مجله مرتع
سال نهم شماره 1 (پیاپی 33، بهار 1394)

There are various methods to measure forage quality but these methods require labor and are expensive and time consuming. Near infrared reflectance spectroscopy (NIRS) has been used to predict forage quality since 1970. This method is a reliable and fast method for measuring forage quality but it requires appropriate calibration instruments with adequate samples. The aim of this study was to develop optimal NIRS calibrations for predicting forage quality of forb species. In order to predict N، CP، ADF، DMD and ME content of forb species through NIRS، a total of 641 samples from three phenological stages (vegetative، flowering and seeding) were scanned by DA7200 Perten instrument. Spectral data was exported into the Unscrambler software to conduct multivariate analysis. The spectral data was smoothed and normalized by S. Golay and SNV methods respectively. Calibration models were developed through PLS1 method and then evaluated based on R2، RMSECV and RPD values. According to the results، the nitrogen and CP contents of forb species can be measured more appropriately than other forage quality indicators. This study indicated that the forage quality of forbs species can be determined by NIRS method، however the accuracy values (PRD values of validation) obtained from this technique in some cases were less than the optimum thresholds.

This study was conducted with the aim of determination of chemical composition, degradability fractions and nutritional value of Astragalus crenatus Schult. Two sites with different elevation ranges (1500-1700 and 1900-2100 meters from sea level) were selected to collect the data in highlands ranges of Hir to Neor, Ardebil County. The data sampling was carried out in three phenological stages (vegetative growth, flowering and seeding stages). Plant samples were analyzed and their NDF and ADF were measured using Van Soest method. AOAC common lab methods were used to measure plant samples chemical composition. Ruminal degradability of samples was determined by in situ technique (e.g. two ruminal cannulated Moghani rams). The results showed that digestibility and degradability of dry matter, organic matter, NDF and ADF of samples from the site located in 1900-2100 meters from sea level ranges were significantly higher than the site in lower site (p<0.01). Moreover, the analysis of the collected samples showed that the NDF and ADF values in form of percentage of dry matter for species in higher elevations range sites were higher. The dry matter contents of plant samples differed significantly in various phenological stages (p<0.01). Results showed that the plant samples in vegetative stage had the highest ash and ruminal and post-ruminal digestibility in both sites. The plants in vegetative stage had lowest NDF, ADF and organic matter content compared to the other phenological stages. In conclusion, the degradability of dry matter of the species in vegetative growth stages was more than other stages, indicating that the nutritional value of plant species is reduced in flowering and seeding stages. It can be concluded that late spring is the best time for grazing this species and it can be considered in grazing management plans of the study area.

The purpose of this study was to measure Lead and Zinc concentration in the soil, shoots and roots of plants in the surrounding rangelands of National Iranian Lead & Zinc Factory-Zanjan. This study can assist managers to identify the plants with phytoremediation capacity. The shoots and roots of 11 rangeland plants in 11 sites were collected in May 2014. Soil samples were also collected and Zn and Pb from the soil and plant samples were determined using ICP-OES. One way ANOVA was used to compare the metal concentrations at different sites and plant types. The bio-concentration factor (BCF), translocation factor (TF) and biological accumulation coefficient (BAC) of the collected samples were calculated to determine the heavy metals phytoremediation capacity of the plant species. In general, the results showed that the Zn and Pb in soil can be absorbed by Stipa hohenackeriana, Scariola orientalis, Descurainia sophia, Stachys lavandulifolia and Echium amoenum. According to the results, Astragalus effesus was effective to accumulate Zn in its tissues. The high amount of Pb and Zn in soil can pose main environmental threats and adverse effects on human and ecosystems health, hence, this type of studies can identify species with phytoremediation capacity.

This study aimed to evaluate the ameliorating effects of silicon nutrition on Festuca arundinacea under salinity stress. A completely randomized design was used to study the effects of different levels of salinity including 0 and 100 mM NaCl and silicon nutrition including 0, 0.75 and 1.5 mM sodium silicate on the species performances. The plants cultivated in greenhouse in sand culture with Hoagland nutrient solution. The results showed that the plants growth was reduced in salinity treatment. The plants performances were improved using silicon nutrition (especially 0.75 mM). Salt treatment increased the Na+ and decreased K+, Ca2+ and Fe content in aerial parts of the species, however, silicon treatment led to reducing the Na+ and increasing Fe content. The activities of soluble and cell wall peroxidase and polyphenol oxidase enzymes were declined in the species under salinity. The application of 0.75 mM Si approved to be an effective way to recover the activities of these enzymes. Salinity imposed significant reduction in contents of chlorophylls, total carotenoids and xanthophylls and soluble proteins, however, the hydrogen peroxide rate as well as lipid peroxidation contents were increased. On the contrary, chlorophylls, total carotenoids and xanthophylls and soluble proteins contents were increased and hydrogen peroxide and lipid peroxidation were decreased in salt-treated plants following Si treatment (0.75 mM Si). Salinity caused significant increase in electrolyte leakage from plant membranes; however, silicon nutrition (0.75 mM Si treatment) reduced these parameters. The result indicated that silicon nutrition (especially 0.75 mM treatment), mitigates harmful effects of salinity through declined Na+ content and increased antioxidant enzymes activities that reduced oxidative stress as evidenced by decreased lipid peroxidation and electrolyte leakage. Consequently, Si application led to better growth of salt –affected plants.

