حسن رمضانپور

The purpose of this research is to investigate the role of reading and reading culture on the social harms of middle school students in Bojnord city. This research is part of applied research in terms of its purpose and descriptive-survey in terms of implementation method. The statistical population of this research includes all high school students of Bojnord city, including male and female students, which are about 15,875 people, of which 377 people are based on Morgan's table (1972), as the sample size, selected by stratified random sampling and questionnaire. Research papers were distributed among them. Two library and field methods have been used to collect information. The tool of data collection is a questionnaire of social harms in the form of 42 questions with 5 options, and to measure the promotion of the culture of reading and reading, a researcher-made questionnaire containing 20 questions was used to measure the validity of the variables using Cronbach's alpha coefficient for the variables of harms. social and promotion of reading and reading culture were calculated as 0.907 and 0.841 respectively. The content validity of the questionnaire was confirmed by expert professors. For statistical analysis, factor analysis method using SPSS version 19 software and structural model method with LISREL version 8 software were used. The results showed that there is a significant relationship between promoting the culture of reading and reading in the family and reducing the social harms of young people.

Due to the dominance of the important trade routes, the Samanids paid special attention to trade. As a commercial commodity, slaves were one of the sources of income for the Samanids. Samani government both imported slaves and allowed slave traders to import slaves in return for taxes. These slaves were exported from the Samanid territory to other regions of the Islamic world, especially Baghdad, the center of the Abbasid Caliphate. The Abbasid caliphate and the Samanid government used imported slaves, especially Turkish slaves, in military affairs, and these slaves had great power in the caliphate and Samanid system. Research data indicate that the slave trade flourished in this period and the Samanids supported it. The main question of the current research is, what was the extent of the role of the Samanids in the slave trade? The findings of the research indicate that the slave trade flourished in this period and the Samanids supported it, they monopolized this trade, supervised the import and export of slaves, imposed taxes and customs duties on them, and gained a lot of income in this way. In addition, the main core of the Samani army was formed by the military forces of Turkish slaves. Based on ancient sources and historical researches and using descriptive-analytical method in this research it has been trried to study the slave trades during the Samanid period.

Salinity of soil and water resources are the most important factors reducing yield in many crop plants, including rice. Considering the increase in salinity of soil and water resources in many paddy farms in Iran, and considering the different sensitivity of rice plants at different growth stages to water and soil salinity, it is necessary to manage saline water resources in these areas. In this experiment, the effects of different levels of irrigation water salinity on grain yield of two hybrid (Bahar) and improved (Dorfak) rice varieties at different growth stages were investigated. The objective of this experiment was to obtain the best application time of saline water with the minimum reduction of rice grain yield.

This study was conducted as a pot experiment in factorial based on completely randomized design with three factors and three replications in the Rice Research Institute of Iran (RRII), Rasht, Iran. The experimental factors included irrigation water salinity in four levels as the first factor, 2, 4, 6, and 8 dS/m, application time of salinity stress in four levels as the second factor, tillering, panicle formation, heading and maturity growth stages, and rice variety in two levels as the third factor, the hybrid variety of Bahar and the improved variety of Dorfak. Moreover, irrigation with normal water with a salinity of 0.4 dS/m was also considered as a control treatment for comparison with the other salinity treatments. A mix of NaCl+CaCl2 salts in a ratio of 2:1 were used to apply salinity treatments. After the end of each growth stage, leaching was carried out and irrigation with normal water was continued until the end of the growth stage. At the end of the growth and harvesting grains, grain yield based on 14% moisture, biological yield and harvest index were measured. SPSS software was used for statistical analysis and Tukey's test was used to comparison of means at 1% probability level.

The results of analysis of variance indicated that the effect of different salinity levels and its application stage on grain yield of both rice varieties was significant at 1% probability level. The results of comparison of means revealed that the improved variety Doefak showed more salinity tolerance and produced more grain yield at different salinity levels compared to the hybrid variety Bahar. The most sensitive and resistant growth stages to salinity stress were tillering (with an average grain yield of 6.82 g/pot for the hybrid variety Bahar and 8.07 g/pot for the improved variety Dorfak) and maturity (with an average grain yield of 14.71 g/pot for the hybrid variety Bahar and 15.90 g/pot for the improved variety Dorfak) stages, respectively. The lowest biological yield (14.37 g/pot) and harvest index (2.53%) in the improved variety Dorfak was obtained at the tillering stage and the salinity level of 8 dS/m. Also, the lowest biological yield (12.89 g/pot) and harvest index (4.61) in the hybrid variety Bahar was observed at the salinity level of 8 dS/m and at the heading and panicle formation stages, respectively. Modeling the effect of different salinity levels on grain yield indicated that yield variations in different salinity levels and at the different growth stages followed a quadratic equation. Coefficients of determination of the regression equations of grain yield in different salinity levels for the improved variety Dorfak at the tillering (R2=0.99), panicle formation (R2=0.99), heading (R2=0.95) and maturity (R2=0.98) stages, and also for the hybrid variety Bahar at the tillering (R2=0.99), panicle formation (R2=0.99), heading (R2=0.99) and maturity (R2=0.99) stages, revealed that the application time of salinity stress is more important than the salinity levels.

Application of different salinity levels caused a significant difference in grain yield of both improved and hybrid varieties, so that a significant decrease was observed in grain yield of both Dorfak and Bahar varieties with the increasing salinity levels, and the lowest grain yield was obtained at the salinity level of 8 dS/m. Application time of salinity stress was also very important and caused a significant difference in reduction of grain yield. The results of this experiment showed that under the water limitation conditions or in the absence of suitable water quality, it is possible to prevent the reduction of rice grain yield by managing irrigation water at different growth stages and using lower quality water in the final and maturity growth stages.

Carbon dioxide is one of the main greenhouse gases that affect the world's air temperature. Small changes in the amount of carbon dioxide emissions from the soil have a significant effect on the concentration of this gas in the atmosphere. Soil respiration, the process that emits carbon dioxide from the soil to the atmosphere, is one of the most important carbon flows in the ecosystem and includes two components of heterotrophic respiration (microbial respiration) and autotrophic respiration (root respiration). Researchers measure the rate of soil respiration for every 10 degrees Celsius of temperature change with an index called temperature sensitivity of soil respiration (Q10). The evidence shows that the Q10 value of the soil is not constant and has a negative correlation with temperature and a positive correlation with soil moisture. Also, the amount of soil organic carbon, incubation temperature and the interaction of these two have a significant effect on soil organic carbon decomposition. Accordingly, this research measures the temperature sensitivity (Q10) in soil under tea cultivation and investigates its relationship with some soil chemical characteristics and topographic indices.

