a. golchin

Soil texture is one of the most influential characteristics that affects the decomposition and retention of soil organic matter, as it directly or indirectly impacts the soil's physical, chemical, and biological properties. Soil clays play an important role in soil organic matter stability. Organic matter adsorbed on phyllosilicate clays is more resistant to microbial decomposition than organic matter that has not interacted with any mineral. Exchangeable cations through the influence of physical and chemical characteristics of the soil probably cause changes in the absorption and retention of organic matter. In previous studies, the effect of soil texture on organic matter retention has been investigated, but the impact of clay type and exchange cation has not been investigated. This study aimed to examine the effect of different contents of vermiculite and zeolite clays and exchange cations on the mineralization of organic nitrogen.

A factorial experiment was conducted in a completely randomized design with three replications to study the effect of the type and content of clay and the type of exchange cations on organic nitrogen dynamics. Experimental treatments include two types of clay (vermiculite and zeolite), four different levels of clay (0, 15, 30, and 45%), and three types of exchangeable cations (Na+, Ca2+, and Al3+). The experiment included 24 treatments and three replications. There were total of 72 experimental units. Artificial soil of 50 grams was prepared separately according to the amount and type of clay and the type of exchange cation. "Next, alfalfa plant residues were added to all samples at a rate of 5% w/w. After inoculating and air-drying the samples, the moisture content was adjusted to 60% of the field capacity (FC) using distilled water. To prevent excess water from affecting the final moisture readings, the samples were first air-dried, and then sufficient distilled water was added to each sample to achieve 60% of FC. The samples were then kept in the dark for 60 days at a temperature of 23 °C. Distilled water was added and sealed to the bottom of the incubation jars to keep the moisture content of the soil samples constant during incubation. The percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were determined in the prepared samples. The data were analyzed using ANOVA, and the means were compared using Duncan's Multiple Range Test (DMRT). Before applying ANOVA, the data's normality and variance homogeneity were checked using Kolmogorov- Smirnov and Levene tests, respectively. The SPSS software (Windows version 25.0, SPSS Inc., Chicago, USA) and SAS software (version 9.4, SAS Institute Inc., Cary, NC) were employed for data analysis.

The results of variance analysis of the data showed that the effect of the type and content of clay and the type of exchangeable cation on the percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were significant (p< 0.01). The results revealed that, regardless of the duration of the samples, with the increase in the amount of clay, the percentage of inorganic nitrogen and the activity of enzymes decreased, but the nitrogen of microbial biomass increased. The highest percentage of inorganic nitrogen was obtained 60 days after incubation of the samples and in clays saturated with calcium, and the lowest amount of these attributes was obtained 15 days after incubation of the samples and in clays saturated with aluminum. The results showed that nitrogen mineralization increased with the samples' incubation time. Also, the highest percentage of mineralized nitrogen, microbial biomass nitrogen, and enzyme activity were observed in soils with vermiculite.

The increase in the incubation duration enhanced the percentage of inorganic nitrogen. The percentage of mineralized nitrogen and microbial biomass nitrogen was higher in soils with vermiculite than in soils with zeolite. Moreover, regardless of the incubation duration of samples, with increasing clay content, the percentage of mineralized nitrogen and enzyme activity decreased, but with increasing clay nitrogen content, microbial biomass increased. The highest and lowest amounts of mineralized nitrogen and nitrogen of microbial biomass were measured in soils with calcium and aluminum, respectively. The results showed the effect of the clay type and content and the exchangeable cation type on organic nitrogen dynamics.

Heavy metals such as lead, aluminum, mercury, copper, cadmium, nickel, and arsenic are now commonly found worldwide. Among these, cadmium and lead are the most hazardous, posing significant risks to both the environment and human health. Cleaning soils contaminated with organic and inorganic contaminants is one of the most significant and fundamental challenges facing society today. One effective method for soil purification is to extract or immobilize the contaminant within the soil.

