Ayad Aazami; Morteza Akberzadeh; Mashaallah Mohmadpour
Volume 27, Issue 1 , April 2020, , Pages 1-12
Abstract
Rangeland capacity depends on forage produced in the rangeland, the permitted range of plant species, forage quality and rangeland health. Range species have a certain production in months and years. Without recognize properties production plants and the rate consumption forage rangeland cannot programming ...
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Rangeland capacity depends on forage produced in the rangeland, the permitted range of plant species, forage quality and rangeland health. Range species have a certain production in months and years. Without recognize properties production plants and the rate consumption forage rangeland cannot programming and management at during a period of grazing. This study was conducted at 2009-2013 years, and rate forage production and utilization was measured. The rate of precipitation annual at 3 years were 138, 200 and 330 millimeter respectively. The results showed that total forage production was significantly different between years (p<0.01). Forage production were 485.7, 1372 and 1844.4 Kg per hectare respectively. The amount of production in the months of growing season (March to August) were significantly different, so 94.7 of pasture growth in the first 2 months (March and April) and three fifths% by feed-in last 4 months. The annual consumption of respectively 400 and 751 and 490 kg per hectare. Although not statistically significant, But in the dry year of 2008, 83% and in the wet year of 1389, 26.6% were used of pasture production. Therefore, in drought, at the same time as the reduction in forage production, the livestock utilization rate increased by 83%, which is not proportional to the rangeland capacity. Therefore, in order to achieve sustainable production, proper management of rangeland and the use of indigenous species such as Onosma bulbotrichum, Ankyropetalum gypsophiloides, Convolvulus reticulatus and Salvia compressa are recommended.
Zahra Saiedifar; Mohammad Rahimi; Sakineh Lotfinasabasl; Mohammad Khosroshahi; Mohammadreza Yazdani
Volume 26, Issue 1 , June 2019, , Pages 143-157
Abstract
Jazmurian basin in the southeast of Iran is one of the most important and vital basins. Due to the lack of surface water resources and placing in the priority of use this basin is faced with a sharp decline in the level of underground aquifers.TheThe aim of this study was to identify ...
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Jazmurian basin in the southeast of Iran is one of the most important and vital basins. Due to the lack of surface water resources and placing in the priority of use this basin is faced with a sharp decline in the level of underground aquifers.TheThe aim of this study was to identify the factors affecting groundwater resources and predict the groundwater level and its variation in Jazmourian Basin. In this study by considering the importance of identifying the factors affecting the condition of groundwater resources and the causes of decline, initially, the geological and geomorphological features of the basin and its impacts on the quantity and distribution of the groundwater resources were studied. Then, the effect of hydrological droughts with using two streamflow index (SDI) and the standardized precipitation index (SPI) at hydrometric, pluviometric, and synoptic stations located in the basin aquifers was studied. The portion of perceptions on changes in groundwater resources by wells, spring, and aqueducts, as well as the impact of surface structures and expenditures on land surface level changes were determined. In addition, the average monthly and annual mean of groundwater levels during the years 1370-93 were investigated using time series models to predict groundwater changes by the year 1420. The study results on the effect of different factors on groundwater water changes showed that hydroclimatic droughts, although affecting underground water changes, did not have a significant effect. The dams and deep and semi-deep wells with negative correlations of 0.83, 0.75 and 0.68 had the most negative effects on groundwater drops, respectively, and the average discharge of wells and springs increased significantly with increasing groundwater level. Also, the study of changes in groundwater level in the basin indicates a significant decrease (0.37 m / year) and predictions show that in the coming years it will face more severe losses. The high level of decline was observed in the summer with a change of 1.96% and in the autumn it was 1.78% lower than the other seasons. Overall, the results showed that if the current trend of exploitation of the groundwater resources continues, the region will be facing more challenges.