After surveying the east and west tea gardens in Guilan province in the north of Iran, 200 samples were taken at a depth of 0 to 40 cm. The experiments were conducted to determine Organic Carbon, Labile carbon, Bulk density, PH, Cation Exchange Capacity, Microbial Biomass and soil microbial respiration. To measure Q10, two temperature treatments of 25 and 35 °C were used. Elevation, slope and aspect were obtained using a DEM map in ArcGIS 10.5 and other topographical indicators such as wetness index, slope length, relative slope position, catchment area, channel network base level, vertical distance to channel network, convergence index, profile curvature and plan curvature were extracted from DEM map in Saga GIS 2.1.0. Pearson correlation was used to investigate whether there is any relationship between soil temperature sensitivity with other soil properties. Then, principal component analysis (PCA) was performed to determine a minimal data set. All the statistical analyses were done with SPSS 24. Regression charts were also drawn using Excel software.

The Q10 values varied from 1.19 to 1.58. This index has the most negative correlation with organic carbon (-0.863), Labile carbon (-0.863), microbial biomass (-0.837), respiration at 25 °C (-0.831) and 35 °C (-0.8) at 1% level and negative correlation with elevation at 5% (-0.159). The principal component analysis showed that the first six components (PC1, PC2, PC3, PC4, PC5 and PC6) have special values of more than one and were able to describe 73% of the total variance. The first main component (PC1) describes 23.125% of the total variance and includes soil organic carbon, labile carbon, microbial biomass and Q10 which have the highest factor loading in this component. The second one (PC2), which explains about 12.99% of the total variance, has the highest factor loading with the vertical distance to the channel network (0.880). The third component (PC3) explains about 12.22% of the total variance. In PC3, clay has the highest factor loading. In the fourth component catchment area, convergence profile and slope length have the highest factor loading, respectively. Finally, the fifth and the sixth components are related to the elevation, slope and plan curvature.

The highest positive factor loading is related to soil organic carbon (0.981). Therefore, the first main component can be "part of the role of organic carbon in microbial biomass, labile carbon and temperature sensitivity". The results showed that Q10 has the highest negative correlation with soil microbial biomass and organic and labile carbon. In other words, the higher the soil organic and microbial biomass carbon, the lower the amount of Q10. Also, the second component can be considered as topographic indicators related to the channel network. Topographic indices can be used very strongly to model making soil organic carbon. The third component is related to clay properties. Several studies have indicated that the amount of clay has a high relationship with cation exchange capacity and it is a good indicator to determine the quality of soil. According to the results, although the correlation between some characteristics obtained from soil topographical analysis can prove the possibility of using them as auxiliary variables in predicting soil organic carbon, this point should be taken into account that other factors also play a role in the process of soil formation and development.

Soil classification categorizes soils into different classes on the basis of their distinguishing characteristics and provides a structured conceptual framework for describing and understanding soil properties. There are two soil classification schemes that are generally regarded as having worldwide application, the Soil Taxonomy (ST) and the World Reference Base (WRB) which are also popular in Iran. These systems of classification consider diagnostic horizons and factors of soil formation as the basis of classification. The aim of this study was to determine the classification of soils of tobacco farms in the Talesh County of Guilan Province based on ST (2022) and WRB (2022) according to the soil diagnostic characteristics, then comparing two systems for soils of tobacco farms to determine the ability of better description of soils by these two systems of soil classification.

Talesh County is considered to be the most important tobacco production areas in Guilan Province and IRAN. The most extensive area of tobacco cultivation in Guilan Province is located in this County and in Jokundan and Mountain districts. The study area has a humid climate with cold winter and hot summer. The mean annual temperature is between 15.6 and 17.2 degrees Celsius and the annual rainfall is between 786 and 1370 mm. Based on the map of moisture and temperature regimes of Iran  and with the help of jNSM software, the moisture and temperature regimes were determined as Udic and the Thermic respectively. In the study area twenty pedons (eight pedons for Mountain and twelve pedons for Jokandan) were described and the morphological characteristics of the pedons layers were studied in the field according to the Soil Survey Manual. Then, the soil of each horizon was collected, air-dried, and sieved by passing through a 2 mm sieve before analyzing the properties of the soil. Soil pH, Electrical Conductivity, Texture, Organic Carbon, Calcium Carbonate Equivalent, Cation Exchange Capacity and Base Saturation were determined in all the samples according to Methods of Soil Analysis. Soils were then classified according to classification criteria of ST (2022) and WRB (2022) systems. For showing changes of tobacco farms soils, eleven pedons were selected as representative pedons and the reference between ST (2022) and WRB (2022) was established for tobacco soils at the level of the subgroup or secondary classification unit.

The results revealed that according to ST (2022), representative pedons of Mountain district were classified as Entisols, Inceptisols and Mollisols orders while, Jokandan had Entisols, Inceptisols, Mollisols and Vertisols pedons. WRB (2022) Reference Soil Groups (RSGs) for Mountain was Regosols, Umbrisols and Phaeozems and for Jokandan district were Fluvisols, Cambisols, Phaeozems and Vertisols. At lower levels of classification, ST (2022) uses climatic data as soil moisture regime whereas WRB (2022) does not use. Therefore, the suborders or great groups of all soils were separated based on the Udic moisture regime. Finally, representative pedons were classified as Typic Udorthents, Mollic Udifluvents, Oxyaquic Udifluvents, Typic Humudepts, Dystric Eutrudepts, Typic Hapludolls, Fluventic Hapludolls, Aquic Argiudolls, Typic Argiudolls and Aquic Hapluderts at great group level.
In regard to the WRB (2022), in the secondary levels, each section had its own series of principal and supplementary qualifications. Among those, the principal qualifications were mainly Eutric, Cambic and so on, and the supplementary qualifications were mainly Clayic, Loamic, Siltic, Humic and so on.

It was found that when compared with ST (2022), the WRB (2022) had stronger abilities to distinguish soil properties for tobacco cultivation which was mainly reflected in the following aspects: 1- The climate-related soil moisture regimes were generally used to classify the suborders in ST (2022). It was found that the soil moisture status of all pedons was Udic, as well as the fixed format of naming soils in ST (2022), Therefore, divisions were limited in the suborders, 2- The flexibility of WRB with the utilization of multiple qualifiers brings out more sensitivity in reflecting soil characteristics in the soil name if compared with Soil Taxonomy. Also, the emphasis put on soil morphology compared with laboratory data makes the system suitable for application in areas with rather modest facilities, 3- The existence of the Mollic or Umbric horizon in pedons is well defined by WRB (2022), while this issue is ambiguous in ST (2022), 4- WRB (2022) have not fixed naming formats, the number of secondary levels qualifiers of the WRB system could be increased or decreased with the number of diagnostic characteristics of the soil pedons. 5- Nomenculture is very complicated in both systems, nevertheless, it is inevitable to transfer information to non- specialist users in a more simpler language, in WRB (2022) this information can be extracted more easily from the soil name.

