Mehdi Ganji; Gholamreza Zehtabian; Mohammad Jafary; Hasan Khosravi; Reyhaneh Masoudi
Volume 22, Issue 1 , June 2015, , Pages 12-20
Abstract
In many parts of arid and semi-arid regions of Iran, agricultural activities such as mismanagement of land as well as inappropriate irrigation systems have seriously led to land degradation and desertification. Therefore, it is necessary to do some researches in order to determine which region is suitable ...
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In many parts of arid and semi-arid regions of Iran, agricultural activities such as mismanagement of land as well as inappropriate irrigation systems have seriously led to land degradation and desertification. Therefore, it is necessary to do some researches in order to determine which region is suitable for agriculture or not and if the region is suitable, what type of agriculture management should be applied prevalently. To achieve this goal, a region in Arak Mighan playa (Savarabad watershed) was chosen. At first, different maps of region including soil map, elevation and land use maps were prepared by ArcGIS 10.1. Five land uses were recognized as treatments including garden lands, dry farming systems, irrigation lands, dry lands and rangelands. Soil samples were taken and soil factors including N, Ca, Mg, and Humus as well as degradation factors such as EC, SAR, pH, Na and Hco3 were measured at two depths of 0-30 cm and 30-60 cm. The analysis of factors was done by SPSS software and results showed that there were significant differences among treatments based on Duncan test. In addition, rangeland was identified as a favorable treatment in terms of EC, pH, SAR in the surface layer. According to the results, it was found that rangelands had ideal conditions and dry farming and dry lands were identified as the most unfavorable treatments.
Firoozeh Moghiminejad; Mohammad Jafari; Mohammad Ali Zare Chahooki; Yaser Ghasemi Arian; Asghar Kohandel
Volume 21, Issue 4 , March 2015, , Pages 643-650
Abstract
Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and ...
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Exclosure is the prevention of livestock access to all or part of the rangeland for one year or a few consecutive years, performed with different goals. This research was aimed to investigate the effect of exclosure on soil physical and chemical properties as well as three main elements of N, P, and K in Nazarabad region, Karaj. Soil sampling was performed in both sites of exclosure and grazing. Soil samples were taken from the beginning, middle and end of the four transects, established in each region, at two soil depths of 0-20 cm and 20-80 cm using systematic random sampling. The following soil properties were measured in the lab: pH, EC, organic matter, saturation percentage, and N, P, K. According to the obtained results, the effect of exclosure on soil N, P, and K was significant; however, exclosure had no significant effect on pH, organic matter and saturation percentage. Overall, our results clearly showed the positive impact of exclosure on soil physical and chemical properties.
Yaser Ghasemi Arian; Hosein Azarnivand; Firoozeh Moghimi Nejad; Mohammad Jafary; Esmaiel Filekesh
Volume 21, Issue 3 , December 2014, , Pages 394-408
Abstract
This research was aimed to determine the rangeland suitability for sheep grazing in Chahtalkh-Sabzevar rangelands using FAO (1990) method. Initially, the DGN maps, including six sheets of 1:25000, topographic map of 1:50000, and geological map of 1:100000 of the study area were prepared and the vegetation ...
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This research was aimed to determine the rangeland suitability for sheep grazing in Chahtalkh-Sabzevar rangelands using FAO (1990) method. Initially, the DGN maps, including six sheets of 1:25000, topographic map of 1:50000, and geological map of 1:100000 of the study area were prepared and the vegetation types were detected. In each vegetation type, range condition, range trend and production were determined to produce the production suitability map. Then, the soil erosion sensitivity map was prepared using EPM method. To study the suitability of water, water sampling was done and the quantity of water was determined. Water samples were transferred to the laboratory to measure TDS, EC and Mg+2 for each sample. Finally, the suitability map of water resources was produced by combining the layers (provided for four slopes including 0-10%, 10-30%, 30-60% and >60%). The final model of rangeland suitability was prepared by overlaying the maps of production suitability, soil susceptibility to erosion and water. According to the obtained results, there is no suitability S1 class in the region and 23.7%, 18.92%, and 56.9% of the study area have S2, S3, and N suitability classes, respectively. Generally, it can be said that the conversion of rangeland to dryland, overgrazing and early grazing, formations susceptible to erosion, low vegetation cover, salinity, and improper distribution of drinking water sources for livestock are considered as the most important limiting factors for sheep grazing.
Abolfazl Rahmatizadeh; Mohammad Jafary
Volume 21, Issue 3 , December 2014, , Pages 496-506
Abstract
Due to the population growth and human intervention in nature, desertification has increased drastically. The Masileh watershed is located in the southern highlands of central Alborz. In this study, vegetation condition, the volume of water entering the area, soil chemical characteristics, and ...
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Due to the population growth and human intervention in nature, desertification has increased drastically. The Masileh watershed is located in the southern highlands of central Alborz. In this study, vegetation condition, the volume of water entering the area, soil chemical characteristics, and agricultural production statistics of the region were examined and compared before and after the construction of dams during two periods with an interval of five years. Results showed that since the construction of 15- Khordad dam in 1995, the volume of water entering the Masileh plain has reached zero.The hydrograph study showed that the groundwater level of Masileh plain has dropped on average five meters/year. Due to the lack of flood entering and soil washing, the salt concentration of soil surface layers in most vegetation types has increased. Due to the lack of root access to water, the canopy cover percentage in halophyte vegetation types with shallow roots such as Aeloropus litoralis and Cyperus sp has been reduced up to 100%, and new species such as Halocnemum strobilaceum and Halostachys caspica have been replaced. In terms of agriculture, significant changes have occurred in the composition and type of agricultural crops. Our results clearly showed that the Masileh plain is turning from a productive agricultural area into a real desert.
