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Showing 292 results for Soil
Volume 0, Issue 0 (1-2024)
Abstract
Zeolites are recommended to utilize in agricultural sector due to their water holding and cation exchange capacity. Effect of zeolite on the hydraulic parameters of sandy loam soil was investigated and HYDRUS-2D was used to simulate the movement of water in the soil. Data needed were collected by conducting laboratory experiments. The studied treatments included four levels (zero, 5, 10, and 15 gr kg-1 of soil) to determine the effect of zeolite on hydraulic parameters including saturation moisture (θs) residual moisture (θr), shape parameter (n), point Check air permeability (α) and saturated hydraulic conductivity (Ks) of the soil. Four rounds of irrigation were done based on readily soil moisture and the soil moisture values before and after irrigation were measured using the Wet sensor in the depth and radial directions and recorded for 45 days. The initial value of hydraulic parameters including θs, θr, α, n and Ks were determined using Rosetta. Results showed that with increasing in the amount of zeolite, the parameters θs, θr and n increased and the value of α decreased, which indicated a decrease in the rate of water discharge from the soil. While the values of Ks tended to decrease. In fact, the mixing zeolite with soil causes to hold more water because of micro-pore structure of zeolites. The HYDRUS-2D model with the efficiency coefficient (EF), which shows the quality and how to fit the observed and estimated data, varied between 0.82 and 0.97, which shows the high efficiency of model in simulating humidity.
Volume 0, Issue 0 (1-2024)
Abstract
The surge in biogas energy production has resulted in an accumulation of liquid digestate, a byproduct with possible agricultural utility. To discern its benefits and shortcomings, a field trial was conducted to evaluate the effects of different doses of liquid digestate on maize yield, soil salinity, leaf and grain nitrogen (N) content. The study included both single-year and consecutive two-year applications of liquid digestate at doses of 10, 30, 50, and 70 t ha-1. Based on maize N requirements, any N deficit was supplemented with chemical fertilizers. For the one-year experiment, the highest grain yield was obtained from the chemical fertilization treatment and 70 t ha-1 dose of liquid digestate. In the two consecutive years, 70 t ha-1 dose gave the highest grain yield. Liquid digestate provided N to the soil as effectively as chemical fertilization and stabilized the soil pH within approximately 1 month. However high doses of digestate resulted in increased soil salinity and decreased N use efficiency (NUE). Consecutive two-year application increased electrical conductivity (EC) and pH stabilization in the soil to a greater extent than single-year applications. However, there was no difference in the N content of the plant between single-year and two consecutive applications. In summary, liquid digestate provides significant agricultural benefits such as pH stabilization and increased inorganic N levels. However, our findings indicate that overuse can lead to soil salinity and N losses, underscoring the importance of balanced application to maximize its benefits while minimizing potential drawbacks.
Volume 0, Issue 0 (1-2024)
Abstract
In Khuzestan province of Iran, the number of traffic passes made by heavy farm machinery in sugarcane land preparation varies depending upon field conditions, ranging from a minimum of 10 to a maximum of 16 passes annually. To reduce energy, time and cost, it is imperative to use conservation tillage as well as controlled traffic systems. The objectives of this research were to develop, and evaluate a combined strip deep tillage machine equipped with a two-level deep tillage implement including a dual sideway-share and a winged subsoiler, cum with a set of discs. For optimizing the dual-sideway-share subsoiler, the effects of share rake angle (7.5 and 15°) and length (150 and 200 mm) on the implement field performance were examined. Also, to optimize the winged subsoiler, it was tested with its wing having different lengths (0, 200, 250, and 300 mm). Finally, the performance of the developed combined strip deep tillage machine was compared with a conventional subsoiler used for deep tillage in the fields. The results showed that the optimized combined strip deep tillage machine should be equipped with the dual sideway-share subsoiler having a share with a 7.5° rake angle and 150 mm length, and the winged subsoiler with 250 mm length for its wing. The results showed that the specific resistance of the developed machine as compared to the conventional subsoiler decreased by 34%. Therefore, the machine has higher efficiency and is an environmentally friendly implement for sustainable sugarcane production in southwest Iran.
