مجله مرتع
سال ششم شماره 2 (پیاپی 22، تابستان 1391)

Changing land use and overexploiting rangelands beyond the ecosystems potential are effective factors reducing species diversity that could threaten these ecosystems’ health and stability. In the present study effects of grazing on species diversity of rangelands and abandoned drylands in Fereydan, Isfahan was evaluated. In each rangeland site the percentage of crown cover and species diversity were obtained and the effects of distance from village were also studied. Along three transects of 100-meters according to sample size one square meter plots were randomly selected. Calculated sample size was 20 for each range site. Non-parametric indices such as Margalof species richness index, Hill (N1) and Shannon-winner species diversity were calculated. Parametric algorithms (frequency-order models) also were used for species diversity evaluation. In order to investigate the relationship between species diversity and environmental factors, multivariate data analysis was (ordination method) applied. Results indicated that Margalof species richness index was significantly higher in good rangelands than others (P>0.01). Non-parametric diversity indices such as, Hill (N1) and Shanonn-winner showed significant differences (P>0.05) between good rangeland and both, degraded rangeland and abandoned dryland sites. Frequency-order model in parametric method indicated that data followed log normal model. Distance from rural area was recognized as the most important variable effective on species diversity and species richness. Ordination analysis (PCA) showed that there is a positive correlation between species diversity and soil organic matter, moisture saturation, lime and clay percentages and a negative correlation with sand percentage and soil electrical conductivity.

The current research was conducted to evaluate effects of a super absorbent polymer (SAP) on growth ptoperties of Haloxylon aphyllum seedlings in nursary conditions in Ashkezar nursary. For this purpose, a completely randomized design with 4 levels of SAP including 0 (control), %1, %2 and %3 of pot weight in 4 replications (each including 6 seedlings) was performed. The evaluated growth properties of seedlings were height, shoot and root fresh and dry weights, root length and collar diameter. The amount of consumed water in each pot was measured during the studyperiod. In comparison with control, enhanced measured properties were observed in treated pots. Using 3 percent SAP treatment resulted to the highest levels of growth properties and it had significant differences compared to the control. Also consumed water in 3 percent SAP treatment was about half of the conrtol. In conclusion applying SAP in nursary for seedling production is beneficial andcould enhance seedling initial growth properties.

Effects of Kraft lignin on germination characteristics of Festuca arundinacea Schreb in loam-clay sandy soils were evaluated. Soil samples were randomly collected from Artemisia herba-alba type in Haraz watershed (Saghelchi Mountain). Soil characteristics were determined in laboratory. Treatments were a (0, 50 and 200) mg Kraft lignin per kilogram soil arranged in a completely randomized design with four replicates. Ten seeds per replicate were planted in pots and then 80 mg urea solved into 120 cc distilled water added to all pots. Experimental period lasted 40 days. Germination percentage, germination rate and above ground growth lengths of F. arundinacea were measured during experimental periods. Lignin used in this study was isolated in the laboratory from Kraft liquor. The data were statistically analyzed by SPSS Statistics 17.0 and Excel softwares. The differences between the means were compared using Duncan test. The results of this study showed that, significant differences between the three treatments crop yield in F. arundinacea Schreb and the maximum germination percentage and growth length aerial of F. arundinacea Schreb was recorded in 200 mg / kg soil, Kraft lignin. The results of this study demonstrate that add Kraft lignin to the soil will improvement plant germination characteristics and growth length

Functionality of rangeland landscape determines the ability of ecosystem to conserve or lose vital resources such as water, soil and organic matter. Therefore, the functionality of rangeland is highly related to its vegetation cover. This study aimed to analyse the applicability of a Cover Directional Leakiness Index, CDLI, in rangeland functionality assessment of a Steppe zone, using satellite imagery in a case study in Soh region, Isfahan, Iran. This index was calculated based on a spectral index called Perpendicular Distance vegetation index, PD54, using green and red bands of Landsat TM 2009 data. The CDLI varies from 0 to 1 where a studied site is fully functional versus fully dysfunctional, respectively. The calculated CDLI for the study area was about 0.79 which indicates low functionality as its low plant cover percentage (<20%) can not capture and conserve resources. Statistical analysis also showed that relationships between CDLI and vegetation cover index was significant at the 95% confidence level. According to the results, the CDLI index can be used as a supplementary tool to field methods for determining and assessing the functionality of Iran’s low-relief rangeland landscapes.