Jewish traders in Iran in the early Islamic centuries were very famous for the slave trade than anything else. The geographers of the first centuries have mentioned a group of Jews called the Radhanites who traveled to different places and took trade goods, including slaves, to different places. They transported slaves from Europe to Byzantium and to the Islamic world and caused the growth and development of this trade. It seems that various wars in Europe and Asia had an impact on the subject of the slave trade, and Jewish traders contributed greatly to the expansion of the slave trade. In any case, despite the prosperity and expansion of the slave trade in the discussed period, this issue has not been much reflected in the historical sources of this period, and even in new studies, it has been less discussed and concentrated on. Therefore, the present study tries to investigate the role of Jewish merchants in the slave trade in Iran from the early Islamic centuries to the end of the 4th century Hijri based on the limited resources available from this period and using a descriptive-analytical method. For this purpose, efforts will be made to collect historical data from library sources and categorize and finally analyze them using the method of historical studies.

In recent years, the use of digital soil mapping (DSM) based on machine learning algorithms with the aim of preparing soil maps has become widespread with the basis of soil class prediction with the help of modeling the relationships between them and environmental variables. One of this method's challenges is the imbalanced nature of soil distribution in landscape, which leads to overfitting and underfitting of classes, and as a result, reduces the accuracy of many used models. This study was conducted to evaluate the ability of two machine learning algorithms, including random forests and support vector machines, for the digital mapping of soil classes with an imbalanced data set. This study was conducted on 95 soil profile classes at the family level, in 4000 hectares of land in the Honam sub-basin, Lorestan province. The issue of imbalance in soil classes was investigated by using six data sets, including the original soil data set and five data sets created by several resampling approaches including two manual classifications and three over-sampling, under-sampling, and Synthetic Minority Over-Sampling Techniques in the R software. The results showed that despite the low values of overall accuracy, the Geographical distribution of soils with high frequency in the study area in digital soil map obtained from the random forest and the original data set as well as Synthetic Minority Over-Sampling Technique, with conventional soil map of study area is significant. Therefore, the low observation number of other soil classes and as a result incorrect training of models can be considered as one of the main reasons for the low accuracy of the used models.

In recent years, the use of the Internet has increased dramatically and has taken a significant part of people's lives, especially teenagers, and we live in an era where we see the increasing use of social networks by family members, especially teenagers. The present study was conducted with the aim of investigating the relationship between family cohesion and flexibility and adolescent Internet addiction: the mediating role of self-differentiation and time perspective. The type of research is correlation. The statistical population of the field research was 20,100 high school students of Bojnord city, 320 people were selected based on the table of Karjes and Morgan and standard questionnaires were distributed among them. In order to analyze and test research hypotheses, correlation method with SPSS software version 20 and structural model method with PSL software version 3 have been used. The results of the research hypothesis test showed that there is a significant relationship between family cohesion and flexibility with adolescent Internet addiction: the mediating role of self-differentiation and time perspective (confirmation of the main hypothesis).

Soil entities depends on its physical, chemical, and biological characteristics. Soil organic carbon (SOC) stocks is one of the main factors whose variations affect all these parameters. So, this study was performed for mapping the coefficient of variations (CV) of SOC stocks in some parts of the Simineh Roud watershed. Soil sampling performed using the Latin Hypercube method (cLHm) at 210 points from 0 to 30 cm of the soil surface, and the organic carbon was measured, then SOC stocks was calculated. In the next step, using Random Forest (RF) model the effective parameters were calculated (in this step, to model the SOC stocks, standardized spectral reflectance index and extracted data from digital elevation model were used). Finally, RF model was performed 100 times, as well as mapping of the values of upper (95th %), lower (5th %), and average SOC stocks for each pixel with a spatial resolution of 30 × 30 m was obtained. To obtain the CV with a confidence coefficient of 90%, the percentile of 95% and 5% were subtracted. The CV was obtained by dividing it by the mean. The results showed that the accuracy coefficient (R2) for modeling SOC stocks by the RF model was 0.81 and the mean accuracy coefficients including RMSE and MAE were 0.44 and 0.34 (kg/m2), respectively. Also, the results of CV mapping for the amount of SOC stocks in the study area showed that the amount of variation of this parameter varies between 3.9- 55%. Based on the results of the CV mapping of the study area, the most and lowest variations were observed in dry farming and grasslands, respectively. Probably, continuous cultivation and low return of organic matter in dry farming have increased the CV of SOC stocks in dry farming use.

One of the concerns of today's society is the emergence and increase of abnormal behaviors in schools and among students, which, if not properly controlled, can have negative consequences for the society. The purpose is to identify and analyze the factors that cause social-behavioral harms among male secondary school students in Bojnord city. The research method was qualitative and quantitative and the statistical population included a number of experts active in the field of related injuries. The research method was qualitative and quantitative and the statistical population included a number of experts active in the field of related injuries. In the qualitative part, 15 people participated in the interview process, and in the quantitative part, 30 people from the staff and experts active in the pathology centers of Bojnord participated in this researchers. methods were used to analyze the data. In the descriptive statistics of the central index and dispersion and in the inferential part of the exploratory and confirmatory factor analysis at the confidence level of 95%, it was done with spss18 and Lisrel 8/80 software.Based on the analysis of qualitative data from exploratory interviews and coding and content analysis of the text, and at the same time their conformity with the theoretical foundations, the results of the research in the qualitative part indicated that the family context is important and after that, the feeling of loneliness and injustice is the second most important and on the other hand, pleasure-seeking tendencies are the least important.Keywords: behavioral-social injuries-family context-students

