مجله مرتع
سال ششم شماره 1 (پیاپی 21، بهار 1391)

This study was conducted in Lia region in Qazvin province to investigate Phragmites australis (Cav.) Trin. ex Steudel remediation capacity of heavy metals in contaminated soils. Soil and industrial wastewater sampling was done radially along transects in distances of 300 m from exit point of wastewater in three aspect at three directions. In each sampling point, along 100 m transects within 5m×2m plots, the plant samples (n=150) and soil samples were collected in depth of 0-20 and 20-40cm from rhizosphere zone (n=150, for each depth). Concentration of Cu, Zn and Cr in root, rhizome, stem and leaves of the plant as well as soil and wastewater (n=45) were analyzed in contaminated areas to detect the differencesin heavy metals accumulation by different plant parts. In addition, plant organs were tested for heavy metals biomonitoring of soil and water. For assessing differential accumulation of a given element in plant parts and in order to detect significant differences of element concentration in soil and wastewater samples, the one-way analysis of variance was used. In addition, correlation coefficients between elements concentrations in plant parts, soil and wastewater was conducted. Results of this study revealed that the highest concentration belonged to roots and rhizomes. Particularly, for all plant parts metal concentrations decreased in the order of root› rhizomes› leaf› stem. Copper had the lowest concentration among of heavy metals studied in plant parts (6.7mgkg-1), soil (17.03mgkg-1) and wastewater (13.43mgkg-1). The highest concentration of Zn (160mhkg-1), Cu (9.27mgkg-1), and Cr (19.38mgkg-1) was observed in roots. Positive correlation was found between concentrations of studied elements between soil and plants (R2=0.70-0.97) and between wastewater and plants (R2=0.72-0.94). In conclusion P. australis is beneficial for phytoremediation of contaminated areas as well as a biomonitor species.

Appropriate utilization of rangelands leads to vegetation stability and reduction of risk of range degradation. Determining allowable utilization of range plant species is required to calculate grazing capacity of rangelands. To achieve this goal, forage production and vigor of Festuca ovina was studied in Qarebagh rangelands of western Azarbayjan Province. Treatments included four harvested intensities (25, 50 and 75 percent of total above ground biomass) and control (no harvest). A split plot over time design was used over four years (1386-1389) using SAS and IRRISTAT software. The results showed that forage production and vitality of F. ovina was significantly different between years of study and different harvesting intensities. No significant differences were detected between control treatment and 25% harvest and also between25 and 50 percent harvest intensities. With increasing harvesting intensity to 75 percent, production and vitality of the species were significantly decreased. Overall vigor of the species have decreased during 1386 to 1389. According to AMMI analysis, the first interaction principal component (IPC1) had a significant effect and expressed 98.6 percent of the interaction of the sum of squares. The first main component biplot interaction showed that the 75 percent treatment had lowest production and stability, and 50 percent treatment had the highest stability. To maintain the plant health and vigor, 50 percent treatment can be recommended as appropriate harvesting intensity for F. ovina.

This study aimed to investigate the effects of phenological stages and species composition on preference value of grazed species by Baluchi camels in Zarrindasht rangeland, Fars province. Key areas were selected in each vegetation types and plant cover were then recorded in ten 2×2 meter plots. Preference values of all species were estimated by recording the time camels spend to graze and browse form edible plants in 2 phenological stages (vegetative and flowering stages). General Linear Model was used to evaluate the effect of phenological stages, plant species and their interactions on preference value. The preference value of plant species in various phenological stages were significantly different and one way ANOVA and post-hoc test were used to compare preference value of different species in each phenological stage, separately. According to results, species such as Ziziphus spina-christ, Seidlitzia rosmarinus and Tamarix aphylla were the most grazed species by camels with measured averages preference indices of 0.21, 0.1 and 0.9, respectively. In flowering stage, the camel's diet preferences were changed towards non-woody species such as Stipa capensis (annual) and Plantago stocksii (perennial) with 6.66 and 4.44 average preference values, respectively. Results showed that camel besides browsing has tendency to graze on annual species.