Mohsen Sharafatmand
Volume 23, Issue 3 , January 2017, , Pages 627-635
Abstract
There are various methods to measure the utilization of grasses that each of these methods has its own advantages and disadvantages. The use of utilization gauge for grasses and grass-like species is one of these methods. This research was aimed to investigate the efficiency of utilization gauge in determining ...
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There are various methods to measure the utilization of grasses that each of these methods has its own advantages and disadvantages. The use of utilization gauge for grasses and grass-like species is one of these methods. This research was aimed to investigate the efficiency of utilization gauge in determining the utilization rate of native grasses in Iran. Thus, the utilization rate of Agropyron cristatum and Stipa barbata was measured by utilization gauge method, and the conformity of results with the weight ratio method (control) was assessed by linear regression. Since the utilization scales are prerequisite to the use of utilization gauge, which currently do not exist in our country, first these scales were developed. For this purpose, 30 plant individuals were sampled, of which 25 individuals were used to provide utilization scales and five individuals were used to evaluate the conformity of the two methods. According to the results, the two methods showed good conformity, so that the utilization gauge could be used to estimate the utilization of grasses. Since this method is rapid, non-destructive, and cheap, the use of utilization gauge is recommended to estimate the utilization rate of native grasses.
Mohsen Sherafatmandrad; Gholamali Heshmati; Mohammadrahim Forouzeh; Hosein Badripour
Volume 21, Issue 3 , December 2014, , Pages 447-454
Abstract
Measurements of production and utilization of key range plant species are of utmost important tools for making range management decisions specially for stocking rate determination. A study was conducted to examine the relationships of production and utilization of Agropyron cristatum and Stipa barbata, ...
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Measurements of production and utilization of key range plant species are of utmost important tools for making range management decisions specially for stocking rate determination. A study was conducted to examine the relationships of production and utilization of Agropyron cristatum and Stipa barbata, as key grasses in Chaharbagh region of Golestan province, with some dimensional parameters. For this purpose, plants height, basal diameter and canopy diameter and their dry weights were measured. Primarily, correlation matrices and Pearson correlation coefficient were used to assess the relationships of these three dimensional variables with production. The three variables were then evaluated for predicting production by using best subset and stepwise regression approaches. Utilization was assessed based on percentage of height removed in relation to percentage weight removed. Results showed that basal and canopy diameters could usefully predict the production of the two grasses. Finally, because of subjectivity of canopy diameter measurements and its weak role in explaining production variations, just basal diameter was considered in models, having linear relationship with production and the coefficient of determinations were calculated to be 72.4 and 71 for A. cristatum and S. barbata, respectively. Therefore, dimension analysis is an appropriate approach to estimate the production and utilization of range key grasses.
Reza Tamartash
Volume 19, Issue 3 , December 2012, , Pages 469-481
Abstract
In mountainous rangelands, there is a complex combination of factors such as topography, vegetation growth stages and water distribution which affect grazing distribution. This research was conducted to investigate the effect of topography on vegetation of summer rangelands of Vaz, Mazandaran province. ...
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In mountainous rangelands, there is a complex combination of factors such as topography, vegetation growth stages and water distribution which affect grazing distribution. This research was conducted to investigate the effect of topography on vegetation of summer rangelands of Vaz, Mazandaran province. Five utilization units were selected on the basis of field survey and identifying homogenous grazing units. Key areas were obtained in each unit and sampling was done randomly. Size of the quadrates was 1m2 and the number was calculated by statistical method. In each quadrate, yield was measured by clip and weigh method and utilization rate was determined using height to weight ratio (based on dry weight). Vegetation cover percentage was also recorded. Finally, comparison of plant characteristics in utilization units was performed by SPSS in a completely randomized design with unequal replications. Then, correlation coefficient between each of the independent variables (slope, aspect and height) and dependent variables (yield, canopy cover percentage and utilization) was determined. Also, the most effective factor and interaction effects of independent variables were obtained by stepwise multiple regression analysis. Results showed that slope and aspect had the most correlation with livestock utilization respectively, but no relationship was found for elevation while it affected yield and canopy cover.