Journal of Rangeland
Year:2007 | Volume:1 | Issue:2|Papers Count:11

Soil, plant and indicators are the main criteria to recognize the function of natural ecosystems, and to evaluate their potentials. The objective of this research was to determine some of the soil and plant indicators at the saline and alkaline terrain of Gomishan rangelands in Golestan province. By using the Landscape Function Analysis method, the potential of inside and outside of enclosing of Gomishan was evaluated, within the terrain areas of Agh-Ghala. Width, height, and density of the patches and inter-patch and the 11 soil parameters were measured on the 3 transects of 50 meters length. The density and volume of grasses and shrubs under the two different management were measured by using point-center-quarter method. The index of landscape stability was higher within enclosure than outside area for patches of litter, and the index of nutrient cycling. Soil infiltration was higher inside than the outside for patches of shrubgrass and litter. Soil infiltration, stability and nutrient cycling indices were significant at bear soil of the two areas. Most ecological indicators of inside and outside areas of enclosing were of the shrubgrass, grass and shrub forms respectively.

Plant community same as its elements is not depended from edaphic, microclimatic and biotic conditions. So soil properties are one of the important factors on distribution of vegetation spatially in saline area. The aim of this research was to investigate the relationship between soil characteristics and halophytic species such az Halonemum strobilaceum, Salsola dendroides, Atriplex verrceftrum to determine the most important factors affecting on distribution and establishment. The study was Gherkhelar range lands that located in Marand of eastern Azarbayjan province. To study vegetation in each plant community ten transects with 50 m length and 100 m intervals were established. Along each transect canopy cover of species was recorded, and density of species was measured using of point-quadrate method.In each community, profiles were dug and soil was sampled in depths of 0-20, 20-40, 40-60 cm. The soil samples were analyzed for physical and chemical characteristics such as: soil texture, Ec, pH, Na, Mg+Ca, ESP and PSW.Multivariate regression was applied to analysing soil and vegetation data using Minitab13 soft ware. Results showed specific relationship between soil characteristics and species. Results of multivariate regression analysis showed that the effect of diferent soil parameters on plant species is not the same and the most important factors effective on distribution and establishment of species in study area were Ec, Na, PSW. Variation in community composition was significantly related to gradient of the aforementioned soil characteristics.Generally, the vegetation community composition in this study could be considered as a key component to expand the growth and development patterns of these species to similar stalinized area.

One of the consequences of rangeland degradation, which makes its reclamation difficult, is the physical decrease and omission of plant species liked by animals.Because high population and presence of animals take away the opportunity of seeding and growth of these species. Also, in these conditions, in some regions of the rangeland, which were not grazed by animals (secure regions) some native plants are disappeared and a decrease can be observed. These ecological nests are the small hopes for rangeland managers to recognize species compatible with the region conditions, getting seeds, and making suitable grazing systems, for plant re-establishment. Based on this view, the relative frequency, and plant diversity of Taleghan rangelands, has been investigated for spotting the places containing these plants.Panning for determination of priority (suitability), based on the criterion of the plants liked by animals (suitable species) has been carried out by FAO method using Geographical Information Systems (GIS) with the scale of 1: 50000. With this result, the places without or reduced plants rangelands, have been determined, with the help of GIS, and the model of suitable plant reserves were designed. The results showed that 17 suitable plant species with ecology and climatic conditions were reduced severely and or are under physical omission condition, and are found in secure regions or under shelters only.The area of these regions, based on spotting reserves maps, are about 3185.88ha (8.4% of the total area) which are called highly suitable classes (for protection, seed taking and seed broadcasting). Also the results showed that 7527.8 ha (19.8%) are moderate suitable (S2), 13472.92 ha (36.3 %) have low suitability (S3) and 13790.52 ha (36.3%) have no suitability from animal nutrition point of view (N).27263.44 ha (71.8%) cannot reproduce itself and are severely dependent on the seeds of S1 and S2 regions.

In this research, we study Fars steppic rangelands vegetation in relation to edaphical and physiographical factors using ordination and classification techniques. A 27295.4 ha region consisted of some ecological sites has been chosen and for determining the vegetation ecological group from 1900 to 2400m parameters such as density and abundance in 268 quadarats sized 1m2 along four 300m transects in length and eight ones 100m transects in width were located. Using Sorenson similarity index and land shape map in ILWIS, 106 profiles for soil sampling has been estimated. Physical and chemical charchteristic’s such as soil texture, structure, organic carbon, elements such as K, P, N, pH, EC, caco3, caso4, Humid percent and physiographical factors such as height, slope and aspect were measured. The results showed this site consisted of 22 vegetation ecological group in related to the most important factors such as soil texture, pH, Humid percent, P, Caso4, K, Caco3 in plain and in terraces and height of the region slope, aspect and precipitation.

This study was carried out to obtain an approach for designing range management plans through Geographic Information System (GIS), to make the planning process quickly with accuracy. In this research, some ground information including slope, elevation, vegetation, soil, range trend and condition were recorded. Then based on integration of these information with the basic consideration of resource management it is possible to improve the existing condition or stabilize the current optimum state.While the new model is ready, then the new and old model should be compared. Based on the results of this method, the GIS integrated model could help us to achieve the information more convenient and quickly. Clarification is an other attribute of this model. The management of rangeland would be better as well. Information of the basic studies would never been lost during integration. Correction of errors would be done quickly as well. Finally these aforementioned items, would lead to higher accuracy.Result of this study, which was performed in Lar rangelands, showed that the total area of rangeland which should be managed in balance method is 7805 ha. The area to be managed in natural method is 4998 ha, the area to be under enclosure is 2916 ha, the area to be seeded is 6579 ha, the area to be inter seeded is 6269 ha, the area to be hoe sowed is 2925 ha and the rest is rocky, river and farmland. Comparison of suggested plans for range management projects with results of this study (through integration of information using GIS) indicates that some suggested plans are not corresponded with Lar rangelands ecological condition and needs to be revised.

