مجید حجازی مهریزی

This research examined the impact of long-term pistachio cultivation on soil inorganic phosphorus (P) fractions. Soil properties and phosphorus fractions, particularly residual-P, were compared at different depths in pistachio cultivated and the adjacent uncultivated lands in Kerman Province. Soil samples were collected from four different depths (0-10, 10-20, 20-30, and 30-50 cm) in triplicates from both pistachio-cultivated and the adjacent uncultivated lands, using a randomized systematic method. The physical and chemical properties of soil samples were measured, along with soil P fractions, and the data were analyzed using the one-way ANOVA. The findings indicated that, with the exception of bulk density, other soil properties exhibited significant differences between the two land uses. The electrical conductivity (EC) of soil in pistachio-cultivated land was lower than that in uncultivated land, whereas the amounts of calcium carbonate and soil organic matter were greater in the pistachio-cultivated land. The highest content of calcium carbonate (26.2%) and organic matter (0.9%) was found at 10-20 cm depth. There was a significant difference between the two lands regarding inorganic phosphorus fractions. The results showed that soil total and available P concentration were higher in pistachio land compared to uncultivated land by 3% and 37%, respectively. Pistachio land had a higher amount of soil residual-P (146.2 mg/kg) as compared to the uncultivated land (129.8 mg/kg). Additionally, it was observed that the concentration of residual-P fluctuated at different depths. The amount of residual-P was lowest at a depth of 0-10 cm (117 mg/kg) and highest at a depth of 10-20 cm (154 mg/kg). Based on the results obtained, it was found that HCl-P was the most prevalent fraction of inorganic phosphorus in both lands. The findings indicated that understanding phosphorus fractions is crucial for effective phosphorus management in pistachio-cultivated land.

Due to the lack of suitable water resources and poor soil quality (high salinity, low organic matter, and plant nutrient deficiency), the increase of arable lands in arid and semi-arid regions has faced severe challenges. The use of organic amendments is recognized as a critical strategy for plant production in such soils. Nowadays, humic acid (HA) is known as one of the eco-friendly fertilizers that not only preserves soil quality but also plays a significant role in increasing the production of high-quality agricultural yields. The present study was conducted to extract humic acid from two sources of cattle and sheep manures and compare their effect on maize growth characteristics and inorganic phosphorus (Pi) forms in a calcareous soil compared to the commercial HA.

25 kg of sheep and cattle manure were collected from the farm of Shahid Bahonar University in Kerman and composted separately under controlled conditions for three months. Humic acid was extracted from composted manure using 0.5 N NaOH (1:10 material: extractant) in a dark environment under no oxygen conditions. The extracted HA's chemical and structural features, such as pH, EC, elemental composition, and functional groups, were determined. To investigate the effect of extracted humic acid on the growth of maize and soil inorganic P forms, a completely randomized design with seven treatments, including 0.1 and 0.2% of cattle manure extracted humic acid (CM-HA), 0.1 and 0.2% of sheep manure extracted humic acid (SM-HA), and 0.1% and 0.2% levels of commercial humic acid (HA), and a control treatment was designed in four replicates. The seedlings of maize were planted in treated pots and kept for 70 days under greenhouse-controlled conditions. At harvest time, the fresh and dry weights of the shoot and roots were measured. Soil Pi fractions, including H2O-extractable P, NaHCO3-extractable P, NaOH-extractable P, and HCl-extractable P, were also determined after maize harvesting.

The results showed that commercial humic acid had the highest pH and the lowest EC compared to the extracted acids. In contrast, humic acid extracted from cattle and sheep manure was more acidic than the commercial HA. The results of FTIR indicated the presence of phenolic hydroxyl, carboxyl, and aromatic rings in the extracted and commercial humic acids. The results showed that only 0.1% of commercial humic acid had no significant effect on maize's shoot fresh and dry weight. In contrast, other extracted acids, especially SMHA, significantly increased both growth characteristics of maize. In all treatments, the overall distribution of Pi forms was HCl-P > NaHCO3-P > NaOH-P> H2O-P. The results showed that HA application at the rates of 0.1% and 0.2%, mainly extracted HA from sheep manure, increased the contribution of more labile forms of inorganic phosphorus, including H2O-P and NaHCO3-P in the soil.

Since extracted HA from sheep manure and cattle manure have better quality than commercial HA and more effectively affect the growth of maize and labile forms of Pi, these resources can be used as an alternative for HA extraction and HA-based fertilizer production. In general, 0.2% of extracted humic acid from sheep manure had a more influential role in increasing the labile P forms in the soil and the growth of maize plants compared to other treatments.

