جستجوی مقالات مرتبط با کلیدواژه « پیتینگ » در نشریات گروه « جغرافیا »

 Saqezchi-Chay watershed is important because of suitable ecological factors, high plant and animal production, and a water reservoir dam in the outlet part of this watershed. However, it is heavily used, overgrazed, and degraded. Therefore, this research aimed to locate different watershed management operations using a multi-criteria approach and compare AHP and ANP decision support methods in the geographic information system environment at the level of the Saqezchi-Chay watershed.

 The research criteria and sub-criteria include soil (depth and texture), climate (climate type and precipitation amount), land use and Normalized Difference Vegetation Index (NDVI), hydrological factors and soil protection (sedimentation rate, and curve number), topography (elevation, slope, and aspect), and economic and social (distance from the village, distance from the road and distance from the spring) were selected. Expert judgments for weighting were collected through a questionnaire in the field with a statistical population of 29 experts and academic staff members.

 The results of this research showed that the spatial prioritization of planting and pitting operations by the ANP method has a significant correlation with the AHP method at the 95% level and with an intensity of 0.937 and 0.957, respectively.

 According to the field visit and the evaluation of the success of the executive operations in the watershed, the ANP method prioritizes more accuracy and resolution due to its network nature and increasing the range of changes.

Innovation:

 In this research, an attempt has been made to develop a new operational framework for extracting and introducing different watershed projects based on information-based methods and mapping and using the AHP and ANP frameworks by removing expert opinions (especially when the expert does not have enough experience) to choose the best project in the best place.

This study aimed to select favorable site using analytic hierarchy process (AHP) for practices including seeding and seed broadcasting, hoeing and seeding, contour furrowing, pitting and flood spreading to restore degraded rangelands Ghayen Plain, Iran. First, major effective criteria in selecting favorable sites for range restoration measures were adopted from the reputable literatures. Then, 80 questionnaires in the form of pair matrix were designed for each restoration measure with regard to the selected criteria. Questionnaires were distributed among lecturers, experts and authorities in local universities and offices. Final score and relative importance of criteria were calculated on the basis of geometric mean of questionnaires. Hierarchical tree structure with appropriate adaptability was generated in Expert Choice software. Results showed that rainfall and slope played an important roles in selecting favorable site for pitting. Soil infiltration rate and runoff volume had the highest relative importance in selecting suitable site for flood spreading project. Furthermore, for seeding and seed broadcasting practices climate and slope showed high relative importance. Rainfall expressed high relative importance in selecting favorable site for hoeing and seeding projects. Finally, slope and runoff volume were the major criteria in selecting site for contour furrowing project. Based on the generated location maps, 628 ha were suitable for flood spreading. In addition, the suitable area for the contour-furrowing and pitting operations was estimated to be 103 and 199 ha, respectively. The area of suitable sites for direct seeding and hoeing and seeding operations was calculated to be 3623 and 2750 ha, respectively.

