فهرست مطالب hamid reza owliaie

Powdered rock phosphate may have the potential of soluble phosphate sorption because its particles are small.  Phosphorus (P) sorption-desorption behavior and sorption kinetics were studied on four different fine powdered phosphate rocks (PPR), from Esfordi, Chadormalu and Yasuj mines. Sorption isotherms were evaluated by equilibrating 1 g PPR with 20 ml CaCl2- 0.01 M containing 10, 50, 100, 200, 400, 600, 800 and 1000 mg P L-1, as KH2PO4 in duplicates. Consequently, P release was studied by equilibrating the samples with 20 ml 0.01 M CaCl2. FTIR analysis was conducted on the blank samples, and those equilibrated with 1000 mg P L-1. Kinetics of phosphate sorption on PPRs was evaluated with two initial P concentrations (50 and 100 mg P L-1) and contact times of 1, 2, 4, 8, 16, 24, and 48 h with 0.01 M CaCl2 as the background solution in duplicate. Results showed that the least P sorption was around 150, and the maximum P sorption was 12000 mg kg-1 PPRs. The highest P release was around 15% of sorbed P, and releasable P was reduced to 2-3% of sorbrd P with the increase of P sorption. P sorption data showed a good fit with Freundlich and Langmuir equations. The kinetic of P sorption showed a fast reaction that rapidly diminished soluble P. Results of the present study suggest that PPRs could reduce soluble P, which is better to be considered at different usage of PPR such as incorporation with organic wastes and its biosolubilization.

Zinc, copper and nickel are classified as micronutrients in plant nutrition and as trace elements in environmental chemistry. These elements are essential for plants and organisms, but they cause toxicity in high concentrations. The main mechanisms of entering these elements into the food chain is the soil-plant pathway. Trace elements are present in soil in different forms with different solubility. Determining the fractions of these elements reveals more precise information about their status, and the probability of their deficiency or toxicity in long period, and in the case of changing environmental conditions. Fractionation sequence is a procedure for determining different forms of elements.

The present study was conducted on 13 calcareous soil samples around Yasuj. The samples were selected from virgin and agricultural fields without pervious application of trace elements fertilizers, and were not contaminated trace elements. Different forms of zinc (Zn), copper (Cu) and nickel (Ni) were successively extracted with F1) distilled water (soluble), F2) neutral one molar ammonium acetate (Exchangeable|), F3) one molar ammonium acetate with pH 5 (Carbonatic); F4) 0.04 molar hydroxylamine hydrochloride (NH2OH.HCl) in 25% v/v of acetic acid with a pH of 3 (FeMn-oxid associated); F5) 30% hydrogen peroxide (pH 2) with 5 ml of 0.3 M NH4OAc ammonium acetate in 20% by volume of nitric acid (OM associated); and F6) 7 M nitric acid (Residual) in duplicate and were measured with atomic absorption spectroscopy.

Water extractable zinc, copper and nickel; and neutral NH4OAc extractable copper and nickel were not detectable in the studied soil samples. Neutral NH4OAc extractable zinc was detected in 5 soil samples. The abundance of zinc, copper and nickel chemical forms were as follows: Zn- NH4OAc pH 7< NH4OAc pH 5 Zn< H2O2 Zn< NH2OH.HCl- Zn< HNO3- Zn; H2O2 Cu

The present study showed that the amount of trace elements is generally less than 100 mg/kg and most of these elements exist in residual or stable form. An increase of calcium carbonate can be associated with a decrease in the total amount of these elements and cause their deficiency.

Determination of the physico-chemical characteristics of soil for sustainable agriculture on large scales is an important factor in achieving a precision agriculture. Different land use and management practices greatly impact soil properties, and knowledge of the variation in soil properties within different land uses, is essential in determining production constraints related to soil characteristics. Laboratory analyses of the soil properties are usually expensive and time consuming. Surmounting these problems is possible using geostatistics. This study was conducted to assess geostatistical methods for the spatial distribution of some soil properties of Darengan region with different land uses in Fars province. 134 surface soil samples at an interval of 1.0 × 1.0 km on a grid design were taken from pasture and agricultural land uses. Physico-chemical characteristics of the soil samples were analyzed. According to the results, the best spatial structure model with the highest accuracy was exponential model for the variables of sand, EC, CCE, pH, and BD, rational quadratic model for silt, and spherical model for clay, OC, and CEC. The spatial structure was weak for CCE, medium for organic carbon, and strong for the other variables. Among the characteristics studied, the variables of silt, clay and cation exchange capacity have the lowest range, and EC has the highest range. Based on the zoning map of the studied properties, the areas with agricultural land use had greater OC, clay, CEC, EC and lower pH. Understanding soil properties with their spatial dependency is of crucial importance for understanding the behavior of soil and hence providing better soil management.

 Soil classification is the systematic categorization of soils based on distinguishing soil characteristics, aiding in the comprehension of soil properties through soil surveys, and establishing suitable strategies for effective soil utilization and management. One of the main reasons for creating soil classification systems is to identify the differences in important soil characteristics for management purposes. Globally, Soil Taxonomy (ST) and the World Reference Base for soil resources (WRB) are widely used for soil classification. However, these two classification systems have varying criteria which can pose difficulties when exchanging classification results. After years of intensive worldwide testing and data collection, new versions of the ST and WRB systems have been released. In its current state, ST has a strong hierarchy with six categorical levels: order, suborder, great group, subgroup, family, and series (Soil Survey Staff, 2022), while the WRB has a flat hierarchy with only two categorical levels: reference soil groups and soil units (IUSS Working Group WRB, 2022). Several scientists have endeavored to evaluate the merits and demerits of these soil classification systems and offer recommendations for their enhancement. The arid and semi-arid regions located in the western and southwestern parts of Kohgiluyeh and Boyerahmad Province, distinguished by their considerable diversity in parent materials, topography, climate, and land use, present an excellent opportunity for scrutinizing and contrasting the effectiveness of soil classification systems. Remarkably, no prior research has delved into this subject in this specific geographical area. Consequently, this research aims to compare the effectiveness of the ST and WRB systems in characterizing soil attributes. Furthermore, it seeks to analyze the alterations that these two systems have undergone during an eight-year period, spanning from 2014 to 2022.