Extraction of humic substances from animal manures can be considered as one of the optimal management solutions for these wastes. This research aimed to identify the characteristics of humic acid from two sources of cattle and sheep manure at two levels of 100 mg and 200 mg and compare their effects with commercial humic acid on the growth of soybeans in a completely random design in greenhouse conditions. Based on the spectrophotometric ratio, E3/E5, the lowest molecular weight was related to humic acid extracted from sheep manure. The infrared spectroscopy results indicated the presence of phenolic hydroxyl, carboxyl, and aromatic ring functional groups in extracted and commercial humic acid. Phenolic OH was abundant in humic acid extracted from sheep manure, and the peak related to aromatic and aliphatic ring was removed in commercial humic acid. The results showed that humic acids extracted from sheep manure in the amount of 200 mg caused 62% increase in the fresh weight of the shoot, 48% in fresh weight of the root; and cattle manure in the amount of 200 mg increased the height of the shoot by 31%. But, the use of commercial humic acid could not influence the mentioned traits. Based on the results of this study, sheep manure can be considered a suitable source for extracting humic acid; and its application to soybean can be recommendable due to its effect on growth indicators, at the rate of 100 mg.

It is essential to use of an inexpensive and eco-friendly method to reduce the environmental hazards of heavy metals. In this study, the effect of humic acid (HA) and fulvic acids (FA) on the availability of copper and cadmium and their uptake by ornamental castor oil was investigated in the greenhouse of Shahid Bahonar University of Kerman. Treatments including two levels of HA and FA (0.5 and 1 %) were added to a Cu-Cd polluted soil with five replications. A treatment received no organic acid as a control. After 90 days, some plant growth characteristics, available Cu and Cd and shoot, and root Cu, Cd concentration were measured. The results showed that application of 0.5% of humic acid to soil increased the growth characteristics of ornamental castor. In contrast, the addition of humic acid at the rate of 1% and fulvic acid at the rate of 0.5 and 1% significantly reduced plant growth characteristics. Soil application of 0.5 and 1% of humic acid increased available Cu by 19 and 37% and available Cd by 30 and 44%, respectively. Available Cu and Cd in soils treated with 0.5 and 1% of fulvic acid were 35 and 39%, and 42 and 54% higher than the control. Shoot and root Cu and Cd concentration were significantly increased in plants treated with 0.5 and 1% of humic and fulvic acids. Bioaccumulation and translocation factors were less than 1 in all treatments and increased in soil treated with 1 % of HA and FA. Based on these results, ornamental castor been could not be considered as a hyperaccumulator plants. However, humic and fulvic acids can increase the phytoremediation ability of ornamental castor for Cu and Cd removal.

Large area of rangeland ecosystems, are being degraded as a result of overgrazing and continuous grazing of domestic livestock, and the vegetation and soil condition in them is not satisfactory. The present study investigates the changes in soil physical-hydraulic quality at different Levels of Management (including One-year grazing exclusion, low-intensity grazing and high-intensity grazing) in three locations of mountain Artemisia habitat of Rabar Southeast, Kerman province. For this purpose, in growing season of 2017, 30 soil samples with 3 replicates were taken from the soil surface horizon from each location, and the hydro-physical and chemical properties of soil such as; texture, bulk density, organic carbon, electrical conductivity, mean weight diameter, saturated hydraulic conductivity, saturated moisture capacity, soil sorptivity and soil erodibility index were measured. By comparing the values of the characteristics in each place with respect to their critical level in the standard tables and considering the potential of the region and the weather conditions, the type and level of protection in each land were identified. Based on the results, applied grazing management had a significant effect on the mentioned indicators. So that intense grazing treatment caused an increase of 23.07% and 12.3% (p <0.05) of electrical conductivity compared to exclosure and low grazing treatment, respectively. Amount of organic carbon in the exclosure treatment decreased from 0.658% to 0.491% and 0.464% in the low and high grazing treatments, respectively. Also a significant decrease (p <0.01) in MWD of the aggregate diameter was observed due to grazing management compared to the exclosure treatment. From a physical-hydraulic point of view, the application of low and compared to the grazed management, while increasing thegrazing intensity caused a significant increase (p <0.05) in soil erodibility index. In general, according to the comparison of indicators with their standard limit; priority of protection in each of the exclisure, low and high intensity grazing; include no need for protection, basic protection, and full protection respectively.

