zahra zangane; Kamalaldin Naseri; Fereydoon Mellati; Mansoor Mesdaghi
Abstract
Because plant density is often measured by using plots and also in most cases are done by the method of estimation and counting the individuals, so one of the important cases that we have to decide on is the size and shape of plot. In this research, the density of Astragalus verus that it's one of the ...
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Because plant density is often measured by using plots and also in most cases are done by the method of estimation and counting the individuals, so one of the important cases that we have to decide on is the size and shape of plot. In this research, the density of Astragalus verus that it's one of the dominate species in the area and has separate and recognizable individuals plant from each other,for investigate the effects of different size and shape of plots on sampling precision and accuracy are estimated in Mayan Mashhad area. The shapes of plot are square, wide rectangular, long rectangular, and sizes of plot are 1, 2, 4, and 8 m2 respectively, that we have been investigated in total 3x4 plots (treatments). In this research, the coordinates of individual plants and the boundary of study area are located by using digital camera. Then, with help of R software, the digital map of study area was sketched. The results show that long rectangular 0.5x4 m plot has the highest accuracy and precision, so it is selected as optimum plot. Finally, it can be concluded that for saving time and expenses in sampling, using of locating coordinates method of individual plants and application of R software can be appropriate approach for estimating the density of shrublands, so for similar shrublands, the optimum plot of this research (4x0. 5 m) can be used.
samaneh Mohammadi Moghaddam; Abolfazl Mosaedi; Mohammad Jankju; Mansour Mesdaghi
Abstract
Although precipitation is the most important factor which effects rangeland production, but there is little information on the relationship between production and the interactions of climatic factors and specially drought indices. .In this research, the relation between production and climatic ...
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Although precipitation is the most important factor which effects rangeland production, but there is little information on the relationship between production and the interactions of climatic factors and specially drought indices. .In this research, the relation between production and climatic factors of rainfall, temperature, evapo- transpiration, and as well as drought indices of Standardized Precipitation Index )SPI) and Reconnaissance Drought Index (RDI) were investigated in Noudoshan Rangelands.Then the data with 33 variables were generated for different time periods of one to four months based the years of available production data. PCA was employed to decrease the number of variable and based on further component analysis, some variable were selected. To find the relation between production and climatic factors, regression analysis was used. Finally, the model with least IPE was selected as preferred model. By comparison equations based on rainfall, temperature, evapo- transpiration, and drought indices, the model resulted from RDI, selected as preferred range production estimator (R=0.969, MARE=0.111).
Tahereh Sadeghi Shahrakht; Mohammad Jankju; Mansour Mesdaghi
Abstract
Rangeland shrubs may provide mechanical facilitation on their understory plants, by protecting themagainst the livestock grazing. However, such a facilitation effect may vary depending on the rangelandutilization rate. In a field research, mechanical facilitation of rangeland shrubs was compared in ahighly ...
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Rangeland shrubs may provide mechanical facilitation on their understory plants, by protecting themagainst the livestock grazing. However, such a facilitation effect may vary depending on the rangelandutilization rate. In a field research, mechanical facilitation of rangeland shrubs was compared in ahighly grazed, a moderately grazed and an enclosure site; in an arid rangeland, Kakhak, Gonabad,Iran, during spring to summer 2011. Twenty line transects were established in various directions andslope aspects. Forage production was measured by clipping method within the paired plots, i.e. underthe canopy of nursing shrubs and their nearby open areas. In the enclosure site, forage production wassimilar under the canopy of shrubs and in open areas, whereas in the highly and moderately grazedsites there were more forage under the canopies. These results indicate increases in mechanicalfacilitation of rangeland shrubs by increasing the grazing intensity. The mechanical facilitation wasalso varied depending on the life forms of understory species. In the enclosure, the greatest facilitationwas on annual forbs, whereas in the highly grazed site it was on perennial grasses. Results of thisstudy show important role of rangeland shrubs on preserving understory forage plant against theintense livestock grazing.
H. Khedri Gharibvand; Gh. A. Dianati Tilaki; M. Mesdaghi; M. Sardari
Volume 62, Issue 1 , June 2009
Abstract
The aim of this research was to determine the effects of Camphorosma monspeliaca species on soil nutrient elements in its habitat. For rangeland, ecological positive or negative effects of plant species on environment must carefully be examined before allowing their plantation in vast areas; on the other ...
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The aim of this research was to determine the effects of Camphorosma monspeliaca species on soil nutrient elements in its habitat. For rangeland, ecological positive or negative effects of plant species on environment must carefully be examined before allowing their plantation in vast areas; on the other hand this species with their special characteristics have special effects on their surrounding environment that should be considered. Camphorosma monspeliaca is one of non-native and adapted species in Chaharmahal and Bakhtiari province that its habitat has 3500 ha area. Effect of this species on environment requires more studies on their different aspects. Here we studied effect of this species on soil in order to assess its ecological effects on environment. This species distributed in all of the landscape but most distribution of species located at southern and northern aspects and in areas with flat topography. Companion species in topography position are different. This species can establish in non saline soil. The research was carried out at three stages of field sampling, soil test and statistical analysis. The research method was based on comparison between adjacent stand and stands of this species. Soil variables in two depth 0-10 cm and 10-30 cm were measured. Result showed that in two depths, were not significant difference but, in case of soil mineral elements, plant stands have significant difference; effect of depth and plant stands was not significant. There was significant difference adjacent stand and stands of this species in terms of Na, Mg, OC and in stands of this species were greater than the adjacent stands. This species increased content of carbon organic¬ and Na, Mg. From the results obtained on three topographic position, despite of negative effect of Camphorosma monspeliaca on sub soil with increase of Na and Mg, it can be concluded that Camphorosma monspeliaca had a positive effect on soil organic¬ matter. In general this plant has a good perspective and further studies about different aspects of this species are necessary.