Delineating landscape into homogenous units is fundamental to managing resources and delivering sustainable development. The importance of this has long been recognized as a critical issue in various studies and it has been examined from different aspects. In soil mapping, the geopedologic approach is used for landscape classification, which was defined by Zinck (1989). This approach differentiates landscapes into landforms to increase the purity of soil map units. Therefore, the aim of this study was preparing geopedologic maps of the study area on the level of landform phases intending to make more homogeneous soil units. Honam sub-basin in Lorestan province is one of the most important agricultural areas in the Karkheh River watershed. Soil moisture and temperature regimes of the area were Xeric and Mesic, respectively. After a primary interpretation, a geopedology map of the study area at the landform level was prepared according to the geopedologic approach. After soil surveying, 31 profiles were excavated, described, and sampled in the largest delineation of this map. Ultimately, this landform unit was differentiated to the landform phase units using morphometric features and normalized difference vegetation index. Pedodiversity index was computed for each landform phase unit to investigate the credibility of the geopedological approach for this unit. The conditional probability of each soil family was also measured in each landform phase unit to compare statistical differences between landform phase units. Furthermore, statistical comparisons were made between the Shannon indices of each unit. The soils of the study area were classified into seven soil families according to Soil Survey Staff (2014). Based on the geopedology map, this area includes two landscapes of Piedmont plains and valleys. These two landscapes were differentiated to 6 and 3 relief/molding, respectively. Geologically, the study area has 5 lithologic units. Finally, 22 landform units were identified in this area. The area of the widest landform with the code of Pi461 was 1223.35 ha. With individual use of NDVI, TRI, and aspect map, this landform unit was differentiated into 3 phases, and with the use of these 3 maps collectively, 11 phases were differentiated. The results showed landform map unit of Pi641 with 31 soil profiles and 7 soil families has the highest value of diversity indices, such as 1.59 for the Shannon index. In addition, this map unit is a compound map unit consisting of several soils, where the highest probability of observing soils is related to soils A and B with 32.5% probability. By differentiating this landform unit into phases, the Pi461 map unit is separated into smaller units that are more homogeneous. For example, when it is separated according to the vegetation characteristics, the three phases Pi4611 (N), Pi4612 (N), and Pi4613 (N) were differentiated that have medium, low, and high vegetation, respectively. In this case, Pi4612 (N) map unit with 75% probability of soil C observation and Pi4613 (N) map unit with 87.50% probability of soil B observation are two homogeneous map units. The Shannon index of these two units is 0.56 and 0.37, respectively, which indicates the purity of these map units. The results also showed that diversity indices and conditional probabilities, respectively, were decreased and increased in most of the landform phase map unit compared to the landform map unit. The use of normalized difference vegetation index compared to other environmental features has been effective in separating the landform phase units and preparation of homogeneous map units. So, the most probability of observing the dominant soils of the study area increased from 32.25% in the landform unit to 52.63, 75.75, and 87.50% in the landform phase unit, and the Shannon index decreased from 1.59 in the landform unit to 1.36, 0.56, and 0.37 in the landform phase units. The use of other environmental features to increase the purity of the landform phase map unit is suggested in future studies. Results of using geopedological approach at landform level in the study area showed that this level is useful at highest levels of soil classification (from order to great group), but due to the complex nature of soils at lower levels of classification (family and soil series) does not have enough efficiency. Therefore, for improving the geopedology method accuracy and to present more uniform map units at lower levels of classification, landform phase maps were presented according to the environmental characteristics of the selected landform. The statistical comparisons between Shannon indices calculated for each map unit in the landform phase map showed a significant difference at the 90% probability level between most of the units, which indicates an increase in the purity of these units at the soil family level.

The entrance of new industries and factories into Iran in the late Qajar and Pahlavi eras had various political, economic, social, and cultural consequences. From amongst its social consequences one can mention the creation of different groups and classes of society that changed people’s lives. Many women were employed by the factories, the effects and consequences of which were inevitable. The study aimed to examine the social effects of the entrance of industry and the establishment of factories on women that worked in them. The main question is: What was the social status of the Iranian women that worked in Qajar and Pahlavi eras? The results showed that such issues as very low wages, long working hours, poor factory hygiene, lack of insurance, employers’ bad behavior and sexual abuse were the most important social consequences of the entrance of the industries for working women. The historiographical study sought to collect data from library sources, analyze the data, and categorize them using a descriptive-analytical method.

One of the main components and in fact the basic element of research through which the researcher explains the research problem is "problem expression”. Due to the lack of a correct definition of "problem expression" and its confusion with other components of research, such as the title, subject and main question of the research, it is often ignored in historical research. This problem can be mostly attributed to the inadequacy and incorrect definition of the basic concepts of research in the methodological research texts, in particular, historical research that its reflection can be seen in the dissertations of history students. This study seeks to examine the pathology of lack of transparency or deficiency in the concept of "problem expression" in dissertations and historical researches. The findings of this research show that due to the lack of correct definition of “problem” in the methodological research texts in history, has led to serious shortcomings in academic dissertations in the field of history. In this research, , however, it has been tried , based on the library resources , dissertations collection (GANJ) from IRANDOC site and using descriptive-analytical method as well as statistical method to analyze the Pathology of “Problem expression” in historical research by case study of history dissertations of Ferdowsi University graduate master degree students.

The Kharijites were political-religious sectarian that gradually entered the land of Iran after their emergence in the first half of the first century AH in today's Iraq. Moreover, they raised the flag of rebellion and revolt against the Umayyad and Abbasid caliphs. The Kharijite uprisings in Iran lasted for three centuries, and some of them were so important that the caliph himself had to take action to handle them. However, the Kharijites have never been a significant threat to the central government, and they revolted intermittently. The main question of the present study is why and how the Kharijites were able to last in Iran for three centuries, and they have fans and also failed to take effective action in Iran? The research findings show that the Kharijites were able to attract different groups due to some of their religious beliefs and fighting spirit, as well as the issues raised for the people of the conquered Islamic lands and on the other hand, due to some belief features, such as stubbornness in defending their personal opinion and a particular interpretation of religious issues and social justice, they failed to create an effective convergence between other groups and elements dissatisfied with the government and finally, they have never been presented as an influential leader in the history of Iran. This research seeks to analyze the Kharijite actions in Iran in a historical method and with a descriptive-analytical approach based on data collection from library sources.

Addition of biochar to soil has been recently considered as an amendment to reduce soil erosion. Biochar contains pyrogenic carbon, which is produced by heating residue of various crops, woods (or in other words various biomass) in restriction or absence of oxygen. Biochar can affect soil organic matter level and aggregate stability. Reduction of soil erosion through maintenance and  the increase of organic matter, increase of aggregate stability and improvement of hydraulic conductivity, and enhancement of moisture retention as a result of biochar application should be considered as an important achievement. It is important to study the effect of the different methods of biochar addition to the soil. The method of uniformly mixing biochar with surface soil which has been used in most studies can disturb the natural structure and lead to soil degradation. Therefore, it is an important issue to introduce a practical method that is associated with minimal soil manipulation, especially in erosion-prone soils. The effect of the biochar addition as suspension in water has never been reported in previous studies. Therefore, the aim of this study was to investigate the effects of adding different levels of biochar produced from two types of feedstocks (horticulture and agriculture wastes) in form of aqueous suspension on the properties of two types of erosion-prone soils in southern Guilan.

