Naser Ansari; Mohammad Fayaz; Mohammad hassan Gasemi
Volume 16, Issue 3 , December 2009, Pages 293-304
Abstract
Rangelands degradation is the most important problem of Iran natural resources, especially in these decade .In this research for determination of the quality and quantity of rangelands degradation,9 provinces distributed within 3 main zones of Henry Pabbot’s climatic zones map of Iran territory, ...
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Rangelands degradation is the most important problem of Iran natural resources, especially in these decade .In this research for determination of the quality and quantity of rangelands degradation,9 provinces distributed within 3 main zones of Henry Pabbot’s climatic zones map of Iran territory, were selected. In these provinces, sample areas in each climatic zone were bounded on topographic maps. In the sample areas, converted rangelands to other usages, from 1955 to 1995(40 years) and then, lost and converted rangelands clarified. Considerable decline in forage production of the rangelands were also well described by comparing dry matter yield in an enclosure and the fenced area. Results showed that 9.1% of the rangelands areas, during 40 years between 1955-1995 periods, had been disappeared. Rangelands degradation in semi-desert zone with degradation index of 28.4% is lowest and in high-mountain zone with degradation index of 60.5% is the highest one. Degradation intensity in high-mountain zone is as twice as semi-desert zones. Average of degradation index for all the country zones, is 49.4% that revealed, about half of the production potential of the rangelands has been lost.
Shahram Banedjschafie; Esmaeil Rahbar; Farhad Khaksarian
Volume 16, Issue 3 , December 2009, Pages 305-316
Abstract
The effect of different level of polymer water absorbent (supper A200) mixed with desert sand were studied in comparing to pure sand and clay soil on survival and growth of Panicum antidotale in pot condition in Research Institute of Forests and Rangeland, Tehran, Iran for three years. The polymer ...
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The effect of different level of polymer water absorbent (supper A200) mixed with desert sand were studied in comparing to pure sand and clay soil on survival and growth of Panicum antidotale in pot condition in Research Institute of Forests and Rangeland, Tehran, Iran for three years. The polymer treatments were 0.2%, 0.6% and 1.0% W/W. The irrigation period was determined based on field capacity of pure sand for all treatments. The results showed no significant differences among treatments for plant growth in the first year. However, the treatment of sand with 0.6% polymer had the most survival plants with average values of 100%. The pots were not irrigated in the 2nd year because there were enough precipitations. All survived plants from 1st year were dead at the end of 2nd year. So, the experiment was repeated at the 3rd year. The results showed significant differences among treatments. The survived plant for clay treatment with average values of 6.17 g dry matter per plant had higher production and followed by 0.6% and 1.0% W/W polymer treatments mixed with desert sand. Those treatments had significant differences with pure sand controls. The lower amount of dry matter was obtained by control pure desert sand with average values of 2.91 g dry matter per plant.
Zainab Jafarian jelodar; Hosein Arzani
Volume 16, Issue 3 , December 2009, Pages 317-328
Abstract
Plant species have important role in other organisms life circle. High diversity of plant species cause equilibrium and stability of this circle, so conservation of plant species is essential for continuity and survival of ecosystems. In this study vegetation species diversity and flora in four sub watersheds ...
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Plant species have important role in other organisms life circle. High diversity of plant species cause equilibrium and stability of this circle, so conservation of plant species is essential for continuity and survival of ecosystems. In this study vegetation species diversity and flora in four sub watersheds of Armoot, Kash, Zidasht and kalanak in Taleghan region with 16320 hectares area were studied. Thirteen vegetation types were recognized in the study area. One key area was selected in each vegetation types (in some of the vegetation types because of vast area and non –homogeneity vegetation, two key areas were selected). Two 100 meter transects were located in each key area, along each transect, 10, one meter square quadrates were located. List of species and number of species were recorded for each quadrates. Then diversity indices, species richness and evenness indices were calculated. Simpson diversity index and Shanon– Wiener diversity index were obtained 0.114 and 2.81 respectively which indicate relatively high species diversity in the study area. Species evenness based on studied indices was estimated. Richness of species was 116 with 18 families and 63 genus in rangelands of the study area.
Abass Miri; Ahmad Pahlevanroy; Alireza Moghaddamnia
Volume 16, Issue 3 , December 2009, Pages 329-342
Abstract
Occurrence of prolonged drought was commenced in Sistan region from 1999 caused by wetland dryness in Hamoun Lake and wind erosion. Severe wind erosion and dust storm cause huge damages to various aspects of the people's life in the study region and thus understanding of the impacts of soil erosion and ...