Volume 0, Issue 0 (1-2024)
Abstract
Topography, parent material, and climate are critical factors influencing pedogenesis and the clay mineralogy of soils. There is a paucity of data regarding the soils and sediments of the Jazmurian Watershed in south-central Iran. This study selected various landforms, including rock and mantled pediments, alluvial fans, piedmont plains, lowlands, and playa, characterized by igneous and sedimentary parent materials and situated within aquic, xeric, and aridic soil moisture regimes. The findings indicated that the most significant soil development occurred on rock and mantled pediments, as well as on older alluvial fan sediments, in contrast to the less developed soils found on younger alluvial fan deposits. The clay minerals identified through X-ray diffraction (XRD) analyses included smectite, illite, chlorite, palygorskite, and kaolinite. The presence of palygorskite in the sedimentary soils was attributed to inheritance from the parent material, while in soils derived from igneous parent material, palygorskite was formed through pedogenic processes. Pedogenic features associated with calcium carbonate, such as coatings, infillings, and nodules, as well as clay coatings and infillings, were observed in both aridic and xeric soil moisture regimes. The occurrence of clay pedogenic features in the arid regions of the watershed may suggest a historical paleoclimate with greater moisture availability. Conversely, lenticular shapes, interlocked plates, and gypsum infillings were exclusively noted in the arid regions and lower elevations of the watershed, reflecting the current arid climate. The study established a strong correlation between soil formation and the factors of climate, parent material, and relief within the area.
Volume 0, Issue 0 (8-2024)
Abstract
Soil stabilization techniques have traditionally relied on cement or lime, yet there remains a significant knowledge gap regarding the mechanical behavior of soil treated with innovative materials. Addressing this gap, this study delves into the mechanical properties of soil stabilized with polyurethane (PU) foam, nano-silica, and basalt fiber. Through rigorous experimentation, unconfined compressive strength (UCS) and direct shear tests were conducted on reconstituted silica and calcareous samples, each treated with various combinations of these additives. A comprehensive examination of parameters such as additive content and curing time was undertaken to elucidate their effects. The results unveiled a noteworthy enhancement in UCS and shear strength parameters (cohesion and friction angle) with the incorporation of PU foam, nano-silica, or their amalgamation with fiber. Particularly striking was the superior performance observed with the combination of PU and basalt fiber, showcasing remarkable improvements in the mechanical behavior of both silica and calcareous sand, especially when considering shorter curing times. The synergistic effects of PU and basalt fiber proved instrumental in fortifying the soil's structural integrity against environmental challenges. Furthermore, it was consistently observed that calcareous samples exhibited elevated UCS, and shear strength values compared to their silica counterparts. This discrepancy underscores the inherent differences in mechanical behavior between these two types of sand, highlighting the need for tailored stabilization approaches. Moreover, the investigation delved into the failure patterns and microstructural changes within the stabilized samples, employing Scanning Electron Microscopy (SEM) for detailed analysis. This microscopic examination offered valuable insights into the efficacy of the stabilizing agents and their impact on the soil's mechanical properties. For instance, SEM imaging revealed significant bonding in fiber-reinforced samples, indicating enhanced load transfer mechanisms. Similarly, the presence of clusters of nano-silica particles adhering to sand particles showcased an improved cohesion within the stabilized soil. PU-stabilized samples, on the other hand, exhibited a cohesive layer enveloping sand particle, thereby enhancing interparticle connectivity and overall stability. The superior performance of PU over nano-silica was underscored by its ability to create a more cohesive matrix and foster stronger interparticle bonds, as evidenced by the SEM analysis. In conclusion, this study sheds light on the potential of innovative stabilization materials such as PU foam, nano-silica, and basalt fiber in bolstering the mechanical properties of soil. The findings not only offer valuable insights into the efficacy of these additives but also pave the way for the development of tailored soil stabilization techniques geared towards enhancing infrastructure resilience and sustainability.