This study was conducted in the western and southwestern regions of Kohgiluyeh and Boyerahmad Province, specifically in the divisions of Gachsaran, Basht, Choram and Kohgiluyeh. A total of 26 soil profiles were excavated, described, and sampled based on aerial photos, satellite images, topographical and geological maps, as well as field observations. These profiles were selected following the soil description guide provided by the Department of Soil Conservation of the US Department of Agriculture. Subsequently, after reviewing the preliminary results and aligning with the research objectives, 12 representative soil profiles were chosen for further analysis. Soil samples were collected from all genetic horizons and transferred to the laboratory. After air-drying, the samples were passed through a two-millimeter sieve and the routine physical and chemical analyses were conducted, including soil texture, pH, electrical conductivity (EC), calcium carbonate equivalent (CCE), organic carbon, cation exchange capacity (CEC), and gypsum analyses. For mineralogical studies, soil clay minerals were separated and identified using standard methods. Additionally, soil thin sections were prepared from intact soil samples of selected soil horizons and examined under a polarizing microscope. Finally, the soil profiles were classified based on the criteria outlined in Soil Taxonomy (2022) and WRB (2022).

Soil Taxonomy and WRB, as the two most popular classification systems, aim to encompass as manysoil characteristics as possible. According to the ST classification, the soils were classified into four orders: Entisols, Inceptisols, Alfisols, and Mollisols. In the WRB system, they were grouped into seven reference soil groups: Regosols, Flovisols, Luvisols, Cambisols, Kastanosems, Gypsysols and Glysols. The results revealed that WRB was significantly more effective in describing the characteristics of the studied soils. One of the key advantages of this two-level system is its flexibility, allowing for the inclusion of additional principal and supplementary qualifiers to cover all essential soil characteristics. Moreover, in many cases, WRB exhibits better prioritization compared to ST. For example, the presence of gypsic, combic, calcic horizons, as well as fluvic and gley properties, can allocate the soil to the reference groups of Gypsisols, Cambisols, Calsisols, Fluvisols, and Gleysols, respectively. However, a limitation of the WRB system is the absence of mineralogical information in soil classification. Enhancing this classification system's quality and making it more appealing to planners could be achieved by incorporating suitable mineralogical attributes for the reference groups or criteria that express soil fertility conditions with relatively straightforward measurements. In addition, it is proposed to add three subgroups to ST: Gypsic Haplustalfs, Fluventic Gypsiustepts and Cambic Haplustolls. Similarly, following the WRB model, it is recommended to introduce a qualifier in ST to indicate the presence of lithological discontinuity. Regarding the WRB system, suggestions include adding qualifiers such as "Cutanic" to gypsisols with clay films, "hypercalcic" to reference groups of Kastanozems and Luvisols with a calcic horizon comprising more than 50% of calcium carbonate, and "aridic" for better expression of soil characteristics with Aridic-Ustic moisture regimes.

The results of this research demonstrated that WRB is more effective in describing the conditions and characteristics of the studied soils. The WRB system, through its diverse set of qualifiers, is capable of representing field conditions more efficiently. However, it is suggested that the surveyors have the freedom to select an appropriate qualifier from the list provided by WRB without limitation, which can enhance its success in practical applications. Furthermore, it is recommended that both classification systems be used to categorize soils, not only to evaluate their efficiency for the soils in other regions but also to gain a comprehensive understanding of their suitability for different contexts.

Potassium occurs in soils in various forms. The behavior of potassium in soil can be difficult due to its interaction with the intrinsic properties of the soil. Although most soils contain large quantities of potassium, but most soils are not able to provide proper amounts for plant nutrition, so that the equilibrium reactions occurring between different forms of potassium have a profound effect on potassium nutrition. This research was carried out with the aim of investigating the relationship between different forms of potassium (soluble, exchangeable, non- exchangeable and construction) with physical and chemical properties of soils in citrus areas of Iranshahr and Khash towns in Sistan and Baluchestan province.

First, according to previous studies, 30 samples of soils in Iranshahr and Khash towns with different characteristics. Then samplings were taken from depths of 0 to 30 cm. Physical and chemical properties of soil and various forms of potassium (soluble, exchangeable, non- exchangeable and construction) with total potassium were measured and relationship between different forms of potassium with each other and physical and chemical properties of soil were investigated.