The optimal land use and suitable management of renewable resources is dynamic characteristics needs evaluation and classification of environment capability and its socio-economic conditions. In order to determination suitable land use and its perfect management, this research was performed in Asadly watershed using GIS. In framework of this procedure, the ecological and socio-economic characteristics of land were studied and mapped. These maps were digitized in Arc/Info software and then were entered to Arc view software with other data for creation database information's.Digital Elevation Model (OEM) was produced in Arc view environment using topographic map. Elevation, slope and aspect maps were made in the base OEM. Then, the environmental units map was prepared trough overlying the maps of elevation, slope, aspect, soil types and vegetation cover in Arc view. The land capability was obtained by Iranian ecological model using structured Query Language (SQL) in Arc view. The generally results showed the area has not any units with first and second class of capability for irrigated agriculture. 53.78% of land is suitable for range and 28.75% is suitable for dry farming. 5.25% of this area determined for irrigated farming with ability degree 3 and 11.79 determined for conservation.

One of the problems of rangelands is early grazing. Regeneration and Sustainability of some of important range species are threatened by improper entering date. Non structural carbohydrate reserves are considered to be very crucial for regrowth and vigor of range plants after defoliation and for beginning of growing period.Bromus tomentellusis one of the important and wide spread species in Iran. This species is palatable therefore is intensively utilized by all kinds of livestock’s specialy in early growth stage. This study was conducted during growing season of year 2005 in Shahid Hamzavi research station Hanna, Semirom, Isfahan province. Non structural carbohydrate reserves change of this species was investigated in two range sites with heavy grazing and proper grazing histories. Phenological stages selected for sampling were: early growth stage (3-4 leaves), Panicle emergence and seed ripening. Shoot (stem base) and root samples were collected from six random plants in pheonological stages in each site. According to AOAC, Sheffer-Somogy (1940) method, total non structural carbohydrates levels were determined. Results indicated that in seed ripening stage in proper grazing site TNC was 2.23mg/g and significantly (p<0.01) higher than in heavy grazing site (1.25 mg/g). Roots contained significantly (p<0.01) higher levels of TNC than Stems. TNC levels were lowest in early growth stage and highest in panicle emergence stage. This results emphasized the degrading effects of early grazing and panicle emergence to be the proper time for beginning of grazing period.

Arid environments often support a low cover of vascular plants, which provide a niche for non-vascular plants such as mosses and lichens. In these environments, bryophytes and lichens are the principal visual components of biological soil crusts.Available information indicates that biological soil crusts contribute to a variety of ecological functions. The present study was carried out in Qara Qir ranges of Golestan province in order to find the effects of non -vascular plants (mosses and lichens) on soil chemical characteristics. For this purpose, soil sampling was performed in crusted and non-crusted areas at depths of 0-5 and 5-20 cm.Properties of Ec, pH, OC, N, P, K, Na, Ca, Mg, and CI related to crusted and non-crusted soils were compared using independent t test. Results indicated that in 0-5 cm layer pH, OC, N (P’ 0.01) and P (P' 0.05) were significantly different in encrusted and uncrusted soils while in 5-20 cm layer only OC and N showed significant differences (P' 0.01). Crusted soils had higher levels of OC, N and P.

Environmental stresses, especially in pastures, cause yield reduction.Therefore, growing species which endure stressful conditions is important. The leguminous species due to their heliotropic functionality could reduce these stresses. Solar tracking leaf movements in some plant families are one of the important ecological adaptations. The leguminous species during the leaf movements regulate the incident radiation and leaf water potential. In favourite environmental conditions leaves are diaheliotropic and intercept more radiation, while during the stress conditions they move away, paraheliotropic, from the sun incident radiation.Therefore, the aim of this research is to evaluate the effect of bean leaf movements at heat stress condition on instantaneous leaf water-use efficiency (WUEi), stomatal conductance and leaf temperature. Potted plants of bush bean (Phaseolus vulgaris L. var.Provider) at the stage of the second extended trifoliate leaf, which were grown in Chicot sandy loam soil under well-watered condition in greenhouse, were chosen for this research. One plant was used to measure the pulvinus water status and pulvinus bending by using a beta-ray gauging (BRG) meter using a point source of thallium-204 (204Tl).Leaf gas exchange measurements took place at air temperature interval of 33-42oC by a steady-state LI-6200 photosynthesis system. A Copper-constantan thermocouple was used to monitor pulvinus temperature. Pulvinus bending followed the daily circadian rhythm. Quadratic significant correlations were found between leaf-incident angle and stomatal conductance (R2=0.54; P<0.01), and photosynthesis rate (R2=0.84; P<0.01). By reduction of leaf-incident angle and increase of air temperature WUEi reduced. The leaf temperature remained bellow air temperature and was a significant function of it (r=0.92; P<0.01). In conclusion, air thermal stress causes leaf paraheliotropic movement, and regulate leaf temperature and leaf water loses.