نشریه آب و خاک
سال سی و چهارم شماره 1 (پیاپی 69، فروردین و اردیبهشت 1399)

Since the agriculture is the main water consumer, it is necessary to increase water use efficiency. As a management practice, deficit irrigation strategy is applied to cope with water shortages, especially during drought periods. A greenhouse experiment was conducted to investigate the impact of water and salt stress on Quinoa plants (Chenopodium quinoa Willd.), Aly et al (2) showed that quinoa plants can tolerate water stress (50% FC) when irrigated with moderately saline water (T1 and T2, respectively). The results of some studies showed that Amaranth was the most responsive plant to water. Quinoa showed the best performance in the treatment with the upper-middle water level among the other evaluated species. Millet showed thermal sensitivity for cultivation in the winter, making grain production unfeasible; however, it showed exceptional ability to produce biomass even in the treatment with higher water deficit. Water stress can affect plants by reducing the plant height, relative growth rate, cell growth, photosynthetic rate, and the respiration activation. Cultivated plants have several mechanisms of adaptation to water deficit, but the responses are complex and adaptation is attributed to the ability of plants to control water losses by transpiration, which depends on the stomatal sensitivity and greater capacity of water absorption by the root system, among other factors. In PRD method, half of the root zone is watered and the other half is kept dry intermittently. The objective of this research was to study yield and yield components of Quinoa (Chenopodium quinoa Willd.) Titicaca cultivar, using PRD irrigation method in three growing bed, under greenhouse conditions.

This research was conducted to study the effects of water stress on yield and its components of Quinoa under the different growing beds in the experimental research greenhouse of Ferdowsi University of Mashhad during 2018. Titicaca cultivar of Quinoa was planted and experimental design was factorial, based on complete randomized design and three replications, included two irrigation managements (FI, full irrigation and PRD, partial root-zone drying method) and three levels of growing bed (S1, silty clay, S2 clay loam and, S3 sandy loam). Research station is located in north-east Iran at 36° 16' N latitude and 59° 36' E longitude and its height from sea level is 985 meters. The seeds of Quinoa were planted at a depth of 1.5 centimeters in the soil of each pot and were irrigated with tap water. Plants were harvested after 4 months and plant height, branches number, panicle number, thousand kernel weights, grain yield, biomass; steam, leaf, and panicle dry weight panicles were measured. Physical and chemical properties of irrigation water and soil were determined before the beginning of the experiment. The obtained data analyzed using the statistical software of SAS (Ver. 9.4) and the means were compared using LSD test at 5 % percent levels.

Results showed that the highest plant height (84.4 cm) was in FI treatment and the shortest plant height (82.5 cm) was in PRD treatment. The highest and the lowest 1000 kernel weights and grain yield were measured in FI (4.0 and 19.7 g per plant) and PRD (3.6 and 17.7 g per plant) treatments, respectively. With a 50 % reduction of water in PRD compared to FI treatment, 1000 kernel weights were decreased by 9.1%. Grain yield was decreased by 10.2% (changing from FI to PRD). The highest and the least grain yield (20.2 and 18.4 g per plant) were obtained in S1 and S2,3 soils, respectively. Silty clay soil with 1000 kernel yield of 4.12 g had higher than clay loam and sandy loam soil, which produced 3.78 g and 3.78 g, respectively.

In general, the effect of the PRD irrigation method on reducing water use in the greenhouse production of Quinoa was positive and recommendable. Silty clay soil with 1000 kernel yield of 4.12 g had higher than clay loam and sandy loam soil, which produced 3.78 g and 3.78 g, respectively.

ng countries on one hand, and the need to provide food for this population, on the other hand, have not been the result of overreaching of resources. In this manner, the continuation of an untapped harvest of resources will endanger the sustainability of the region in the near future. Food production is largely depending on the water so that 70 to 80 percent of the water extracted from resources is consumed for irrigation, which is the reason why irrigated cultivation is regarded as inefficient consumers. Understanding how to extract, manage and consume water is the key to solve this problem. On the other hand, the health and safety of communities and agricultural production require energy. Principally in irrigation, it is not possible to extract water without consuming energy. Seeking to establish the goals of the third millennium of the United Nations, researchers have presented a variety of interdisciplinary approaches to achieve a dynamic balance in the food production and consumption of resources, most notably the approach of Water, Energy and Food (WEF) Nexus. Considering the limitation of the resources which is increasing day by day. This approach causes productivity increase by integrating water, energy and food cycles. Managing water, energy and food, despite the inherent systemic differences, are very similar, due to the close relationship between the system perspective and their interaction with each other, a new concept is now called a Nexus approach. This viewpoint describes the interconnected nature and the interplay of the three sectors.

This research was carried out in Sefid-Rud dam Irrigation and Drainage Network. Sefid-Rud basin is located in the Guilan province, which is benefits from high precipitation, but factors such as dams construction in the upper reaches of the Sefid-Rud dam, the timely inconvenient precipitation and the lack of infrastructure to harvest the runoff, causes water shortages in the area. It is worth mentioning that 50% of the Guilan households have engaged in rice cultivation and more than 70% of the lands are located in the irrigation and drainage network of the Sefid-Rud dam. Hence, reducing rice cultivation in this region will have a great impact on economic and social life. Managing a Nexus approach to provide WEF security requires integrated and analytical approaches that can identify cross-sectoral exchanges, cost-effective planning, policy, and strategy management. Therefore, in this study, WEAP and LEAP software were used for managing water and food resources and managing the energy sector in Sefid-Rud irrigation and drainage network, respectively. Then, the integrated water resources management in the area was addressed by establishing a linkage between these two applications. In the first part of this study, the parameters output such as net water demand, water resources share for each demand node, unmet demand and the coverage regardless of the energy sector were compared.

The results reveal that the annual water requirement of the Sefid-Rud irrigation and drainage network in 2016 with the NEXUS approach estimated about 8 million cubic meters more than the nonNEXUS approach. Agriculture is the most water-consuming node in the region and there are lots of dependencies on rice cultivation as the most water-consuming crop in the Guilan region. The next step aims to balance the supply and demand, the unmet demand at the agricultural section in the Foomanat, Central and East areas under various management scenarios. These scenarios are including dredging, increase the efficiency of transmission and distribution channels of irrigation and drainage networks, and eliminating unauthorized wells were evaluated.

By examining the results of the applied management scenarios mentioned above, the 30% increase in the efficiency of transmission and distribution channels of irrigation and drainage networks in SefidRud has the greatest impact on meeting the demand and reducing the unmet demands of triple areas. As a result of the 30% efficiency improvement scenario, decrease the agricultural demands of the Foomanat area, the central area, and the east (about 29.1, 84.5 and 62.1 million cubic meters, respectively) more than the reference scenario.

Infiltration is found to be the most important process that influences uniformity and efficiency of surface irrigation. Prediction of infiltration rate is a prerequisite for estimating the amount of water entering into the soil and its distribution. Since the infiltration properties are a function of time and space, a relatively large number of field measurements is needed to represent an average of farm conditions (Bautista and Wallender, 1985). In recent years, researchers have proposed methods to reduce the requirement of the regional and field data in order to describe water dynamic in the soil. One of these methods is scaling which at the first was presented by Miller and Miller (1956) and developed on the similar media theory in the soil and water sciences (Miller and Miller, 1956; Sadeghi et al., 2016). According to similar media theory, soils can be similar, provided that different soils can be placed on a reference curve with ratios of a physical characteristic length, called "scaling factor". The objective of the present study was scaling the Philip infiltration equation and analyzing the spatial variability of infiltration characteristics by using minimum field measurements. In this research, a new method was presented for scaling infiltration equation and compared with previous methods scaling including: based on sorptivity (), transmissivity (), the optimum scaling factors () arithmetic, geometric and harmonic.

The basic assumption of scaling through this method was “the shape of the infiltration characteristics curve is almost constant despite the variations in the rate and depth of infiltration”. The data required for infiltration scaling were a reference infiltration curve (whose parameters are known) and the depth of water infiltrated within a specified time period in other infiltration curves. In this method, first, equation infiltration parameters are specified for one infiltration curve, called the reference infiltration curve (). If, for other infiltration equations, the depth of water infiltrated is obtained after the specified time(ts) (for example, depth of infiltration water after 4 hours), the scale factor (Fs, dimensionless) is equal to the depth of water infiltrated after ts in the reference infiltration equation to depth of infiltrated water after ts even infiltration equation is as follows: (1) where Ii (i=1,2, …,n) is depth of infiltrated water after a given time (ts) for each infiltration families and is depth of infiltrated water after a given time in reference, and and are parameters of reference curve.In order to assess the proposed scaling method, root mean square error (RMSE), mean bias error (MBE) and coefficient of determination (R2) were used for a totally 24 infiltration tests.