In order to study the impact of wild boar (Sus scrofa) disturbances on plant diversity and richness of soil seed bank, five plant communities were selected i.e. Festuca ovina, Bromus tomentellus, Alyssum minus-Astragalus sp., Poa pratensis-Trifolium repens and Chenopodium folisom. In each plant community, one disturbed site was selected and 4 one square meters plots were established inside each disturbed patch and control patch (no sign of wild boar disturbance). Soil samples were collected using auger and transferred to the greenhouse, and seedlings were identified through seedling emergence method. Then Simpson and Shannon diversity indices and, Margalef and Menhinick richness indices of soil seed bank were calculated using PAST software. GLM and post-hoc tests were used to compare mean values of different diversity and richness indices using SPSS software. The results showed that there were significant differences between soil seed bank density, diversity and richness indices between disturbed and control patches in the all vegetation communities. Maximum value of Menhinick (1.28), Margalef (1.79), Simpson (0.64) richness indices, Shannon (1.72) diversity index and density of soil seed bank (46.25) was observed out of patch. In addition, minimum value of Menhinick (1.09), Margalef (1.36), Simpson (0.52) richness indices, Shannon (1.11) diversity index and density of soil seed bank (39.21) was observed in of patch. Generally, wild boar (sus scrofa) decreased diversity, richness and density of soil seed bank.

Water harvesting methods such as small arc basins have been identified as effective methods to increase forage production in rangelands. In this study, the effects of these small arc basins on forage production, soil moisture and soil texture conditions were investigated. A systematic-random sampling was used to collect data from three transects established perpendicularly to the dominant slope of the study area. Productions of range plants were measured in 40 samples (at the end of spring) and then dried in shadow and weighed. One hundred sixty samples were collected from 0-20 and 20-40 cm of soil surface at the beginning and the end of rainfall season. Data were analyzed by General Linear Model (GLM) procedure. The results indicated that the used water harvesting method resulted to a significant two times increase of plant productions in compare with the control site (p<0.01). Also the findings of this study indicated that the main interaction effect of depth, season and sampling area on soil moisture fluctuations were significant (p<0.01). The results also showed that the construction of this system had a positive effect on the texture and silt content of soil in the study area. Therefore, this method can be suggested as an appropriate method for storing rainfall and increasing forage production in rangeland ecosystems.

Understanding the behavior of the species in relation with various ecological factors can assist range managers to select appropriate management practices. This study aimed to evaluate the effects of site characteristics and management factors on vegetation distribution in experimental range site near to Zayanderod dam in Chadegan- Isfahan. Some parts of the study area were experienced restricted grazing over the past 20 years. The study area was stratified based on the various management types (grazed and non-grazed) and aspects, and samples were collected randomly in each layer. Four perpendiculars transects with 500 meters length were established along the differences in site and grazing situations. Fifteen plots with size of 1 by 1.5 meters were established along each transect. The cover percentage and density of all perennial plant species were recorded in each plot. The management condition (grazed and un-grazed), slope percentage, aspect, elevation from sea level, and the hillside shapes of the all studied plots were also recorded. Soil samples were collected from 24 established plots randomly and some physical and chemical properties of the collected samples were measured. Canonical Correspondence Analysis (CCA) was used to evaluate the relationships between treatments with the species distribution. Cluster analysis was also used to group the studied plots. According to the results, the plant cover percentage and densities of perennial plant species were increased in the un-grazed sites significantly (α= 5 %). The canopy cover and density of perennial species in exclosure and grazed areas were 43/29 % and 12 plants/m2 and 24/24 % and 7 plants/m2 respectively. Some soil characteristics were modified considerably in the grazed sites in compare with the un-grazed sites. Calcium carbonate and phosphorus soil contents, soil texture, cation exchange capacity and grazing history were identified as the most important ecological and management factors to separate the identified plant species groups in the study area.

Social capital is one of the important criteria in relation with social system. In this study, we used social capital for Adaptive Co-management. We applied social network analysis and indices in the whole network level of “Goormomenin” common rangeland, Kalateh Roudbar region in Damghan city. The level of social capital in co-management procedures was evaluated. The density, centrality, reciprocity, transitivity, geodesic distance, and core- periphery in actor’s level were calculated based on trust and cooperation metrics. The results revealed that the degree of trust, collaboration, social cohesion, and social capital among rangeland stakeholders network was poor. The rate of trust and collaboration ambulation was measured as poor to average. According to the core-periphery index, central and peripheral actors and the group’s solidarity were identified. For adaptive Co- management with stakeholder’s social situation, we must preferment social capital based on social network principal indices.