Two erosion-prone soils which were undisturbed, were sampled by metal cylenders (diameter and height of 25 and15 cm, respectively) of marl lands located in southern guilan. These soils were named as SL and L. Texture of SL and L were sandy loam and loam, respectively. Two types of biochar were produced from different feedstocks including pruned branches of ash tree (Fraxinus excelsior) and rice husk by slow pyrolysis at a temperature of 550 °C in a muffle furnace, titled as WB and RB respectively. The yield of biochar was determined based on weight of biochar produced per unit weight of raw material. The amount of ash in the biochar was determined by heating five grams of biochar at 500 °C for more than 8 hours and weighing it again. The pH and electrical conductivity were measured in a mixture of biochar and deionized water with a weight ratio of 1: 20 (biochar: water). The total amount of carbon, hydrogen, and nitrogen in biochars was determined by dry combustion. Two types of produced biochars were milled with a particle size of 63-250 microns, at levels of 0.7 and 1.4% by weight. Three repetitions in the form of aqueous suspensions were added to the cylinders containing undisturbed soil. Three cylinders of soil without biochar were also considered as control treatment. Soil cylinders were placed in a greenhouse for six months at a temperature range of 20-25°C and underwent several cycles of drying and wetting. At the end of incubation period, soil samples were obtained from cylinders. Soil properties including pH, electrical conductivity, organic carbon, hydraulic conductivity and aggregate stability were also measured. Thin sections were also taken out of soils and state of soil structure and voids were studied. The effect of two factors, including biochar type and biochar application level were analyzed as factorial in a completely randomized design by SAS statistical software. The comparison of the means was done by Duncan's test at the probability level of five percent.

The WB compared to RB, had a higher yield, and less ash content, pH, electrical conductivity and H/C and O/C. More mineral ash in biochar is likely to provide more electrical conductivity in RB. Both biochar had an alkaline pH (more than 7). The biochar used in previous studies were usually alkaline, but biochar can be produced with any pH in the range of 4 to 12. The raw biomass has a H/C  molar ratio of about 1.5, but with the pyrolysis, this ratio decreases. WB had less H/C compared to RB. Therefore, it can be concluded that WB had more aromatic carbon and it can probably be a more effective tool for carbon sequestration in soil. Presence of a lot of pores in biochar, especially WB which were visible in SEM photos, are very effective on vital soil functions such as aeration and hydrology. The organic carbon content of SL and L soils were significantly higher at biochar treatments compared to control. The hydraulic conductivity of SL soil at both application levels of WB and RB was significantly lower than the control. However, both application levels of WB and 1.4% of RB led to significant increase and decreases of hydraulic conductivity of L soil, respectively. The mean comparison showed no difference between bulk density of treatments and application levels of biochar to control treatment of SL soil. However, Bulk density of biochar treated L soils were less than control. Biochar treatment also result in significant increase of: mean weight and geometric mean diameter and decrease of fractal dimension of aggregates in L Soil.

WB and RB biochars had no significant effects on indexes of soil aggregate stability and bulk density of SL soil, but they led to significant improvement of bulk density and aggregate stability of L Soil. Although, assessment of thin section showed partial improvement of soil structure of both SL and L soils. Therefore, more time than 6 months of incubation probably is needed to significant improve of aggregate stability of SL. Application of both biochars led to increase of organic carbon of both SL and L soils. Hydraulic conductivity was decreased in SL soil as result of both biochar application which can lead to the increase of water retention. Although the increase of hydraulic conductivity of  L soils due to WB can be considered as a suitable approach for the decrease of  the runoff, Generally, it can be concluded that due to the significant effect of feedstock type on biochar characteristics and different characteristics of soils, various types of biochar do not have a similar effect on a particular soil, therefore, a type of biochar cannot have the same effect on different types of soil.

Knowledge of the spatial variability of soil properties is vital for improving productivity and sustainable management of agricultural practices, as it is directly contributing to variability in crop yields. This study was conducted to investigate the spatial variability of some soil properties and their relationships with spatial variability of tea yield in the Fouman region of Guilan province. Soil samples were collected from 0 to 40 cm depth in 70 observation points. The green tea leaves were harvested at a 4 m2 plot at each site. Physicochemical soil properties and tea yield were determined according to standard methods. In order to address the cumulative impact of soil properties on tea yield, some soil physicochemical layers were subjected to delineate the study area into management zones. Soil parameters varied throughout the study area and their coefficients of variation ranged from 5.1% to 37.2% for pH and available potassium, respectively. Experimental semivariograms indicated moderate to strong spatial dependencies for all selected parameters. Spatial distribution maps, derived by kriging interpolation, showed that the spatial trend of the yield was approximately similar to pH, organic carbon and available potassium, which expresses the spatial correlation of these soil properties with the tea yield in the region. Correlation analysis revealed that tea yield was significantly positively correlated with organic carbon and available potassium (0.53 and 0.37, respectively) while negatively correlated with pH (-0.45). The results suggested the significant effect of soil properties, especially pH, organic carbon and available potassium on the tea productivity. The results indicated that the study area was successfully delineated into four distinct management zones based on spatial variability of soil properties. The spatial variations of soil properties can be used to identify the major sources of variability in crop yields and also to delineate the management zones. Therefore, the spatial variability of soil properties provides a basis of information for sustainable production in the tea gardens in the study area.

Gypsiferous and calcareous soils comprise an important part of soil resources in arid and semiarid areas of south of Guilan province. This study in order to investigation of gypsum and lime in soils of the hilly lands of Aliabad region in Guilan province by soil thin sections was performed. Soil sampling as air-dried undisturbed clods from gypsiferous-salty and calcareous parent material with three replicate at two slope positions (back slope and foot slope) and into surface (0-20 cm) and subsurface (20-40 cm) depths was performed. Results showed that soils with gypsiferous-salty parent material had heavier textural class than the calcareous soils. The results of micromorphology showed that the number of channel and chamber voids and excrements is higher in calcareous soil due to the presence of larger pores and more biological activity. Micromorphological pedofeatures of gypsiferous-salty soils include the forms of gypsum interlocked plates, gypsum lenticular crystals, gypsum pendant, infilling of gypsum as dense complete and incomplete, and loose discontinuous in voids and channel walls and hypo-coating of iron and manganese and in calcareous soils include excrements, halow iron and micritic nodules, rock fragments, gypsum and calcite pendant and different forms of pedogenic calcite as columnar, cluster, needle, micritic and sparitic. The fine fraction in both soils were mainly crystalitic b-fabric and locally stipple speckeld and undifferentiated b-fabric. The micromorphological index for soil evolution index (MISECA) showed that both soils had weak development. Results of clay mineralogy showed that chlorite, illite, vermiculite, smectite and hydroxyl-interlayer minerals were prominent in in both soils. Furthermore, the difference between soils of two parent material was the presence of palygorskite mineral in gypsiferous-salty soil.