Volume 0, Issue 0 (8-2024)
Abstract
Despite the particular importance of the subject of soil-structure interaction, unfortunately, this issue has received little attention from engineers, and seismic codes have not given much recommendation to consider its effects. Seismic wave frequencies vary continuously, and the stiffness of springs and damping of dampers connected to structural supports also vary with the loading frequency. To simplify time-domain numerical analysis, a constant target frequency can be used to keep stiffness and damping values constant. In the substructure method proposed in this study, the optimal target frequency is the one that yields results that most closely match those of a more accurate nonlinear 3D model analyzed using a direct method. A common simplification is to ignore the foundation’s non-linear response, justified by design requirements to prevent permanent deformation and the complexity of frequency-dependent soil behavior. Though not fully precise, this approach (considering soil heterogeneity and optimal target frequency) offers a forward-looking analysis and a basis for future nonlinear studies. This study presents a three-dimensional (3D) numerical model for analyzing the seismic response of soil-foundation-structure systems embedded in granular soil (with different relative densities) considering the effects of soil heterogeneity (With varying shear modulus with depth and compatible with the practical HSsmall model). The model is capable of accounting for the effects of loading frequency along with the radiation damping of the soil system and can integrate with the widely-used substructuring method considering an optimal target frequency. After verifying the proposed model, the dynamic equilibrium equations of the substructuring system were solved in the time domain using Matlab software. The target frequency was determined using i) Case 1: the fundamental frequency of the soil (or the dominant frequency of the excitations), ii) Case 2: the fundamental frequency of the structural system, iii) Case 3: the fundamental frequency of the soil-foundation-structure system; iv) Case 4: the fundamental frequency of structure with static stiffness and damping support (Case 4); and v) the fundamental frequency of fixed base structure and modified stiffness, and the results were compared together. A comparison of the impedance (dynamic stiffness and damping) of foundations situated on homogeneous and heterogeneous soil, as well as an investigation of the structural response in both cases, is another objective of this research. The analysis results demonstrated the accuracy of the proposed model and the acceptable calculation speed for estimating the dynamic response of structures located on heterogeneous soils under frequent operational earthquakes. The results also showed that with an increase in soil relative density, the seismic behavior of structures on homogeneous and heterogeneous granular soils converges. For instance, the response of the foundation on homogeneous soil bed with relative densities of 55%, 75%, and 95% is on average 23%, 19%, and 15% lower than that of heterogeneous soil, respectively. Additionally, for determining the target frequency, the use of frequency‐independent Kelvin–Voigt models (i.e., Cases 1-5) provides acceptable responses. According to the data presented in Table 4 and Figs. 9 and 10, the following conclusions can be drawn: 1) The soil's fundamental frequency (Case 1) yielded the least precise results. 2) While Case 3 offered the most favorable response, closely matching the direct method, determining the soil-structure system's fundamental frequency through complex integration in numerical software is often impractical. 3) Employing the target frequency in Case 2 produced more satisfactory results than Case 1. 4) Cases 4 and 5 generated nearly identical frequencies. Compared to Case 2, these cases enhanced response accuracy, bringing them closer to the best response (i.e., Case 3). Therefore, for practical applications, it is recommended to utilize the fundamental frequency from either Case 4 or Case 5 instead of the soil-structure system's fundamental frequency (Case 3) to establish the optimal target frequency.