Soils were in general light in texture, non-saline and calcareous. Organic carbon values in soils ranged from 0.6 to 1.6 percent, cation exchange capacity ranged from 7.0 to 10.5 centimoles per kilogram, and the pH ranged from 7.0 to 7.4. The amounts of different forms of potassium in the city of Iranshahr, potassium soluble ranged from 1.4 to 20.4, exchangeable from 122 to 315, non- exchangeable from 177 to 388, construction from 5709 to 13987 and a total 8420 to 14200 mg kg-1 soil. In Khash city, potassium soluble ranged from 5.7 to 14.3, exchangeable from 129 to 273, non- exchangeable from 293 to 493, construction from 5412 to 14085 and a total 9892 to 13850 mg kg-1 soil. Correlation test showed that there was a significant positive correlation between soluble potassium and sand (r= 0.5*) and negative correlation with silt (r= -0.5*). There was a significant positive correlation between exchangeable potassium and organic matter (r= 0.7*), significant positive correlation with clay (r= 0.5*) and significant positive correlation with cation exchange capacity (r= 0.7*). Between non- exchangeable potassium and calcium carbonate there was a significant negative correlation (r= -0.8*). Significant positive relationships among various fractions of soil K indicated existence of a dynamic equilibrium between different forms of K.

The amount of potassium available in the plant (soluble, exchangeable, non- exchangeable potassium) is good in citrus growing areas in Sistan and Balouchestan province of Iranshahr and Khash, and therefore does not require potassium fertilizers in these two regions

Assessing the variation of different soil properties through the land use changes may provide useful information for land managers. The present study aimed to assess the soil quality variation due to the land use changes from dense (non-degraded) to semi-dense (degraded) oak forest and then to dry-farming in Mokhtar plain located in Yasouj region. A total number of 100 surface soil samples were collected in order to analyses of the selected physicochemical soil properties. After statistical analyses, the continuous distribution maps were prepared for all soil variables using ordinary kriging and inverse distance weighting methods in ArcGIS software (ver. 10.2; ESRI). Analyses of the average values of selected soil properties showed that after changing the land use from dense to the degraded oak forest and then to dry-farming, organic matter and CEC changed in a decreasing trend and bulk density changed in an increasing trend. Moreover, electrical conductivity, carbonate calcium equivalent and clay percentage decreased in lower contents; whereas soil pH and sand percentage inconsiderably increased. Among the soil properties, organic matter content as one of the most important soil quality indices showed a significant change with an average of 6.74%, 3.42% and 1.58% in dense forest, degraded forest, and dry-farming lands, respectively. Supporting these findings, spatial distribution maps of the selected properties revealed that the most optimum soil properties were found in the southwest of the studied area, i.e. in the soils covered with dense oak forest; whereas increasing distance to the dry-farming lands in the northeast of the area, the selected soil properties were adversely changed. According to these findings, it can be stated that wide deforesting and land use change have been led to the considerable soil quality decline and therefore if deforesting will not be stopped a huge portion of the studied soils may lose their vital capabilities.

Different factors may affect potassium (K) content in calcareous soils. Potassium forms distribution as a function of various soil physicochemical properties was examined on seventy surface (0-20 cm) and subsurface (20-40 cm) soil samples of Kohgilouye and Boyerahmad province, southwest of Iran. Soil physical, chemical and mineralogical properties were determined according to standard methods. The soil was classified in Xeric and Ustic moisture regimes and Mexic, Termic, and Hyperthermic thermal regimes. As the result, the common clay minerals associations were found to be illite, smectite, chlorite and palygorskite with less content of vermiculite, kaolinite and quartz. Smectite, illite, and palygorskite were the main clay minerals occurring in humid and arid regions respectively. Soil soluble, exchangeable, non-exchangeable and structural K concentrations ranged from 1.2-12.1, 111-521, 153-1705 and 4584-10379 mg kg-1 at the surface and 0.2-5.0, 25-403, 72-1016 and 3227-9541 mg kg-1 at the subsurface soil samples respectively. Exchangeable, non-exchangeable, structural and total K concentrations positively correlated with soil clay content and cation exchange capacity (CEC), however negatively significant correlation was obtained with calcium carbonate content. Different forms of K (except soluble K) had positive and significant relationships with each other (r of 0.48-0.99) and this indicated the equilibration among K forms. Mineralogical studies indicated the positively influence of clay minerals, especially illite and smectite, on exchangeable and nonexchangeable soil K. While the structural and total K contents most affected by smectite and illitic clay minerals. Future studies are required about the mineralogy of soil sand and silt fractions and their influence on soil K status.

In recent decades, site-specific management (SSM) has been specifically considered to achieve to increased input efficiency, improved economic margins of crop production and reduced environmental risks. Short-scale spatial variability of soil properties caused more necessity of SSM techniques. Natural variability of soil results from complex interactions between geology, topography and climatic factors, as well as land use change and land management strategies. Deforesting and vast land use changes are considered as the important land management strategies that have been extensively used in recent decades. Therefore, determining the effects of land use change on soil properties in conjunction with local environmental conditions and on the spatial variability of soil properties may drastically help the land use planners. Therefore, the present study was done aimed to explore the effects of oak trees deforesting in Shah-Mokhtar region in Yasouj and land use changes to dry farming on the spatial variability of nutritional elements using geostatistical techniques. The present study was conducted in a Shah-Mokhtar, north, and northwest of Yasouj, in Kohgiluyeh Province, southern Iran. Spatial variability of seven soil fertility properties, including N, P, K, Fe, Cu, Zn, and Mn concentration in soil, were examined in three land uses, including dense forest, degraded (semi-dense) forest and rain-fed lands. A total of 100 surface (0-30 cm) soil samples were collected and analyzed for the nutritional elements after preparing in the laboratory. Data were analyzed statistically and their normal distribution pattern was examined using the Kolmogrov-Smirnov test. In the geostatistical analyses step, the spatial structure of studied variables was analyzed by fitting the suitable authorized models on calculated experimental semi-variograms. The concentration of studied elements was interpolated using ordinary kriging (OK) and inverse distance weighting (IDW) estimators and finally, the spatial distribution map of each soil nutrient was prepared using ArcGIS 10.3. The results showed that the highest mean soil concentration of almost all of selected nutrients belonged to the dense forest lands and due to the land use changes to the degraded forest and then dry farming, average values of selected elements significantly decreased. Among the studied properties, soil N concentration with an average of 0.34%, 0.17% and 0.08% in dense forest, degraded forest, and rain-fed soil samples, had the most decrease caused by deforesting. Semi-variogram analyses showed that spherical model had the best performance. For interpolating the soil K and Mn concentration, IDW method and for other studied elements, OK method was efficiently used. The spatial correlation class was strong for N, Cu, and Fe; whereas a moderate class was calculated for soil P and Zn concentration. The spatial distribution maps of selected nutrients revealed that the dense forest and dry farming soils had the highest and lowest contents of soil nutritional elements. According to the findings of the present study, it can be stated that degradation of oak forest may lead to the significant decrease of soil nutritional elements, specifically soil N concentration as one of the main soil fertility quality. Therefore, it seems that not only the significant soil quality decline but also the extensive degradation of whole ecosystem and unfavorable climatic consequences will be the unavoidable results of deforesting in Shah-Mokhtar region.