Soil texture is the average size of soil particles which depends on the relative proportion of sand, silt and clay contents. Soil texture is one of the most important features used by soil and environmental scientists to describe soils. Soil texture directly affects the soil porosity, which in turn, determines water-retention and flow characteristics, nutrient-holding capacity, internal drainage, sorption characteristics and long-term soil fertility. High-resolution soil maps are essential for land-use planning and other activities related to forestry, agriculture and environment protection. Given the soil texture roles in controlling the soil functions, it is necessary to understand the spatial distribution of this feature in regional scale. As soil texture is a staticproperty, regional scale soil texture maps can thus help environmental scientists to predict different soil-related processes. The objective of this study was to develop a soil textural class map using Terra satellite MODIS sensor images. To achieve this goal, the digital elevation model SRTM radar of the studied area for soil samples from different altitudes and slopes was prepared in foursen consecutive 30 meters time frame. The nearest neighbor method with an error of less than 0.5 pixels was used and the elevation layers were mosaicked and transmitted to the UTM ZON-38 coordinate system and GIS Ready Became. The normalized difference vegetation index of bands 1 and 2 of the matrix was obtained to isolate the reflection of the electromagnetic spectrum of vegetation and soil. This final mosaicked digital elevation model was then divided into different altitudes to accurately evaluate the surface texture. The 60 spatial points were selected to estimate the texture of surface soil in thestudied area with systematic randomized sampling. In the current study, soil texture was determined forthe air-dried samplesusing hydrometer. The SWIR bands of MODIS with resolution of 500 meters were selected for sampling dates. After corrections, DN values of the bands for sampling points were extracted. The Pearson correlation coefficient and step wise regression techniques were used to establish proper relationships between the DN values of the SWIR bands and the soil particles. Kriging and cokriging methods were also employed to create a spatially distributed map of the soil textural classes. The results showed that there is a close correlation between the SWIR bands of the terra satellite and the MODIS sensor with band 3, and using this auxiliary variable significantly reduces the estimation error. The best model for fitting semivariogram for clay, silt and sand contents were spherical, spherical and exponential models and the best fitting Cross-semivariogram for clay, silt and sand contents were spherical, exponential and exponential models, respectively. The highest and lowest error estimation was, respectively, related to sand and clay content. The maximum and minimum decrease of estimation error by the auxiliary variables was found for sand and clay content, respectively. The nugget/sill ratio of the kriging semivariograms was greater than 25%for sand and claycontentand lower than 25%for sand and silt content. This indicates that sand and silt contents had a strong spatial dependency, and clay content hada moderate spatial dependency. These ratios for cokriging cross-semivariograms of sand, silt and clay contentsware less than 25%. The interpolation of estimated soil texture was also determined using the cokriging method with 70% of the soil texture measured in the laboratory. Our results indicated thatcokriging method estimated the soil particles more accurately as compared with linear multi-variable stepwise regression and kriging methods. Application of cokriging method also reduces the number of sampling points and the estimation error of soil texture zoning. Therefore, cokriging method seems to be better suited in impact assessments for data-scarceregions such as Iran.

Land use surveys and investigations are a prerequisite for the study of watersheds, because regional planning is dependent on the awareness about land use type and future changes. As a result, modeling and predicting of land use is essential for land planning and management in the future of a country such as Iran, where land use is changing rapidly In this regard, in order to reveal the land use changes in the 15 years and modeling the changes for the next 20 years, the markovin transmission estimator was used with Landsat 7 and 8 Landsat satellite imagery data from the Roze Chay basin of urmia. Based on the controlled classification algorithm with the maximum probability of land use as seven classes of land uses in this watershed were seven garden, irrigated farming, dry farming, grass land, residential area, water and salt marsh with a mean Kappa coefficient of 0.88 and overall accuracy of 0.9 for 2000 and 2015 were extracted. The changes of 15 years showed that the variation of water dependent uses in the region decreased during the mentioned time period (percentage reduction in the area of ​​agricultural crops and gardens, 32.51). The modeling of land use changes in the region with the markovin transmission estimator suggests that the use of gardens, arable and dry lands, villages and water resources will decrease, and the use of grass land and salt marsh will increase in the region (from 2020 to 2035 percent increase in area grass land 13.11 and the percentage of dry farming 17.56). The results indicate that soil and water resources are used improperly in the studied area, which requires comprehensive planning and management in the watershed.

Rapid development of industrialization, heavy metal and radionuclide contaminants from industrial activities have posed a major threat to the environment owing to their toxicity, non-biodegradability and persistent accumulation. So various ecosystems are continuously contaminated with high levels of high-risk chemicals with different structures and levels of toxicity. Cadmium is one of the high-risk elements that enters the environment and can accumulate in the body of fish and other aquatic organisms, plants and livestock and be transferred to the human body. Therefore, the remediation of contaminated soils with cadmium in order to protect human health is very important. One method for remediation of pollutants is immobilization of them in the soil by adsorbents. Among the absorbents, bentonite has been identified for its unique properties, including high surface area and cation exchange capacity and adsorptive affinity for organic and inorganic ions, low cost and ease of access. If the physical and chemical properties of natural bentonites are improved by a special modification process, the adequate supplies for environmental purposes can be obtained. Among the biosorbents, rice husk has also been reported to be suitable for adsorption of cadmium and other heavy metals. This research was designed with the aim of decreasing the amount of cadmium in the soluble and exchangeable phase of a polluted soil under laboratory conditions in the presence of bentonite and rice husk. Considering that biological properties of the soil are an indicator of soil health and quality, so, after application of adsorbents, biological properties and some soil ecophysiological indices were also investigated. The experiment was done with 13 treatments and 3 replications in a completely randomized design. Treatments were bentonite (B) and modified bentonite with iron (B-Fe), manganese (B-Mn), iron and manganese together (B-Fe-Mn), rice husk (RH), modified rice husk with phosphoric acid (RH-P) in two levels (2 and 5%) and control treatment (without adding adsorbent). Modification of bentonite was done with iron chloride (FeCl3.6H2O), manganese chloride (MnCl2.6H2O) and a mixture of FeCl3.6H2O and MnCl2.6H2O. Some of the characteristics of bentonite and rice husk adsorbents including pH, electrical conductivity, cation exchange capacity and organic carbon were measured. The contaminated soil with CdCl2 was treated with adsorbents and incubated for 2 months under constant lab conditions. After the incubation time, soil biological properties such as basal respiration, substrate-induced respiration (SIR), microbial biomass carbon (MBC), activity of some enzymes and also some ecophysiological indexes were measured. The results showed that the basal respiration, SIR, MCB, activity of phosphatase, dehydrogenase and urease were less in the control treatment. The basal respiration and phosphatase activity in RH-P 5% treatment were 2.6 and 2.25 times more than those in the control, respectively. SIR and urease activity were highest in RH-P 5% treatment. The application of adsorbents to contaminated soil reduced soluble and exchangeable cadmium fraction. The lowest amount of soluble and exchangeable fraction of cadmium was in RH-P 5% treatment that showed 2.5 times reduction in comparison to control. In other words, immobilization of cadmium from these fractions improved soil conditions and caused increasing of biological soil properties and activity of microorganisms. The metabolic quotient was higher in the control treatment, probably due to lower microbial content, and decreased by adding adsorbents. Microbial quotient in control treatment was lower than other treatments which prove again the lower biomass carbon of control treatment. Carbon availability that is the ratio of basal respiration to SID, also was more in control in comparison to other treatments, perhaps due to the suppress or inhibition of dormant or zymogenous microbes by cadmium in the control treatment which can be stimulated to growth in the SIR experiment. The results of this study revealed that cadmium with concentration of 30 mg kg-1has a toxic and inhibitory effect on the microbial activity of the soil. The addition of bentonite and rice husk adsorbents in particular modified form reduced mobility of cadmium and thus improved the biological properties of the soil and also had a positive effect on ecophysiological indexes.
The use of these adsorbents can be a cost effective, succeeded, and operative management strategy for immobilization of cadmium in contaminated soils that reducing the risk of plant reclamation, washing and entry into groundwater and food cycle.