Rangelands not only contribute to forage production, but also play an important role in terms of sustaining environment and habitats, by production (medicine plants), biodiversity, soil and water conservation, curtailing greenhouse gasses as well as enhancement of truisms industry. However, rangelands, particularly winter-side ranges are suffering from improper utility, converting to other land uses (mainly rain-fed lands) and fire burning. The preset study, which was conducted in the Ghasreshirin (Kermanshah, Iran), aims to to evaluate the effects of rehabilitation measures on vegetation and soil. The measures were selected as the experimental treatments including Furrowing-Pitting-Preservation (FPP), Pitting, Brush- planting- Preservation (PBP), Grazing Management (GM) and Current Utility (CU). The characteristic of vegetation including biomass production, capacity, trend, condition were assessed using both transect and quadrate performance. Soil sampling also carried out from soil surface (0-10 cm) and subjected to soil analysis mainly texture, pH, electrical conductivity (EC), calcite (TNV) and soil organic carbon (SOC). The statistical analysis revealed that there were significant differences for some variables among treatments. Thus, forage production in PBP was significant higher level (551 kgha-1) compared to CU treatment (196 kgha-1). Furthermore, the respective values of SOC in the first, second, third and fourth treatments were 0.82, 0.90, 0.86 and 0.38 percent, indicating the effect of measures on SOC enhancement in the study area, while there was higher in PBP treatment. By and large, we can prioritize the effective treatments for sustaining rangeland FPP, PBP and GM, respectively. These rangelands are being degraded through over utility of these rangelands and converting them to other land uses. Moreover, these rangelands are located at the geological marls formation (Aghajari Formation) inducing a soil with high level of silt content and subsequently susceptible to wind erosion where subjected to overgrazing and converting to other land uses. This situation may attributes to severe water and wind erosion as well as desertification making sources for dust blowing and other environmental impacts.
Extended Abstract
1- Rangelands cover most parts of lands worldwide. In Iran, rangeland includes 54% of country area in which 1.2 million ha is located in Kermanshah Province. However, rangelands are suffering from improper management and utilization activities, impacting environmental hazards and unsustainable activities at the local, regional and global scale. Considering relevant literature review and research results, both soil and vegetation of rangelands are negatively affected by improper grazing (early and heavy grazing) and management that can be curtailed through rangeland rehabilitation measures mainly grazing management, seed sowing, furrowing, pitting and runoff harvesting. ), the objective of this research which was conducted in the Ghasreshirin Kermanshah, Iran, was to evaluate the effects of rehabilitation measures on vegetation and soil characteristics.
2- The study site (Chegha-hamam) is located in Ghasreshirin, west Kermanshah province, Iran representing the winter rangelands within province. The mean annual rainfall is about 300 mm, thus Salsola regedula and annual species are dominant vegetation. The rehabilitations practices were measured based on range management projects that was planned and lunched by Natural Resources Office of Kermanshah province during 2010-12. In this study, each measure supposed as an experimental measure comprise furrowing + shrub planting (FSP), pitting + shrub planting (PSP), grazing system management (GSM) and current improper grazing or control treatment (CT). The planted shrub was Atriplex sp. Total 32 soil samples were taken from surface layer (0-10 cm) and air-derided for soil analysis including soil organic carbon (Walky and Black method), particle size distribution (hydrometric method), carbonate (titration method), pH (saturated paste) and bulk density (natural core sample). The characteristic of vegetation including biomass production, capacity, trend, condition were assessed using both transect and quadrate performance.
3- Results explored that FSP, PSP and GSM contributed considerable improvement in vegetation cover compared with CT. Thus increasing in plant cover was found about 60% for Salsola regedula and Atriplex sp.in these treatments, while there was 395 in CT.Furthermore, plant litter also enhanced and soil bare was reduced as the consequent of plant cover. However, the hit of heavy and early grazing in CT caused negative rangeland trend and subsequently reduction in plant cover pattern mainly frequent of annual vegetation and accelerating soil erosion and compaction. The statistical analysis revealed that there was a significant difference for some SOC level among treatments. The higher level of SOC was found in PSP (0.90%) compared with CT (0.38%). In contrast there were no significant changes through treatments for electrical conductivity, pH, sand, silt and clay variables. In other hand, the furrowing and pitting did not affect these soil characteristics, while the change in plant cover, SOC and its sequestration was significant through treatments. The sequestered SOC in FSP, PSP, GSM and CT was 1043.91, 1145.60, 874.71 and 509.20 kg ha-1, respectively indicating higher level (p<0.05) in FSP compared to CT. Thus, biomechanical measure (furrowing and pitting) cause reduction in SOC emotion.
4- Considering these results, proper grazing and biomechanical measures attribute to significant increase in vegetation cover, plant litter and adversely reduction in bare soil. Although some chemical and physical soil characteristics were not affected by treatments, the SOC was improved followed by vegetation cover leading to the enhancement of SOC from 0.28% to 0.90%. Based on relevant literature reviews, most similar researches confirm the effects of proper management and soil conservation measures, particularly grazing management, furrowing, pitting and rainwater catchment on SOC stock and carbon sequestration.
By and large, we can prioritize the effective treatments for sustaining rangeland FPP, PBP and GM, respectively. These rangelands are being degraded through over utility of these rangelands and converting them to other land uses. Moreover, these rangelands are located at the geological marl formation (Aghajari Formation) inducing a soil with high level of silt content and subsequently susceptible to wind erosion where subjected to overgrazing and converting to other land uses. This situation may attribute to severe water and wind erosion as well as desertification making sources for dust blowing and other environmental impacts.

The aim of this research is control of run off and its storage in the ground in other to increase th evegetation cover through increase soil moisture. In this research, the effects of two mechanical structure of pitting and contour furrowing techniques in comparison with the witness on the changes of vegetation cover of the adjacent area of Iranshahr thermal powerplant were studied. In this relation, for recognition of the effect of each structure and the presence of vegetation cover, by three pitting, contour furrowing and witness in four repetition of a slope of about 3% has been conducted in the form of a full random statistical plan form. For this purpose, with respect to the amount of input run off, some rigs with dimension of 20*40 m , by considering the slope direction were established and at the farthest end of each rig, some basins have been constructed for run off measuring.Upon each growing season, the measurement of vegetation cover has been made and at the end of the research, the data were intered in to SPSS software and statistical analysis have been made on them. The findings indicated that there is a significant difference( 0.01%) between different treatments ( witness, pitting ,contour furrowing) from the view point of producing fodder , percentage of vegetation cover and young plants. It means that the performance of storage operations of precipitation is effective on the amount of foddy the vegetation cover. Variance analysis of witness treatment and pitting by lSD sttatistical method showed that the amount of obtained LSD (0.113) is more than the mean differences of witness and pitting treatment. On the other words, performing pitting operations has no effect on the increase of foddy production. Also comparing the data of witness and contour furrowing treatments, revealed that LSD amount has a lower significant difference than the mean difference of contour furrowing and witness. Therefore, performing contour furrowing operations has had a positive impact on foddy production.