Soil salinization is a predominant process in the degradation of arid and semi-arid soils that causes reduced the yield of crops, increases erosion and intensifies desertification. The Zahed Shahr studied area is located in the south and east of Fasa city, Fars province and in recent years the soil salinity has affected large areas of the farms and gardens in this area. The aim of this study was to evaluate the salinity changes of the soils during a 17 year period using Landsat 7 and 8 satellite images using the spectral angle mapping method. To do research, the salty soil spectra were extracted from satellite data and then using supervised classification the areas with salty soil were identified changes in salinity soils in ArcGIS software were investigated. Field studies, soil surface sampling, chemical analysis and spectral analysis of soil were performed by Spectroradiometer, and X-ray diffraction analysis for mineral identification was done. The results obtained from visible and shortwave infrared Spectroradiometer, and X-ray diffraction analysis showed the presence of evaporites minerals (calcite, halite, gypsum). By comparison with real ground data, the spectral angle mapper method was identified to be efficient in the classification of soil salinity. The results of the SAM method for a period of 17 years show four times spatial increase in soil salinity in this area. The area of saline soils has increased from 1600 hectares in 2000 to 6500 hectares in 2017.

Land use changes such as conversion of forest to cultivated lands, significantly affect soil properties and modify soil forming processes. Land use changes can drastically affect the soil environment, which in turn markedly affect soils and soil processes. Human activities that are not associated with proper planning have undesirable effects on natural resources such as soil, including land use change. The results of the investigations in different parts of the world show that changing the use of natural ecosystems to managed ecosystems has destructive effects on soil properties. Cutting off the forest trees and converting pastures into agricultural lands will destroy or disrupt natural ecosystems and reduce the current or future production capacity of the soil. One of the important issues in the world is the destructive effects of agriculture on soil quality. These destructive effects can include a wide range of soil changes including physical properties such as soil compaction, soil water depletion, soil structure destruction and soil texture change, chemical properties such as accumulation of some elements such as N, P, K, and soil salinity, and soil biological properties such as soil microbial population and soil fauna activity changes, soil organic matter reduction and also effect on useful soil enzymes. Land use change from forest to agriculture does not necessarily lead to soil degradation. Land use changes and forest destruction in Yasouj region has increased in last decades. In this study, we investigated the effects of land use change on some soil characteristics in Servak plain, Yasouj region.

Servak region is located in 4 km south of Yasouj city. Three main land uses of dense forest, degraded forest, and dry farming were chosen to study the role of land use change on some soil properties.. The elevation of the region varies from 1833 to 1869 m above sea level. Five soil samples (0-20 cm) were taken from each land use. Samples from each land use were taken from almost similar elevation and slope to minimize the effect of topography. Soil samples were transferred to the laboratory, air dried and passed through a 2mm sieve. The chemical and biological analyses were carried out. The determination of soil organic carbon was carried out based on the Walkley-Black chromic acid wet oxidation method. Available K was extracted with 1N ammonium acetate at pH=7 and was determined by flame photometry. The Olsen method was used for the determination of available phosphorus. Total nitrogen was measured using the Kjeldahl method. Soil bacterial communities were counted using culture medium (Nutrient agar. The basal respiration rate was estimated by back-titration of the unreacted NaOH to determine CO2 evolved over 10 h. The substrate-induced respiration was measured by adding 2 ml of 1% glucose to soil samples over 6 h. Soil suspensions were prepared by 10-fold serial dilutions with 1g soil. Counting the soil fungal community was done using a culture medium (Potato dextrose agar) and was prepared by 10-fold serial dilutions. The activity of alkaline and acid phosphate enzymes was measured based on a colorimetric method using p-nitrophenol.

The land use change from a dense forest to dry farming has modified many chemical and biological soil properties. The results of analysis of variance and comparison of the means of data obtained from this study showed that as a result of land use change from dense forest to dry farming, Organic matter, total nitrogen, exchangeable potassium, basal and substrate-induced respiration, fungal community, acid phosphatase and alkaline phosphatase enzymes contents were decreased. Also, soil bacterial communities were increased at 1% level in dry farming land use. The amounts of phosphorus did not show any significant difference. In general, it can be concluded that following the degradation of the forest and land use change, the soil organic matter and relevant properties, especially biological indices, are more affected compared to the other properties. Soil organic matter plays a key role in ensuring agroecosystem productivity and the long-term conservation of soil resources.