The parameters of this model (i.e. sorptivity S and transmissivity factor A) showed a wide variation among the study sites. The variation of these parameters showed no significant difference between sorptivity and transmissivity factors. In addition, Talsama et al. (1969) illustrated that there is a weak relationship between sorptivity and saturated hydraulic conductivity. Results showed that scaling achieved using αA was better than that obtained using αS. Mean curve was chosen as reference curve and scale curve was obtained by different methods. The results of statistical analysis showed that the proposed method had the best performance (RMSE=0.006, MBE=0.0019 and R2=0.9996). In order to evaluate the effect of the reference curve selection on the results, the scaled cumulative infiltration curve based on different reference curves (different infiltration equation) was evaluated. The results showed that the selection of the reference infiltration curve is optional and each cumulative infiltration families can be selected as the reference curve. For defining the relationship between and , , αS، αA ، ، ، data, a statistical analysis was performed. According to our results, had the highest correlation with .

In this study, a new method for penetration scaling was presented. In this method, the infiltration curve can be obtained using the minimum information including a reference curve and the depth of infiltrated water after a given time. The selection of the reference infiltration curve is optional and each cumulative infiltration equation can be selected as the reference curve. In the light of the results of this research, it can be concluded that the proposed method in this study is promising to be used for surface irrigation management.

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Runoff estimation is one of the main concerns of hydrologists and plays a key role in various engineering calculations and designs. Many factors such as climate, topography, soil properties, land cover, etc, are involved in producing surface runoff. Land use and land cover changes have a direct impact on the hydrological cycle in the ecosystem. The most common model of surface runoff estimation is the curve number model developed by the US Soil Conservation Service (SCS-CN). Accurate estimation of its important parameters increases its precision and performance. Land use is one of the most important parameters of this model.Remote sensing (RS) and geographic information system (GIS) technologies are used in order to increase its speed and accuracy of estimation. One of the problems that have occurred in the Kashaf-Rood Basin is the extensive land use changes that may cause changes in peak discharge and surface runoff volume. In this study, due to the great importance and impact of land cover change on increasing flood risk, the effects of land use change over 28 years (from 1987 to 2015) on flood hydrograph characteristics were investigated.

The Kashaf-Rood basin is a part of the Ghara-Ghum basin. The total area of the basin is 16779 square kilometers with the highest and lowest elevation of 3235 and 378 meters above sea level, respectively . The length of the Kashaf-Rood River from the highest point to the outlet of the basin is about 374 km and its average and gross river slope are 0.0028 and 0.0043 m/m, respectively. The digital elevation model was used to calculate the topographical properties, hydrological properties and geometrical corrections required on satellite images. In this research, the data of the Global Digital Elevation Model (ASTER) with a spatial accuracy of 30 m was used. Also, the soil hydrologic group map prepared in Ghara-Ghum water resources balance studies was used. Since no land use change occurs in the short term and can be detected at long intervals, a 28-year interval was chosen for satellite imagery. In general, five images of Landsat satellite are needed for full coverage of the Kashaf-Rood Basin. For the oldest data, Landsat 5 images and for the latest data, Landsat 8 images were used. ERDAS IMAGINE 2014 software was used to digitally process satellite images. The images were classified in three

The Minimum distance, Mahalanobis distance and the Maximum Likelihood. In order to select the appropriate method, after applying different classification algorithms for the image of 2015, the accuracy of their classification was evaluated and, the image of 1987 was also classified based on the selected method. By combining soil hydrological group and land use map derived from Landsat satellite imagery using ArcGIS 10.3 software, the curve number maps for 1987 and 2015 were prepared. In the present study, the US soil conservation service standard curve number method (SCS-CN) was used to calculate the amount of rainfall and losses in the HEC-HMS model. For the calibration of the HEC-HMS model, four flood events at the bridge of Khatun Kashaf-Rood hydrometric station with relatively concomitant precipitation were selected. Three flood events were used for calibration and one flood event for validation.

The images were classified into three methods: The Minimum distance, Mahalanobis distance, and the Maximum Likelihood. Comparing the results of these three methods showed that their overall accuracy in evaluating and identifying land use was 78.5, 83.7 and 87.3, respectively. Thus, the maximum likelihood algorithm was used to classify the images and the image of the year 1987 was classified with this method. Ten land use classes were identified in the study area. The results showed that during the 28 years of study, the area of rocky lands and rangelands did not change. The highest percentage of change was due to water zones, poor rangelands and residential lands, which increased by 189, 143 and 50 percent, respectively. The highest amount of increase in the area occurred in the poor rangelands, which 1514 km2, and the highest decrease occurring in moderate rangelands which is 1278 km2. By combining soil hydrological group maps and land use maps in ArcGIS software and using standard tables, the curve number maps for 1987 and 2015 were prepared. The weighted average of the curve number in the mean moisture conditions for 1987 and 2015 was 77.5 and 78.4 units, respectively. After performing the calibration and validation steps, the HEC-HMS hydrological model was used to investigate the impact of land-use change on the flood hydrograph of the Kashaf-Rood River between 1987 and 2015. According to the results, in all four events which were studied, land-use changes have increased the peak of discharge and the flood volume over the 28 years of study. On average, the peak flood discharge in 2015 was 15.2% higher than the peak flood discharge in 1987, and similarly, the flood volume increased by 13.7% during the study period.

In conclusion, it can be derived that in recent decades, land-use changes which were caused by human interference, affected the flood characteristics and increased the risk of flooding in the Kashaf-Rood river. Therefore, land use must be managed and prevented further destruction of natural resources to prevent flooding in the area.

Land use is an aggressive process applying to human activities and different uses accomplished over land. It can be argued that human actions can lead to significant changes in current state of earth’s surface. Changes in surface cover (land cover change) may in turn lead to alternations in balance of energy, water, and geochemical fluctuations at local, regional or global levels. Thus, studies on different land uses changes seem necessary in general environmental evaluation. LULC change detection include implementing multi-temporal Remote Sensing (RS) knowledge to analyze the historical LULC data (maps) and therefore helps in determining the trend of changes associated with LULC properties.

Image processing and performing supervised image classification helps to extract information from imageries. In this study, ENVI 5.3 software was used for processing two selected imageries in this project (2014 and 2017). Five LULC classes were established as forest, bare land, vegetation, mountain and water body. For each LULC class, 500 samples were collected at least and used for the supervised classification of images in ENVI. About half of these samples, which were used as “training samples” were collected from the study area through Land Surveying Geographical Positioning System GPS (ground truth data) and Google Earth images. The first step in pre-processing of LANDSAT 8 OLI data in this study referred to the collection of training samples for each class and validating the geometric accuracy of Landsat images, while the next step belonged to the conversion of DNs into At-Satellite radiance using algorithms such as FLAASH. Two dated Landsat images were compared via the supervised classification technique. In this classification technique, two or more images with different dates are independently classified. Maximum Likelihood Classification (MLC) algorithm as a supervised classification method was carried out using training areas and test data for accuracy assessment in ENVI 5.3 and accuracy assessment was done for both images using ENVI v5.3.

In order to recognize the past land use pattern of Tarom, researchers first focused on imagery of Landsat 8 ETM+ for the year 2014. Summary of supervised classification accuracy for the 2 different time frames (2014 and 2017) found from accuracy assessment showed that the highest accuracy was found for 2014 supervised classification (92.16% accuracy). Kappa value is also used to check accuracy in classification and having a Kappa value (0.81–1.00) denotes almost perfect match between the classified and referenced data. Different LULC classes had been recognized and used as the base map. From the identified LULC classes, Mountain area by 3524 km2 (62.75% of total land area) was the highest category, after which, came bare land areas with 1295 km2 (24.0%) coverage and vegetation area with 194.6 Km2 (3.7%). Forest was the next class with (2.7%) coverage whereas, water body (1.4%) and unknown pixels 8 km2 (0.15%) specified the least amount of coverage, respectively. Based on the 2017 image classification results, the highest category belonged to mountain area (3532 Km2, sharing 67.7% of total area). The remaining land uses were bare land (23.21%), forest (2.73%), vegetation (4.3%), and water body (1.75%). The unknown and uncategorized pixels were identifiable in this stage that shared 0.31% of the total area. The relative changes in land use and land cover from 2014 and 2017 images showed some irregular patterns in the study area. Land-use change from this period showed positive changes in most of the categories. About 31.4 Km2 of vegetation area had increased in 2014–2017 period which showed a positive change of (+16.14%). While a negative decrease (83 Km2, -6.4%) in bare land category. The results showed that the extraction of adequate samples from different classes of land cover/land use would increase the possibility of correct distinction of image pixels received from the satellite and accurate extraction of LULC classes. Thus, obtaining accurate results from the classification of images via the maximum likelihood method is depending on adequate and appropriate training samples. The trend of land-use changes found in this study, especially percentage increase in forest land and a decrease in bare lands will be helpful for policymakers to make appropriate decisions.