Grasses, forbs and shrubs are the most important life forms which have considerable role in livestock feeding in arid and semi-arid environment. Shrub plants have important role in the feeding of livestock and stability of range ecosystems because there are short favorite growth condition for other forms of range plants and fragile environment in these ecosystems. Sampling was carried out in three growth stages (vegetative, flowering and seed shatter) with three replications. Five individual plants of each species were collected in each replication and crude protein, acid detergent fiber, dry matter digestibility, metabolizable energy, phosphorus and calcium contents were measured in each mixed sample. One-way ANOVA and Duncan’s test were used to analyze the data. The results showed that different life forms have different nutritive values and varies during phenological stages. Amount of crude protein in forbs (13/2%) was higher than those of shrubs (11/2%) and grasses (9/9%) and indicated significant differences Result of acid detergent fiber indicated grasses had significantly higher acid detergent fiber (42/2%) than those of forbs (36/5%) and shrubs (24/1%). Dry matter digestibility in shrubs (68/3%) was higher than those of forbs (58/3%) and grasses (52/6%). Result also indicated that percent of crude protein decreased in the forbs from 20/1 to 3/1 and in grasses from 14/4 to 5/1 and in shrubs from 12/1 to 9/5 in vegetative to maturity stages respectively.

Kurdistan province is dominated by the semi-steppe rangelands and dryland farming is the main land use and therefore the main degradation factor. To determine the effect of rangelands conversion to rain-fed farms on ecosystem carbon stocks, dryland farms and nearby natural rangeland sites (as control) were considered as experimental units. In all experimental units, soil was sampled in depth of 50 cm. Ecological characteristics (soil, topography and climate) in all experimental unites were relatively similar and the only variable was land use. Data analysis was performed using independent t-test and one-way analysis of variance (ANOVA). The results of 114 soil samples analysis showed that there was a significant reduction of soil carbon contents in converted rangelands to dry land farming. The type and intensity of changes depends on planted species and topography. Cultivation of perennial species compared with annual species such as wheat had less negative impact on soil carbon stocks. Abandoned dry land farms were evaluated as the worst kind of land use in terms of the soil organic carbon storage and the average decrease of soil organic carbon was 25 percent. Also the degree of the effect of rangelands conversion to dry land farms on carbon stocks depends mainly on the degree of the slope. As with the increase of the slope degrees, carbon contents of the soil showed great reduction.

Some indicators of plant and soil surface were assessed at different distances from watering point, to identify distinct structural -functional zones of Shourabad village, winter rangelands of Kerman. For this purpose, 4 m2quadrates were plotted systematically along 8 transects in 8 main directions. In these plots species density, vegetation cover and soil surface indices of Landscape Functional Analysis (LFA) method were evaluated. Clustering analysis was resulted in three distinct structural zones. According to cluster analysis, distinguished structural zones were located at 300 m, 300 to 1250 m and 1250 to 2000 m of watering point. Results of ANOVA showed that structural zones was significantly different in respects of vegetation composition and soil surface indices (p<0.01 PCA also showed that six functional indicators included stability, and nutrient cycling, soil cover, litter cover and micro topography were the most important functional factors to differ structural-functional zones. To improve management in shrublands of Zygophyllum eurypterum of the winter rangelands, a state and transition model was proposed by using of distinct structural-functional zones.

This study aimed to evaluate the effects of seed spaces in and between planting lines on forage yield and its quality in common vetch (V. sativa). Randomized Complete Block Design based on factorial experiment with three replications was used in research station of University of Mohaghegh Ardabili. Treatments included inter row spaces (20, 35 and 50cm) and intra row spaces (10, 15 and 20cm). Results showed that effects of inter and intra row spacing was significant on fresh and dry forage yield. Forage yield was increased using narrow spaces planting pattern. Nitrogen and protein contents in common vetch were decreased by inter and intra row space reduction. Although planting pattern had no significant effects on plant height, number of branches, weight per plant, and potassium and calcium contents, there was a negative and significant relation between forage yield and nitrogen and protein contents. In conclusion, 20×20 was the best planting spaces to achieve maximum fresh and dry forage yield in common vetch and 50×20 planting pattern had the highest protein contents.