Volume 0, Issue 0 (8-2024)
Abstract
Foothills, plains, alluvial areas, and sloping areas whose soil is geologically susceptible to landslides, can become unstable and dangerous. In Iran, because of their soil type, Mazandaran, Gilan, Lorestan, Golestan and Khuzestan provinces are more vulnerable to landslides than other provinces. But taking into account factors such as earthquakes, extreme weather, and human interference, other parts of the country can also be prone to landslides. In case of rainfall and absorption of water by clay layers, the possibility of landslides increases. If the slope of the land is suitable, the slope will move on the clay layer and the thrust will occur downwards. In many mountains and steep areas, the conditions for slope failure may be available in terms of the slope angle, the type of soil and the presence of clay layers. But in the absence of sufficient soil moisture, this phenomenon is not observed. Landslides occur whenever rainfall happens and water penetrates the clay layer. Cutting down forest trees, destroying vegetation and pastures, along with possible rainfall and soil moisture, cam cause landslides on steep slopes. In fact, land use changes contribute to landslides. By examining the statistics over the last three decades in the northern provinces of Iran, it can be seen that landslides were far less likely when there was proper vegetation. The occurrence of heavy rains can cause failure in a large number of soil slopes. During these heavy rainfalls, the underground water level rises and increases the pore water pressure and reduces the stability of the soil. The purpose of this study is to investigate changes in pore water pressure and the factor of safety for slope stability. The flow of water inside the soil is numerically modeled as a two-dimensional, saturated-unsaturated, unsteady flow. The finite element method (FEM) is used to calculate the pore water pressure and the limit equilibrium method is used to determine the factor of safety for slope stability. To simulate the unsteady flow, time duration of 4 days is used with a time step of 0.1 days. The rainfall duration was assumed to be 24 hours. The intensities of different rainfalls are used as the input flux on the soil surface. The soil moisture curve, which shows the relationship between suction-moisture content and suction-hydraulic conductivity, is used. The results show that different rainfall intensities have different effects on soil moisture profile. As the intensity of precipitation increase, the factor of safety of slope stability decreases. This decrease is steeper for the first 24 hours of rainfall and over the three days after the rain stopped, its slope decreased. For example, for a rainfall intensity of 2.04 mm/hour and the duration of one day, resulted in a factor of safety of slope stability equal to 1.853, and at the end of the fourth day, it was 1.743. In other words, the factor of safety decreased by 5.9%.
Volume 0, Issue 1 (5-2011)
Abstract
Ground skidding on skid trails affects the physical properties of soil. The objective of this study was to evaluate changes in soil physical properties on skid trails formed due to traffic of metal-tracked skidders with regard to soil bulk density, total porosity, water content and penetration resistance. The studies were implemented on two levels of slope – <20% (SC1) and >20% (SC2) – and three levels of traffic (one, five and nine traffic cycles). The treatment plots with three replications, consequently, were 6 m long and 4 m wide. The measurement of soil penetration resistance was carried out using a cone penetrometer. The samples were taken from 10 cm of top soil at six points in each plot. The results indicated that the skidder traffic did not significantly affect the soil physical properties measured in three levels of traffic at SC1, whereas it was significant between one and five traffic cycles in SC2. Most of the changes in the measured properties in the skid trails occurred after the first loaded skidder traffic. Within all traffic of SC2, differences in the mean values of water content and soil porosity were greater compared with the mean values at the same traffic of SC1, although these differences were not significant. The bulk density and penetration resistance at five and nine traffics of SC2 were significantly different from the same traffic of SC1.
Volume 0, Issue 2 (8-2011)
Abstract
The relationship between topography, soil factors, and distribution of ecological vegetation groups in the Nodoushan arid rangelands of Yazd province (Iran) was investigated. The present species were recorded in each vegetation group using a randomized-systematic sampling method. Plant cover and density were estimated quantitatively using the transect and quadrate methods, and the two-way indicator species analysis (TWINSPAN), after which vegetation was classified into different groups. Soil samples were taken from 0–30 cm in each quadrat. In each vegetation group, 20 environmental variables including altitude, slope, aspect, percentage of bare rock, grazing intensity, percentage of gravel, soluble ions (Na+, K+, Mg2+, Ca2+), total nitrogen, organic matter, lime, gypsum, EC, pH, and percentage of sand, silt and clay were measured. Multivariate techniques including detrended correspondence analysis (DCA) were used to analyze the collected data. The results showed that the vegetation distribution was related to elevation, slope, and soil characteristics such as texture, organic matter, gypsum, acidity, lime, and gravity percentage.