providing the food needed by the world's ever growing population has led to changes in cultivated areas, water resources, and the overuse of chemical fertilizers and consequent environmental pollution. Providing essential nutrients to the plant is one of the most important factors related to the optimum production of agricultural crops. In recent years, most of essential nutrients are provided through the natural fertility of the soil and chemical fertilizers. Today, one of the most important ways to increase soil fertility is the use of fertilizers. Consistent and excessive use of fertilizers such as nitrogen and phosphorus (in the form of ammonium salts, urea, nitrate or phosphate compounds) in recent years has caused problems in the agriculture and environment. In recent years, the efficiency of application of nitrogen, phosphate and potash fertilizers has been about 30-35, 18-20 and 35-40-40, respectively. This indicates that a large part of the fertilizer used remains in the soil or enters the aquatic ecosystems and negatively affects the natural balance and biodiversity of agricultural lands. Accordingly, to overcome these problems, it is necessary to use solutions such as better water and fertilizer management, change in the structure of fertilizers and the use of new technologies. One of the effective methods to overcome the problems of low efficiency of chemical fertilizers is to develop the controlled release fertilizers. Slow-release fertilizers can be a good way to overcome the problems expressed by common chemical fertilizers. Release control fertilizers are usually prepared using the coating method and reducing the solubility of water-soluble fertilizers by creating a physical barrier. The biggest problem with slow release fertilizers is their high production cost. Therefore, it is necessary that the fertilizers covering chemical fertilizers be economical and compatible with the environment and have desirable coating properties. Nanocomposites are among the polymer coatings that have received much attention in recent research. Among the many materials used to form nanocomposites, polysaccharides such as cellulose, starch for economic reasons, biocompatibility, non-toxic and biodegradable are widely used compared to synthetic polymers. Despite many studies in the field of fertilizer production, the use of slow release fertilizers as a source of required nutrients and also the use of hydrophilic and hydrophobic polymers such as pure cellulose compounds with conventional fertilizers have not been studied. The need for this research is to use cellulose from agricultural waste in slow release of chemical fertilizers in order to increase the efficiency of fertilizers, prevent its overuse in agriculture, and also waste agricultural waste around orchards. In this study, cellulose compounds were extracted from paper, palm and pistachio branch and these cellulose compounds were then used to slow the release of urea fertilizers.

First, the sufficient amounts of pruned wastes from branch of palm, pistachio, and paper waste, were collected from agricultural regions in Kerman Province; then they were transferred to the laboratory of Kerman Agricultural Research Center. After washing and drying, the samples were ground. In the next step, 10 g of each of the air-dried cellulosic sources was passed through a 60-mesh sieve in an Erlenmeyer flask with 200 ml of 1% NaOH solution for 1 h. Then, it was entirely washed with distilled water and the resulting contents in the Erlenmeyer flask were re-boiled along with a mixture containing 300 ml of 80% acetic acid plus 30 ml of 67% nitric acid for 30 min at 120°C. At the end of the reaction time and partial cooling of the mixture, the cold distilled water was added to the reaction mixture and the resulting cellulose pastes were then washed thoroughly with distilled water until reaching the neutral pH. At the end, the samples were air-dried. Finally, the cellulose samples were washed with distilled water and air dried. In the second stage, slow release of urea fertilizer with cellulose from palm wastes in a ratio of 1 to 2 (fertilizer to cellulose) was made and they were made in the form of small tablets. Nitrogen release kinetics from these fertilizers in soil up to 90 days were measured and kinetic equations were also investigated.

After cellulose extraction of wastes, FTIR device was used to identify the extracted celluloses and compare them with Sigma Aldrich pure cellulose. The peaks obtained from the FTIR apparatus were similar to the pure cellulose peaks. The yield of extracted cellulose in the form of paper waste was 70%> palm branch 33%> branch of pistachio 28%. In the second stage, the extracted cellulose was used to cover urea fertilizer in a ratio of 1 to 2 (urea fertilizer to cellulose) and the desired fertilizer was made in the form of small tablets with diameter of 0.5 cm and height of 2 cm. The SEM scanning electron microscope was used to study the structure of the manure. Microscopic images showed that the urea fertilizer placed as white spherical particles around the cellulose rod particles, indicating that the urea fertilizer particles adhered to the cellulose particles without any adhesive. The FTIR diagram of the fertilizer showed that the shift of the diagram upwards at the common wavelengths in urea and pure cellulose and a strong physical bond is established between them. Nitrogen release kinetics for all treatments that were less than pure urea fertilizer and significant differences observed between treatments and pistachio branch cellulose caused a slower release of urea fertilizer. The kinetic equation of the power function was selected as the best model for fitting the kinetic data. The studied wastes in this study have a high potential for producing pure cellulose to slow the release of urea fertilizer.

The increase in population has led to the production of large amounts of agricultural wastes that pollutes the environment. Today, the use of agricultural wastes to extract cellulose and nano-cellulose is increasing. In this study, cellulose and nanocrystalline cellulose were extracted from three types of palm waste, including fibers, leaves and palm clusters and used to identify cellulose and compare it with pure cellulose SigmaAldrich from devices using FTIR, TGA and XRD. Cellulose extraction yield was measured at 25% in palm fibers, 20% in green leaves and 33% in clusters. The FTIR and XRD spectra of isolated cellulose was similar to pure cellulose and the degree of crystallization was in order of leaf > fibers > clusters. The loss of weight for all cellulose samples in TGA charts at 350 oC was similar to that of pure cellulose and the nanoparticle length range of these cellulose was determined by the FE-SEM electron microscope 20 to 36 nanometers.