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Occurrence of prolonged drought was commenced in Sistan region from 1999 caused by wetland dryness in Hamoun Lake and wind erosion. Severe wind erosion and dust storm cause huge damages to various aspects of the people's life in the study region and thus understanding of the impacts of soil erosion and dust storms on human's lifefor making better decision is vital. The meteorological data of Sistan region and WRPLOT software were used to study wind erosion and draw wind rose in the study area. In addition, meteorological code numbers of 30 and 35 and the data of wind speed and direction as well as visibility were used to analyze dust storms datasets. The results show that prevailing wind has north to north west directions. It is found that droughts have increased the frequency of dust storms with mean dusty days, from 10 to 54 days in 1980 and 1999, respectively after drought occurrence. As above- mentioned, over period (1980-1999), there have been 324 dust storm days. The furthest horizontal visibility, between 1-5 km, took place in 2001, particularly in July, August, and September. It is found out that number of dust storm days which are recorded in summer season (June, July, August and September) is more than others. The length of dust storms in the region was between 3 to 110 hours. The frequency of dust storms occurred in more than 3 hours was fairly high. It can be concluded that wind erosion in the Sistan region has significantly increased after drought.
Ghasem Asadian; Morteza Akbarzadeh; Mohammad reza Sadeghimanesh
Volume 16, Issue 3 , December 2009, Pages 343-352
Abstract
Study of vegetation changes of grazed and ungrazed rangelands is most important in range management programs. Vegetation changes were studied for four years (1996-99) inside and outside of the exclosure in Gian rangelands of Hamadan province. Measurements were made in permanent plots that have been established ...
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Study of vegetation changes of grazed and ungrazed rangelands is most important in range management programs. Vegetation changes were studied for four years (1996-99) inside and outside of the exclosure in Gian rangelands of Hamadan province. Measurements were made in permanent plots that have been established in study areas since 1996. Forage production was measured in randomized plots each year. Data were compared whit T test analysis. Results showed that there were significant differences in total cover of perennials during study period inside exclosure and the cover increased about 80 percent. The cover of all plant forms, such as shrubs, grasses and forbs increased significantly inside the exclosure in this period. The cover of perennials increased about 16 percent outside of exclosure during this period too, but there were significant differences in shrubs and grasses and no difference in forbs. Decreasers and increasers increased and invaders decreased inside, but outside of exclosure there was an opposite trend. Frequency of good quality plants increased inside and decreased outside. Range condition increased from poor to fair inside and decreased to very poor outside of exclosure. A positive and negative trend was observed inside and outside the exclosure area. In second year of study, rainfall was greater and In final year annual precipitation was more than first year but seasonal rainfall that is effective in growth, was less than the first year. Relationship between species canopy cover and annual and seasonal rainfall evaluated, however the correlation coefficient between rainfall and some species was significant. Overall, in comparison inside and outside, exclosure improved vegetation condition, forage production and range condition, under this climatic condition. Because of good precipitation condition of these years, it is necessary to continue the study to cover a series of drier years.
Ghader Karimi; Saadat Mozafari; Mansour Nikbakht
Volume 16, Issue 3 , December 2009, Pages 353-361
Abstract
The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and siol degradation in many natural rangelands of Iran. Changes of canopy cover, species composition, forage production, in Margoon station were studied. In this study cover estimated by quadrates and forage ...
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The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and siol degradation in many natural rangelands of Iran. Changes of canopy cover, species composition, forage production, in Margoon station were studied. In this study cover estimated by quadrates and forage yield were measured by clipping and weighting method. Results showed that species diversity in this region was relatively good (about 31 species). Palatability class I, II and III were 12.6, 27.5 and 9.5 percent respectively. Cover, density and yield of Bromus tomentellus and Hordeum bulbosum increased inside the station (enclosure). Also, canopy cover changed from 33.4 to 55.5 percent. Forage production increased from 309 to 569.8 Kg/ha due to management practices.
Akbar Ghasemi; Heshmat Hydari; Farhad Fakhri; Davud Azadfar; Musa Sadeghi
Volume 16, Issue 3 , December 2009, Pages 362-374
Abstract
Plant cover is one of the best index for recognizing and describing the environmental changes in the forest. This paper attempts to determine the effects of different desert soil classes on some distinctive plant vegetative characteristics. For the purpose of sustainable management, application of floodwater ...