Volume 1, Issue 1 (3-2013)
Abstract
In order to determine effects of chicken and cattle manures in culture of Chlorococcum, an experiment was designed in six treatments including; 0.1, 0.4, 0.8 g/l of chicken manure and 0.1, 0.4, 0.8 g/l of cattle manure as completely randomize design with three replicates for 28 days. Results showed that the mean maximum density (87.1 × 105 cell/ml), specific growth rate (0.054 day-1), algal dry biomass (0.644 g/l), and chlorophyll a (9.42 mg/l) were obtained with 0.8 mg/l chicken manure. In order to compare performance of these manures with other culture media, second experiment with five treatments including; BBM (control) (Bold’s Basal Medium), BBM + soil extract, 0.8 g/l chicken manure, 0.8 g/l cattle manure and mixture of all treatment (BBM, BBM + soil extract, chicken manure and cattle manure) was designed as completely randomize design with three replicates for 15 days. Comparative results showed that BBM + soil extract had highest algal density (11.6 x 106 cells/ml), highest algal dry biomass (0.81 mg/ml), maximum SGR (0.13 /day), highest chlorophyll a (10.15 mg/l) and minimum doubling time (4.97 days). In conclusion, performance of BBM + soil extract was better in terms of biomass and growth parameters of Chlorococcum.
Volume 1, Issue 1 (3-2013)
Abstract
The effect of soil and phanerogam characteristics on bryophytes composition, richness, abundance and functional groups were investigated in order to understand the factors responsible for bryophytes distribution patterns. Three different sand dunes were selected: untouched, artificial sod-covered and planted by Ammophila. Along 10 transects perpendicular to the shore, a total of 142 permanent relevés, located in three sand dunes, were sampled. In each plot, total cover of vascular herbaceous and bryophytes, and the percentage of litter were estimated. The average of vascular herbaceous height was measured. In each plot, EC, pH, CaCo3, texture and organic matter content of the upper 5 cm layer were also measured. Analyses using DCA and GLM showed that bryophytes abundance was decreased by EC and phanerogam abundance, while pH increased the species richness of bryophytes. EC increased the relative abundance of sexual species while decreased the relative abundance of asexual bryophytes species. The relative abundance of colonists increased in planted Ammophila sand dune while the relative abundance of perennial stayers was the highest in untouched sand dune. The successional stage should also be important in distribution pattern of bryophytes.
Volume 1, Issue 1 (3-2023)
Abstract
The overarching goal of this research is to use polymeric composites enriched with diatomic soil to improve petroleum-contaminated clayey soil. The effect of petroleum on the geotechnical properties of clayey soil was investigated in the laboratory in the first stage using uniaxial, direct shear, and permeability tests. The polymeric composite material was then created and mixed with the diatomic soil. The geotechnical properties of petroleum-contaminated clayey soil were studied using a polymeric composite material mixed with diatomic soil (PCD). Petroleum reduced the shear resistance, internal friction angle, and uniaxial resistance of the clay for contamination percentages ranging from 0% to 12%. Whereas 12 percent petroleum content causes the greatest changes in soil mechanical resistance. According to the results of the direct shear test, adding 5.5 percent PCD increases the shear resistance of the base material and contaminated base material to average values of 32 and 48 percent, respectively. Furthermore, the results of the petroleum permeability test show that adding 5.5 percent PCD reduces soil permeability. The results show that the improved clay by PCD can be used as a liner for the base of petroleum reservoirs.