Today, soil pollution is an important environmental issue that should be taken into account. Industrial activities cause pollution and accumulation of heavy metals in the soil. Soil pollution significantly reduces the quality of the environment and threatens human health. Heavy metals are one of the most important pollutants in the environment, which has received a lot of attention in recent decades. Heavy metal pollution is a serious problem in developing countries and urban areas. Among heavy metals, lead is found in large amounts in the Earth's crust, which has several effects on human health and the environment. Lead is an essential element for the plant and one of the most important pollutants, which is toxic even at very low concentrations. Its presence in the culture medium has a negative effect on germination rate, water status in the plant, dry root weight and aerial part of the plant, photosynthesis, absorption of nutrients and enzymatic activity. Much research has been done to use alternative and modern methods to clean the environment of heavy elements. One way to stabilize heavy metals in the soil is to use biochar. Due to its cation exchange capacity and high specific surface area, biochar is able to reduce the pollution caused by organic pollutants and heavy metals, stabilize heavy metals and improve the condition of plants and soil in terms of pollution. The aim of this study was to investigate the effect of modified biochars rice husk and almond soft husk on lead desorption kinetics in contaminated calcareous soil. To conduct this research, a sufficient amount of soil from a depth of zero to 30 cm was collected from the farm of Shahid Bahonar Agricultural College in Kerman. Physical and chemical properties of the studied soil were measured after air drying and passing through a 2 mm sieve. To prepare the biochars (rice husk and almond soft husk), the residues, after collection, were air-dried and ground and then packaged in aluminum foil to limit the oxygenation process. They were then placed in an oven at 500 0C for four hours to produce a charcoal called biochar. Also, to prepare the modified biochar (NaOH and HNO3), one gram of biochar was added to 100 ml of distilled water and then 10 ml of concentrated acid (or 10 g of alkali) was added to it. Stirring at 60 0C for 24 hours. Finally, it was filtered using a centrifuge and washed several times with distilled water to neutralize the pH. The produced powder was dried at 70 0C for 24 hours. The lead desorption kinetics experiment was studied at several times (5, 15, 30, 60, 120, 240, 480, 960, 1440 and 2880 minutes) in two levels of biochar (0 and 4 wt %) and three levels of lead (0, 300 and 600 mg kg-1), which were incubated for 5 months under field moisture in a greenhouse. The kinetics results showed that the desorption of lead has the same pattern in all the time studied. Early rapid desorption occurred in the early desorption times (initial 30 minutes) followed by low-velocity desorption (8 hours) and finally, equilibrium was observed in the treated and control samples. The significant difference between the amount of lead released from the treated soils and control indicated a positive effect of both used engineered biochars on reducing lead desorption. The highest amount of lead desorption was observed in soil without biochar, while the lowest desorption rate occurred in treatments of rice husk and almond soft husk modified by sodium hydroxide. The application of modified biochar rice husk highly reduced lead desorption, compared to modified biochar almond soft husk. According to the results, the modified biochar with sodium hydroxide caused a significant reduction in lead desorption compared to other treatments, and this reduction was more in biochar rice husk than the almond soft husk one. It can be stated that rice husk biochar has been more successful than almond soft husk biochar due to its more porous structure and cation exchange capacity. Among the equations used for lead desorption estimation, the two-constant rate equation was selected as the best model for data fit due to high explanatory coefficient (R2) and low standard error (SE). According to the above, the use of biochar can be recommended as a modifier in lead contaminated soils.

One of the best methods for managing coal wastes to prevent their accumulation in nature and reduce environmental pollution is their application as the sorbents of pollutants. The objective of this study was to investigate the capability and behavior of the coal wastes in three forms of pristine powder (cp), nanoparticles (cnp) and FeCl3 modified nanoparticles (mcnp) for phosphorous (P) sorption from aqueous solution. Characterization of the sorbents was carried out using XRD, SEM-EDS and FTIR analyses. Equilibrium sorption experiments were done in batch systems and the effects of pH, initial P concentration and contact time were studied. The results showed that the P sorption process was pH dependent and the maximum P sorption occurred at 2-6 pH ranges. The maximum P removal efficiency of the sorbents obtained in the range of 0-50 mg/L of initial P concentration and it was increased with time and reached equilibrium after 2 hours. The P removal efficiencies of the sorbents were determined to be 3.3, 18 and 78.8 % for cp, cnp and mcnp, respectively. The pseudo-first and pseudo-second order kinetic models and Langmuir isotherm described the P sorption data well. The maximum P sorption capacities were calculated to be 0.37, 3.97 and 30.39 mg/g for cp, cnp and mcnp, respectively. Results revealed that the modified coal wastes have the potential to use as cost-effective and environmental-friendly sorbents.

