فهرست مطالب علی خانمیرزایی

The main objective of this study was to develop machine learning models for predicting soil organic carbon (SOC) content in agricultural soils enriched with calcium-rich materials in the central region of Iran. Soil samples were collected from 336 points in agricultural lands with two land uses, namely cropland and orchard, from Alborz Province. The soil organic carbon was measured using the Walkley-Black oxidation method. Remote sensing data, obtained from various sources such as Landsat 8 imagery and MODIS sensor, were utilized for soil organic carbon analysis. Three machine learning models, including Artificial Neural Networks (ANN), Support Vector Regression (SVR), and Gene Expression Programming (GEP), were employed in this study to estimate the soil organic carbon content. The results of this research demonstrated positive outcomes, indicating that the simultaneous use of Landsat 8 imagery and MODIS sensor data through the SVR model yielded better performance (R2 = 0.62, RMSE = 0.63, R2/RMSE = 0.98) compared to the use of each image separately. Therefore, this study concluded that the simultaneous synergy of remote sensing data from different sources (referred to as data synergy) can significantly improve the accuracy of predicting soil organic carbon content in calcium-enriched agricultural soils in the central region of Iran. It is recommended to use advanced fusion techniques and deep learning methods for combining features at a higher level.

The behavior of heavy metals in the soil as one of the environmental challenges has attracted the attention of many researchers. The present study was conducted to evaluate the phosphorus solubilizing bacteria on remobilization of cadmium (Cd) and lead (Pb) in two calcareous soils.

Phosphorus, cadmium and lead in the forms of KH2PO4, Cd(NO3)2 and Pb(NO3)2 simultaneously were introduced to the soils to promote the formation of phosphate minerals of added metals in two selected soils. Ater two months the soils were inoculated with two Pseudomonas species and incubated for 3 months. Sequential extraction scheme were applied to determine the chemical forms of Cd and Pb 5, 25, 60 and 90 days after incubation.

The results showed that application of phosphorus solubilizing bacteria changed chemical forms of Cd and Pb. Inoculation with Pseudomonas decreased the soluble and exchangeable cadmium while increased organic matter-bound Cd concentration. Inoculation by Pseudomonas increased carbonate-bound Pb and decreased Fe-Mn oxide and organic matter bound Pb. In the other hand, phosphate solubilizing bacteria (Pseudomonas) decreased mobility and bio-availability of cadmium and immobilization of lead.

In fact, the behavior of heavy metals in the presence of phosphorus solubilizing bacteria was different and depends on the type of metal and soil properties. In present study, bacteria cause immobilization of cadmium and remobilization of lead.

Recent researches have proven the effect of salinity of water and soil resources on the bioavailability of cadmium.In this study, the effect of different sources of salinity including sodium chloride, sodium sulfate and calcium chloride on cadmium transport in two different soils was investigated.Soil columns with a height and inner diameter of 50 and 10 cm, respectively, were subjected to leaching of cadmium solution at a concentration of 100 mg/L along with various salts of sodium chloride, sodium sulfate and calcium chloride at a concentration of 100 me/L for 10 days. The drained solutions were analyzed at three depths of 3, 7 and 50 cm. The simulation of cadmium chemical species in the soil solution was performed using Visual MINTEQ 3.The presence of salinity along with cadmium solution caused more transport and drain of cadmium than the control soil. The highest cadmium concentration drained from the columns was belonged to the soils which received calcium chloride with the mean of 19.6 mg/L whereas the lowest was determined in soil received sodium sulfate with the mean of 6.1 mg/L. Due to the formation of chloro-cadmium complexes, treatments containing chloride had a more obvious effect on the transport of cadmium in the soil columns. The simulation of cadmium speciation in solution containing chloride showed that CdCl+ and CdCl2(aq) account for more than 80% of the cadmium species, while in those containing sodium sulfate, this dominant mainly included two species of Cd(SO4)2- 2 and Cd(SO4)(aq). Generally, salinity conditions affected by chloride ions in cadmium polluted lands can increase the potential of this toxic metal entering water sources and food chain.

Environmental stresses such as drought, temperature, heavy metals and salinity greatly reduce plant growth and development, among non-biological stresses, drought stress is one of the environmental factors which limits crop production and reduces average yield by 50% or more (Wang et al.,2 003). Heavy metals are another environmental stress that in recent years as it has become one of the biggest problems of the agricultural sector. Due to technical and economic limitations of heavy metal removal methods, the search for new methods has received a great deal of attention and in this regard biological absorption as a new method has received special attention(Maleki and Zarasvand, 2008).