Large-scale conversion of indigenous forests to cultivated land, driven by long-term agricultural development in the Servak region, has greatly affected the physicochemical and biological properties of the soils. Generally, the conversion of the natural ecosystem to agroecosystems decreased organic carbon content and relevant indices such as basal and substrate-induced respiration, fungal community, acid phosphatase and alkaline phosphatase enzymes contents in the top-soils at depth of 0 to 20 cm. The decrease of organic carbon in cropped farms could be attributed to the enhanced oxidation of soil organic C caused by cultivation. The results of this study showed that any management and type of land use that decreases soil capabilities can reduce soil quality and increase the susceptibility to degradation. So, in order to maintain soil quality, appropriate management practices should be done.

Degree of soil evolution, type and amount of clay minerals are among the factors affecting potassium release from the soils. The release rate of non-exchangeable K (NEK) plays a significant role in supplying K for plants; particularly in soils that they are rich in K bearing minerals such as mica and feldespar. Kinetics of K release was studied by extraction with 0.01 M CaCl2 in 14 surface soils of different climatic regions of Kohgilouye and Boyerahmad Province, southwestern Iran. Mineralogical analyses revealed that smectite, illite, chlorite and palygroskite are major clay minerals of the soils studied. The release rate of NEK at the end of extraction (656h) was in the range of 38.1 (Typic Xerorthents) to 320 mgkg-1 (Calcic Haploxeralfs). In addition, the release rate of K showed higher correlation with the properties such as clay content, non-exchangeable K , CEC as well as illite and smectite contents. The amount of K release was in the sequence: Alfisols (222.3 mgkg-1) > Inceptisols (111.3 mgkg-1) > Entisols (105.0 mgkg-1). Power function, first order and parabulic diffusion equations could reasonably describe the K release kinetics. Fit of the data to these equations indicated that release of K is controlled mainly by diffusion process.

Potassium and nitrogen are two major nutrients, have important role in increasing rice quantity and quality. Potassium like nitrogen is taken up in large amount by rice. Evaluation of nutrient status in soil is important from nutritional, environmental and economical aspects. This study was conducted in order to evaluate 11 different chemical extractants for determining suitable extractants for estimation of available potassium of rice in 11 selected soils of Kohgiluyeh Province. Rice seeds were cultivated in 1.5 kg pots in three replications and harvested after 10 weeks. Plant potassium was extracted with 1N HCl. Soil available potassium was extracted using 1M NH4OAC, 1 and 2M sodium chloride, 0.025 M sulfuric acid, 0.1M barium chloride, 0.01M calcium chloride, Morgan-Wolf, AB-DTPA, 1N NaOAC, 1M magnesium acetate and 2M Hydrochloric acid. The amount of K extracted by 1N NaOAC and 1N NH4OAC, was significantly (r=0.85** and 0.73**, respectively) correlated with K concentration, followed by Morgan and 2N NaCl. The lowest correlation is belonged to 1N HCl. Therefore, due to the simplicity and economy, the rate of extraction and the high correlation, extractants of 1N NaOAC and 1N NH4OAC are recommended as suitable extractants for determining the available K uptake by rice in the soil studied.

Cadmium is one of the toxic heavy metals which is highly problematic in today's industrial world. It is essential to study the techniques for removing or reducing its availability, toxicity and consequently its hazardous effects in environment. Biochar is an amendment reported to be efficient in fixing heavy metals. Pyrolysis temperature is among the most important factors affecting biochar's characteristics, such as pH, CEC and specific surface area and generally it's potential to sorb heavy metals. On the other hand, soil moisture regime could affect pH and EC and consequently the Cd availability. Iran is the second producer of pistachio in the world and consequently a large volume of pistachio waste byproducts would be created annually. Converting this byproduct to biochar may be an efficient tool to prevent its accumulation. On the other hand, the produced biochar could be used as a soil amendment. The present study was conducted to evaluate biochar produced from pistachio nutshell under different temperatures for reducing Cd availability under different moisture regimes.
The soil texture in the present study was sandy-loam. Raw pistachio nutshell (RPN) was used to produce biochar under different temperatures. RPN was rapped in aluminum foils and heated for 2 h in a muffle furnace under 200, 400 and 600 °C. The pH, EC and concentrations of P, K, Fe, Mn, Zn and Cu of RPN and produced biochars were determined. A completely randomized experimental design with factorial arrangement including nine biochar treatments (control (no amendment), RPN and biochars produced under 200, 400 and 600 °C at 2% and 4% rates), and two moisture regims (20% w/w and waterlogging) was carried out with two replications. The samples were spiked with 25 and 50 mg Cd kg-1 and incubated for 90 days under laboratory temperature. Available Cd extracted by DTPA-TEA on 15, 30, 60 and 90 days after incubation. Cadmium concentration determined by Atomic Absorption Spectrometry (Mark and Model: HITACHI- ZCAST 2300). Analysis of variance and compare of means used to evaluate the effects of various treatments on DTPA-Cd.
The nutrient concentrations of biochar were increased with increasing the production temperature. The RPN and biochar of 200 ºC had the least nutrient concentrations while the biochar of 600 ºC showed the highest nutrient concentrations. The increases of pH and EC occurred with increasing the biochar production temperature. The pH ranged from 6.36 to 9.36 and EC range was 13.5-31.9 dS m-1. The analysis of variance showed that biochar, moisture regime and their interaction significantly affected DTPA-Cd on all of the studied times (P Generally, regarding the decrease of DTPA-Cd by biochars, especially biochar of 600 °C, it can be concluded that biochar of pistachio nut shell particularly under 600 °C might be considered as an inexpensive and green environmental sorbent for Cd, however its potential to reduce Cd uptake by plants and Cd movement in environment requires further studies. Furthermore, the knowledge of the mechanisms that are responsible for Cd retention on biochar and desorption kinetic of sorbed Cd need further investigation.