 Salinity is one of the common stresses in agricultural lands of arid and semi-arid regions in Iran. Furthermore, excessive CaCO3, high pH, nutritional disorders have been known as limited factors for plant growth and productivity in such soils. The cultivation of salt tolerant plants such as rosemary (Rosmarinus officinalis L.) is important from the point of view land reclamation. Rosemary is a woody plant, evergreen, perennial herb belonging to Lamiaceae family. It is native to Mediterranean but it can tolerate undesirable conditions such as drought and salinity stresses. Zinc (Zn) and copper (Cu) are essential micro-nutrients that play important roles in plant metabolic processes and can increase plant tolerance to salinity. Zn is vital for protein synthesis, protein stability, and different enzyme activities such as Zn/Cu superoxide dismutase and carbonic anhydrase. On the other hand, chlorophyll production, photosynthesis and enzyme activities are the most important role of Cu in plants. Superoxide dismutases (SOD) are metalloproteins that catalyze superoxide radicals (O2-) produced under salinity stress into oxygen molecules and hydrogen peroxide, resulting to increased tolerance of plants to salinity. The most abundant superoxide dismutase isozyme in plants is Cu / Zn SOD, in which the role of Zn is structural and copper plays a catalytic role. 

 There is limited information about the effect of micronutrient application on the growth and salinity tolerance of rosemary. This study was conducted to investigate the effect of Zn and Cu co-application on some physiological and biochemical characteristics of rosemary under saline condition. For this purpose, a completely randomized design was carried out in a factorial experiment. The factors consisted of four types of fertilizer treatments (T1: control, T2: control + zinc, T3: control + copper and T4: control + copper + zinc) and three levels of salinity stress (S0: 0, S1: 60 and S2: 120 mM as NaCl) in four replications in a calcareous soil under greenhouse conditions. After 90 days, the plants were harvested and some growth characteristics including shoot and root fresh and dry weight were measured. Some physiological and biochemical properties such as leaf relative water content (LRWC), membrane permeability (MP), malondialdehyde (MDA), shoot and root Na concentration, and shoot and root K concentration were also measured. 

The results showed that salinity had no significant effect on fresh weight of shoots, while shoot dry weight of rosemary decreased as 60% in control treatment, 44% in zinc treatment, 38% in copper treatment and 27% in zinc + copper treatment. Leaf relative water contents of rosemary decreased in response to salinity stress, and the only co application of zinc and copper under 120 mM NaCl stress resulted to a significant increase of LRWC (9%). Salinity stress increased the membrane permeability of rosemary leaves. In contrast, at all salinity treatments, addition of Zn and Cu caused a significant decrease in membrane permeability of rosemary leaves. However, there was no significant difference between fertilizer treatments. Salinity stress induced a significant increase in the malondialdehyde content of rosemary. For example, MDA content increased by 39% in control and by 24% in Cu treated plants when salinity level reached from 0 to 120 mmol L-1. Based on the results, in soil treated with 60 mmol L-1, addition of Zn and Cu and at the higher salinity level (120 mmol L-1) addition of Zn to soils had a significant effect on leaf and root Na concentration and thereby improvement of plant salt tolerance. Also, the result showed that co-application of Zn and Cu could reduce the undesirable effect of salinity on shoot and root K concentration and thereby improving plant tolerance to salinity stress. 

In conclusion, zinc and copper, especially in combination form, increases the tolerance of rosemary to salinity by reducing of cell membrane damage, malondialdehyde content, shoot and root plant Na concentration and increasing of LRWC and shoot and root K concentration.

