جستجوی مقالات مرتبط با کلیدواژه « خاک آهکی » در نشریات گروه « آب و خاک »

More than 60% of the country's soils have less than 1% organic matter. Due to the calcareous nature of most soils, nutrients are insoluble and therefor not absorbed by the plants. One of the effective solutions in this situation is the use of humic acid, because it is the active part of the organic resources and has a higher utilization efficiency than other organic fertilizers. This compound is extracted from various natural sources such as soil, compost, Leonardite (oxidized lignite), sediments, peat and different types of coal. In the present study, humic acid was first extracted from five organic sources (cow manure compost, urban waste compost, vermicompost, sheep manure and poultry manure). Then, added at 5 concentration levels (0, 0.25, 0.5 and 1 g of humic acid per kg of soil) to a calcareous soil under incubation condition (temperature of 25°C and field capacity moisture). After 70 days, forms of nitrogen, available phosphorus and potassium were determined. The highest and lowest amounts of nitrogen, phosphorus and potassium were observed in poultry manure and vermicompost, respectively. The effect of different types and concentrations of extracted humic acid on soil nitrate, ammonium, available phosphorus and potassium was significant at the probability level of 1% (P < 0.01). The highest value of nitrate was found at the level of 1 g kg-1 of humic acid of poultry manure (234.53 mg kg-1) which was about 10 times more than the control (23.97 mg kg-1). The highest value of ammonium at the level of 1 humic acid extracted from poultry manure (144.48 mg kg-1) was approximately 5 times more than the control (30.92 mg kg-1). The maximum value of available phosphorus in humic acid 1 g kg-1 of poultry manure (25.40 mg kg-1) was about 1.8 times more than the control (13.91 mg kg-1) and the highest value of available potassium at the level of 0.5 humic acid of sheep manure (472.47 mg kg-1) was approximately 1.2 times more than the control (394.69 mg kg-1). In general, results showed that with increasing the concentration levels of humic acids, the available forms of nutrients increased in the soil. The greatest effect on the availability of nutrients in the soil was observed in humic acid extracted from poultry manure at the level of 1 g kg-1 soil. In order to better analyzing and understanding the real effect of humic acid, it is better to measure the contents of nitrogen, phosphorus and potassium and other characteristics of humic acids in future studies.

The most soils of Khuzestan province are calcareous with different degrees of salinity, however, they play a significant role in the country agricultural production. One of the new methods to deal with environmental stresses is the use of plant growth stimulants. The aim of this study was to investigate the effect of application of growth stimulants on wheat yield components in saline soil, environmental and climatic conditions of Khuzestan province. Experiment was performed in three replications as randomized complete block design with soil salinity of 8 dS m-1 and water salinity of 3-4 dS m-1 under seven different treatments consisting of control, free amino acid, seaweed, seed treatment, humic acid, fulvic acid and combination in 2018 for two years. The use of seaweed, humic acid and amino acid caused a significant increase 30, 25 and 24 % of grain yield as compared to control treatment (p ≤0.05). The results of economic analysis showed a significant advantage of the humic acid application in increasing wheat yield (profit to cost ratio = 13.38). Application of plant growth stimulants on the macro and micro nutrients concentration in wheat leaves was not significant in almost all stages of plant growth compared to the control (p ≤0.05). In addition, the application of growth stimulants in calcareous soils of Khuzestan due to high soil buffering capacity did not have a significant effect on soil salinity, pH and sodium uptake ratio. Therefore, it is recommended that in wheat fields of Khuzestan province with saline and calcareous soils, in addition to basic fertilizers, humic acid be used as foliar application in two growth stages of tillering and booting to increase stress plant resistance and improve crop yield.

Microplastics (MPs) have been reported as emerging contaminants. There was little information about their effect and behavior on soil properties. This study aimed to investigate the changes in exchangeable concentrations (extracted with 1 M ammonium acetate) and water-soluble (ratio of 1 to 2.5 soil to water) of sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) elements under the presence of Low-Density Polyethylene MPs particles in the soil. The experiment was performed as a factorial experiment based on a completely randomized design with three replications. Experimental factors included the amount of MPs particles (zero, 1, 2, and 4% w/w) and incubation time (3, 17, 31, 45, 90, and 180 days). The results showed that MPs particles affected exchangeable and water-soluble elements. MPs particles reduced the exchangeable amounts of Na, K, and Ca. The largest decrease was related to the level of 4% MPs. Briefly. In the level of 4%, the amount of exchangeable Na, K, and Ca decreased by 7.2, 5.7 and 2.6 %, respectively, in comparison with control soil (without MPs). On the other hand, water-soluble K and Ca under the influence of MPs particles (4% MPs level) decreased by 6.97 and 8.4 % respectively, as compared with control. MPs particles reduced water-soluble Na in the first (3 days) to fourth (45 days) incubation periods. Also, MPs particles reduced the amount of exchangeable and water-soluble Mg, but it was not significant. In summary, the presence of MPs particles in the soil, especially in higher amounts (ex: 4%), can affect the availability of cationic elements such as Na, K, Ca, and Mg.