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Plant cover is one of the best index for recognizing and describing the environmental changes in the forest. This paper attempts to determine the effects of different desert soil classes on some distinctive plant vegetative characteristics. For the purpose of sustainable management, application of floodwater spreading for irrigation of desert plants will meet increase the essential water supplies for desert plants, which in turn create the optimum conditions for desert plant growth. In order to examine the effects of flood water distribution on physico-chemical properties of soil and finally on vegetative characteristics of desert plants an area of approximately 300 hectares located at Tangestan flood water experimental station, in Bushehr, has been divided into three sections of each 100 hectares. Each section received different amount of flood water as entry (treatments).The process of irrigation have been conducted since 1997(11 years). Each section has been divided into two subdivision of upland and down-land subdivisions. Each subdivision has been divided into three secondary subdivisions (18 secondary subdivisions).In each secondary subdivisions soil samples were collected to study the physico-chemical properties of the soil, meanwhile in each secondary sub sample a Cluster sample of 4 plots were studied for the proposed vegetative characteristic of deserts plants: Prosopis juliflora, Ziziphus spina-christi and Acacia nilotica. The experiment has been conducted in the form of split plot design. The results indicate that the mean stem diameter, height and crown diameter differ significantly in sections; section number one has the best growth conditions. Comparison of subsections indicate that the upland and down-land mean stem diameter and crown diameter differs significantly in that the down-land has a better condition of growth. The comparison of soil physico-chemical properties indicate that there is a significant differences between sections and section one is dominated over the others.
Aliasghar Naghipour Borj; Ghasemali Dianati Tilak; Hosein Tavakoli; Maryam Haidarian Aghakhani
Volume 16, Issue 3 , December 2009, Pages 375-385
Abstract
Climate change and increase of global warming is one of the most important challenges in sustainable development, which is due to increase of concentration of greenhouse gasses in atmosphere. CO2 is the main part of greenhouse gasses. In order to mitigate atmospheric CO2 and create balance in greenhouse ...
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Climate change and increase of global warming is one of the most important challenges in sustainable development, which is due to increase of concentration of greenhouse gasses in atmosphere. CO2 is the main part of greenhouse gasses. In order to mitigate atmospheric CO2 and create balance in greenhouse gasses, atmospheric carbon must be absorbed and sequestrated in different forms. Rangelands ecosystems have approximately half of the worldٰs land area and they store over third of trrestrial biospher carbon. In order to evaluate the effect of grazing intensity on content and distribution of soil carbon sequestration and plant biomass, a study was carried out at Sisab semiarid rangelands of North Khorasn province. After survey, three sampling area has been specified (reference, key and critical). The content of above ground and under ground biomass carbon, litter carbon and soil organic carbon (in two depths 0-15, 15-30 cm) was determined in three area. The result showed that the total carbon sequestration in reference area was 39.79 ton/ha, in key area was 28.97 ton/ha and in critical area was 24.43 ton/ha. The results of carbon distribution showed that the soil organic carbon content was >97% of total carbon sequestration, In addition the carbon content in underground biomass was higher than above ground biomass. It was concluded that the grazing intensity cause to decrease of vegetation cover, content of plant biomass and decrease of carbon sequestration in soil and vegetation biomass, and soil is the most impotant sink for organic carbon storage in this rangelands.
Payman Lotfi anari; Gholamali Heshmati
Volume 16, Issue 3 , December 2009, Pages 386-400
Abstract
Application of new rangeland ecosystems monitoring methods is essential for ecological studies. LFA principles and soil surface assessment parameters are based on ecological conditions of Australia. The aim of this study was calibration of LFA method for an arid rangeland ecosystem located in central ...
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Application of new rangeland ecosystems monitoring methods is essential for ecological studies. LFA principles and soil surface assessment parameters are based on ecological conditions of Australia. The aim of this study was calibration of LFA method for an arid rangeland ecosystem located in central part of Iran with 188 mm annual mean precipitation. In LFA 11 soil surface parameters are ranked to determine soil surface indices (infiltration, stability and nutrient cycling of soil). To calibrate LFA, soil surface assessment had been done with 10 replications. Then sensitivity analysis of 11 parameters had been done. Soil texture and kind of erosion and its severity parameters with lowest sensitivity had been deleted from LFA and available pebble in soil surface added to LFA as a new parameter (Calibrated LFA). Verification of LFA and calibrated LFA soil surface indices had been done by regressing them against field and experimental measurements and the results compared together. Results indicate that LFA and calibrated LFA soil surface indices are in moderately verified class (R: 0.4-0.6) and strongly verified class (R>0.6) respectively. This represents more efficiency of CLFA revised method in comparison with LFA method for using in the study area and similar areas.