Land cover is the physical material at the earth’s surface and an essential variable which links the physical environment by human activities, and land use is the description of how the land has been utilized for the socio-economic activities purposes. Population growth increases the demand for food, water, and energy, which causes a prompt change in land cover and pattern of land-use. The mentioned process depends on the social and economic development of the nation. In order to have appropriate and unrestrictive management of natural resources (water and soil), it is necessary to have complete information about the pattern of land use and its alteration pattern over time. Thus, it can be concluded that remote sensing is a proper technique to investigate the land-use changes using satellite imagery. Spatiotemporal analyses of LULC help us to manage the environmental changes, which are an appropriate tool for decision-makers on water resources’ to enhance their decisions. In the presented study, LULC map for Tarom basin, Iran, acquired from OLI sensor data sets (Landsat-8) by applying a pixel-based classification method (MLC) with the aid of remote sensing technology. The results that are presented in this study proved the usefulness, effectiveness and also convenience of the MLC technique for generating land-use maps by using a free archive of Landsat data and processing the digital images through the ENVI software. Accuracy assessment using overall accuracy and kappa coefficient for 2014 and 2017, shows the performance of the used algorithm. What matters most in this regard is the accuracy, speed, and quality of land-use maps. In the present study, it was shown that due to high speed and accuracy in generating land-use maps of Tarom, MLC method, would act as the best classification method in this area. However, it is suggested to classify the data by using other methods and compare the results with image outputs provided by Landsat 8 satellite.

Cellulase enzymes are the second largest group of the enzymes with many industrial applications such as in textile industries, production of detergents, animal and human food processing, paper industries and biofuel production. Many microorganisms are capable for production cellulases, but only a small number of them produce significant amounts of this enzyme. The main sources of cellulases production are microorganisms including fungi and bacteria. Among the cellulose degrading aerobic and anaerobic bacteria, most of the studies have been done on Cellulomonas spp. and Clostridium spp., respectively. Also Bacillus spp. has been used for production of cellulase in a homologous manner. Expression of cellulases in some bacterial genera such as Bacillus, Pseudomonas, Ralstonia and Zymomonas, as well as some yeast species such as Saccharomyces cerevisiae and some fungal genera such as Aspergillus and Trichoderma has been reported too. Low levels of cellulase production has always been a major concern that leads to researches for finding of highly active microorganisms strains and employing biological technologies for identification of their enzyme coding genes suitable for probable transformation other organisms. The purpose of this study was the screening of the cellulose degrading bacteria in Mazandaran forest soils and detection of the enzyme coding gene in the isolate with the highest cellulase activity.

In order to isolate cellulase producing bacteria, soil samples were obtained from different regions of Mazandaran province forests including Nanoacla (A), Siaocla (B), Someesara (C), Namakabroud (D), Noor (E), Izadshahr (F), Sisanghan (G) and Sehezar (H) forests. Cellulase producing isolates were selected on carboxymethyl cellulose agar using congo red dye and the amount of their endoglucanase activities was measured by assessment of released glucose using dinitrosalicylic acid reagent. Each micromole of released glucose in 1 ml of enzyme solution per minute was considered as an enzyme activity unit (U/min.ml). Identification of bacterial species was performed by amplification and sequencing of a 1500 bp length fragment in 16S rDNA by using 1492R and 27F universal primers. Enzyme production by the selected isolates was also detected in different growth conditions. In order to investigate the effect of carbon source concentration, the amounts of 2-10 g/L of carboxymethyl cellulose were added to bacterial growth culture media. The effect of growth pH values in the range of 4 to 10 and sodium chloride at concentrations of 0 to 10 g/L were studied on endoglucanase production by the selected isolates in carboxymethyl cellulose media. Then the endoglucanase coding sequences in different strains of the bacterial sp. with the highest endoglucanase activity were investigated in Gen Bank and the primers were designed based on the obtained data for the gene amplification.

The results of heterotrophic bacteria counting showed the highest number at station B (Siakla forest). Subsequently, station A (Nanocla forest) and station G (Sisangan forest) had the highest number of heterotrophic bacteria, respectively. From the eight selected forest stations, eight top cellulase producing isolates were selected in carboxy methyl cellulose broth medium. The highest endoglucanase activities were belonged to the isolates A2 (1.92 U/min.ml), B2 (1.65 U/min.ml), and H3 (1.51 U/min.ml), respectively. The amplification of the 16SrRNA gene resulted in the formation of a 1500 bp band after electrophoresis in agarose gel electrophoresis. Sequencing results of the purified PCR products showed that B2 and A2 isolates belonged to Bacillus subtilis with 99% similarity. H3 isolate also belonged to Bacillus cereus with 99% similarity. In other studies in the forest soils of Iran for isolation of cellulase producing bacteria, Bacillus had been one of the most active cellulase enzyme producers. The present study showed that Noor forests are among the best places to isolate bacterial cellulase-producing strains. PCR amplification protocol was designed and the total sequence of endoglucanase with 1072 bp length was amplified. Molecular evaluation of endoglucanase gene in Bacillus subtilis (B2) showed 77% similarity to the endoglucanase gene (elgS) in Bacillus subtilis subsp. subtilis. Since the strain B2 had the highest production of endoglucanase among the isolated bacteria, it was attempted to enhance the production of the enzyme using this strain by changing the growth conditions. The isolate B2 was able to grow at different concentrations of carboxymethyl cellulose as a carbon source, but the highest endoglucanase activity was observed at the concentration of 8 g/L with a significant difference compared to other concentrations. The pH equal to 7 and the absence of sodium chloride salt was also led to significant highest endoglucanase production by this isolate.

The endoglucanase gene obtained in this study was reported for the first time with a new sequence. The enzyme showed more sustainable activity than other aerobic bacterial endoglucanases which had previously been studied. This sequence can be introduced into high expressional bacterial strains and used to produce high amounts of endoglucanase for bio-energy industries applications.

In recent decades, industrial and technological advancements have led to the gradual increase of heavy metal concentrations. As such, this phenomenon of heavy metals being present in the environment at high concentrations causes deleterious effects on various terrestrial creatures and human beings. Mercury (Hg) is one of the most toxic elements and can cause renal and neurotoxicity to humans and wildlife. It has been identified as a priority toxic substance in many countries. It is, however, rare to find information on Hg in soils from industrialized areas of Iran in literature. In order to ascertain the distribution of Hg, as well as the extent of contamination with Hg, and to provide policymakers with remediation measures for the affected soils, a study of surface soils was conducted in areas around of Kerman cement plant.

Soil samples were collected from the depth of 0 to 20 cm. 103 samples were taken and analyzed. Mercury concentration in soil samples were determined by atomic adsorption method coupled Graphite furnace. Statistical analysis and indices calculation were performed by SPSS and EXCEL, respectively, and distribution maps were prepared by kriging method in ArcGIS software. For evaluating pollution, Geoaccumulation index, enrichment factor and contamination factor were also calculated and interpreted.

The mercury concentration in soil samples ranged from 6.70 to 340.96 μg/kg, with a mean value of 164.06 μg/ kg. Mercury is naturally present in very low concentrations in the soil. The concentration of this element in soils ranges from 0.01 to 0.5 mg/kg around the world. The average Hg concentration in the earth crust is reported to be 80 μg / kg. In soils of the study area, the Hg concentration was higher than most of the reported values for soils worldwide and earth crust. This indicates that industrial activities have increased the concentration of mercury in the soil. In fact, the concentration of mercury more than the amount of earth crust indicates the onset of contamination due to various anthropogenic activities. The coefficient of variation of mercury concentration in the soil was 55%, which shows a high variability (CV≥ 35%) according to the classification proposed by Wilding et al. (19). The high variability coefficient shows the heterogeneous and non-uniform distribution of the property. Therefore, there is a high concentration of mercury in some areas of the study region. In other words, soil was affected by external factors in some areas. Based on the cleaning standards of soil for mercury in soils used for industrial purposes in some countries, all soil samples in the studied area have a much lower concentration of mercury than standard values. In other words, although the activity of the cement plant has increased the concentration of mercury in the soil, it can continue its industrial activity. The plant’s managers should, however, take a close look at the release of this metal and other pollutant. According to the results derived from Igeo, Hg was graded as unpolluted to moderately polluted. Low levels of contamination (CF <1) to significant contamination (3.00 ≤ CF <6.00) of mercury were observed based on the contamination factor. The results suggest that anthropogenic sources control the concentration of mercury in the soil. The average contamination factor more than one (CF> 1) indicates that the soils of this region have been exposed to mercury contamination. Spatial distribution map indicates that the highest concentration of mercury in the soil is between 200 and 341 μg/kg, which was observed around the factory and south-east of the region. Release of mercury in the environment is related to natural processes and human activities. Mercury release due to human activities is mainly due to combustion of fossil fuels, iron ore processing, steel industry and cement plants. Considering the high concentrations of mercury in the southeastern part of the region, the lower part of the plant, it seems that environmental factors such as the topography of the area may affect its distribution. The high concentrations of Hg were observed at low elevations, on the south side, and over the areas with relatively low slope gradients.