Phosphorus (P) is often lacking in calcareous soils. To investigate the effect of organic matter and elemental sulfur (S) on P availability and fractions in two calcareous soil with different textures (Clay ‌loam and Loamy sand) and total iron and aluminum concentrations, incubation studies were carried out for 12 weeks. This study was conducted in the soil science laboratory of Malayer University in 2019. The treatments include the simple treatment of sheep manure (organic matter=OM) (0, and 2 %), S (0, 0.25, and 0.5 %), and integrated treatment of OM and S in the presence of Thiobacillus bacteria. Every week, P concentration in control and treated soils was measured. At the end of incubation period, EC, pH, ECC percentage, gypsum percentage, and inorganic P fractions in control and treated soils were measured, too. At the end of the incubation period, EC and gypsum percentage increased in both treated soils. The presence of OM decreased the gypsum in soils and increased P concentration in the soils. In Clay loam soil treated with 0.25, and 0.5 percent of S, adding OM decreases the rate of P transformation, from 0.226 to 0.153 and from 0.168 to 0.154 mg kg-1 week-1, respectively and in Loamy sand soil caused an increase from 0.129 to 0.161 and from 0.125 to 0.184 mg kg-1 week-1, respectively. In both soils, simple and integrated treatments increased the dicalcium phosphate fraction and decreased the octacalcium phosphate fraction, and the apatite fraction decreased in integrated treatments. In Loamy ‌sand soil, simple and integrated treatments increased the aluminum phosphate fraction. The results showed that integrated treatment of OM with 0.25% of S in both soils increased the P availability, and despite the fixation of P in Loamy ‌sand soil, due to high total iron and aluminum content, OM increased the P availability in Loamy ‌sand soil.

Considering that most of the calcareous soils of Iran are deficient in one or more micronutrients, optimal nutrition of nutrients such as silicon under the influence of biological treatments can be highly effective in these conditions. Therefore, this study was conducted to investigate the effects of silicon and phosphate-soluble bacteria on the availability of micronutrients for wheat. We used a completely randomized design in three replications and treatments included 0, 150, 300, 600 mg/kg silicon from a source of silicic acid and three levels of bacteria (non-inoculation of bacteria, Bacillus and Pseudomonas). The study was conducted in the greenhouse of Soil and Water Research Institute. The results showed that the combined use of silicon and phosphate-solubilizing bacteria increased the uptake of manganese and iron compared to the control treatment. However, the antagonistic effect between nutrients reduced zinc uptake at higher levels of functional silicon. The effect of inoculation with Bacillus and Pseudomonas on the amount of zinc, manganese and iron uptake by wheat was superior to the control bacterium. On the other hand, application of silicon (600 mg silicon/kg soil with Pseudomonas bacteria) significantly increased the concentration of phosphorus in wheat to the optimum level. Since excessive use of phosphate fertilizer in calcareous soil reduces absorption of micro nutrients, the combined use of silicic acid and phosphate-soluble bacteria can be recommended as an effective method for increasing availability of micro nutrients in greenhouse conditions.