Evaluation of the nutrient status in soil is important from the nutritional, environmental, and economical aspects. Potassium is an essential element for plant growth and is a dynamic ion in the soil system. Soil testing is a useful tool that can help to ensure the efficient use of applied plant nutrients. Soil tests measure the quantity of a nutrient element that is extracted from a soil by a particular chemi¬cal extracting solution. The measured quantity of extractable nutrient in soil is then used to predict the crop yield response to application of the nutri¬ent as fertilizer, manure, or other amendments. Over the years, many different soil testing pro¬cedures and extracting solutions were evaluated in an effort to identify a method that provides the most reliable prediction of crop yield response to nutrient application. It was determined that some soil testing procedures are best suited for particular soil types and climatic regions, whereas other soil testing procedures are better suited for different soil types and climates. Olive is a strategic and economic product in Iran. Fars province is the second largest olive producer in Iran. There is no general information about K status in the soils and olive trees of the Fars province as well as no introduced appropriate K extractants for theses soils. Therefore, the objectives of this study were: i) evaluating potassium status of some soils of olive orchards of Fars province and ii) introducing appropriate k extractants for extracting available K in these soils.
Fars province, with an area of 122000 km2 is located in southern Iran. The elevation varies from 500 m to 4400 m above mean sea level. Based on the information regarding olive orchards of Fars province, 13 typical olive orchards were selected. 26 surface (0-30 cm) and subsurface (30-60 cm) soil samples were taken. Physiochemical properties of the soil samples were determined based on standard methods. Soil reaction, texture, electrical conductivity, calcium carbonate, organic carbon, and cation exchange capacity were identified. The 12 K extracting solutions were 1M NaCl, 2M NaCl, 0.01M CaCl2, Morgan, AB-DTPA, 1M NH4OAC, 0.25M NH4OAC, 1M NaOAC, 2M HCl, 0.1M HNO3, 1M HNO3, and 0.025M H2SO4. The K contents of leaf samples were determined in 1g of each sample. The samples were dried and then ashed in 450°C for 4 h. 2M HCl was used to digest the samples. Potassium in all the filtrated extracts were then analyzed using flame photometer.
The all soils were calcareous (average of 48.7 and 50.2% calcium carbonate equivalent in surface and subsurface, respectively) with pH in range of 7.05-7.8. The textural classes were loam, clay loam, and sandy loam. The results showed that the concentrations of K extracted varied widely with the used method, because each extractant remove different portions of K. Among the 12 tested methods, boiling 1 mol/L HNO3 extracted highest amount of K (mean 696.1 mg/kg and range of 203.3-1893 mg/kg) which extracted soluble, exchangeable, and non-exchangeable potassium forms due to its high concentration of H and 2mol/L HCl removed the lowest amount of K (mean 32.7 mg/kg and range of 2.6-148.5 mg/kg). Correlation coefficients between K extracted by 12 extractants were de¬termined. The correlation between potassium extracted by all the chemical methods was positive and significant except for boiling 1M HNO3. Between all tested extractants, 0.25M NH4OAC and 1M NH4OAC had the highest correlation (p≤0.01, r= 0.999). The relationship between soil potassium and potassium concentration in olive leaves were evaluated. Maximum correlation between leaf K and extracted soil K were noticed in 2M NaCl, 0.25M NH4OAC, 1M NaOAC, and AB-DTPA (r=0.721, 0.718, 0.717, and 0.714, respectively) and the minimum correlation was noticed in 1M HNO3 (r= 0.661).
The concentrations of K extracted varied widely with applied method, because of desorbing different portions of K by each method, different concentrations of each extracting solution, and the different times of equilibration. On average, the quantity of extracted K by 12 methods were in the following order: boiling 1M HNO3> 1M NH4OAC> 0.25M NH4OAC> AB-DTPA> morgan> 0.1 HNO3> 0.025M H2SO4> 0.01M CaCl2> 1M NaCl> 1M NaOAC> 2M NaCl> 2M HCl. This study showed that 2M NaCl, 0.25M NH4OAC and 1M NaOAC would be suitable as soil testing methods for determining available K for olive in the soils of Fars province. These extractants were the best because of high correla¬tion with plants potassium. In addition, advantages of these extractants are low cost and simplicity. As a recommendation, using of K fertilizers in most olive orchards of the province will improve quantity and quality of the yield.