In order to Evolution Ability of Remediation Heavy Metal Cadmium by Some of Plant Species and Biochar in drought stress conditions experimental in years 2017-2018 was carried out for two years in the research farm of the Faculty of Agriculture, Islamic Azad University, Karaj Branch. The experiment was factorial in a completely randomized design with 3 replications. Experimental factors included cadmium chloride salt at four levels (control, 10 mg.kg-1, 20 mg.kg-1, 30 mg.kg-1), Biochar at three levels (control, biochar at the time of first year planting, biochar after first year harvest and at the time of second year planting), 3 crop species (clover, alfalfa, canola) and drought stress (control, 40% available moisture discharge based on gypsum block, 60% available moisture discharge based on gypsum block). One month before planting the soil was contaminated with cadmium chloride at specific levels in the experiment then biochar treatment was added to the soil of the desired pots. After cultivating crops and sufficient vegetative growth shoot and root specimens were carefully removed from the soil of the pots and after washing and drying according to the protocol in this experiment extracts were taken for reading in an atomic absorption apparatus. For analyze the measured data, Mean and Bartlett comparison were performed using MSTATC, SAS and Excel software.

The results of analysis of variance showed that Triple interactions of cadmium, crop species, drought stress for all studied traits(Dry weight of shoots, dry weight of roots, amount of cadmium in shoots, amount of cadmium in roots, measurement of metal element, accumulation coefficient, extraction coefficient) It became significant with a one percent error probability. The results also showed that the triple interactions of cadmium, crop species, biochar only for traits Translocation factor, Accumulation factor, Enrichment cofficient became significant with a probability level of one percent. And for other traits, this triple interaction was not significant. The results of mean comparison showed that the highest mean amount of cadmium in the shoot(2.68 mg.kg-1) And roots(1.78 mg.kg-1) Related to canola treatment at the level of 30 ppm cadmium And under drought stress conditions, 60% of available moisture discharge was based on gypsum block. Most average Translocation factor related to the triple interactions of cadmium, crop species, biochar related to treatment Canola cadmium at the level of 20 ppm and biochar at the time of crop cultivation in the first year(a3b3c2) with average (3.73) and the lowest was related to cadmium control treatments (a1b1c1) with mean (0.1). The most common triple interactions of cadmium, crop species, drought stress are also related treatment of cadmium Canola at 20 ppm level without drought stress (a3b3d1) (3.98) and the lowest mean was related to cadmium control treatment (a1b1d1) with mean (0.1). Most average Accumulation factor corresponding to the triple interactions of cadmium, crop species, biochar related to the treatment of cadmium Canola at the level of 30 ppm and biochar at the time of crop cultivation in the first year(a4b3c2) with average (70.137) and the lowest was related to cadmium control treatments (a1b1c1) with mean (0.0044). Most of the triple interactions of cadmium, crop species, drought stress also related to cadmium Canola treatment at 20 ppm level without drought stress (a3b3d1) (148.87) and the lowest mean was related to cadmium control treatment (a1b1d1) with mean (0.0043). The highest mean of triple interactions of cadmium, crop species, biochar for Enrichment cofficient related to the treatment of cadmium Canola at the level of 30 ppm and without biochar in the first year (a4b3c1) with a mean (0.182) and the lowest was related to cadmium control treatments (a1b1c1) with mean (0.0117).

Most of the triple interactions of cadmium, crop species, drought stress are also related Treatment of cadmium Canola at 30 ppm level and drought stress 60% available moisture discharge based on gypsum block (a4b3d3) (0.180) the lowest mean was related to cadmium control treatment (a1b1d1) with mean (0.0011). The results of this study showed that Canola had a higher uptake and transport of cadmium metal than clover and alfalfa.

The presence of abundant calcium carbonate and alkaline soil reaction in most of the country's soils has reduced the bioavailability of some elements for plants. The application of some soil amendments such as sulfur and organic matter can improve the nutrient status of the soil. For this purpose, a factorial experiment was conducted in a randomized complete block design with 18 treatments and 3 replications on the underground soil of walnut trees. The experimental factors included Thiobacillus at two levels (without inoculation and with inoculation), sulfur (S) at three levels (0, 1000 and 2000 kg. ha-1 ) and organic matter (OM) at three levels (0, 5 and 10 T. ha-1 ). The results showed that S treatment significantly affects soil pH (p <0.01), P (p <0.05) and iron (Fe) concentration on soils beneath the tree covers (p <0.05). The highest P concentration (9.06 mg / kg) and available Fe (6.34 mg / kg) was observed in the treatment of 2000 kg. ha-1 of sulfur. Organic matter treatment significantly has changed the soil pH (p <0.01), available Zn (p <0.01) and plant available P and Fe concentration in soils beneath the tree covers. As the level of applied OM increased, the soil pH decreased. The highest concentration of available P, Fe and Zn was observed in the treatment of 10 tons per hectare of OM. Inoculation with Thiobacillus bacteria decreased the soil pH and increased soil available P concentration. According to the results, the simultaneous application of S, Thiobacillus and OM can increase the phytoavailability of P, Fe and Zn in soils beneath the walnut trees.