The use of organic waste in the form of biochar in order to ameliorate soil is a novel approach in the management of organic waste. In previous studies, researchers mostly focused on the amount of biochar that was added to the soil. However, the aim of this study was to investigate the characteristics of biochars prepared from different feedstock (wheat straw, vermicompost and apricot firewood) and the interaction effects of amounts and particle sizes of biochars on yield and water use efficiency (WUE) of winter wheat. In a factorial experiment with a randomized complete block design with three replications, the effects of these three biochars in the amount of 0.5% (R1), 1.5% (R2) and 3% (R3) with a particle size of ≤0.5 (S1), 0.5-1 (S2) and 1-2 (S3) mm were evaluated in two consecutive cropping years. The studied biochar were added to the soil only in the first year to a depth of 0-15 cm. A control plot was considered in each replication. The interactions of experimental factors (except interaction effect of year and biochar amount) on yield and WUE were significant. Comparison of average yield and WUE in each type of biochar showed that, in the first and second year, wheat straw biochar treatment of R3 S2 had the highest yield (5,200 kg ha-1 and 6664.3 kg ha-1, respectively) and WUE (1.6 kg m-3 and 2.1 kg m-3, respectively). In the first year, in vermicompost biochar treatments, the highest yield (4517.7 kg ha-1) and WUE (1.4 kg m-3) were observed in the R2 S3. In the same year, in apricot wood biochar, treatment R3 S3 had the highest yield (3871.7 kg ha-1) and WUE (1.2 kg m-3). In the second year, in vermicompost treatments, the highest yield (6615.7 kg ha-1) and WUE (2.04 kg m-3)  was observed in the R3 S2 and, in the same year, in apricot wood biochar treatments, the highest yield (5263.7 kg ha-1) and WUE (1.6 kg m-3) was observed in the R2 S3. The highest yield and WUE (in the two years) was observed in wheat straw biochar with the R3 S2. These results showed that in addition to the type of biochar, the interaction of the amount and size of biochar particles had a decisive effect on increasing the yield and water use efficiency of wheat.

Recently, biochar has been considered as a soil conditioner. In research, the effect of the type and amount of biochar on soil properties has been emphasized. This field study was conducted to investigate the combined effect of type, amount and size of biochar particles on the total porosity (TP), penetration resistance (PR), mean weight diameter of aggregates (MWD) in a sandy loam texture. Factorial experiment was performed as a randomized complete block design with three factors of type, amount and biochar particle size in three replications. Wheat straw, vermicompost and apricot firewood biochard were added to the soil in 0.5, 1.5 and 3% and particle sizes of 0.5, 0.5-1 and 1-2 mm. All three biochar increased TP significantly and decreased PR significantly compared to control. Biochar type had the largest contribution in TP and PR changes. The highest TP was obtained in the wheat straw biochar treatment with 3% and particle size of 1-2 mm. The greatest decrease in PR was observed in wheat straw biochar with a value of 3% and a particle size of 0.5-1 mm. Interaction of type, amount and size of biochar particles had the largest contribution to MWD change. The largest MWD (1.22 mm) was observed in wheat straw biochar with biochar amount of 0.5% and particle size of 0.5 mm. The results showed that the amount and size of biochar particles had different effects on soil properties depending on the type of biochar.

Low efficiency of phytoremediation process of some heavy metals in calcareous soils, due to low mobility of these elements, has led to a significant growth in research on the use of chelating agents and biostimulants to improve the efficiency of this process. In present study, the efficiency of cadmium (Cd) phytoremediation of Calendula officinalis L. was investigated in a Cd-spiked calcareous soil as affected by foliar and soil application of humic acid. For this purpose, in a greenhouse experiment, seedlings of C. officinalis were transferred to Cd-spiked soils (0, 50 and 100 mg kg-1) and treated separately by soil (soil drench) and foliar (spraying plant leaves) application of humic acid at different levels (0, 10, 20 M). The humic acid treatments were applied two weeks after transferring plant and eventually the various biochemical-physiological traits and phytoremediation indices of Cd in C. officinalis were measured at specific times. According to the results, in Cd-spiked soils, the C. officinalis had apparently a normal growth without any toxicity signs (chlorosis and necrosis symptoms), however with increasing the Cd levels, the dry weight biomass decreased and antioxidant enzymes activities (catalase, peroxidase, superoxide dismutase and ascorbate peroxidase) increased. Both foliar and soil humic acid application in Cd-spiked soils increased dry weight biomass, Cd concentration, and bioconcentration factor (BCF). Furthermore, the application of this organic substance, obviously moderated the Cd stress since the antioxidant enzymes activities reduced compared to the control. Based on the results, the obtained translocation factor (TF) and BCF values of Cd, which were >1, indicated that this plant is a Cd-hyperaccumulator, which could extract Cd via phytoextraction mechanism. Generally, among the studied treatments, the application of 20 M (especially soil drench application) had the best effect on increasing Cd phytoremediation efficiency in the studied soil.