Magnetic susceptibility measurements can serve a variety of applications including the determination of changes in soil-forming processes, the study of parent material effects, understanding sedimentation processes, soil drainage conditions, and even the separation and identification of soil delineations. The technique is especially attractive since it is relatively rapid, non-destructive, and can be applied to both intact and disturbed samples of soils. Magnetic susceptibility is defined as the ratio of the total magnetization induced in a sample relative to the intensity of the magnetic field that produces the magnetization. Iron oxides are the most abundant of the metallic oxides in most soils; they are present in all climatic regions, in several mineral forms, and at variable concentrations. Typically, selective dissolution techniques are used to quantify the relative proportion of Fe oxides. Due to the large contribution of iron-bearing minerals to magnetic susceptibility, their presence in most soils, and the effects of the biophysical environment on them, pedologists have been paying growing attention to magnetic susceptibility as a means to understand soil and landscape processes. The effects of topography on χ were studied for example by many workers. They found that soil susceptibility changes with the position of a soil profile on a slope. Texture and drainage class assumed to be the main reasons. The soils of the Beshar Plain formed on the relatively same parent materials and are mainly affected by topography and land use. The objective of this study was to examine the role of topography and land use on pedogenic processes and their relation to soil χ, as well as, profile distribution of secondary Fe oxides, and the χ profiles.
This study was conducted on the Beshar Plain, Kohgilouye Province, in southwest of Iran. Physiographically this plain comprises hill, piedmont plain, river traces, and plateau. Eleven representative pedons were dug along a transect crossing the main physiographical units. Five pedons demonstrated aquic soil moisture regime. The mean annual temperature and precipitation at the site was 14.7°C and 800 mm, respectively. Soil moisture and temperature regimes of the study area were xeric and thermic, respectively. The soils were classified according to soil taxonomy and WRB. The soil pH was measured in a saturation paste and electrical conductivity (EC) in a saturation extract. Cation exchange capacity (CEC) was determined using sodium acetate (NaOAc) at a pH of 8.2. Soil texture was determined using the pipette method. Calcium carbonate equivalent (CCE) was measured by acid neutralization. Organic carbon was determined by wet oxidation method. Pedogenic Fe (Feo) and pseudo-total Fe (Fen) were extracted with the CBD method and HNO3, respectively.The magnetic susceptibility of bulk samples was determined using a Bartington MS2 meter equipped with the MS2B Dual Frequency sensor, capable of taking measurements at both low (χlf at 0.46 kHz) and high (χhf at 4.6 kHz) frequencies.
The soils were classified as taxonomic orders of Entisols, Mollisols, Inceptisols and Alfisols, according to the world reference base for soil resources (WRB) as reference soil groups of Kastanozems, Regosols, Gleysols, Luvisols, Fluvisols and cambisols. The dominant pedogenic processes in the soils were the accumulation of organic matter, the leaching of carbonates, and formation of calcic horizons, the mobilization of clay and development of argillic horizons. The results indicated that the soils are affected mainly by topography, drainage class and land use. Most pedons exhibited maximum of χ at the soil surface, suggesting preferential loss of diamagnetic components, as well as more pedogenic formation of antiferromagnetic minerals. Magnetic measurements showed that the χ values of aquic soils were much lower than those of non-aquic soils (43%). The highest value of χ was noted in pedons which are located on stable physiographic units and the lowest belong to those which are located on river lower terraces. Fed and fen was also positively correlated with χ in the soils studied. Aquic condition also decreased Fed and Fed/Fen, 44 and 65 percent, respectively with no clear effect on Fen. Low to medium amounts of χfd in the studied soils indicated that superparamagnetic gains are not too dominant in the soils. Higher values of χfd were typically observed in the A horizons than at depth, suggesting a greater proportion of ultrafine grains at soil surface. A positive correlation existed between χfd and χ in the soils.

Potassium is an essential element for plant growth and exists as four forms in soils: soluble, exchangeable, non-exchangeable, and mineral. Soluble and exchangeable K are considered as readily available and non-exchangeable K as slowly available. Organic matters and acids play an important role in increasing the bioavailability of nutrients especially potassium in the soils. Organic acids are low-molecular weight CHO containing compounds which are found in all organisms and which are characterized by the possession of one or more carboxyl groups. Depending on the dissociation properties and number of these carboxylic groups, organic acids can carry varying negative charge, thereby allowing the complexation of metal cations in solution and the displacement of anions from the soil matrix.The ability of an organic acid to release K from soils depends on some factors such as: diffusion rate of the organic acid in soil, the diffusion capability of organic acid-element complexes, the contact time of the organic acid on a mineral surface, the ionization of the organic acid, the functional group of the organic acid and its position, and the chemical affinity between the organic acid and the mineral elements. This study was conducted in order to evaluate the effect of organic acids and vermicompost on transformation of K in some selected soils of Fars Province, southern Iran.
In this study, nine soils with enough diversity were selected from different parts of Fars Province. The experiment was done as a completely randomized design with three replications, consisting of three incubation times (5, 15 and 60 days) and four organic compounds (including 2% vermicompost, three acids of citric, malic and oxalic acid eachat a concentration of 250 mmolkg-1and one control). The samples were incubated at 50% of saturation moisture at 22°C. Routine physicochemical analyses and clay mineralogy were performed on soil samples. Soil reaction, texture, electrical conductivity, calcium carbonate, and gypsum were identified. Soluble, exchangeable, non-exchangeable and mineral potassium were measured. The amounts of K forms in each sample were determined. Total K was determined following digestion of soil (110°C) with 48 % HF and 6 M HCl. Water soluble K was measured in the saturated extract. Exchangeable K was extracted with 20 ml 1.0 M NH4OAc (pH 7.0) for 5 min. Nitric acid-extractable K was measured by extraction of a soil sample with boiling 1.0 M HNO3 for 1 h. Potassium was measured on all filtrated extracts by flame photometer. The content of clay minerals was determined semi-quantitatively, using peak areas on the diffractograms of ethylene glycol solvated specimens. Statistical analysis was accomplished using the SPSS 16.0 software and the comparison of mean values was done using the Duncan test at the 5% level of significance.
The amount of different forms of K including water soluble, exchangeable, HNO3-extractable, and mineral K are relatively high in the studied soils. Mineralogical analysis indicated that smectite, illite, palygorskite and chlorite were the major minerals in the clay fractions. The results also showed that exchangeable, non-exchangeable and total potassium were in the range of 166 to 378, 282 to 1694, and 2312 to 8437 mg/kg-1, respectively.Organic acids and vermicompostwere led toa significant increase in soluble K at all times compared to control and vermicompost treatment exhibited greater effect. These treatments also significantly increased exchangeable potassium compared to control. Significant differences between exchangeable potassium of organic acids and vermicompost treatments were not observed at 5 and 15 days, but significant differences were observed between treatments of mallic and oxalic acids at 60 days. Compared to the control, the non exchancheable K showed significant increase in all three organic acid treatments and vermicompost at 15 and 60 days.
Based on the results, while exchangeable and non-exchangeable (NEK) potassium showed a clear trend in treatments, solution potassium was first increased and then showed a decreasing trend due to the rapid changes in liquid phase compared to the solid phase. All treatments significantly increased soluble potassium in each 3 times. The greatest potassium increase associated with vermicompost. In general, oxalic acid> malic acid>vermicompost> citric acid, were increased exchangeable potassium, while the trend for NEK was in the order of oxalic acid> malic acid> citric acid>vermicompost, respectively. All treatments at all times (except for treatment 5 days of NEK), showed a significant increase in the exchange and NEK potassium compared to the control. The results also reflect the effect of the dominant soil clay mineral on transformation of exchangeable and NEK, so that the highest and lowest rate of increase was related to the soils with dominant palygorskite and illite, respectively. In general, it seems that the use of organic acids and organic matter leads to a rapid increase of potassium, which must be properly managed in the soils with high leaching. Due to the complexity of soil environment in terms of soil physical, chemical and biological aspects and the role of these factors on potassium transformation, repeating of this experiment in other soils is recommended.