The results demonstrated that the concentration of Hg was higher than most of the reported values for soils worldwide and earth crust. This indicates that industrial activities have increased the concentration of mercury in the soil. According to the results derived from Igeo, Hg was graded as unpolluted to moderately polluted. In addition, the level of contamination was identified to be low to high, based on the contamination factor (CF). The spatial distribution map of the total concentration of mercury shows that the highest concentration of mercury was observed around the factory and to the south and southeast of the region. The high concentrations of this metal were at low elevations and on the south side of the catchment and in areas with relatively low slope gradients. It is concluded that although the concentration of this pollutant is not critical in the study area, due to the close proximity of the industrial area to the residential area, planning to control the release of this metal and other pollutants should be seriously considered.

Sorption and desorption are important processes that influence phosphorus (P) chemistry in soil. Desorption is a process more complex than sorption and usually not all that is adsorbed is desorbed. This indicates that adsorption and desorption mechanisms are not similar and it seems that such reactions are irreversible. Such irreversibility is usually called hysteresis. Major factors such as chemical changes in the structure of minerals, non-equivalent processes, inflation of adsorbent material, changes in the strength of crystals, irreversible fixation of adsorbed molecules in fine pores and equilibrium time less than its true value lead to hysteresis phenomenon. The concentration of phosphate in soil solution and thus its availability for plant are closely related to sorption processes by soil components. This relationship can be explicated by sorption isotherms. Soil organic matter (SOM) especially in arid and semiarid regions is one of the important indices of soil quality and plays important role in phosphate chemistry and fertility. Organic matter could decrease P sorption, maximum buffering capacity, and bonding energy and could increase P concentration in calcareous soils solution. Organic matter and organic acids resulted from its decomposition may coat calcium carbonate surfaces and prevent the formation of apatite precipitation. There are several methods to remove soil organic matter including using hydrogen peroxide and sodium hypochlorite solutions. It has been reported that H2O2 is penetrated into the interlayer spaces of phlogopite and vermiculite through exchange with water and cations and decomposes into H2O and O2. Therefore, this study was conducted to quantify the hysteresis indices, to investigate the effect of organic matter removal on phosphorus (P) hysteresis indices and to evaluate the relationship between hysteresis indices and soil characteristics and selection of index with the close correlation.

This study was carried out to obtain soil organic matter (SOM) removal with sodium hypochlorite solution (NaOCl, pH=8) effects on P hysteresis indices in 12 calcareous soils of Iran with different characteristics. For experiment of P sorption, 2 gr of soil subsamples was placed in separate 50 mL centrifuge tubes, to which were added 20 ml of monocalcium phosphate containing 5, 10, 15, 20, 30, 40, 60, 80 and 100 mg P L-1, which had been prepared in 0.01 M CaCl2 solution as background. Centrifuge tubes were shaken in a shaker incubator for 48-hour period to reach an equilibrium. Then, they were centrifuged at 4000 rpm for 5 minutes. The supernatant was filtered through a filter paper and the P concentration of filtrates determined using a spectrophotometer. The difference between initial and final P concentrations was assumed to be the amount of P adsorbed by the soil. Desorption experiments were assumed at the end of sorption experiments at the highest initial concentration of P with 0.01 M CaCl2 solution. The tubes were shaken to reach phosphate desorption equilibrium time (24 hours) at 25 °C in incubator shaker. Then, it was centrifuged for 5 minutes at 4000 rpm and 15 ml of the supernatant solution was pipetted and then 15 ml of solution of 0.01 M CaCl2 was added to tubes and the above steps continued to 9 steps. Freundlich model was used to describe the sorption – desorption isotherms data. DataFit 9.0.59 software (1995-2008) was used for nonlinear fitting of Freundlich to sorption data.

According to the results, P sorption and desorption data showed hysteresis which indicates adsorption and desorption mechanisms are not the same. As expected, nonlinear Freundlich equation showed a best fit (R2=0.96) to the data. The mean value of desorbed P in studied soils after SOM removal was decreased by 40%, so it was concluded that P sorption was more irreversible. In NaOCl treated soils, the mean values of seven studied hysteresis indices (HI) increased. Regression analysis indicated that the fourth hysteresis index, obtained from the distribution coefficient (Kd), had close relation with clay (r = 0.69, p < 0.05) and active calcium carbonate (r = 0.7, p < 0.05) concentration. Moreover, this hysteresis index showed significant (p<0.01) positive correlation with Kfsorb and Kfdesorb, which suggests that increasing bonding energy in sorption and desorption isotherms decreased desorption amount due to the strong interaction between adsorbed P and absorbent surface, increasing this hysteresis index.

It was concluded that among seven used hysteresis indices, HI4 can be introduced as the best index for the studied calcareous soils. It is predicted that using organic matter or preventing its reduction in arid and semi-arid calcareous soils may increase the efficiency of P fertilizer, given an increase in hysteresis index after the removal of the organic matter.

According to important ecological roles of soil organic matter in stabilizing ecosystems, it is essential to consider soil organic carbon condition for managements of worldwide problems such as soil quality, carbon cycle and climate change. Also, organic matter is one of the main component of soil which have vital impress on its evolution. Therefore, assessing soil organic matter fate in various environmental conditions and its relation with environmental factors will be useful for management decisions. Determining soil organic carbon content, stocks and forms by the physico-chemical and micromorphological studies may respond to the question about soil organic matter evolution from the different point of views. Based on mentioned reasons, our research work focused on soil organic matter content, stocks and forms under various environmental condition of the forest ecosystem to find new aspects of its relation with environmental factors.

This research work was carried out in Arasbaran forest, northwest of Iran, which recognized as a part of the international network of biosphere reserves and has unique species of plants with special ecological properties. Sampling was carried out in a Kaleybar Chai Sofla sub-basin as a part of Arasbaran forest with eastern longitude of 46º 39´ to 46º 52´ and northern latitude of 38º 52´ to 39º 04´. Based on the Amberje climate classification, the climate of the region is semi-humid and moderate. The soil moisture and temperature regimes are Xeric and Mesic, respectively. Hornbeam (Carpinus betulus) and Oak (Quercus petraea and Quercus macranthera) were identified as the main woody species in this area and volcano-sedimentary rocks were the geological structure. Primary site surveying showed 5 forest stand types such as Oak (Quercus macranthera), Hornbeam-Oak (Carpinus betulus-Quercus macranthera), Hornbeam (Carpinus betulus), Hornbeam-Oak (Carpinus betulus-Quercus petraea), Oak (Quercus petraea) along altitudinal transects, that used as environmental parts with different conditions. In each environmental part, a soil profile was described and sampling was done for physical, chemical and micromorphological analysis. After preparing soil samples in the laboratory, soil physico-chemical routine analyses were carried out by standard methods and then the studied soils were classified on the basis of 12th edition of soil taxonomy. To achieve the main aim of the study, various aspects of soil organic matter evolution were assessed. Soil organic matter content was determined according to the Walkley–Black wet oxidation method and using alteration factor f = 1.724 recommended by USDA. Variance analysis and means compare of soil organic matter content in surface horizons of different environmental parts were performed by using the SPSS software package and Dunkan's multiple range test, respectively. Soil organic carbon stocks were calculated for each soil horizon and weighted average based on profile depth was used to calculate this index for each soil profile. The prepared thin section for micromorphological study was examined under both plane-polarized light (PPL) and cross-polarized light (XPL) using a polarized microscope and explained based on standard terminology to identify various forms of soil organic matter all over the study area.