The aim of this study was to investigate the chemical forms of Pb, Zn, Cd, and Cu in two concentrations and three pH values in a calcareous soil. Metals as nitrate salts were added at two levels of 1.0 and 10 mmol kg-1 for Pb and Zn and at two levels of 0.1 and 1 mmol kg-1 for Cu and Cd all at three levels of pH (6, 7 and 8). The soil to solution ratio (w/v) was 1 to 20. The soils were incubated at 30±1°C for 30 days. Chemical forms of metals in the soils were determined by Tessier method. The results showed that the distribution of native forms of Pb and Zn was independent of pH. With increasing pH values from 6 to 8, the residual form of Cu decreased, whereas its organic form increased. Regarding the limit of quantitation (LOQ) for the atomic absorption instrument, the native cadmium was not measurable. The effect of pH on metal distribution between different forms varied with respect to metal nature and its concentration. The oxide and organic forms were dominant in low concentration of Pb and the oxide and carbonate forms were dominant in high concentration of this metal. Moreover, the added Zn and Cu were mainly dominated in oxide and organic forms, respectively. The added Cd was accumulated in organic form at low concentration and accumulated in exchangeable form at high concentration.

Calcareous soils are described as soils containing quantities of calcium carbonate which have an enormously effect on the soil properties (physical, consisting of soil water relations and soil crusting, or chemical consisting of the availability of plant nutrients) and plant growth. Calcareous soils arise clearly in arid and semi-arid areas due to rare precipitation and little leaching. It has been evaluated that these soils contain over one-third of the world's surface zone and their CaCO3 content ranged from a few to 95%. Calcareous soils faced many challenges such as shortage of organic matter, low structure stability, low water holding capacity, low CEC, high pH, surface crusting and cracking and great infiltration rate which cause loss of essential plant nutrients via leaching or deep percolation. Another problem in calcareous soils is low availability of plant nutrients particularly phosphorous and micronutrients specially zinc, iron and manganese, and a nutritional imbalance between elements such as potassium, magnesium and calcium. Although a calcareous soil is dominated by free lime, it could also incorporate large quantities of iron, aluminum, and manganese. These metals provide more strong sorption sites for phosphorus and are mostly more significant in controlling phosphorus solubility in calcareous soils than calcium carbonate itself. Under such severe conditions, desired yield levels are difficult to attain. Calcareous soils lack the organic matter required for optimal crop yield. Therefore, numerous studies have made efforts to increase the availability of nutrients in the soils through different treatments. Common methods for dealing with these deficiencies, is the use of chemical fertilizers that have the risk of environmental pollution in addition to the high cost and low efficiency. Oxidation of sulfur leads to sulfuric acid formation which can decrease the soil pH and increase dissolution of insoluble soil minerals and release of essential plant nutrients. Furthermore, the addition of organic amendments improves the soil chemical and physical properties, initiates nutrient cycling, and provides a functioning environment for vegetation. The objective of this research was to increase solubility of nutrient elements in a calcareous soil considering nine treatments (i.e., control (Blank), Soil + Humic Acid (HA), Soil + Sulfuric Acid (H2SO4 ), Soil + Thiobacillus (T), Soil + Sulphur (Sº), Soil + Sulphur + Thiobacillus (Sº +T), Soil + Vermicompost (VC), Soil + Vermicompost + Thiobacillus (VC+T) and Soil + Sulphur + Vermicompost + Thiobacillus (Sº +VC+T)). The experimental design was factorial arrangement in randomized complete block, with all the treatments replicated three times. All the treatments were incubated under the laboratory condition for 90 days in 25 ± 2 °C and 70% of water holding capacity by distilled water. During the incubation period, the moisture of the samples was kept at 70% FC by daily addition of deionized water based on weight loss. At the end of incubation period the pH value, electrical conductivity (EC), available form of macro elements (K, P and N) and micro elements (Zn, Mn, Fe and Cu) were determined in all treatments by standard methods. The results showed that, the soil pH value significantly decreased in Sº+T and Sº+VC+T treatments, in compared to the blank. While, the EC of these treatments significantly increased with respect to the blank. The results also showed that most of the treatments have been able to increase the solubility of the nutrients. However, the effect of Sº +VC+T treatment on increasing the availability of studied soil nutrients and decreasing pH value was more significant than the other treatments. Analysis of  the results obtained from this study using classical statistic methods showed that applying a single treatment cannot remove all obstacles to increase nutrient availability in calcareous soils. This may be attributed to high buffering capacity of calcareous soils and complexity of factors which control mineral solubility and nutrient availability. While, treatments that simultaneously provide soil organic matter and lower pH (such as Sº+VC+T) can significantly remove barriers to increase nutrient uptake in these soils. As a result, the simultaneous application of organic fertilizers, elemental sulfur and Thiobacillus bacteria can be a promising approach to increase the solubility of nutrients in calcareous soils and to increase the quantitative and qualitative growth of plants in these soils.