This study was performed in order to assess land suitability of saline and gypsiferous soils of Barm-e- Alvan region, Kohgilouye-va-Boyerahmad Province for sustainable use of these lands. The main objective of land suitability assessment is evaluating the land characteristics in the current economic conditions for optimum use of available resource in order to have a moderate income with minimum soil loss. Salt and gypsum occurrence in soils are key factors of lowland soils cause limitations for crop cultivation. For this study the soil map was prepared. After preparing soil map of the region as basic map, the operation of land suitability classification for the region main crops (rain-fed wheat and barley) was carried out by simple limitation method based on FAO guideline and tables of climatic and soil needs of the crops. The results indicated that soils were classified in three soil orders of Entisols, Inceptisols and Aridisols and topography was the main soil forming factor. It was also distinguished that no major limitation was for the production of these crops. Selection of appropriate varieties of wheat and barley with more resistance to limiting factors with shorter growth period cause more production, hence improving water and soil resources of the region

Vermicomposting could increase nutrients availability including phosphorus. During vermicomposting, a decomposition of organic substrates leads to the production of several organic acids, such as malonic, fumaric, succinic acids. Microorganisms both in the intestinal organ of the worms and the organic waste have the ability to convert insoluble P into soluble forms. Little information exists about the effects of vermicomposting on rock phosphate (RP) solubilization. Present study was conducted to evaluate the solubilization of powdered RP during vermicomposting.

Vermicomposting and RP application increased NaHCO3-Pi. Rock phosphate application in vermicomposting significantly increased NaHCO3-Po. Vermicomposting significantly increased NaOH-Pi in all of the treatments. RP application and vermicomposting increased HCl-Pi in both organic sources. Generally, vermicomposting increased HCl-Po. Vermicomposting decreased pH but its effect was more evident in the presence of RP. Vermicomposting increased EC in both organic sources.

Present study showed that vermicomposting helps to enhance the transformation of P from RP into various organic or inorganic P forms, which would be readily or moderately available, thus, increase the availability of P from both RPs.

Carbonates are the main component of the most soils of arid and semi-arid regions in the world. Most soil characteristics are greatly influenced by carbonates. Therefore، determination of soil carbonates by a relatively precise، rapid and economic method has a great importance. The acid-titration technique used in most laboratories is a relatively time-consuming and costly method. In this study، 30 soil samples (with a calcium carbonate equivalent of 13-91% in different land uses) with three replications were used to compare acid-titration method with acetic acid (pH)، pressure and، weight-loss methods. No significant differences were observed in measured carbonate levels using different methods. However، dot plots indicate that pressure method is the most precise among the four compared methods. One-way ANOVA results exhibited that pressure and acid-titration methods have minimum and maximum values of coefficient of variations، respectively. Overall، the pressure and weight- loss methods are recommended for soil carbonate measurement in the studied soils.

To investigate effects of different super absorbent polymer and animal manure ratios on the quantitative and qualitative characteristics of soybean under drought stress, a split plots experiment was conducted based on randomized complete block design with three replications in Marvdasht, Iran in 2009. Main factor included of irrigation with 50, 100 and 150 mm evaporation from pan class A and sub factor included of control, 40 t.ha-1 animal manure, 200 kg.ha-1 super absorbent polymer, 50 percent super absorbent polymer + 50 percent animal manure, 65 percent super absorbent polymer + 35 percent animal manure and 35 percent super absorbent polymer + 65 percent animal manure. The results showed that, number of pod and grain per plant, 1000 grain weight, grain yield, biological yield, protein yield and oil yield were decreased by drought stress occurrence and were increased with super absorbent polymer and animal manure application. The highest yield (2148.3 kg.ha-1) was obtained in control treatment. Results showed that the combinations of super absorbent polymer and animal manure significantly increased grain, biological, oil and protein yield compared with control. Finally, combination of 35 percent super absorbent polymer and 65 percent animal manure was the best treatment in this experiment.