With regard to increasing population of country, need to high agricultural production is essential. The most suitable method for this issue is high production per area unit. Preparation much food and other environmental resources with conservation of biotic resources for futures will be possible only with optimum exploitation of soil. Among effective factors for the most production balanced addition of fertilizers increases production of crops higher than the others. With attention to this topic, determination of soil fertility degree is essential tobetter use of fertilizers and right exploitation of soils. Using fuzzy logic and Analytic Hierarchy Process (AHP) could be useful in accurate determination of soil fertility degree.
The study area (at the east of Rasht city) is located between 49° 31' to 49° 45' E longitude and 37° 7' to 37° 27' N latitude in north of Guilan Province, northern Iran, in the southern coast of the Caspian sea. 117 soil samples were derived from0-30 cm depth in the study area. Air-dried soil samples were crushed and passed through a 2mm sieve. Available phosphorus, potassium and organic carbon were determined by sodium bicarbonate, normal ammonium acetate and corrected walkly-black method, respectively. In the first stage, the interpolation of data was done by kriging method in GIS context. Then S-shape membership function was defined for each parameter and prepared fuzzy map. After determination of membership function weight parameters maps were determined using AHP technique and finally soil fertility map was prepared with overlaying of weighted fuzzy maps. Relative variance and correlation coefficient criteria used tocontrol groups separation accuracy in fuzzy fertility map.
With regard to minimum amounts of parameters looks some lands of study area had fertility difficulty. Therefore, soil fertility map of study area distinct these lands and present soil fertility groups for better management of soil and plant nutrition. Weight of soil parameters was0.54, 0.29 and 0.17 for organic carbon, available phosphor and potassium, respectively. Fuzzy map of study area includes five soil fertility groups as: 22.9% very high fertility, 27.7% high fertility, 35.53% medium fertility, 10.48% low fertility and 3.39% very low fertility. Consequently, a separated map for soil fertility prepared to evaluate soil fertility of study area for rice cultivation. Toinvestigatethe efficiency of fuzzy model and AHP in increasing the accuracy of soil fertility map, soil fertility map with Boolean method prepared as well. Boolean map showed 58.88% fertile and 41.12% unfertile.15 soil samples from different soil fertility groups of study area were derived fromcontrol of maps accuracy. 13 renewed samples of 15 and 9 soil samples have matched with fuzzy and Boolean map, respectively. Comparison of parameters mean in fuzzy map fertility groups showed that parameters mean amounts of very high and high fertility groups are higher than optimum level except potassium that is a few lower than optimum level in high fertility group, therefore, addition of fertilizers in these groups could not be useful to increase rice crop production. Phosphorus parameter amount is lower than the critical level in very low, low and medium fertility groups, then in these groups phosphorus fertilizer should be added to the soil toincreaserice production. The amount of potassium parameter is higher than the critical level and lower than optimum limit in very low, low, medium and high fertility groups, then in these groups addition of potassium fertilizer will results in theincrease of production. Organic carbon amount is lower than optimum level in very low and low fertility groups. With regard to the relation between organic carbon andnitrogen and phosphorus, therefore, the addition of organic carbon fertilizer could compensate deficit of nitrogen and phosphorus in these groups as well. Attention to the presented explanations and comparison of fuzzy and Boolean maps using parameters amounts in renewed sampling points for control of maps accuracy, it is distinct that fuzzy logic could influencetheoptimum using of fertilizers with increasing map efficiency and accuracy. In addition, relative variance and correlation coefficient amounts showed that fuzzy map has separatedquite wellparameters changes.
Effective parameters in soil fertility, includingorganic carbon, phosphorus and potassium were used topreparesoil fertility map for rice cultivation. With regard to the minimum amounts of parameters looks some lands of study area had fertility difficulty. Therefore, soil fertility map of study area distinct these lands and presents soil fertility groups tobetter management of soil and plant nutrition. Fuzzy and Boolean methods were used topreparesoil fertility map. Comparison of these two approaches showed that fuzzy method with AHP caused to increase theefficiency and accuracy of fertility map for rice. Separated and distinguish soil fertility groups in fuzzy map help suitable distribution and optimum use of fertilizers for rice production.

Slope characteristics (aspect and position) and parent material are effective factors on soil properties. This research was conducted to study the soil physico-chemical properties formed on north and south faces as well as back slope and summit positions which developed on two selected parent rocks such as peridotite and pegmatite in Masouleh area. Thus, 6 representative soil profiles in different positions and aspects were dug and described and then, the soil samples were taken from the two depths of 0-15 and 15-30 cm in 3 replicates from distances of 10-20 meters around the soil profiles. Physico-chemical properties such as soil texture, pH, organic carbon, exchangeable cations, cation exchange capacity (CEC), amorphous and free iron oxides were measured. The results showed that the soils formed on the different parent materials had significant differences (p

Accumulation of heavy metals in soil has resulted in several environmental problems in different parts of the world. High concentrations of these elements in soils may lead to high absorption by plants and this is the main route into the human food chain and animal and biological cycles. Consequently, investigations are necessary to find out how accumulation of these elements can be prevented that creates soil and ecosystem contamination. Among heavy metals, cadmium is one of the most dangerous due to its high mobility in biological systems and ability to accumulate in plant tissues without causing any visible symptoms. Considering the high mobility of Cd in acid soils and the optimal growth of rice in such soils, and according to the role of rice in public health, this study was conducted to assess of the contamination of paddy soils with Cd in Guilan Province. For this purpose, 100 soil samples were randomly taken from 0-20 cm depths using GPS devices from different paddy farms. The soil samples were then passed through a 2-mm sieve after drying. The total cadmium concentration and some soil characteristics such as EC, pH, bulk density, particle density and soil organic matter were then measured. The spatial distribution of cadmium was investigated using different geo-statistical methods including IDW, Spline, and Kriging with a GIS software. The results of the soil physical and chemical analyses showed that the average pH of the soils and saturated electrical conductivity were 6.48 and 1.59 ds/m, respectively, indicating no salinity hazard for rice production. The sand, silt and clay contents of soil samples were between 4 to 35, 28 to 49 and 39 to 65, respectively, so the soil textures were in the range of clay loam, silty clay and clay. These soil textures were moderately heavy to heavy and so are suitable for rice cultivation. The average amount of organic matter was 1.78 and the total Cd concentration before cropping varied between 0.65 to 1.40 and, after harvest, was 1.97 to 11.05. From the geo-statistical methods studied, the ordinary Kriging with spherical model was selected as the best method. According to the results obtained, part of the study area becomes contaminated after harvesting, based on the Kelly index which can show the effect of chemical fertilizers use and incorrect land management, and so the use of these fertilizers should be carried out with care.