Environmental implications of cotinious application of chemical fertilizers, while ongoing demands for healthy products has made the attentions to the sustainable agriculture. Integrated soil nutrient management inclouding part replacement of chemical fertilizers by biofertilizers is among the sustainable agriculture nesseserities in recent years. Varius biofertilizers aleady are producing or importing into Iran's market. This study was conducted to evaluate the efficiency of some biofertilizers with brand names Multifunctional, Bioumik, Fulzyme plus, Nitrokara, Golden Nitrokara and Inoculum on morphological characteristics and concentration of nitrogen (N), phosphorous (P) and potassium (K) of peppermint plant. A greenhouse experiment was conducted with five replications. Four plants was grown in pots containing 5 kg soil treated with 2% w/w solution of biofertilizers, two times during growing period. Results showed that biofertilizers had significant effect on the number of leaves and stems, root fresh weight, as well as shoot P and root and shoot N. The highest effect on root and shoot N (1.49 and 2.26%) and shoot P (1.18%) were related to Bioumik and Nitrokara, respectively. Nitrokara efficiently resulted in increased shoot P, which was significantly higher than the other treatments. According to the results among biofertilizers best N nutrition and number of leaves was with Bioumik while lowest shoot P was observed in this treatment.

To investigate simultaneous effects of Thiobacillus bacteria, sulfur, and organic fertilizer treatments on chemical forms and quantity of phosphorus absorption by corn, an experiment was conducted based on completely randomized design using eight treatments and three replications in a greenhouse located in Hashtgerd, in 2014. Treatments included control, Thiobacillus, sulfur, organic fertilizer, and two ways and three ways combinations of these factors. Results showed  that the highest and lowest yield, root dry weight, root fresh weight, shoot weight, and phosphorus uptake were obtained in the Thiobacillus + sulfur +organic fertilizer treatment and control treatment (without any added Thiobacillus, sufur, and organic fertilizer), respectively. Thiobacillus + sulfur +organic fertilizer treatment caused significant change in inorganic and organic phosphorus elements and enhanced available phosphorus in soil, so that the highest available phosphorus was related to the treatment number eight with 16.22 mg/kg soil and this treatment showed four more mg of available phosphorus compared with control treatment. On the other hand, the Thiobacillus +sulfur treatment resulted in more reduction in mineral forms of phosphorus including dicalcium phosphate and apatite joint phosphorus compared with other treatments. The most organic and total phosphorus in soil was observed in sulfur + organic phosphorus and Thiobacillus + organic phosphorus treatment, respectively. Taken together, results of this study showed that using Thiobacillus bacteria along with sulfur and organic fertilizer would result in enhanced phosphorus uptake and improved phosphorus status in the plant, which would cause more reduction in chemical fertilizers in extensive scale.

Twenty two soil samples with various chemical and physical properties were collected from different sites of Khuzestan province and chemical forms of soil cadmium (Cd) were determined using a sequential extraction technique. A greenhouse study was conducted to evaluate the relationships between the chemical forms of cadmium and its availability for wheat plant. The results showed a positive correlation between soil DTPA-extractable Cd and electrical conductivity (EC) in the studied soils (r = 0. 65، p < 0. 01). The soluble+exchangeable form was lowest (5. 1%) and the carbonate fraction was the highest (40%) cadmium fraction in these soils. Soluble+exchangeable fraction was positively correlated with soil DTPA-extractable Cd and electrical conductivity. Carbonate fraction showed a significant correlation between clay and active carbonate calcium content in the studied soils. The results also showed that cadmium concentration in wheat grain was not correlated with any soil physico-chemical properties as well as soil Cd fractions. Although comparing the results for soil total Cd with those reported as contamination threshold revealed that more than fifty percent of the studied soils were Cd contaminated، only 3. 1% of the grain samples exceeded maximum permissible Cd concentration suggesting total Cd concentration is not an appropriate index for Cd uptake from soil.