Despite the abundance of iron in the earth's crust and soil, this nutrient is not usually available for plants in calcareous soil with high pH. In the present study four superior isolates with alternative physiological traits (No. 3, 8, 20 and 23) isolated from 10 soil samples for producing siderophore and their contribution in solubilizing insoluble iron-containing compounds in calcareous soil were evaluated. Results showed that in spite of higher halo diameter to colony diameter of isolate No. 23 in CAS agar medium (3.46mm) at soil incubation test, DTPA-extractable iron using isolates No. 3 and 20 was greater than the ones in isolate No. 23 as 10.7 and 14.67 percent, respectively. Greatest amount of DTPA-extractable iron in the soil sample was obtained during 40-days incubation. Molecular test showed that isolate 20 was 99 percent similar to the strain Bacillus Sporothernodurans. Biochemical tests also revealed that isolate 8 probably belong to Entrobacteriaceae family and isolates 3 and 23 belong to Pseudomonas Genus.

Nowadays, the heavy metal pollution caused by the landfill leachate becomes very serious because of their potential to impact on human health through the food chain. In this study, the effect of landfill leachate on the accumulation and selected indices of soil pollution to heavy metals (Zn, Cu, Cd, Pb, Ni, Mn) including contamination factor (CF), modified degree of contamination (mCd), and modified pollution index (MPI) were investigated in four different soil sites. Results indicated that soils were significantly enriched by the metals in the sequence of Zn> Cd> Ni> Cd> Cu> Mn. However, only the Cd contents exceeded the standard levels based on national and international references. Considering CF, Cd and Zn showed a high pollution class (3≤ CF< 6) in the majority of soil sites and other metals (Cu, Pb, Ni, and Mn) categorized as moderate pollution (1≤ CF< 3). Except site 1, the values of MPI were found to be moderate contamination (3<MPI <5) in the examined soils and its highest value observed in site 2.  The mean mCd content, appeared the moderate pollution class (2≤ mCd< 4), were in order of P2> P3 > P4> P1 in different soil site under the influence of leachate probably due to the quantity and quality of the leachate. Overall, the finding of the study can provide a valuable benchmark for the design of appropriate strategies and management of those agroecosystems by both local and national managers.

In recent decades, soil pollution with heavy metals in world countries (such as Iran) has been one of the most challenging issues. Stabilization of heavy metals by using absorbent in remediation of heavy-metal-contaminated soils is one of the low-cost and fastest methods. In order to study the effect of diatomite on chemical forms of Cd in calcareous soils, a factorial experiment was conducted in a completely randomized design (CRD) with 3 levels of diatomite application in soil (0, 2 and 5 %), 4 levels of incubation time (1, 2, 4 and 8 weeks) and twocontaminated soils in three replications. Chemical distribution of Cd in soils were determined using Tessier sequential extraction method at the above-mentioned incubation time and reduced partition index (IR) and mobility factor (MF) of metal were calculated as a Cd mobility index in soils. Results showed that application of diatomite significantly (p ≤ 0.01) decreased the exchangeable and carbonate fractions and increased iron and manganese oxide bound organic and residual fractions in comparison to the control treatment. In 5% diatomite treatment after 8 weeks’ incubation the IR (42-71%) and pH (5-8%) values increased but the amounts of MF (30-33%) and DTPA-extractable Cd (33-28%) decreased, demonstrating a decrease in the mobility of metal in soils. It was concluded that addition of diatomite in soil lead decreasing the mobility of Cd and Pb in soils. According to the results, diatomite due to greater efficiency for immobilization of Cd in contaminated soils as a low-cost amendment can be used for immobilization of the high amount of Cd ions from contaminated soils.