Azin Jafarian; Mohammad Jafari; علی طویلی
Volume 21, Issue 1 , June 2014, , Pages 51-61
Abstract
Ecological effects of Haloxylon plantation on natural vegetation and soil properties were investigated in this study. For this purpose, three regions with 1 to 5-year-old, 5 to 10-year-old and over 20-year-old Haloxylon (Haloxylon persicum) and a control area for each region were determined. Vegetation ...
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Ecological effects of Haloxylon plantation on natural vegetation and soil properties were investigated in this study. For this purpose, three regions with 1 to 5-year-old, 5 to 10-year-old and over 20-year-old Haloxylon (Haloxylon persicum) and a control area for each region were determined. Vegetation sampling was conducted along a 300-meter transect to record crown cover percentage, density, production, litter, gravel ،bare soil ،species diversity and dominant species. In addition, soil sampling was performed at depths of 0-30 and 30-90 cm to measure soil properties including EC, pH, percentage of organic carbon, soluble calcium, magnesium and sodium, and silt, clay and gravel percentage. The study was performed through random-systematic sampling. Data were analyzed using independent t-test in SPSS software. Results indicated that Haloxylon plantation led to increase in percentage of crown cover, litter, and standing crop production. It also caused improvement in species composition, condition and trend as compared to the control area. Plantation of Haloxylon with different ages affected and increased soil electrical conductivity.
Mohammad Jafari; Hossein Azarnivand; Mahshid Souri; Seyedeh Khadijeh Mahdavi
Volume 21, Issue 1 , June 2014, , Pages 95-108
Abstract
Water deficiency and low soil moisture, are considered as limiting factors in rehabilitation and improvement of semi-arid rangelands. Considering the problem of water deficiency and low soil moisture in pastures discussed, rainfall storage projects can be one of suitable strategies to compensate for ...
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Water deficiency and low soil moisture, are considered as limiting factors in rehabilitation and improvement of semi-arid rangelands. Considering the problem of water deficiency and low soil moisture in pastures discussed, rainfall storage projects can be one of suitable strategies to compensate for water shortages in such areas. On the other hand, considering several criteria that must be considered in this selection, makes it difficult to choose the appropriate locations to execute projects such as pitting and furrowing. These factors include technical and social-economical criteria. Meykhoran region in Kermanshah Province was considered in this research. In this study, in order to locate suitable areas for pitting and furrowing projects, spatial decision support system were used in three stages. The first stage involves determining hierarchical levels consisting of object, criteria, sub-criteria, and factors. During the second stage, the standardization of criteria based on fuzzy logic, weighting criteria and sub-criteria based on analytical hierarchy process, and paired comparisons of criteria and sub-criteria, with preference values of one to nine and an inconsistency rate of less than one-tenth, were done in ARC-GIS software by using AHP subprogram. In the final step, after integration of these layers, the final maps of optimal sites for pitting and furrowing were prepared. Using this template to locate other natural resources projects will help to optimize use of spatial data, save time and costs.
Hossein Arzani; Javad Moetamedi (Torkan); Mohammad Jafary; Mehdi Farahpour; Mohammad Ali Zare chahooki
Volume 20, Issue 2 , June 2013, , Pages 271-250
Hamed Joneidi Jafari; Hosein Azarnivand; Mohammad Ali Zare Chahooki; Mohammad Jafary; Ebrahim Kargari
Volume 20, Issue 2 , June 2013, , Pages 298-308
Zeinab Jafarian; Hossein Arzani; Mohammad Jafari; Ghavamedin Zahedi; Hossein Azarnivand
Volume 19, Issue 3 , December 2012, , Pages 371-381
Abstract
This research was aimed to investigate the relationships between dominant rangeland species and environmental factors in the Rineh rangelands located on the southern slope of Damavand Mountain. Stratified random sampling method was applied and the study area was classified to 37 sample units based upon ...
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This research was aimed to investigate the relationships between dominant rangeland species and environmental factors in the Rineh rangelands located on the southern slope of Damavand Mountain. Stratified random sampling method was applied and the study area was classified to 37 sample units based upon elevation, slop and aspect.
In the study area, 750 plots 1m2 and 75 plots 25m2 were established. One hundred and fifty soil samples were dug at the depth of 0-30 cm and 16 soil properties including pH, CaCo3, bulk density, particle density, total phosphorus, total nitrogen, absorbed potassium, organic matter, saturation moisture, soil texture, field capacity, permanent wilting point, available water capacity and water holding capacity were measured in laboratory. After collecting the climate data, 16 climate factors including average relative humidity, average rainfall, average temperature, average minimum temperature, average maximum temperature in spring, summer and annual as well as annual frost days were selected to reconstruct the missing data. IRS images including red and near-infrared bands and PAN band as well as combined bands derived from RVI, NDVI, and PCA were selected. Regression equation was developed for each species using logistic regression. Results indicated that most of the factors including slop, aspect, average minimum temperature in spring, number of frost days, average daily temperature in summer, and most of the soil factors were entered in regression models. Also, satellite data were used as effective tools in showing the presence of plant species.