Majid Dashti; Amrali Shahmoradi; Hamed Zarif ketabi; Asghar Paryab; GHolamreza Hosseini-Bamrood; Sadegheh Zarekia
Volume 16, Issue 3 , December 2009, Pages 401-408
Abstract
Salsola orientalis S .G.Gmelin is a perennial plant species of chenopodiaceae family. Because of its palatability, as a range plant, and recent drought it has been overgrazed in a way that it was eliminated in some areas, or only the individual plants of this species could be found. This research was ...
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Salsola orientalis S .G.Gmelin is a perennial plant species of chenopodiaceae family. Because of its palatability, as a range plant, and recent drought it has been overgrazed in a way that it was eliminated in some areas, or only the individual plants of this species could be found. This research was conducted to map the habitats of the plant in Khorasan region and investigate on its habitat characteristics (topographic, climatic, edaphic), phenology, regeneration, root system, density, and canopy cover. Results showed that elevation range for the habitats of this plant is 500-1500 meters above sea level. It could be found on different aspects and slopes of 5-40 percent. Annual precipitation and temperature are 150-400 mm and 10-17.5 degree centigrade, respectively. In most of its habitats, in Khorasan region, this plant is accompanied with dominant species of Artemisia diffusa, Artemisia sieberi, Poa bulbosa and some other species of genus Salsola. This range plant grows on moderately deep to deep soils with sandy loam to silty loam texture, acidities of about 7.4-7.8, and EC of 0.8-7.2 ds/m. It has a tap root system. So many small branch roots are connected to the main root. The root system can infiltrate into the soil to a depth of 1.5 meters. Phenology stages for Salsola orientalis showed that vegetative growth is from early March until early June. Flowering starts in late May. Seed ripening is in late October until mid November. Seed dissemination happens in late November until early December. Plant regeneration is via seeds. At phenological stage of seed formation, chemical analysis of forge portion resulted in 13.4% protein, 18.28% ashes, 2.62% calcium, and 26.19% fiber.
Ali Tavili; Mojtaba Janat rostami; Khadejeh Ebrahimi Dorcheh
Volume 16, Issue 3 , December 2009, Pages 409-418
Abstract
According to importance of Salsola rigida in arid and semi arid regions, also due to Artemisia sieberi allelopathic property, this research was carried out to find whether or not Sa. rigida is sensitive against Ar. sieberi allelochemicals in germination stage when they are planting with together. For ...
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According to importance of Salsola rigida in arid and semi arid regions, also due to Artemisia sieberi allelopathic property, this research was carried out to find whether or not Sa. rigida is sensitive against Ar. sieberi allelochemicals in germination stage when they are planting with together. For this purpose, Sa. rigida seeds were taken from Pakan Bazr Cooperation in Isfahan. Aerial parts of Ar. sieberi were gathered from Jafarieh region in Qom province, dried and powdered. They were mixed with distilled water in a ratio of 1:3 (one part Sa. rigida powder, 3 parts distilled water). Based on standard methods, extracts with different concentrations were prepared. Sa. rigida seeds were put in Petri dishes and watered with different concentrations of the prepared extracts. Experiment was done in a completely randomized design with 4 treatments (0, 25, 50 and 100 percent extractions) and 4 replications. Understudy germination properties were Final Germination percentage (FG), Rate of Germination (RG), Mean period of Final Germination (MPFG) and Percentage of Inhibition (PI). Duration of experiment was 13 days. Results based on statistical analysis revealed that there was significant difference between FG, MPFG, and PI under different extract concentrations effects (P<1%) while for RG difference was significant at 5% probability. Totally, it is concluded that Sa. rigida could be affected by Ar. sieberi allelopathic property in germination stage.
Vahid Habibi arbatani; Mojtabah zareian jahromi; Ali sadeghi sangdehi
Volume 16, Issue 3 , December 2009, Pages 419-430
Abstract
The goal of this research was climatic zoning of Esfahan province using Domarten and geostatistic methods. We used 30 years data of 35 climatologically stations. At first we calculated Domartan aridity index of climatological stations using mean annual precipitation and temperature. In order to climatic ...
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The goal of this research was climatic zoning of Esfahan province using Domarten and geostatistic methods. We used 30 years data of 35 climatologically stations. At first we calculated Domartan aridity index of climatological stations using mean annual precipitation and temperature. In order to climatic zoning, Kriging, Cokriging and IDW with powers of 1 to 5 were used. After normalization, the variogram were drawn. To fit the best model on empirical variogram, the lowest values of RSS were applied. Highly correlated values of precipitation with Domarten index were used in Cokriging method. For selection of the best interpolation method, cross validation and RMSE were considered and errors were calculated. Cokriging has the lowest error .Using cokriging and GIS, climatic zoning map of Esfahan province were prepared. Climatic zoning map showed that 80 % of studied area has arid and semi-arid climate