Powder sulfur is the most common used substance for improvement of calcareous soils particularly their pH while its efficiency in the soil is highly depend on its oxidation condition. The Objective of this research is to evaluate the efficiency of various amounts of sulfur to improve calcareous soils in presence of sulfur-oxidizer bacteria. Hence, 15 soil columns containing a calcareous soil including four sulfur treatments labeled S(0.125), S(0.250), S(0.375) and S(0.500) and a control treatment with lack of sulfur, each with three replications were manufactured and inoculated using Thiobacillus thioparus and then brought under leaching once a two weeks for six months. The results showed that the leakage of sulfate caused by sulfur oxidation was intensified for the temperatures above 25°C and reached a maximum in 30°C. Moreover, statistical analysis among sulfur treated columns approved presence of positive significant relationships between temperature and sulfate leakage (α= 0.01) from one hand, and negative significant relationships between temperature and pH (α= 0.01) on the other hand.

The presence of heavy metals in water and soil are major concern for the environment due to their toxicity to many life forms. Stabilization of heavy metals in remediation of contaminated soils is one of the cost-effectiveness and rapid implementation method. In order to study the effect of diatomite on chemical forms of Lead in calcareous soils, a factorial experiment was conducted in a completely randomized design (CRD) with three levels of diatomite application in soil (0, 2 and 5 % by weight), four levels of incubation time (1, 2, 4 and 8 weeks) and in twocontaminated soils with three replications. Chemical distribution of Lead in soils were determined using Tessier sequential extraction method during the mentioned incubation times and reduced partition index (IR) and mobility factor (MF) of the metals were calculated as a Lead mobility indices in the soils. The obtained results showed that the application of diatomite significantly (p ≤ 0.01) decreases the lead in the exchangeable and carbonate fractions and increases it in the iron and manganese oxide, organic and residual bond fractions significantly in comparison to the control treatment. The IR and pH values increased but MF and DTPA-extractable Lead values decreased with increasing diatomite level and incubation time which demonstrates a decrease in the mobility of lead in the soils. Lead mobility reduction in the clay loam soil compared to the one in the sandy loam soil was probably due to higher content of clay and lower content of Calcium Carbonate Equilibrium.  Generally, itcan be concluded that the addition of diatomite into the soil especially with high levels (5%) reduces the bioavailability and mobility of the Lead in the soil.

  Iron deficiency is one of the most common problems in the plant nutrition in arid and semi-arid regions soil, especially calcareous soil. Since iron oxides account for about 53. 8% of the slag, it can be used as a fertilizer. The use of copper slag of Sarcheshmeh Copper Complex sub-products was evaluated with organic compounds as the source of iron supply in calcareous soil. The purpose of this study was to study the effect of copper slag and organic compounds on the amount of extractable iron by DTPA and some characteristics of calcareous soil. In order to investigate the effect of slag on soil absorbable iron, an incubation test was performed for 3 months as a factorial experiment in a completely randomized design with three replications. The experimental factors consisted of 5 levels of organic matter (pistachio shell, cow manure 2 and 4% w / w and control sample) and 10 iron levels (copper slag, copper slag with sulfur, copper slag with sulfur and Thiobacillus, acid slag (each at two levels), Chelate Sequestrene and control sample). 10, 30, 60 and 90 days after incubation, changes in parameters such as pH, EC and iron content were measured by DTPA-TEA extractor. The results showed that by applying the organic compounds' treatments during the incubation time reduced the iron extraction capability. The results showed that during the three-month incubation period, slag treatments increased soil EC. The highest amount of EC increase in slag treatment is 4 times the recommended value of the soil test based on the absorbable iron content of this compound with sulfur and Thiobacillus S4S°T at 2. 21 dS / m at the end of the incubation period. In the soil sample studied, proportional to the amount of slag, the amount of iron extracted by DTPA increased. However, during the incubation period, the iron extraction capability was reduced; however, the amount of iron increased significantly after 90 days from the beginning of incubation in S4S°T and S4S°، S4 treatments compared with the control. The interaction effect of slag treatments and organic compounds showed that the highest amount of EC and the lowest pH were related to 4% cow manure application with slag with sulfur and Thiobacillus. Meanwhile, the amount of absorbable iron in the soil from 1. 43 mg / kg in the control treatment of CS° reached 8. 17 mg / kg in the treatment of 4% pistachio shell as 4 times of the recommended value of the soil test with sulfur and Thiobacillus (P4S4S°T). Organic compounds during the incubation period led to a reduction in iron compared to the control sample. Slag of copper smelting has nutrient micro-elements, including iron, so that at high levels of slag consumption, the amount of iron increased, as well as the use of slag with sulfur, Thiobacillus and pistachio shell had the most amount of absorbable iron As a result, slag has the potential to be used as an iron source for plants