Volume 1, Issue 2 (6-2013)
Abstract
Global warming is claimed to be the cause of climate change, which is often held responsible for water shortage. Let geopedology represents the complex process of soil formation, out of which much can be learnt about paleoecology; soil formation being a dynamic interaction between the atmosphere, biosphere, lithosphere, and the hydrosphere. In a multidisciplinary sustainability-oriented study in northwestern Iran, geopedologic data were analyzed and cross-referenced with some historic and archaeological information to reconstruct paleoecologic conditions in several time periods, through which the changes both in climate since upper Pleistocene, and in landuse and their consequences in terms of land degradation could be concluded. The occurrence of a (sub-) surface layer of travertine, dated 27,000 y BP that is coated by a thin organic layer with traces of rancienite (mineral), dated 13,000 y BP, implies a humid environment, corresponding with the pluvial uppermost Würm. The geopedologic survey, supported by soil micromorphology, revealed that between 6,000 and 2,600 years ago the area was subject to cycles of erosion and sedimentation that have led to glacis formation. A type of climate that is characterized by the alternation of wet and dry periods is also supported by the occurrence of Petrocalcic and Argillic horizons in the soils. Cultivating rice, tobacco and cotton, which was practiced until over a century ago, also implies relatively wetter conditions. The study concludes that aridification has never been as degrading as it is today, due to the over-exploiting of the non-renewable fossil groundwater.
The Effect of Planted Saltbush (Atriplex lentiformis) on Edaphic Factors in Grazed and Ungrazed Area
Volume 1, Issue 2 (6-2013)
Abstract
Re-vegetation of bare soil is believed to increase, or at least maintain the organic matter levels of soil. The aim of this study was to investigate the soil characteristics changes, nutrient pool sizes and their availability under mid canopy, and canopy gap positions of saltbush in an area re-vegetated with Atriplex lentiformis. Some of the physical and chemical soil characteristics (the particle size distribution, soil bulk density, EC, pH, Na, K, organic C, N, P, C/N ratio and C/P ratio) were measured in two different soil depths at both planted shrublands and control area. The results from samples analysis showed that the soil of the control area is significantly different from the Atriplex shrublands area. Maximum of K and Na proportion were measured in 0 to 20 cm under mid canopy in the planted sites. K and Na in different soil layer showed a significant difference between ungrazed area, grazing area and control area (P
Volume 1, Issue 3 (9-2013)
Abstract
This study was conducted to choose the best species for plantation on a poor drainage soil in southern coast of Caspian Sea, Iran. Nutrient concentrations in live and senescent leaves and soil properties were compared among Alnus subcordata C.A.Mey (N-fixing tree), Populus deltoides Marsh. (Non N-fixing tree)and Taxodium distichum (L.) Rich. (Coniferous tree) plantations. In each of these plantations and an adjacent natural forest, six 20×20m plots have been selected according to a 100m × 100m randomly systematic grid. Leaf samples of green trees were collected from the bottom one-third of the tree crown by clipping two small twigs located on opposite sides of the crown (six representative trees were sampled in each plot). Senescence leaves have been collected inside wooden trap-based in each stand. Results revealed different effects of species on soil nutrients. Alnus subcordata increased soil N (%) whereas Populus deltoides and Taxodium distichum reduced it.The results of nutrition, litter quality, retranslocation and soil properties indicated that Alnus improve soil quality in comparison with the two others.
Volume 1, Issue 3 (9-2023)
Abstract
Changes in pore fluid can significantly impact the geotechnical behavior of soil, especially clayey soil. One source of soil contamination is leachate, which can infiltrate nearby soil during the collection, transportation, and deposition stages of the residential waste disposal process, exerting geotechnical influences on the soil in the surrounding area. To assess these effects, four leachate samples were collected from different sites. The specimen comprises fine soil, created from a mixture of sand, bentonite, and kaolinite. Experimental results reveal a decreasing trend in the liquid limit, compaction parameters, and cohesion values of the soil with an increase in contamination level. However, the internal friction angle exhibits an increasing trend with higher leachate concentration, resembling the behavior of sandy soil, as opposed to the typical behavior of clay.
