisable energy for an animal unit. Results presented in this paper are important for livestock and range management in the studied area.

Spatial variability and heterogeneous geographical distribution of soil physical and chemical properties in rangeland ecosystems are affected by physical and biological factors including different managements, soil microclimate and topography, leading to the vegetation changes. Therefore, this research was aimed to study the spatial variability of production, density and canopy cover of Artemisia aucheri in the line with some soil properties variability in Vavsar rangelands of Kiasar. The sampling method was random-systematic. A total of five transects of 100m length were selected in the study area with a distance of 100m on which 10 plots of 2m2 were established with a distance of 10m. Soil samples were taken from a depth of 0-15 in each plot. In addition, production, density and canopy cover of Artemisia aucheri were measured in each plot. According to the results of geostatistical analysis in GS+ software, the percentage of clay and the density of Artemisia aucheri, showed the highest variation coefficients with the values of 82% and 53%, respectively. The variogram's amplitude varied from 196.2m for production to 910m for the percentage of moisture, lime, EC, and canopy cover. According to the results of cross validation, the models of lime percentage, density and production of Artemisia aucheri showed spatial correlation, and, consequently, had higher accuracy to be used in Kiriging interpolation.

This research was aimed to evaluate the environmental factors affecting the distribution of vegetation in Sarchah Amari ranglands, Birjand. After field visits, five vegetation types were selected based on physiognomy method and soil and vegetation sampling was done in key area of each vegetation type along the transect and within square plots with systematic random method. Depending on the type and distribution of plant species, the plot size was calculated to be 1.3 and 16 m2 and 45 plots were established in each vegetation type along transects. The percentage of vegetation cover was measured in all plots but soil sampling was done in the first and last plots of each transect at soil depths of 0-30 and 30-80 cm. Soil characteristics including soil texture, percentage of lime, saturated moisture, gypsum, pH, electrical conductivity, sodium, calcium, potassium, magnesium, chlorine and topographic features including slope, aspect and altitude above sea level were measured. Soil and vegetation data were analyzed by PCA and ANOVA. The results of PCA showed that among the environmental factors, EC, the percentage of sand, slope, gypsum, organic matter and the soluble sodium were the most important environmental factors affecting the distribution of vegetation. Overall, these factors could explain 89.73% of the vegetation distribution. The results of ordination (PCA) showed that 70.74% and 18.63% of vegetation distribution were explained by the first and second axes, respectively. The first axis variables included the percentage of sand, electrical conductivity (EC), percentage of gypsum, sodium and the organic matter of first depth. According to the algebraic sign of variables, the distribution of vegetation was positively correlated with the percentage of sand while it showed a negative correlation with electrical conductivity (EC), gypsum, sodium and organic matter in first depth. The second axis variables of the ordination diagram included the percentage of slope and organic matter of second depth and according to the algebraic sign of variables, the distribution of vegetation had a negative correlation with the percentage of slope and soil organic matter of second depth.

Knowledge of digestibility of different plant species and relationship between digestibility and chemical composition of forage is one of the basic requirements in order to qualitative and quantitative management of livestock nutrition in rangelands. This research was aimed to evaluate the changes in chemical composition of forage during the growth stage and relationship between forage digestibility and forage chemical composition in most important tropical range grasses including Cenchrus ciliaris, Panicum antidotale, Pennisetum divisum and Cymbopogon olivieri. Sampling was replicated every two weeks. Forage quality parameters including CP, WSC, CF, ADF, Ash, and DMD were measure using NIR technique. Results showed that forage quality differed significantly in the studied species and growth stages. According to the obtained results the highest and lowest forage quality was obtained for Cenchrus ciliaris and Pennisetum divisum. The results of correlation between forage quality parameters and growth stages of the studied species showed a significant negative correlation between dry matter digestibility and growth stage progress in the first three species but it was not significant for Cymbopogon olivieri. CP and ash showed a significant negative correlation with the progress of time in all three studied species. However, CF and ADF were positively correlated with the progress of time.

In the current study, the salinity tolerance of Atriplex leucoclada, a native species to Iran with appropriate nutritional value for livestock, was investigated under greenhouse condition and natural habitats of Fars province. For this purpose, NaCl treatments at different concentrations of 0, 100, 200, 300, 400, and 500 mM were applied on pots in a growth chamber at 20°C and a photoperiod of 8/16 h (light: dark), and growth characteristics were measured. Soil and plant sampling was conducted in natural ecotypes of Atriplex leucoclada in Darab region. Plant samples were collected randomly from the roots and shoots in vegetative growth stage, and soil samples were taken from two soil depths of 0- 10 and 10-45 cm. The results of NaCl effects on growth characteristics of Atriplex leucoclada in vegetative growth stage showed that significant differences were found among the studiedconcentrations of NaCl as compared to the control group. Our results clearly showed that all studied growth characteristics including shoot fresh and dry weight, root fresh and dry weight,LWR, LAR, SLA, plant height and LA increased at concentrations of 0, 100, 200, and 300 mM in comparison with control. However, increasing salinity stress more than 300 mM caused to the reduction of growth characteristics significantly. As a result, salinity stress up to 300 mm NaCl not only limited the growth of Atriplex leucoclada but also increased the growth characteristics, indicating that this species is an obligatory halophyte in vegetative growth stage.