Nickel (Ni) is an element that has recently been added to the list of essential micronutrients of plants. On the other hand, accumulation of Ni in soils and plants has increased concerns about humans and other living organisms for toxicity of Ni. To study the effect of Ni and iron (Fe) on the growth characteristics of corn (Zea maysL.) plant in the soil a factorial experiment on the basis of randomized complete blocks design with three replications was carried out under greenhouse condition in a calcareous soil. The factors included the concentration of the applied Ni at four levels (0, 10, 50 and 100 mg Ni kg-1 soil) as pure nickel sulfate (NiSO4.6H2O) source and Fe at five levels of 0, 10 and 20 mg Fe kg-1 soil, as iron sulfate (FeSO4.7 H2O) and commercial Fe sequestrene (FeEDDHA). According to the results, at the applied levels of 50 and 100 mg Ni kg-1 soil, the shoot dry weight was decreased by 21.1 and 31.9%, and the relevant decrease of root dry weight was 30.8 and 28.5% respectively, as compared to the control. Stem height was decreased by 2.1% in the presence of 100 mg Ni kg-1 soil, as compared to the control. Chlorophyll index was decreased by 32.4 and 40.5% in levels of 50 and 100 mg Ni kg-1 soil, respectively, as compared to the control. Increasing Fe levels of the two applied Fe sources significantly increased the shoot dry weight. But the shoot dry weight was decreased by 81.9 and 29% at 20 mg Fe level of Fe-EDDHA, as Ni was increased from the levels of 10 to 50 mg and from 50 to100 mg, respectively.

In calcareous soils of Iran, using fertilizers that reduce soil pH over long periods are prioritized. Reducing pH in calcareous soils increases the concentration of essential nutrients such as phosphorus, iron, zinc, copper and manganese in the soil solution. The use of organic and inorganic acids in calcareous soils may also have other advantages in addition to gradually decreasing the soil solution pH. The effect of organic and minerals acids on plant growth and uptake of essential nutrients has not been studied. The aim of this study was to evaluate the effect of organic acids like acetic, citric and oxalic acid and mineral acids like sulfuric on the growth of forage corn.

The experiment was based on randomized complete block design and carried out in pots in a greenhouse. A calcareous soil with electrical conductivity of 0.86 dS m-1 and organic matter of 4.3 g kg-1 was collected from research farm of University of Zanjan. Treatments were T1 & T2: citric acid with concentration of 5 and 10 mM (C5 & C10), T3 & T4: acetic acid at a concentration of 5 and 10 mM (A5 & A10), T5 & T6: oxalic acid at a concentration of 5 and 10 mM (O5 & O10), T7: mixture of citric, acetic and oxalic acid each at a concentration of 3.33 mM (mix):, T8: sulfuric acid at a concentration of 5 mM (S), and T9: control. Treatments were applied in three stages: immediately after sowing, four-leaf and eight-leaf stages. Irrigation of pots was done with water with EC value of 400 μS /cm. Considering the possible effect of acids on increasing the availability of phosphorus, potassium, iron, zinc, copper and manganese, fertilization was done only based on nitrogen demand and 0.55 g urea was added to each pot (equivalent to 200 kg ha-1) with irrigation water in three steps. The shoots of plant samples were harvested after 50 days and the roots were carefully removed from the soil. Some growth related characteristics such as stem height, fresh weight, dry weight, and moisture content of vegetable tissue were also measured. Concentration of nitrogen, potassium, phosphorous, iron, zinc, manganese and copper in roots and shoots was measured. Translocation factor (TF) indicating the transfer rate of the elements from root to shoot was obtained by dividing the concentration of the element in the shoot by that in the root.

The results showed the significant effects of the treatments on the growth factor (fresh weight, dry weight and plant height). The percentage of moisture content was the same in all treatments. Citric acid treatment (T2) significantly increased fresh weight of shoot (18.3 percent) and dry weight (20.9 percent) of the plant. Organic acids also increased the concentration of nitrogen in shoots and roots. The concentration of nitrogen in the shoots was roughly twice as compared with that in the plant root. As for the potassium treatments, except for A10 treatment (T4) (the lowest concentration), other treatments did not show a significant difference with control. The highest concentration of potassium in roots was observed in sulfuric acid treatment (T8). The highest translocation factor of potassium (3.34) was observed in O10 treatment (T6). The results indicated a positive effect of 5 mM citric acid, acetic acid, mix treatment and sulfuric acid on shoot phosphorus and the positive effect of acetic acid and mix treatment on the phosphorus root. Citric acid treatments (T1 and T2) were the most effective treatments in increasing the concentration of iron (289 mg kg-1) in shoots. For roots, C10 treatment (T2) and Mix treatment (T7) showed the highest iron concentration. The highest TF for iron was observed in A10 treatment (T4). Acetic acid treatments (both concentrations), and sulfuric acid were more effective than other treatments and significantly increased the manganese concentration of the shoots. Sulfuric acid also caused a significant increase in the manganese concentration of the root. Acetic acid treatment (T5) showed the highest amount of TF for manganese. The amount of zinc element in shoots and roots was significantly affected by the mix treatment (T7). There was no significant difference between all Cu treatments.