Results revealed increasing of soil evolution with decreasing of elevation. Entisols, Inceptisols, Alfisols and Mollisols with different families were the soil observed along altitudinal transects by decreasing elevation. According to the obtained results, environmental effects caused different soil organic matter content and evolution with various soil organic carbon stocks in each part. Improvement of environmental condition by decreasing elevation resulted in more evolution of soil organic matter, dominant of decomposed forms of organic matter and rise of soil organic carbon stocks from the highest part to the lowest one. Soil organic matter content in soil surface increased by elevation, although the main source of soil organic matter have better condition in lower parts due to ecological reasons. This inverse statue can be explained by special environmental conditions causing limited organic remnants decomposition in the highest parts. In the same trend with soil evolution, soil organic carbon stocks increased by decreasing of elevation. This trend refers to the relation of mentioned index ability with various soil-forming processes. Micromorphological study showed that organic intact remnants were the dominant forms in upper parts which changed to well-decomposed forms in the lowest parts. This observation revealed the occurrence of mechanical decomposition processes of organic remnants in high elevation while biochemical ones happen in the lower parts. Also, this distribution of soil organic matter decomposition processes can explain soil organic carbon content and stocks all over the study area.

Elevation was identified as an important environmental factor controlling soil organic matter in the studied scale. Generally, results confirm the same trend for soil organic matter evolution and soil organic carbon stocks with soil development, especially in pedogenesis processes in relation to organic matter. Thus, it can be recommended to use soil map for management of soil organic matter under various environmental conditions in large-scale studies.

Due to the increasing development of edible oil processing industries, large amounts of wastewater and solid wastes (SW) are inevitable in these industries. Organic wastes can be used as soil conditioners in agriculture due to the high content of organic matter and nutrient loads. Phosphorus solubilizing bacteria including Bacillus spp., Pseudomonads and Rhizobium spp. can release phosphorus from insoluble organic and mineral sources in soil. Most soils in the semi-arid regions, including southern parts of Guilan province, have low organic matter content and do not support plant cultivation due to the low fertility and instability of soils. Hence, industrial wastes can be applied as a suitable and low-cost source of organic materials and nutrients in these soils. As phosphorus is one of the most important essential nutrients in plant nutrition which is also present in oil refinery soild wastes and P solubilizing bacteria can release phosphorus from the organic phase of the wastes and make it available in the soil solution, this study aimed to investigate the available phosphorus (Pava) content of soil after simultaneous addition of olive refinery-solid wastes and P solubilizing Bacillus spp.

the solid waste obtained from Ganje Rudbar oil refinery plant (located in Rudbar, Guilan province) and a soil sample was collected from a surface layer (0-30 cm) of a pasture, located in Lowshan area (Guilan province). A native strain of Bacillus sp. was isolated from the sampled soil based on its P-solubilizing ability in Sperber medium. An indicator strain, Bacillus persicus was also included in the experiments. P-solubilizing ability of the indicator strain was also evaluated in Sperber medium. The experiment was conducted in a completely randomized design based on factorial arrangement and three replications. Factors included three levels of solid waste (0, 2 and 4%), three levels of inoculated bacteria (no bacteria, native Bacillus sp. and Bacillus persicus) and eleven sampling times (0, 2, 7, 14, 28, 42, 56, 86, 116, 146, and 176 days). Different levels of solid waste were added to the soil, inoculated with bacteria (106 cell/g), and incubated at laboratory condition (~25 ºC) for six months. The moisture content of the soil mixtures fixed around 0.7 FC and kept constant during the incubation period. Sampling was done at desired times. The pH, organic carbon (OC), soil Basal Respiration (BR), available phosphorus concentration (Pava), and phosphatase enzyme activity were measured in soil samples. Data analysis and means comparison were done by Duncans’ test using SAS software package.

The studied soil was loam in texture, and had slightly alkaline pH, moderate Pava, and low OC content. The studied solid waste contained considerable OC and total P load. The effect of solid waste (SW), bacteria, sampling time and their interactions were significant on most of the measured characteristics (p < 0.05). SW application decreased soil pH and mixtures inoculated with native Bacillus sp. had lower pH values compared to those inoculated with Bacillus persicus, probably due to the greater effect of Bacillus spp. on SW decomposition compared with B. persicus. The highest average BR was attained in mixtures contained 4% SW which was 1.24 and 1.73 times greater than that in mixtures contained 2 and 0% SW, respectively. While the effect of SW on soil BR was obvious, bacteria inoculation had different impact on soil organic material decomposition and the lowest BR was measured in soil (0% SW) inoculated with Bacillus persicus. OC content of mixtures increased with SW application. The highest OC level (3.21 g 100g-1) was obtained in uninoculated mixture contained 4% SW, which was significantly greater than OC levels in mixtures inoculated with bacteria (p < 0.05). The lowest OC level (3.21 g 100g-1) was observed in uninoculated soil (0% SW). SW application significantly increased Pava. The greatest Pava concentration (142.77 mg Kg-1) was attained in uninoculated mixture contained 4% SW which was not significantly different from Pava concentration in 4% SW-mixture inoculated with native Bacillus sp. (P > 0.05). In control treatments (0% SW), Bacillus persicus was efficient in P release from soil native organic carbon and/or phosphate minerals. However, among the soils contained 2% SW, those inoculated with native Bacillus sp. had the highest Pava concentration. The average Pava concentration in the 4% SW-mixtures was 136.33 mg Kg-1 which was 3.5 times greater than that in control treatment (0% SW). Although soil Pava was related to phosphatase enzyme, this enzyme activity was not affected by treatments. In the P-releasing trend, it was found that 4% SW-mixtures had the highest Pava concentration after 6 months of incubation, and bacteria inoculation made the P-release trend to be flatter compared to control.

The application of oil refinery plant-solid waste improved the basal respiration of the studied soil and increased available phosphorus concentration. The comparison of applied solid waste levels showed that the inoculation of soil with Bacillus bacteria had a positive effect on available phosphorus concentration only at 2% solid waste level.

Dust is one of the most important destructive phenomena in the world, that annually causing damage to human health and the environment. This issue ranks after two major challenges of climate change and water scarcity as the third most important challenge facing the world in the 21st century that is considered. Microbial-induced calcite precipitation (MICP) is a relatively green and sustainable soil improvement technique. It utilizes biochemical process that exists naturally in soil to improve engineering properties of soils. The calcite precipitation process is uplifted by the mean of injecting higher concentration of urease positive bacteria and reagents into the soil. In this process, the enzyme present in the bacteria hydrolyzes the urea in the environment and through reacting with the calcium ion, leads in the deposition of calcium carbonate. The main objective of this study is isolation native ureolytic bacteria from different soil of around Urmia Lake and then, the evaluation their efficiency in the MICP for stabilization of sandy soils and reduce windy erosion.

In order to isolate ureolytic bacteria, 25 soil samples were taken from different land use in West Azarbaijan province, Iran. To increase the number of ureolytic bacteria in soil samples were used from the enrichment solution and then ureolytic bacteria were isolated and purified. These isolates were subjected to various biochemical tests, as well as the growth curve and urease activity were determined. In order to investigate the potential for soil improvement, a factorial experiment was conducted based on a completely randomized design with two factors including microbial treatment in eight levels (including five isolated bacteria (U3, U8, U16, U35 and U40) and Bacillus pasteurii (as control Positive), non-bacterial and non-cementation (as control negative) and non-microbial but with cementation solution treatments) and another factor including different concentrations of calcium chloride solution with urea at three levels (0.1, 0.5 and 1 molar), in three replications. After injection of cementation solution and bacterial solution to soil, penetration resistance and windy erosion rates in sandy soil were assessed

In study, overall 45 isolates of the bacteria were isolated and purified. Among of 44 isolates, five bacterial isolates (U3, U8, U16, U35 and U40) had the highest urease activity. The growth curve of bacterial isolates showed that the highest urease activity and microbial population were in the time period of 13 to 16 hours after microbial culture, which it is represents the best time use bacterial solution in the MICP process. According to the results of soil improvement tests, the amount of soil erosion in the MICP treatment at a wind speed of 25 m/s was zero and the rate of penetration resistance was averaged over 13 MPa, which has a very impressive impact on MICP in controlling wind erosion, especially at high speeds of wind. The results showed that U3 and U16 isolates had the highest amount of urea hydrolysis and also U16 and U3 had the lowest and the highest tolerance to salinity, respectively. The results of the wind tunnel showed that the wind erosion threshold in negative control samples (non-bacterial and non-cementation) were 9.4 m/s and for MICP samples (including five isolated bacteria and Bacillus pasteurii ) were much higher than the wind tunnel speed in the wind tunnel machine in Urmia university (25 m/s). The maximum penetration resistance (13.5 MPa) was obtained in the sample treated with U3 isolate and 1 molar calcium chloride, but negative control treatments (non-bacterial and non-cementation) as well non-microbial but with cementation solution treatments were 0 and 97.0 MPa, respectively.