This study aimed to investigate the similarity between above ground vegetation and soil seed bank in order to evaluate the possible potential of seed bank for recovering eroded communities in Vaz watershed located in northern part of Iran. Soil samples were collected from two depths 0-5 and 5-10 cm in 40 plots established along four 100 m transects (two of which parallel to the slope gradient and two of which perpendicular to the slope gradient) in winter of 2010. Above ground vegetation was also studied and recorded in the next growth season, (2011) in each plot. Sorenson index was used to measure the relationship between soil seed bank and above ground vegetation. Paired t-test was applied to compare the similarities of above ground vegetation with upper- layer and deeper-layer soil seed banks. Relative abundance of each plant species in each plot was calculated and the relative abundances were recalculated into life form and life-span for each plot for both seed bank and above ground vegetation. Paired t-test was also used to compare each life form and each life-span between soil seed bank and above ground vegetation. The results showed that the similarity between soil seed bank and above ground vegetation was generally low and the similarity was lower for deeper soil seed bank (27% vs. 10%). Perennials were higher in the above ground vegetation than soil seed bank. Therophytes were higher in soil seed bank while hemicryptophytes were higher in the above ground vegetation. We also concluded that it was impossible to predict soil seed bank using above ground vegetation and vice versa.

Ground cover is a key indicator of rangeland health. Therefore determination of most suitable method of cover measurement in each climatic zone with enough precision and fast is important. To conduct this study four vegetation types (two grass communities and two grass-shrub communities) in Taleghan region were selected. Then in each vegetation type 6 transects were established. Along each transect 10 one meter square plots were located based on random- systematic sampling. Within each plot canopy cover percentage of each species was measured by ocular estimation and photographic methods simultaneously. Also, canopy cover percentage of each species on images was determined using Arc View software at office. Moreover, the spend time for measuring cover percentage using two methods (ocular and photography) was recorded and compared. Then, the percentage of canopy cover by life forms, obtained from ocular and photography methods were compared using SPSS ver.15 software and paired T-test. In general, the results of this study showed that in grass and grass- shrub communities, there were significant differences between canopy cover of grasses measured by two methods. The canopy cover of grasses was measured by photographic method, was more than canopy cover estimated by ocular method. Also differences between means compared with shrubs and forbs were higher. In shrub- grass vegetation type differences between canopy cover percentage of shrubs and forbs obtained from either ocular or photographic methods were not significantly different (P<0.05). The mean of time consumption for field survey at ocular method in order to estimating canopy cover in each plot was more than photography method. As a result we can conclude that photographic method because of less time consumption in ground survey and consequently less ground activities because of using digital images and interpretation by software in office is more applicable.

In this study marginal sea vegetation of Ameri region in the North West of Boshehr province were evaluated. Boundary of plants types were distinguished by ETM satellite images and GPS. We found six plant types in study area. In each plant type 20 plots (2m2) were established by using of random- systematic method and in addition to species recording, soil sampling was done. According to method, species relative importance was calculated and vegetation grouping was done by TIWNSPAN. Finally plant diversity was obtained by Shanon and Simpson index. Totally 68 species representing 22 families were collected. The largest families were Poaceae, Asteraceae, Chenopodiaceae and Fabaceae representing 16.3%, 13.7%, 10.8%, and 10.6% of the total flora, respectively. Results showed the highest diversity was in 4th group included Gymnocarpus decandera - Platycheat munronifolia plant type which had 1.63 of Shannon index meanwhile lowest diversity was occurred in first group with Halocnemum strobilaceum dominant species which is located after seashore and had 0.8 of Shannon index. Results of correlation between species diversity, soil salinity and soil particles (clay, silt and sand) showed species diversity had highest correlation with soil salinity and there is an exponential correlation between these two parameters according to correlation when salinity reaches to 50 ds/m species diversity will decrease less than 1 of Shannon index.

The purpose of this survey was to identify the stumbling blocks in range management cooperative activities in North West Provinces (Ardebil, East Azerbaijan and West Azerbaijan). Descriptive study method was used to obtain information for directory board members cooperatives in those provinces. The sample (n=349), was selected using a stratified random sampling including; (48 from Ardebil, 105 from East Azerbaijan and 196 from West Azerbaijan cooperatives). Data was collected through a questionnaire which its (Faced and content) validities of the questionnaire were examined by a panel of agricultural extension experts and Tehran university professors and research Institute for forests and rangelands. The reliability of questionnaire was assessed by Cronbach's – alpha formula (α=.96) and showed that the reliability of the questionnaire was acceptable. SPSS/win 11.5 Software was used for data analyzing, and ANOVA and factor analysis methods were employed to identify effective factors. The results showed that seven effective factors explained 73.3 percent of the total variance. The first factor was public dependency and low productivity of cooperative activities factor with 25.3%, as the first factor. Other factors were ignorance and lack of coherence and coordination within the cooperative responsibility with 20.29%, inability to satisfy and meet the expectations of members with 4.21%, weaknesses in outside communications with 6.16%, inability to create new job opportunities and the complexity with 5.8%,, public bureaucracy with 3.91%, and low per capita income of cooperatives with 2.95%. In addition results indicated that there was significant differences between provinces in relation to range management cooperative inactivity.