Grazing affects vegetation in several ways including forage harvesting, food recycling and mechanical compaction on soil surface. This study aimed to investigate the effects of goat, sheep and camel foot pressure on soil surface in Baghdar- Bafgh rangelands in Yazd province. Herd scattering patterns was also studied as it affects soil compaction in rangelands. Twenty animals of each Najdi goat, Kemani sheep and camel were selected randomly from Bagdar-Bafgh herds. Samples were weighted and ink stamper was used to measure selected livestock feet sizes using. Camel foot sizes were measured by footprint on sand. Foot pressure were calculated by dividing livestock weight to its foot surface area.. Herds scattering patterns were studied in five stations during daily grazing. The livestock distances from each other in the time of grazing were measured as herds scattering index.. According to the results, the foot surface area of goat, sheep and camel were about 39.79±6.78, 40.22±7.65 and 753.7±87.08 cm2, respectively. The ANOVA test showed that there was significant differences between goat-sheep and camel foot surface area (p=0.00). No significant difference between goat and sheep foot surface area was found using Duncan test. Foot pressures were 0.5±0.11 kg/cm2, 0.46±0.07 kg/cm2 and 0.6±0.08 kg/cm2 for goats, sheep and camels respectively. Camel foot pressure was significantly greater than foot pressures of sheep and goats (p=0.00). Herd scattering study revealed that the distance between goats, sheep and camels in herds were 30±2.80, 9±6.70 and 246±156.2 meters respectively. According to the results, sheep graze more closely than goats and more in lines. Therefore it was concluded that the potential soil surface compactness of sheep is higher than goat and camel.

Considering seed quality beside production quantity is essential in range seed production stations. A field experiment was conducted to evaluate tiller density effect on seed characteristics and yield in 2005 at the Nyshaboor station. Five treatments in tiller removing including 50% as row full removal every other ones, 50% (250 tillers), 65% (325 tillers), and 75% (375 tillers) on long row, and plus control (500 tiller per m2) were applied on 3 or 6 years old plants at booting stage in A. elongatum. After ripening seed, seed yield, seed purity and seedling vigor (root and shoot dry weight under hydroponics condition) were measured. The experiment was conducted as combination factorial (plant age and tiller density) using completely randomized design with four replicates. The results showed that 3 years old plants were better than 6 years old for seed yield and qualitative characters (P<%5). Thinning treatments had no effects on germination percentages. Yield reduction by 17 and 40% occurred with 50 and 75% tiller removal respectively compared to control. Decreasing density by75% resulted in increased root and shoot dry weights, seedling vigor and seed purity by 5, 12, 12, and 8 percent respectively. These results suggest that for high seed quality supply the plant density should be reduced at least 50% at this station. Also, better management is needed for increasing seed yield and seedling vigor by decreasing tiller production and vegetative growth to allocate more carbohydrates to seed production.

Since participation has a key role in the success of all soil and water conservation programs. Monitoring field descriptive approach was used to study 2695 people of eleven villages in Avard watershed located in Behshahr area. Cochran’s formula was used to determine the sample size (n=219) for each village using stratified random sampling method. Questionnaire was used to obtain the data and its reliability was tested by some experts. Also the validity of questioner was calculated using Cronbach Alpha from 20 primary samples, which was 0.83. In order to calculate the obtained data set, it is used central indices to classify the data and Chi-square test is employed to compare the experts and utilisers’ opinions. Spearman's rank correlation coefficient is used to determine the correlation between independence and dependence variables. Results have shown that relationship between number of sponsorship people, education level, and social altitude level with participation index in soil and water protection’s practices are not meaningful. The results showed that there is significantly difference between age, view rate to participation, flash-forward, reliance rate to different people, participation to social charters, and tendency to carrying out the plural activities with partaking adjustment in conservation practice of watershed management, especially, terrace and sediment dams. Hence, in order to protect the soil in revisory plans of watersheds, using of participative potentials of people, who live in each catchment, can guarantee the efficiency of plans as well and can also decrease the soil erosions.