Range improvement in saline rangelands is considered as one of the most important priorities. The first step in this process is the identification of suitable plant species, with emphasis on native species having suitable establishment, growth capacity and forage production under field conditions. Therefore, in this study, the compatibility of four plant species was studied in Meyghan playa of Arak. The research was carried out in a complete randomized block design with four replications, for three years (2008-2010). The study area has a mean annual rainfall of 327 mm. The soil texture is silty-clay-loam, with an electric conductivity ranged between 2.1- 7.1 dS/m and a pH of around eight. Groundwater table level was over three meters. The seedlings were cultivated with a distance of 2.5 meter from each other in mid November. The establishment of seedlings, canopy cover percentage, vitality, forage production, and palatability were measured. Results showed that all species were successfully established. Significant difference was found for the canopy cover, vitality, palatability and forage production of species. The highest and the lowest canopy cover percentage were recorded for Atriplex canescens and Atriplex leucoclada, respectively. Halimion verrucifera and A.canescens, respectively, showed the maximum forage production and maximum vitality.. According to the results of palatability, a significant difference was found for forage, i ntake so that the highest and the lowest forage intake were recorded for H. verrucifera and Camphorosma monspeliacum, respectively. Overall, H. verrucifera, a native plant species in the study area, showed the superior palatability and more forage production as compared to other species. Therefore, the cultivation of this species in this area is recommended.

In order to understanding of the grazing cycle and grazing behavior at different slopes of Kordan rangelands, the grazing behavior of Fashandy breed sheep was investigated for four years. Parameters examined in this study included daily distance traveled by livestock, livestock path in the rangeland considering the slope, livestock speed (mean, maximum and minimum) and the time spent for livestock rest and movement per day. To determine the parameters, Garmin GPS was used on the back of a 4-year-old ewe using a special belt. After livestock exit from the fold, GPS was active and at the end of the day all recorded data were extracted by Mod-track in Ilwis software. The livestock path was determined by shepherd. Results showed that during the first month of grazing season and when vegetation was more, the distance traveled by livestock was less than that of other months. In addition, the maximum and minimum distances traveled by livestock were obtained at slopes of 30-60% and less than 15%, respectively. According to the results of grazing behavior during the months of grazing season, maximum and minimum livestock speed were recorded in July and in May and June, respectively. Therefore, the grazing program in similar areas could be managed at different slopes using the obtained results in this study.

In order to management of rangeland ecosystems, understanding its components and the effect of their interactions on each other including soil and vegetation is essential. For this purpose, present study was conducted to investigate the effects of Haloxylon spp and Tamarix spp species on soil properties in Niatak region of Sistan. After identifying the cultivation sites of these species, soil sampling was conducted for each species in representative areas at the end of the growing season based on randomized systematic method. Soil sampling was carried out at beginning and the end of each transects from 0-10 and 10-20 cm soil depths. Soil sampling was also conducted in the control site and then soil properties including pH, EC,N, P, OM, HC 3, Na, Mg and K were measured. All data were analyzed by independent t-test. Results showed that soil properties significantly decreased at both depths excluding acidity. Other soil properties under Haloxylon spp and Tamarix spp species significantly increased compared to control sites. Potassium content at both depths under Haloxylon spp significantly decreased compared to control site. According to the obtained results, a significant increase in soil fertility indices was recorded for Haloxylon spp plantation, while soil destructive properties increased significantly in Tamarix spp plantation. Therefore, although soil properties were improved by the cultivation of both studied species, Haloxylon spp is recommended for this region considering more positive effects of this species on soil properties as well as some negative effects of Tamarix spp.

Nowadays, heavy metal contaminated soils is one of the most important concerns of the world and cleaning these soils with minimum environmental damage is necessary especially in urban and agricultural regions through advanced biological methods. Phytoremdiation is one of the modern technologies that could be used in large scale with minimum damage to environment. High concentration of cadmium, as an environmental pollutant, could be harmful for human and animals. Regarding to this reason, a study was carried out on 11 plant species in Irankouh region at three sites including three levels of high, medium and low cadmium contamination. The bioaccumulation of cadmium in shoots and roots of plants, and translocation factor were measured. According to the results, Astragalus glaucanthus, Ebenus estellata and Acantholimon sp. showed the highest values of cadmium concentration (1.40, 1.53 and 1.97 mg/kg dry matter), and also the highest translocation factor (2.09, 1.37 and 12.6), respectively. Because of the high values of biomass and bioaccumulation, these three plants are recommended for phytoremediation of cadmium-contaminated soils under the same conditions.