Introduction Phosphorus (P) is an essential nutrient for all forms of life on the earth, but in excess concentrations, it can act as a serious water pollutant through eutrophication. Thus, it is very important to remove P from aqueous solutions before their release into natural water resources. Among the various P removal techniques that have been developed, the sorption process is widely accepted to be an effective water treatment technique because of low cost, ease of operation, simplicity of design, and high sorption capacity in dilute solutions. Layered double hydroxides (LDHs) are a type of two-dimensional nanostructure anionic clays with high capacities to sorption of anions. These non-silicate clays consist of positively charged brucite-like octahedral sheets which neutralize by a negatively charged interlayer containing relatively weak bonded anions and water molecules. The positive charges generated by the isomorphous substitution of trivalent cations for divalent cations are balanced by interlayer anions that can be exchanged by other anions making them good anion-exchangers with high selectivity. LDHs have been widely used as environmental sorbents because of their high charge density, large interlayer areas, good thermal stability, and high anion exchange capacities of the interlayer anions. The aim of the present study was to synthesize a Mg-Fe LDH as a sorbent for P removal from aqueous solution. Materials and Methods The Mg-Fe LDH was synthesized using the co-precipitation method. In brief, a mixture solution containing 0.03 mol MgCl2. 6H2O, and 0.01 mol FeCl3. 6H2O was added dropwise into a flask containing 100 ml of 1 M NaOH solution under vigorous stirring at pH=10. The obtained slurry was filtered and washed repeatedly with DW until the filtrate pH reached neutral. Mg-Fe LDH particles were then obtained by drying the filtrate at 70 °C in an oven overnight. The crystallinity of the sample was studied using X-ray diffraction (XRD) analysis. In order to investigate the performance of the synthesized LDH as a P sorbent, batch experiments were carried out in polyethylene centrifuge tubes. The suspensions were shaken for 24 hours at 250 rpm, and the supernatant was then separated by centrifugation at 4000 rpm for 10 minutes and were filtered by Whatman ashless grade 42 filtration papers. Equilibrium P concentration was determined according to the ascorbic acid method using UV-vis spectrophotometer at the wavelength of 880 nm. The effects of pH, initial P concentration, and contact time on P sorption were investigated in the ranges of 2-10, 0-300 mg/L and 0-1440 min, respectively. Results and Discussion The XRD pattern of the LDH sample showed typical structure of hydrotalcite-like compounds with sharp and reflection peaks corresponding to the (003), (006), (012), (015), and (110) crystal planes which are characteristic planes of hydrotalcite-like compounds. The efficiency of LDH to remove P decreased with the increasing of initial P concentration and the maximum removal efficiency of LDH occurred in the range of 5-20 mg/L of initial P concentration. With increasing of initial P concentration from 20 to 300 mg/L, the P removal efficiency of LDH decreased from 98.7 to 24.6 %. The P removal efficiency was increased with time and reached equilibrium at 60 min. The P removal rate of LDH in this time was about 66 % and no significant decrease in residual P concentration was observed after 60 min. The sorption of P on LDH was highly pH dependent, and the maximum P removal was found at pH of 4. The sorption kinetic and isotherm data were well described by pseudo-second-order and Langmuir equations, respectively. According to the Langmuir equation, the maximum P sorption capacity (Qmax) of LDH was obtained as 13.96 mg/g. Conclusion It was found from the results of this study that the mechanisms involved in the P sorption onto LDH included electrostatic attraction, ligand exchange, and surface complex formation. In addition, the results suggested that the synthesized Mg-Fe LDH can be potentially used as an effective sorbent for the removal of P from aqueous solutions. Further research is needed on the regeneration of the LDH after P sorption and the evaluation of desorption behavior of P from LDH under different conditions.

Environmental pollution by heavy metals has been known as a serious problem associated with industrialization. Due to high stability nature, heavy metals could be accumulated in soils at toxic levels and insert to human food chain. The total concentration of heavy metals can indicate the extent of contamination, but is not usually an accurate indication of the bioavailability, mobility and phyto-toxicity and thus the fractionation procedures have been used to show environmental risks of toxic metals. Heavy metals in soils occurred in soluble, exchangeable, organically bound, oxides bound and residual fractions. There is limited information about bioavailability heavy metals in soils around coal washing factories of Iran. This study was conducted to investigate the distribution of chemical fractions of copper, lead and cadmium in a coal washing factory located in Zarand.
The study area (Zarand coal washing plant) is located about 70 kilometers from Kerman city (Western Iran). A nested grid sampling scheme was adopted using Google Earth. In this study, 4 areas were selected according to dominant vegetation. Composite soil samples (5 samples per point) were systematically collected from 0 to 30 cm depth. Soil samples were air dried and passed through a 2 mm sieve. For determination of total concentration of heavy metals (Cu, Cd and pb), 20 mL of 5N HNO3 was added to 0.2 g of soil samples and heated for 10 minutes and then kept at room temperature for 24 h. after centrifuge, the concentration of heavy metals was determined using atomic absorption spectrometer. Chemical fractions of heavy metals including acid-soluble/exchangeable fraction, reducible (bound to Fe-Mn oxides), oxidizable (bound to organic matter) and residual fractions were sequentially extracted. After each successive extraction, separation was carried out by centrifugation at 3000 rpm for 30 min. the supernatant was filtered with Whatman 42 filter. The concentration of Cu, Cd and pb in supernatant was determined using atomic absorption spectrophotometer.
The results showed that the total contents of Cu, Pb and Cd in 4 areas was higher than the standard range provided by Iranian soil and water office of human environment Bureau, showing the serious pollution of studied heavy metals in soils. Based on Geoaccumulation Index (GI), site 4 were highly polluted by Pb whereas Cu and Cd were in non- polluted to slightly polluted status. Spatial distribution of heavy metals showed that the highest content of Cd, Pb and Cu were found in the northwest and the west direction of factory with agricultural land use showing the alarming status of this area. In all sites, the residual and exchangeable fractions of heavy metals had the greatest and lowest values among other fractions, respectively. The distribution of studied metals (Cu, Cd and Pb) were lined in the order of residual fraction > reducible fraction > oxidizable fraction > exchangeable fraction.
According to average concentration presented by soil and water office of human environment Bureau, Cu, Pb and Cd values are in alarming status. The changes in chemical fractions of Cu and Pb following the order of residual> Reducible > Oxidizable fraction > exchangeable. Based on Geoaccumulation Index (GI), the areas were highly polluted by Pb. The results showed that in comparison with Cd and Cu, the main fraction of Pb is deposited in residual fraction in soil. Based on these results, the Cd and Cu are more dangerous than Pb in this region and are capable to transport in food chain.