The amount of soil wind erosion was zero in MICP treatment with the wind tunnel speed 25 m/s that indicates very important effects MICP to control wind erosion of sandy soils to compare control treatments (non-bacterial and non-cementation and non-microbial but with cementation solution) in high wind speeds. The application of MICP treatment in the soil, in addition to increasing its wind erosion resistance, also increased penetration resistance in the soil. Increasing the penetration resistance of MICP treatments (including five isolated and Bacillus pasteurii) can be due to the activity of bacterial isolates, chemical interactions, and the formation of calcium carbonate precipitation into soil cavities, which causes to form a hard layer in soil. Also, obtained resistance by using isolated bacteria indicates that there are many unknown microorganisms that can carry out MICP better than Bacillus pasteurii and probably they will be better compatible and establish because they are native.

Chromium (Cr) is one of the toxic metals widely used in leather tanning, alloy preparation, electroplating, drilling mud, refractory steel and catalytic manufacture. Besides the toxicity of chromium to human, it also disturbs the soil ecology and plant growth due to its toxic nature even at low concentration. Phytoremediation is effective and can be viewed as a relatively low cost, solar energy driven process for the management of contaminated soils. Hiwever the heavy metal toxicity adversely affects the plant growth and development. We can use some chemical compounds to increase plant resistance to heavy metal and increase the efficiency of phytoremediation. These days, foliar application of plant growth regulators such as Gibberelic acid Indole acetic acid and Benzyl amino purine are considered for various purposes such as enhancing plant growth and resistance to salinity, drought and heavy metals. Exogenous application of phytohormones can modulate the toxicity of Cr on plants most probably by maintaining hormonal balance of plant under metal stress. surfactants effectively enhance metal ion transfer to aqueous and hence increase their availability. Assessing surfactant assisted phytoremediation is important in order to ascertain the extent of its effectiveness under different conditions and to find its optimum level for metal phytoremediation. The application of plant growth regulators and surfactants can be an effective way to cope with stresses such as heavy metal contamination. The objectives of this study were to determine the effects of the growth hormones Gibberelic acid, Benzyl amino purine and Indole acetic acid alone and combined with surfactant on plant growth, concentration and uptake of Cr, Fe, Mn, Cu and Zn and some phytoremediation factor for Cr.

The soil was air-dried and grounded to pass through a 2-mm sieve then was analyzed to determine various soil physic-chemical properties using standard methods. A greenhouse experiment was conducted in a completely randomized design with a factorial arrangement of 3 × 4 including three levels of surfactant (control, 2.5 and 5 mmol kg-1 soil) and four levels of plant growth regulators (control, Gibberellic acid, Indole acetic acid and Benzyl amino purine). All soils were contaminated by 5 mg/kg chromium and incubated for 1 month. During incubation, the soil samples were maintained at field capacity by distilled water. Safflower (Cartamus tinctorius L.) seeds were disinfested with 10% sodium hypochlorite, washed three time with distilled water and planted in the pots. Growth regulators were sprayed at three stage of 30, 20 and 40 days after planting at concentration of 1 mM. The plants were kept in the standard condition of greenhouse and the soil moisture content was maintained at field capacity by distilled water. Sixty days after planting, the plants were harvested and washed with distilled water, and then dried in oven at 65 Celsius until they reached a constant weight. Afterwards, the over-dried plant samples were grounded. Then dry ashing and extracting with 2 normal hydrochloric acid, the concentration of Cr, Fe, Zn, Cu and Mn in shoot was determined by atomic absorption (Shimadzu AA-670). The analysis of variance (ANOVA) was performed using a completely randomized design. Significantly different treatment means were separated using Duncan test (P < 0.05). Biological accumulation coefficient (BAC) and uptake index (UI) were calculated with a specific formula.

The results showed that addition of surfactant and growth regulators caused a significant increase in shoot dry weight, biological accumulation coefficient, uptake index and chromium concentration and uptake. Addition of surfactant reduced the concentration and uptake of iron in the absence of growth regulators, but in the presence of plant growth regulators, application of tween 80 increased iron concentrations. Application of 5 mmol kg-1of surfactant decreased mean concentration of manganese, copper and zinc. While addition of 2.5 mmol kg-1 of surfactant increased metals concentrations. Although addition of 5 mmol kg-1 surfactant increased dry weight, it did not have a satisfied effect on increasing the concentration of the elements in the plant. Plant growth regulators increased uptake of elements which is a protective mechanism against stresses.

It appears that using plant growth regulators increased the resistance of the plant to chromium toxicity probably through increasing absorption of the elements such as Fe, Mn, Cu and Zn. According to the results, application of tween 80 along with plant growth regulators could increase safflower capability to cope with chromium toxicity.

Nowadays, because of climate change, there is a great interest in carbon cycle. In most of the soils, the main part of carbon is held as soil organic carbon (SOC) whereas, in soils of the arid and semiarid regions, inorganic carbon, primarily carbonate, is the majority of carbon in the soils. The major minerals found in the soils of arid regions of Iran are calcite (CaCO3) and dolomite (Ca Mg, CO3) which mainly exist in the soils of the southern and southwestern Iran. Thus, quantifying both SOC and soil inorganic carbon (SIC) is essential to know the way of occurrence of the carbon cycle in the soils. The aim of this study was to compare different methods for the determination of organic carbon in calcareous soils under different land uses of Lorestan province.

The study area is located in the Polhoro region of Khorram Abad district, Lorestan Province in western Iran. The sampling area spanned sides of the Polhoro region, which has various land uses, including forest land, cropland, and grassland. Dry and irrigated farming were between cultivated lands. In each land uses, a study plot was chosen. At each sampling point, five subsamples were taken at a depth of 0–30 cm (root zone) and mixed to form a composite sample including one central point and four other points by the distance of 15 m in the four cardinal directions. A total of 40 soil samples were taken across an agroecological region in southwest Iran. The soils had a clay-loam and sandy-clay-loam texture classes and pH above 7. Representative samples were analyzed for SOC and SIC measurements by different procedures. The procedures were included the modified traditional Walkley-Black method (WB) for SOC, Loss-on-Ignition (LOI) Procedure given by Nelson and Sommers (1982) for SOC, and CN analyzer (Vario-EL III) for SOC and SIC. The method presented by Boden, VDLUFA-Verlag, Darmstadt (2016) was chosen for organic carbon and carbonate measurement. This method was used as a reference method to compare results of different methods.

In the present study, the soil samples of forest land showed the highest values for TOC and TN, but lowest values for TIC. The measured SOC concentration by WB, LOI and CN analysis methods in the top soil varied among land uses. The highest C concentration (4.52%) was observed in the forest land while the lowest concentration (0.52%) was for dry farming land both by the use LOI method. SOC values varied from 0.8 to 2.3 in modified WB, 0.52 to 4.52 in LOI and 0.93 to 2.72 in CN analysis methods between different land uses. The differences in C concentrations between rangeland, forest, irrigated and dry farming lands were statistically significant and showed the following order for the WB and LOI

forest land > irrigated farming > rangeland > dry farming. As expected, C concentrations of LOI and WB were highest in the forest, intermediate in irrigated farming and rangeland and lowest in the dry farming. The relative content of SOCLOI differed significantly across forest and irrigated farming land uses while the difference was not significant in the other two methods. A significant difference also observed in the SOC of forest and irrigated farming with dry and range lands obtained by all three methods. The results of the correlation between the bulk soil and SOC in different methods from the Spearman correlation analysis showed that there was a positive correlation between the TN, TC, clay, and silt of the bulk soil with SOC in the separated methods with the correlation coefficient ranging from 0.1 to 0.92. Conversely, the negative correlation was found between TIC and sand content of the bulk soil with the SOC in the different methods. It can be concluded that calcareous nature of these soils could be one of the reasons for low organic carbon in this research. By comparison between the SOC values measured by WB and LOI methods with CN analysis as a reference method, the WB method showed the results were more near to CN analysis than LOI. The high SOCLOI values for the forest and range land in this research may be related to weight loss from some non-SOM. The results of this study demonstrate that the CN method with combination of dry combustion is a potent method for the accurate estimation of SIC and SOC in calcareous soils. The common approach often involves pretreatment with acid to remove carbonate, which may cause remove organic matter in soil samples and also erosion the instrument. Thus, the combustion method could be a good substitute for acid treatment of soil samples.

Three methods were applied for determinations of SOC concentrations in calcareous soils of Polhoro region and the results were compared. There was a wide range of values in soil properties, but in general, TIC was more than SOC. The results show that the Walkley-Black method with external heating can provide precise estimation for soil organic carbon for these soils. This study illustrates that the WB and LOI technique could be comparable with the CN analysis method and regarded as potent methods to produce accurate results for estimating of organic carbon in arid soils. The results supported the elemental analysis as a precise method to the estimation of SOC and TIC in calcareous soils. Further study is suggested for testing TIC by LOI approach on a wider range of arid and semi-arid soils.