Temporal and spatial factors have different effects on grazing behavior so that different temporal parameters including the speed and distance walked by livestock are among the factors that can serve as an important tool in grazing management. This research was conducted in Anjedan, a semi-steppe region in Arak province, in different months of grazing season (five months) during 2007-2010. To determine the parameters, a GPS, attached to the livestock, was used in a certain day of each month of grazing season. The speed of livestock movement, the length of distance walked by livestock, and the time spent for grazing, rest and movement were recorded. The data were analyzed in a completely randomized design and the means were compared using Duncan’s Multiple Range Test. According to the obtained results, the speed of livestock movement, the length of distance walked by livestock and the time spent for rest and movement showed significant difference during the studied years as well as in the months of grazing season. The time spent for grazing did not show significant difference in different years; however a significant difference at 5% level of probability was recorded in different months. More grazing, movement and rest and less distance walked by livestock were recorded when the environmental and climatic conditions were appropriate for the growth of range species especially annuals.

Sagebrush rangelands in Iran with 39.71 million hectares include more than 46% of the total rangelands, and are recognized as an important and dominant rangeland species in Iran Turan flora. These lands are often associated with grazing of livestock and wildlife. To determine how to better manage this important resource, a rangeland-livestock model was tested in the Hablerud river basin located in Tehran and Semnan Provinces of Iran using the Soil and Water Assessment Tool (SWAT). With regard to climate variation, this watershed consists of three ecological zones: semi-steppe, steppe, and desert. Calibration and validation of model were tested with the Sequential Uncertainty Fitting Program (SUFI-2). Results showed that observed data of forage production were inside or quite close to the predicted bands in three zones. Also, based on the model results, simulated forage production varied from 0.35 to 0.5, 0.15 to 0.26, and 0.033 and 0.1 ton ha-1 in semi-steppe, steppe, and desert, respectively. Sensitive analysis showed that whatever we move from semi steppe to desert, the number of sensitive parameters increases and water and soil parameters becomes more sensitive in forage production.

To study the allelopathic effect of Cymbopogon olivieri on germination and growth properties of two millet cultivars, an experiment was carried out in a completely randomized design (CRD) with three replications. The treatments included different levels of 0 (control), 12. 5, 25 and 50 gL-1 extract. In another experiment, carried out in the greenhouse, the treatments included four levels of soil. According to the obtained results, all studied traits of kcm7 cultivar were more affected by allelopathic effect of Cymbopogon olivieri, compared to kcm2 cultivar, and all traits (except germination velocity) showed a negative response, immediately after applying 12.5 gL- 1 extract. In kcm2 cultivar, the negative response of germination percentage and germination velocity was recorded at 50gL-1 extract. In addition, the negative effect of plumule length and radicle length was recorded at 12.5 gL-1 and 25 gL-1, respectively. The results of greenhouse showed that the radicle length of both cultivars was affected by allelopathic effects of Cymbopogon olivieri. Our results clearly show that kcm2 cultivar is more resistant against the allelopathic effects of Cymbopogon olivieri compared to kcm7 cultivar.

This study was performed in the Qorveh rangeland of Kurdistan for five years (2006 2010) to determine the preference value of range species and grazing behavior. The preference value of range species was measured with two methods (time study and preference index). According to the obtained results, significant differences were found for the years and plant species in terms of grazing time percentage, at 1% level of probability. Mean comparison of grazing time percentage showed that Bromus tomentellus with an average of 12.31% together with annuals was classified in one class, and Galium verum, Thymus daenensis, Pterocephalus canus, Poa bulbosa and other species were classified in another class. The lowest grazing time percentage (0.33%) was recorded for Prangos ferulacea. Our results clearly showed that Stipa bromoiedes and Festuca ovina were much less grazed by livestock.

The relationship between the distribution of Festuca ovina and ecological factors such as topography, climatic and edaphic characteristics was investigated in 45 sites of Southeastern rangelands of Sabalan in Ardabil province.Within the determined sites, three large plots of 10 × 10 m, 40 meters away from each other, were established along a 120–meter transect from lower slopes to highlands. The measurement of canopy cover parameters was performed in three plots with dimensions of 60 × 25 cm within the middle plot and the lower and upper plots were used as control. Different parameters including altitude, slope and aspect were calculated and averaged for three plots. In the middle plot, a soil profile was dug to a depth of 30 cm and soil samples were collected from two depths of 0-15 and 15-30 cm to measure soil parameters. Cluster analysis and principal components analysis (PCA) were used to classify the sites and the importance of parameters was determined by discriminate analysis (DA). Using multivariate analysis, the study sites were classified into four groups.The sites having high canopy cover percentage of F.ovina were classified in group 3, in which altitude, slope, and precipitation were higher than those of other groups, while temperature, salinity and pH were lower. This shows that this species is more compatible to higher altitudes and lower temperatures and dose not tolerate soil salinity. It is more compatible to a pH of 7.1 to 7.3. Organic matter, phosphorus and potassium will provide better conditions for growth. Results of principal component analysis showed that the two main components could explained 95% of the data variations, and the classification of sites using these two components confirmed the results of cluster analysis. According to the obtained results, the distribution of F.ovina was affected by several ecological factors including temperature, climate, soil, and aspect.