Some of heavy metals such as copper (Cu) and manganese (Mn) are toxic and represent as hazardous pollutants due to their persistence in the environment. Heavy metals can be introduced into soils and aqueous environment by natural processes or anthropogenic activities. They are non-degradable in nature and highly toxic to plants, animals and human beings. Various methods exist for the removal of heavy metal ions from solution, such as filtration, chemical precipitation, ion exchange and sorption by activated carbon and others. Discarded tires are an interesting and inexpensive medium for the sorption of heavy metals. There has been little research on heavy metal sorption into tire rubber in competitive systems. Therefore the present study was conducted to assess the sorption behavior of Cu and Mn on different size of tire rubber in a competitive system.
The finely ground discarded tire rubber with three sizes including 0.088-0.125, 0.177-0.250 and 0.353-0.500 mm were prepared from Yazd Tire Company in Iran. A batch experiment was conducted by adding of 200 mg of ground tire to 10 ml of Cu aqueous solution of the desired concentration (10 to 50 mg L-1). After 24h, supernatant was separated by filtration and analyzed for remaining Cu and Mn by atomic absorption spectroscopy technique.
Sorption of Cu and Mn on tire rubber increased with increasing of metal concentration from 0 to 50 mg L-1. The greatest sorption of Cu (1088.9 mg Kg-1) was found at the smallest tire rubber size (0.088-0.125 mm) and decreased by 35% when the largest size (0.353-0.500 mm) was used. At the highest concentration, sorption of Cu was restricted by Mn competition. In the whole range of studied metal concentrations, Mn occupied the least sorption sites of tire rubber. The sorption of Mn was not affected by tire rubber size and was restricted by Cu competition. Based on average, the experimental data were fitted in Langmuire (R2=0.94) better than Freundlich one (R2=0.87), showing monolayer sorption of Cu and Mn on discarded tire rubber. The values of maximum sorption capacities calculated from the fitted Langmuir equation showed that Cu sorption was higher than Mn. There was an increase in the qm values of Mn when the tire rubber diameter decreased. In this study, separation factor (RL) was used to predict if an adsorption system is favorable or unfavorable. In all cases, the values of RL were between 0 and 1, pointing to the favorable sorption of Cu and Mn on three size of rubber.
Results clearly showed that ground discarded tire rubber (especially, the smallest size) are an effective adsorbent for the removal of Cu and Mn in competitive system. The equilibrium sorption isotherm of Cu and Mn onto discarded tire rubber is well described by the Langmuir and Freundlich models, but the Langmuir model fits the experimental data better than the Freundlich model.

Iron (Fe) and zinc (Zn) deficiency has been known as a key factor in limiting crop production in calcareous soils of arid and semi-arid regions. Since the components of organic matter can change Fe and Zn availability, this study was conducted to investigate the effects of humic treatments including humic acid (HA), fulvic acid (FA), vermicompost (Verm), HA and HAᐏ镺 and mycorhiza inoculation on some growth characteristics of soybean and Fe and Zn uptake under greenhouse conditions. Results showed that significant differences among humic substances and mycorrhiza were recorded for soybean growth and Fe and Zn uptake. The response of soybean plants to humic substances was different. The largest increases in plant height, shoot fresh weight, shoot dry weight, root fresh weight and root dry weight were found in humic acid amended soil, being 0.9 fold, 2.37 fold, 6.11 fold, 3.54 fold and 5.5 fold, respectively, as compared to the control. Mycorrhiza also improved soybean growth characteristics. Humic treatments (with an exception for humic acid and vermicompost) increased Fe and Zn content of soybean aerial parts. The highest Fe content (657.3 mg/kg) and Zn content (87.4 mg/kg) was measured in plants treated with fulvic acid. Mycorrhizal inoculation resulted in 10% increase in Fe and 64% in Zn content of soybean as compared to control plants. The results of this research revealed that application of humic acid and mycorrhiza can improve soybean growth by increasing the uptake of Fe and Zn.

Organic amendments are an excellent source of phosphorus (P) for plant production in sustainable agriculture. This paper describes the short term (100 days) effects of sewage sludge (SS), cow manure (CM) and poultry manure (PM) on the soil organic P (OP) fractions and their availability to wheat in a calcareous soil of Kerman Province . The experiment was arranged on a completely random design consisting of control (with no P fertilizer) and two levels (2 and 4%) of SS, CM and PM in four replications. Organic amendments markedly (pCM>PM. A significant correlation were observed between labile organic P with soil available P (r=0.92**), P uptake by wheat (r=0.92**) as well as between MLOP and shoot dry weight (r=0.96**), showing that labile and moderately labile organic P fractions have more contributors to available P than the others. These results suggest that adding of organic amendments can increase P availability and plant growth due to increase in soil OP fractions especially labile and moderately labile organic P fractions.