Soil erosion is one of the most important and serious threats to food security and as a consequence of human life. In order to perform soil protection activities against soil erosion, knowledge about the amount of soil loss tolerable is very important. In fact, the soil loss tolerable is the potential for soil erosion, loss of productivity and lost production, and the final criterion for controlling soil erosion and degradation of land. Soil thickness methods, particularly Skidmore equation, based on their ability to estimate the tolerable amount of soil loss have been widely used. In the mathematical function developed by Skidmore based on soil thickness, the soil loss tolerable is calculated based on the soil's current depth, the lowest and maximum soil depth for sustained growth of crops, and the upper limit of tolerable erosion in accordance with the environment. Since the determination of soil loss tolerance by soil thickness method and the Skidmore equation requires time, cost and energy, the researchers have tried to estimate the soil tolerance is supported by regression methods using pedotransfer functions and easily available soil properties. Therefore, the present study was carried out with the aims of determining the tolerable tolerance of soil loss by thickness method and the development of regression pedotransfer functions for estimating this property in the upstream of the dam.

The study is place on Kamfiruz Watershed with an area of 422 km2, an average annual precipitation of 443 mm and an average annual temperature of 14 °C. It is closed to the Dorudzan Dam sub-basins and is considered as one of the five parts of Marvdasht plain in Fars province. For this work, 60 soil profiles were excavated by excavating machine. In addition to measuring the depth of soil, some physico-chemical soil properties were measured from the surface layer (0-30 cm) including; soil texture, organic matter, salinity, percentage calcium carbonate, mean weight diameter in the laboratory and filed. In order to develop regression models for estimating the tolerable soil loss, information from 60 soil profiles was divided into two data-sets. One set of the data with 42 samples (70% of whole samples) was used for developing the models and another set of the data with 18 soil samples (30% of whole samples) was used for validation. Multiple linear regression was used to develop the linear models. The same soil properties used in the multiple regression method were considered as inputs in the tree regression method to estimate the tolerable amount of loss.

The results showed that the minimum and maximum Z1 parameters (the lowest soil depth for stable growth of crops in the study area) were considered as 0.25 and 0.51 m based on the current depth of soil. Organic matter of the soils with the highest standardized coefficient (Beta = 0.44) and the highest correlation (-0.77) with soil loss tolerance was the most important soil properties for estimating the soil loss tolerance. In the regression model, only the coefficients of four characteristics of permeability, soil aggregate stability, pH and organic matter appeared among the soil grazing characteristics and entered into the model. Based on the evaluation statistic, tree regression method with the highest determination coefficient in both calibration data sets (R2 = 0.96) and validation (R2 = 0.78) and the lowest error value in the validation data (RMSE= 0.29 ton ha-1 year-1) and validation (RMSE = 0.125 ton ha-1 year-1) were more efficient than the multiple regression method in estimating the tolerable soil loss.

Soil loss tolerance was estimated using regression methods (multiple linear regression and regression tree) in Doroudzan Watershed, Fars province. The soil loss tolerable determined using Skidmore method, was 1.04 tons per hectare per year ranging from 0.29 to 2.25 ton ha-1 year-1. The soils of this area are slightly deep and their depth varies from 0.4 m in the marginal areas in the upstream parts of the catchment area of the dam and the slope of mountain up to 2 meters in the center of the plain with agricultural lands uses. In general, the tree regression method had a better performance than linear regression method for estimating the soil loss tolerance based on the statistical indices.

nZVI particles are strong reducing agents, capable of degradation and detoxification of a wide range of organic and inorganic pollutants in contaminated aquifers. Understanding the transport and retention of these nanoparticles in subsurface environments is required for treatment systems and in situ groundwater remediation. During the last decade, several studies have been conducted to investigate the effect of different physicochemical conditions on the transport and retention of nZVI in saturated porous media. This study aimed to evaluate the effect of sand grain size and nanoparticle concentration on fundamental processes governing CMC-nZVI nanoparticle transport and retention in saturated porous media.

nZVI (NANOFER STAR, NANOIRON, s.r.o. Czech Republic was employed in this study. To prepare CMC-nZVI, nanoparticle, suspension and polymer solution was added by the relative dose of CMC to nZVI mass 1:2, in a 250-ml flask reactor. pH was fixed at 9.5 by NaOH and the solution was mixed for 144 h under ambient temperature condition at the absence of oxygen. Quartz sands with ∼ 99.38% SiO2 and 0.27 Fe2O3 based on XRF analysis, was used as the porous medium. The experiments were conducted using a cylindrical Plexiglas column 30 cm in length and 2.5 cm in inner diameter. In order to capture the effect of particle concentration and grain size, 12 tests were conducted with four different concentrations (C = 10, 200, 3000, 10000 mg/l) and three sizes of grain (dc = 0.297–0.5 mm, 0.5–1 mm, 1–2 mm). In each test, ∼4 PVs of nZVI suspension were introduced into the columns and to complete the test, ∼6 PVs of deionized water were flushed. The column effluent was collected every 2 min and analyzed for total Fe using UV-Vis. The normalized effluent iron concentration (C/C0) for each transport test was plotted as a function of pore volumes. The spatial distributions of retained CMC-nZVI in the sand columns were determined to right after the breakthrough experiment. The quartz sand in each column was carefully excavated in ~3 cm increments, transferred into 50 mL vials and analyzed for total Fe. The concentration of retained CMC-nZVI in all the sand columns was also plotted as a function of travel distance.

The breakthrough curves indicate that both grain size and nanoparticle concentration had a relevant impact on CMC-nZVI mobility, even if the influence of nanoparticle concentration was more evident. In all experimental conditions, the BTCs were not symmetrical, which indicates that attachment and detachment phenomena occurred in different modes. The breakthrough curves can be interpreted in two steps: injection and flushing times. The maximum relative concentration (C/C0) decreased, during injection time, for three different grain sizes while influent concentration increased from 10 to 10,000 mg/L, which can be attributed to the increase in particle-particle interaction (aggregation) and particle-sand interaction (attachment). The breakthrough curves, after the initial increase, showed a strong decline, which is a clear indication of the ripening phenomenon. This phenomenon affected the porous medium properties such as porosity and hydraulic conductivity. Moreover, At higher influent CMC-nZVI concentration, Na+ ion and subsequently ionic strength increases because of higher doses of Na-CMC. As a result, aggregation and deposition will occur under a shallower secondary energy minimum well, that they are reversible. At the same nZVI concentrations, the breakthrough curve decreased by a decrease in grain size. Decreases in grain size can lead to an increase in surface area, decrease in pore throat size; and consequently, retention of nanoparticles by straining phenomena. However, another behavior was governed during the flushing time. During the flushing time, a narrow sharp increase in C/C0 was observed called flushing peak. In this study, CMC-nZVI aggregates deposited onto surfaces of sands due to secondary energy minimum were eventually released during the flushing period of the column with DI water. The results suggest that the grain size and particle concentration can have a positive effect on this peak. The results of retention profiles demonstrate that the CMC-nZVI retention in low concentration (10 mg/L) is consistent with filtration theory; whiles the highly concentrated polymer-modified nZVI dispersions (especially 3000 and 10000 mg/l) contradicts filtration theory. Based on filtration theory (Elimelech et al. 1995; Tufenkji et al. 2004), if all factors affecting the transport of colloids are kept constant, grain size increase can lead to a decrease in surface area and attachment efficiency (α). The contradiction at high concentration can be explained by considering the effect of hydrodynamic forces (especially fluid shear) on agglomeration and disagglomeration and deposition and detachment. The size of stable aggregates formed in the pores of finer sands is smaller than when they are formed in the pores of larger sands because the magnitude of local shear is higher for narrower pores. This led to decreased retention in finer sand.

The results of this research show that during the injection time, ripening and straining phenomena are key retention mechanisms of nanoparticles by decreasing the sand size and increasing particle concentration. While during the flushing time, secondary energy minima and hydrodynamic forces play critical roles in the deposition and transport mechanisms of CMC-nZVI. At high particle concentration (3000 and 10000 mg/l), these factors can lead to an increase in nanoparticle mobility by decreasing sand size. However, the results of retention profiles were consistent with colloid filtration theory at low particle concentration (10 and 200 mg/l).