Volume 2, Issue 1 (1-2000)
Abstract
Floodwater spreading (FWS) for the artificial recharge of groundwater (ARG), is an easy and economical method of desertification control. An integrated approach to desertification control based on FWS for the ARG was adopted in the Gareh Bygone Plain in southern Iran. Deposition of the suspended load (SL), carried by floodwater into the sedimentation hasins and infiltration ponds, stabilizes the drifting sand and reclaims the eroded rangeland on which the ARG projects are executed. Results of some of the physical and chemical analyses performed on the one to four-year-old sediment samples obtained from the first three sedimentation basins at the Gareh Bygone Plain ARG scheme show that of the 19 factors analyzed, only two changed significantly due to the settlement of the SL in the basins: sand content decreased by 7.9 and 3.8% at the 0-10 and 0-30 cm depth respectively; and the ESP increased by 17.2% at the 0-30 cm depth. Regression equations were developed correlating soil content of organic matter, total N,P, saturation percentage and CEC with silt + clay content. These relationships indicate the geological origin of N and perhaps P and the importance of SL in the fertility status of the drifting sand.
Volume 2, Issue 1 (3-2014)
Abstract
This research investigates the vegetation of 4600 ha of Polour semi-steppe rangelands in relation to edaphic and physiographical parameters in Mazandaran province. For this purpose, 23 land units were selected from overlaying slope, aspect and elevation maps using geographic information system (GIS). Within each unit, 3 parallel transects with 100 m length, each containing 10 quadrates (according to vegetation variation) were established. Sampling method was Random systematic. Measured soil properties included texture, organic matter, pH, electrical conductivity, nitrogen, phosphor, and litter. Soil and plant data were analyzed with redundancy analysis and SHAZAM 10 package. RDA analysis suggesting that there is a relatively high correspondence between vegetation and environmental factors that explain 93% of the total variance in data set. RDA results showed that soil slope, aspect, soil texture, acidity, phosphor, and litter were the major environmental factors responsible for variations in vegetation patterns. Furthermore, results also showed that for F .ovina and P .bulbosa, acidity and nitrogen, for A .gossypinus, organic matter and salinity and for D .glomerata, nitrogen have the most important role in plant presence and absence probability.
Volume 2, Issue 1 (3-2014)
Abstract
The present study was conducted to determine the most appropriate tree species planted in the same ecological condition considering different variables at Darabkola forest, Mazandran Province. For this purpose, the success of planted species (maple, walnut, oak, pine, ash and elm) was assessed according to ninecriteria (soil nitrogen, soil phosphorus, soil potassium, leaf nitrogen, leaf phosphorus, leaf potassium, growth of diameter at breast, diameter at breast, H/D: height/diameter at breast height ratio). Analytical Hierarchy Process (AHP) was used to assess forest stands based on multiple criteria. Results showed that the maximum local priority of average annual growth, and leaf and soil nitrogenwere observed in pine stands, while the highest levels of phosphorus, potassium, and DBH were recorded for maple plantation. The calculated overall priority showed that based on concerning criteria, pine stand had higher growth and nutritional potential compare to the other stands, while other stands ranked as maple> elm> walnut>oak> ash. In conclusion, our findings from AHP suggested that the growth rate and nutrition ofpine and maple stands had more appropriate condition and efficiency than other stands and therefore found suitable for plantingin the study area.
Volume 2, Issue 2 (6-2013)
Abstract
Edaphic Mesostigmata are important, because these feed on arthropods and other invertebrates which may affect on natural equilibrium position of oter living micro-organisms. In order to study the fauna of mesostigmatid mites, samples of soil, litter were collected from different parts of Esfahan region. Mites were extracted by means of Berlese funnel, cleared in Lactic acid and mounted with Hoyer's medium. In this research, the world and Iranian distribution of species with some information about their habitats were provided. Two genera and 3 species were recorded as new records for Iran mite fauna that are marked by an asterisk. The list of identified genera and species is as follows: Ascidae: Arctoseius cetratus (Sellnick, 1940), A. pristinus* Karg, 1962, A. venustulus (Berlese, 1917), Gamasellodes bicolor (Berlese, 1918); Blattisociidae: Lasioseius sugawarai Ehara, 1964, L. youcefi Athias-Henriot, 1959; Melicharidae: Proctolaelaps pygmaeus (Muller, 1860); Parholaspididae: Proparholaspulus* angustatus* Ishikawa, 1987 Trachytidae: Uroseius* traegardhi* (Hirschmann & Zirngiebl-Nicol, 1969).