In general, application of citric acid in both concentrations is useful to increase the biological yield and product quantity in maize farms. These treatments increased fresh and dry weight of shoots and roots. Acetic acid seems to improve translocation of elements in plants. The use of other acids is likely to enhance concentration of nutritional elements in roots and shoots.

Investigating the status of nutrients in calcareous soils shows that despite the abundance of some nutrients (such as phosphorus, iron, and zinc) in these soils, the available form of these nutrients is less than the amount required for plant growth, and the deficiency of nutrients is one of limiting factor in the production of plants especially wheat in these soils. Sulfur application and soil inoculation with Thiobacillus bacteria may improve the availability of nutrients in calcareous soils and consequently increase the plants growth. The purpose of this research was investigating the effect of sulfur application and Thiobacillus bacteria on the yield and nutrient uptake of wheat at different levels of phosphorus in a calcareous soil and in field conditions.
Material and In 2011 a factorial experiment arranged in a complete randomize block design consisting of three levels of sulfur along with Thiobacillus bacteria (without sulfur and Thiobacillus (S0T0), application of 500 Kg S 10 Kg Thiobacillus (S500T10), 1000 Kg S 20 Kg Thiobacillus (S1000T20) and 2000 Kg S 40 Kg Thiobacillus (S2000T40) per hectare) and three levels of triple super phosphate (without phosphorus (P0), 65 (P65%) and 100 (P100%) percent phosphorus recommended based on soil test) with three replication in field conditions. The leaf samples were collected before pollination and the content of phosphorus; zinc and iron were measured in them. After harvest, the yield components such as grain and straw yield, panicle length and 1000 seed weight in each treatment were determined. Then, from each plot, five kilograms of soil was taken from 0 to 15 cm depth and after dried out and sifted with a two-millimeter sieve, the concentration of phosphorus, zinc and iron of soil was determined in them.
With the application of sulfur along with Thiobacillus bacteria, the yield components and uptake of iron, zinc and phosphorus of wheat leaf increased compared to the control treatment, although the grain yield, straw yield and uptake of iron between the different levels of sulfur along with Thiobacillus bacteria showed a no significant difference. Using of phosphorus significantly increased the grain yield, straw yield, 1000 grain weight and uptake of iron and phosphorus of wheat leaf, but no significant difference was observed between treatments 65 (P65%) and 100 (P100%) percent phosphorus recommended based on soil test. In conditions of without phosphorus (P0), with consumption of 1000 kg ha-1 sulfur along with 20 kg ha-1 of Thiobacillus (S1000T20), grain yield, straw yield and panicle length increased compared with the control (124, 123 and 31% respectively), but with increasing levels of sulfur and bacteria, a decrease was observed in these parameters. The highest uptake of leaf iron and phosphorus were showed in combined treatments S1000T20 P100% and S2000T20 P65%, respectively. With the increase of sulfur along with Thiobacillus bacteria, Zn concentration and pH of soil decreased and the lowest values of these characteristics were observed at the highest levels of sulfur and bacteria. At all levels of phosphorus application, the consumption of 500 kg ha-1 sulfur along with 10 kg ha-1 Thiobacillus bacteria (S500T10) increased the phosphorus concentration in soil and highest contents of it was were obtained of combined treatments S500T10 P65% (31% more than S0T0 P0 treatment).
In conditions of without Sulfur and Thiobacillus bacteria (S0P0), consumption of 65 percent (P65%) phosphorus recommended based on soil test is appropriate for optimum yield for wheat. Consumption of 1000 kg ha-1 sulfur along with 20 kg ha-1 of Thiobacillus (S1000T20) in conditions of without phosphorus (P0), are recommended for use in agriculture and wheat yield increase.