Organic amendments considerably affect balance of nutrients such as phosphorus (P) by influencing the chemical, physical, and biological properties of soil. In the incubation study, the effects of two levels of P (100 and 200 mg kg-1) from two sources (poultry manure and KH2PO4) on inorganic P (Pi) fractions were investigated during 90 d (5, 15, 30, 45, 60, and 90 days). Phosphorus fractions were sequentially extracted with water (H2O-P), 0.05 M NaHCO3 (NaHCO3-P), 0.1 M NaOH (Al and Fe bound P) and 1 M HCl (Ca-P). The results showed that most of soil Pi in the control treatment was present in the HCl-P fractions (102-187.4 mg kg-1). Poultry manure and KH2PO4 application significantly increased NaHCO3-P, NaOH-P and HCl-P. Labile Pi fractions (NaHCO3-P and NaOH-P) were increased after organic and inorganic P amendments and then converted to most stable Pi fraction, Ca-P, by the end of the incubation period. This transformation was more severe for KH2PO4 amended soil indicating that poultry manure allowed P to be retained in more labile fractions for a longer period. Supporting this idea, highly significant correlation (r=0.81-0.93, P<0.01) was found between NaHCO3-P and available P in all incubation times. According to the results of the study, combined use of poultry manure and chemical P-fertilizer in calcareous soils could act as a source of plant available P.

Phosphate reactions with soil components are important from the viewpoint of plant nutrition and P fertilizer use efficiency. Phosphorus buffering capacity in calcareous soils at upper-, mid-, and lower-slope positions of two arid and two semiarid landscapes were investigated. Sorption data were fitted to the Langmuir, Freundlich, Temkin and Van Hay models to determine P buffering indices. The best fit is found to be with the Freundlich isotherm for all landscapes in terms of the coefficient of determination (R2=0.865-0.994) and the standard error of estimate. Maximum P sorption (derived from Langmuir and Freundlich) were found at lower-slope position of four landscapes. Among the physico-chemical properties of soils, di-thionate extractable Al (Ald) and Fe (Fed) were positively correlated with maximum P sorption showing that P availability in these soils was affected by Fe and Al oxides. Buffering capacity indices such as maximum buffering capacity, standard buffering capacity and K at lower-slope position were higher than other position. All P buffering indices in landscapes showed a positive correlation with Ald. High correlation coefficients between P buffering indices let us to use any buffering indices for prediction of P availability in soils. For maximum production, appropriate P management is needed at lower- slope position (agricultural lands) on the basis of higher P buffering indices and standard P requirement.

Application of sewage sludge has been considered as an organic fertilizer in arid and semi-arid regions of Iran. This study was conducted to investigate cumulative and residual effects of sewage sludge on soil inorganic fractions and their relation to phosphorus (P) availability. Two levels of application (50 and 100 Mg ha-1) and three consecutive times of sewage sludge application (1, 3 and 5 years) with a control treatment were studied in a randomized complete block split plot design with three replications. Composite soil samples were collected from 0-30 depth at the end of 5th year of application. Increasing the rate and application year of sewage sludge enhanced dicalcium phosphate (Ca2-P), octacalcium phosphate (Ca8-P), apatite (Ca10-P), aluminum phosphate (Al-P), iron phosphate (Fe-P) and available P but decreased occluded P (OC-P). Residual effect of sewage sludge application resulted in increased inorganic fractions in blocks treated for 1 year compared to control. Positive correlations were observed between inorganic P fractions and Olsen P, wheat yield and P uptake (except OC-P). We concluded that inorganic P fractions and P availability increased in sewage sludge amended soil.

Rosemary (Rosmarinus officinalis L.) is one of the medicinal plants exhibiting potential for secondary metabolite production. In the present study, the interaction effects of zinc nutrition and salinity on growth of Rosemary, total phenolic content, DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP) were studied in a Zn deficient soil. Two zinc levels (0 and 10 mg kg-1 Zn as ZnSO4) and three salinity levels (0, 50 and 100 mM NaCl in irrigation water) were used as treatments in a factorial experiment based on completely randomized design with four replications. According to the results, salinity did not show significant effect on shoot dry weight production which indicates salinity tolerance of Rosemary. 100 mM NaCl salinity increased total phenolic content, DPPH radical scavenging activity and FRAP up to 3, 8 and 5 percent respectively. 10 mg Zn added to the soil also increased total phenolic content (2%), DPPH radical scavenging activity (4%) and FRAP (3%). The results of correlation test showed that increase of antioxidant activity in Rosemary grown under salinity condition was due to the increase of total phenolic content. Our findings suggest that salt stress and suitable Zn nutrition increase antioxidant compounds in Rosemary.