Several archaeologists believe that there is a relationship between cultural residuals, human beings, and soil. Soil related factors such as age index, climate change, and paleoclimate are important in archaeology. Soils could be accounted as records of invaluable information. Appropriate compiling of these data cause better understanding of soil and landscape genesis, and human activities in the past. There are two distinguished archeological sites of Daqyanous (Islamic Era) and Konarsandal (before Islamic Era) in Jiroft area. Besides, Konarsandal site is surrounded by old and new Halilrood channels. Since no data about the comparison of soil evolution in the mentioned archeological sites were available, the present research was conducted to compare soil evolution of archaeological sites using soil classification, clay mineralogy, and micromorphology in Jiroft area.

soil samples were collected from three different archaeological sites including new channel of Halilrood (pedon 1), old channel of Halilrood (pedon 2) and, Daqyanous (pedon 3). The samples were air-dried and sieved (2 mm). Routine soil physical and chemical analyses including pH, EC, soil textural class, soluble sodium, calcium, and magnesium, and gypsum and calcite contents were performed. The studied pedons were classified using Soil Taxonomy system according to morphology, laboratorial results, and field observations. The clay minerals were determined by X-ray diffraction (XRD) method after carbonates, organic matter, and Fe were removed using Jakson (1965) and Kittrik and Hope (1963) procedures. Ten undisturbed samples were selected for micromorphology studies and thin section preparation.

Pedon 1 is affected by Halilrood River sediments, that is why an old soil together with a young soil was formed. Salinity and SAR in the old soil were higher than the upper young soil. A textural discontinuity was found between the old and the young soils. Natric, calcic, and gypsic horizons were found in pedon 1 and caused a Typic Natrargid to be formed in new Halilrood channel. Natric horizon due to high Na cation was formed in pedons 1 and 2. On the other hand, salic, natric, and cambic horizons formed a Typic Haplosalid in pedon 2 (old Halilrood channel). High salinity and SAR in the upper layers caused salic and natric horizons to be formed. Pedon 3 with argillic horizon is an old polygenetic soil. Available humidity in the past caused removal of carbonates from upper layers that followed by clay illuviation and argillic horizon formation. Salinity and SAR in this soil were low and a heavy texture was found in pedon 3. Since pedon 3 showed cambic, argillic, and calcic horizons, it was classified as Arenic Haplargids. Calcium carbonate, gypsum, Fe oxides, and clay coatings were among dominant micromorphological features observed in the studied pedons. Konarsandal archeological site is located in the lowlands of Jiroft plain downward Rabor and Baft elevations. Lenticular gypsum crystals could be attributed to the solution of upward Neogene formations and groundwater close to the surface which evaporates due to capillary. Powdery calcite, Fe-oxides, and clay coating and infilling of gypsum in pore spaces of pedon 1 were observed by micromorphological investigations. Diffused clay coating around pore spaces is explainable by high sodium content and Natric horizon formation. Lenticular, interlocked plates, and infillings of gypsum were observed in pedon 1. However, gypsum with irregular shapes and low content was investigated in pedon 2. This is due to location of this pedon in Halilrood old channel. That is why pedon 2 affected by Halilrood during long periods of time is unstable and shows less evolution compared to pedon 1. Irregular and lenticular forms of gypsum show weak soil development due to low rainfall, high evaporation, and excess salt. High NaCl is reported as a requirement for lenticular gypsum formation. This form of gypsum is supported by high salinity in pedons 1 and 2. High Na and natric horizon formation in pedons 1 and 2 caused dispersion of clay and ceased formation of clay films around pore spaces. Gypsum was not found in pedon 3 during filed and laboratory studies. Besides, gypsum was not observed by micromorphological observations. Clay and calcite coatings and calcite infillings were among the micromorphological features observed in pedon 3. Calcite coating on clay coating in this pedon could be attributed to the climate with more available humidity in the past followed by an arid climate. Carophyte algae fossil was only observed in pedon 3. Kaolinite, illite, chlorite, smectite, and palygorskite clay minerals were determined by X-ray diffraction. Palygorskite is highly related to the parent material and climate. Pedogenic palygorskite formation from transformation of 2:1 clay minerals and/or neoformation is reported by several studies. Due to the impact of paleoclimate with more available humidity, palygorskite was not found in Daqyanous archeological site. It seems that higher humidity in the past did not allow palygorskite formation or transformed it into smectite. Chlorite and illite are originated from parent material. Evidences of pedogenic mica minerals in arid and semi-arid environments were also found which is due to K fixation among smectite layers. Smectite with pedogenic origin is also reported by Sanjari et al. (29) in the study area. Chlorite, illite, and kaolinite clay minerals seem to be originated from parent material in the present study.

Laboratories analyses and micromorphology observations clearly showed weak development in Konarsandal pedons compared to high evolution of soils in Daqyanous archaeological site. The same results were also found for unstable surfaces of pedons 1 and 2 compared to stable surface of pedon 3. The stable surface provided the accumulation of clay and calcite coatings around the cavities and the formation of argillic and calcic horizons indicating high soil development. Results of the study showed polygenetic formation in soils. Soils in old Halilrood channel show high salinity and Na adsorption ratio compared to other two pedons under study.

In the past century, the climate has been changing on both regional and global scales over the earth. It is also expected that such changes will continue in the near future. Climate change is due to increased greenhouse gas emissions in the atmosphere. The concentration of these gases is directly related to the temperature increase. Climate change affects the hydrological cycle through changes in time, amount, the shape of precipitation, evaporation rates and transfer, soil moisture, runoff, etc. Today, the use of hydrological models have been developed to have the factors affecting the hydrological cycle in the watershed. The Soil and Water Assessment Tool (SWAT) is an example of these models. The common method of assessing the effects of climate change on flow is using hydrological models along with general circulation models (GCMS) or regional weather models (RCMS). The purpose of this study is to investigate the effect of climate change on runoff and evapotranspiration (real and potential) of Mehrgerd Watershed using the SWAT hydrologic model and the CanESM2 climatic model.

For modeling the change rate of regional climate parameters in the future period (2017-2030) and the effect of these changes on hydrological parameters, the daily data of minimum and maximum temperature of the Borujen station and precipitation of the Tange Zardaloo station for the base period (1984-2005) were used as inputs of the CanESM2 model. Accordingly, using the model of SDSM5.2 under the scenario of RCP8.5 was performed the downscaling operation. To evaluate the efficiency of the SDSM model were used statistical criteria R2, RMSE, and NS. In the next step, the SWAT 2012 model was used to simulate the hydrologic conditions. After introducing the DEM map with a precision of 20 meters, the region was divided into 18 sub-basins. From the combination of land use maps, soil, and slope, 54 units of hydrological response (HRU) were obtained. Then, climatic data including precipitation, minimum and maximum temperature, relative humidity, wind speed, and solar radiation were introduced to the model. Due to the presence of the dam and the two water transfer lines in the area, physical data and discharge were calculated and introduced into the model. The calibration and validation of the model were done by Sufi-2 algorithm. The calibration process was conducted for the period 2004 to 2012 while the validation process was from 2013 to 2016. In order to evaluate the performance of the model, coefficients NS, R2, P-Factor and R-Factor were used. For this purpose, the model was restarted to obtain the appropriate range for each parameter. After calibrating the hydrological model was introduced the simulated climate to the SWAT model. Finally, the effect of climate change was investigated on runoff and evapotranspiration (real and potential) of Mehrgerd Watershed.

The results of the downscaling of the climatic model in this region indicate a decrease of 53.48% of precipitation and increase minimum and maximum temperatures for a future period (2017-2030), 0.84 and 3.99%, respectively. Based on the results of the sensitivity analysis of the SWAT model, 10 parameters were identified as the most sensitive parameters. In the hydrological section, the statistical criteria of R2, NS, P-Factor and R-Factor were obtained for the calibration period 0.73, 0.69, 0.52 and 0.24, respectively and for the validation period, 0.71, 0.58, 0.45 and 0.29, respectively. Comparing runoff simulation in the future period under the influence of climate change and comparison of its values with the base period showed a decrease of 23.82% in an annual average of runoff. Climate change will also reduce actual evapotranspiration by 26.03% and increase potential evapotranspiration by 10.20%.

Based on the results of the SDSM model, it was determined that the precipitation is strongly reduced in comparison with the observation period, and the minimum and maximum temperatures increase with a slight difference compared to the observation period. According to statistical criteria, the SDMS model has succeeded in simulating the parameters for the future period. Accordingly, the values of R2, RMSE, and NS for precipitation, were equal to 0.92, 5.81 and 0.39, respectively, and for the minimum and maximum temperatures were obtained 0.99, 0.16, 0.99 and 0.99, 0.21, 0.99, respectively. In the hydrological section, the statistical criteria were acceptable values for the calibration period and the validation. Finally, it was found that under the influence of climate change, runoff decreases. Real evapotranspiration is also declining due to a lack of available water, but potential evapotranspiration is increasing due to the close relationship with temperature.