Paddy soils are important and the base of agriculture in Guilan province. It is necessary to recognize these soils for understanding of their limitations and optimum use. Unsaturated soil submerging is the cause of collection of chemical and electrochemical process that has significant effects on soil fertility. Eh, rH and pH are important indexes that are used to investigate oxidation and reduction condition in submerged soils and have abundant effects on activity and sorption rate of nutrients. Decrease of Eh and rH in poorly drainage of paddy soils affects availability and solubility of nutrient. Different Fe forms are used for analysis of soils evolution trend and submerging influences on changes of Fe forms. The aim of the present study was conducted to investigate the effect of redox potential changes on soil characteristics and analysis of soils evolutional trend in different physiographic units.
The study area with 40000ha (at the east of Rasht city) is located between 49° 31' to 49° 45' E longitude and 37° 7' to 37° 27' N latitude in North of Guilan Province, Northern Iran, in the southern coast of the Caspian sea with different water table depth. The climate of the region is very humid with the mean annual precipitation of 1293.6 mm. The mean annual temperature is 15.8°C. The soil moisture and temperature regimes are Aquic, Udicand Thermic, respectively. The parent materials are derived from river sediments. The soils formed on the plateaues and upper terraces, river alluvial plain and lowland physiographic units were classified as Inceptisols and the soils formed on coastal plain physiographic unit as Entisols. Air-dried soil samples were crushed and passed through a 2mm sieve. Particle-size distribution, organic carbon and cation exchange capacity were determined by hydrometric, wet oxidation and ammonium acetate methods, respectively. Eh by Eh electrode, total iron, free iron and amorphous iron were determined using nitric acid, dithionite-citrate-bicarbonate and ammonium oxalate methods, respectively. The means of different Fe forms values compared through LSD test.
It can be seen especial morphological and physicochemical characteristics in studied paddy soils with high groundwater table due to artificial submerging in rice growing seasonDifferent Fe mottles such as orange mottles include lepidocrocite mineral was observed in studied soils. Low redox potential with average 145/7mV and rH with average 19.6 in lowland and coastal soils implicate intense reduction condition. In lowland soils Eh was lower than other units and it was lower in top horizons than to sub horizons in all of units. Eh index had inverse relationship with organic matter, because of high organic matter amount caused high activity of anaerobic micro-organisms, increase of iron reduction and reduction soils degree decrease. rH index amounts showed that studied soils had reduction condition and presence of brown iron and black manganese minerals proved this condition. CEC was high in top soil of physiographic units due to high amount of organic matter and clay content. Clay particles in plateaues were lower than other units because of alteration and suitable aeration and showed high evolution in these soils. Clay coatings were not observed due to high ground water table and its alternative fluctuation. Results showed amorphous iron in surface horizons with average amount of 24.3g kg-1 was higher than subsurface in all soils and had positive correlation with organic matter, because of high activity of anaerobic micro-organisms that prevent from transformation of amorphous iron to crystallized iron, therefore amorphous iron amount increased in presence of organic matter. Pedogenic iron was high in A and B horizons with regard to BC and C horizons due to aeration and weathering. In lowland and coastal land Fed was lower than plateaues and upper terraces and river alluviums units because of ground water presence and its alternative fluctuation. Fed-Feo index showed crystallized iron oxides, high amount of Fed-Feo index proved soils evolution and high weathering. Feo/Fed ratio was related to amorphous pedogenic iron and high amount of this index showed few evolution of soil. Fed/Feo and Fed-Feo indexes indicated the lower rate of crystallized iron with average 6.8g kg-1 in lowland and coastal soils and implicated the lower evolution of these unit's soils, due to higher surface groundwater and its more fluctuation than soils of plateaues, upper terraces and river alluviums unites with average amount of crystallized iron 15/8g kg-1.The comparison of different Fe forms using LSD method showed significant difference at the 0.01 level for different Fe forms values in different physiographic units.
Submerging, high groundwater table and severe fluctuation caused noticeable changes in morphological, physical, chemical and electrochemical properties of studied paddy soils. Noticeable organic matter amount added to soil and their burial by puddling operation and slow decomposition were effective factors in redox potential changes of studied wet soils. In equal anaerobic condition, more organic matter caused to decrease redox potential in surface horizons of soils with aquic condition and reverse, lower organic matter caused increasing in redox potential. lower amount of Eh and rH proved severe reduction condition in lowland. Investigation of Fed-Feo and Feo/Fed showed that their amount in lowland and coastal land were lower than plateaus and river alluviums, therefore lowland and coastal soils had lower evolution. Mean comparison of different Fe forms values using LSD method showed significant difference at the 0.01 level for different Fe forms in different physiographic units.

The aim of this study was to determine diversity of plant species in Hackberry sites in Taniyan and Rezvanshahr areas in Guilan province. For this aim, circular sampling plots of 0.1 ha were implemented selectively based on presence of the Hackberry trees in study area. In sampling plots, DBH of all trees and number of all shrubs were measured. For wood species regeneration, a sampling plot of 100 m2 was implemented in center of large sampling plots and regeneration counted. Also, for record of herbaceous species, Whittaker nested plot method used that 32 m2 obtained. Values of diversity, evenness and richness were calculated using biodiversity indicators in trees, shrub, regeneration and herbaceous layers. The results showed that Menhinic richness index in tree (1.47) and regeneration (0.91) layers in Rezvanshahr site has more than Taniyan site. Maximum of Shannon-wiener index value in both site was in the tree (2.05) layer and lowest was in shrub (0.27) layer in Rezvanshahr site and in regeneration (1.05) layer in Taniyan site. Shannon-wiener diversity index in tree (2.05) and regeneration (1.56) layers in Rezvanshahr site was more than Taniyan site. Amount of this index in shrub (1.36) and herbaceous (1.2) layers in Taniyan site was more than Rezvanshahr site. Also, Smith and Wilson evenness index in each four layers of tree (0.45), shrub (0.58), regeneration (0.63) and herbaceous (0.54) in the Taniyan site more than Rezvanshahr site. Also, in study areas, species abundance followed in tree layer of the broken stick model and in herbaceous layer of log normal model in Rezvanshahr site and followed of broken stick model in Taniyan site.