It is unclear how water-soluble polymers contribute to the immobilization of heavy metals. The purpose of this study is to examine how various polymers affect the immobilization of lead, zinc, and cadmium in the soil near a lead and zinc mine in the province of Zanjan. A factorial experiment with three replications was conducted using a randomized complete block design. The experimental treatments included one type of soil and three different kinds of acrylic polymers (cationic, nonionic, and anionic) applied at four different levels (0, 0.05, 0.1, and 0.2). The absorbable amounts of lead, zinc, and cadmium were tested at various intervals after the polymers were applied to the soil samples. After that, SAS statistical software was used to examine the data. To do this, the Duncan multiple range test was used to compare the means. The necessary tables and graphs were then created using Excel.

The findings demonstrated that, at 1% probability level, the kind of polymer had a considerable impact on the amount of lead, zinc, and cadmium that may be absorbed in the soil. The average concentration of soil-absorbable lead for the different types of polymers employed was 239.8, 260.15, and 267.65 mg/kg; anionic polymer had the lowest concentration. Stated differently, anionic polymer decreases the capacity to absorb lead and stabilizes more lead in the soil than the other two forms of polymer. Anionic polymers most likely have a stronger impact on soil granulation. Additionally, at 1% probability level, the impact of acrylic polymer intake on the amount of lead, zinc, and cadmium absorbable in the soil was considerable. With an increase in the amount of polymer utilized in the soil, the greatest absorbable lead concentration (301.58 mg/kg) in the control treatment dropped to the lowest absorbable lead concentration (0.2). It was possible to determine the polymer percentage and the lead concentration, which came out to be 205.9 mg/kg of soil. Zinc concentration dropped as acrylic polymer consumption increased; in the control treatment, absorbable zinc concentrations ranged from 0.2 to 83.5 mg/kg of soil, with 0.2 being the highest concentration. At 1% probability level, the impact of the polymer's contact time with the soil on the amount of lead, zinc, and cadmium that the soil may absorb was significant. As a result, the tested soil had 414.52 mg of these elements at the initial stage of polymer treatment. The quantity of absorbable lead in the soil became 66% immobilized after a month, and after 720 hours, the amount of absorbable lead dropped to 141.83 mg/kg. As the polymer's contact time with the soil increased, so did the concentration of absorbable zinc in the soil. At 1% probability level, there was a strong correlation between the kind and amount of acrylic polymers and the amount of lead, zinc, and cadmium that may be absorbed in the soil. The ingestion of 0.2% anionic polymer resulted in the largest amount of lead immobilization, lowering the soil's absorbable lead concentration from 300 to 192 mg/kg of soil. A higher amount of anionic polymer immobilized the lead, and both cationic and non-ionic polymers were positioned after it. Additionally, anionic polymer was more prevalent than cationic polymer. It caused the non-ionic polymer's absorbable zinc to become immobile. Following 720 hours of polymer treatment, the soil's absorbable zinc element was immobilized to a greater extent by the anionic polymer (20%) than by the cationic and non-ionic polymers (26%), respectively. In comparison to the original concentration, the largest amount of immobilization by anionic polymer after one month was 78%, and the lowest amount of immobilization by nonionic polymer was 61%. Anionic polymer was 27% more effective than non-ionic polymer, 18% more effective than cationic polymer, and stabilized more cadmium.

 The results of this study showed that with increasing the duration of contact of polymers used with the soil, the amount of mobility of heavy metals in the soil decreased and also with increasing the amount of polymer consumption, the rate of metal stabilization in the soil increased. Anionic polymers immobilize more lead, zinc and cadmium in soil. To reduce the mobility of lead, zinc and cadmium and improve the stability and increase aggregation in soil, the use of acrylic polymer in contaminated soil is recommended.

Every country relies on soil as a vital natural resource that significantly contributes to environmental conservation and food production. Preparation of soil nutrient distribution map serves as a valuable tool for managers to make decisions. Due to the time-consuming and expensive nature of laboratory analysis for these variables on a large scale, efforts have been made to explore soil nitrogen through remote sensing. The current research deals with the application of remote sensing methods along with regression and random forest models to predict total soil nitrogen in Gilan province. This study aimed to answer two main questions: (1) Can SAR data be used to quantify total soil nitrogen (TSN) (2) How do SVM, BRT and RF algorithms perform in predicting soil nitrogen content?

This study focused on evaluating the data capabilities of Landsat-9 and Sentinel-1 satellites individually and in combination, using advanced algorithms such as Support Vector Machine (SVM), Boosted Regression Tree (BRT), and Random Forest (RF). The purpose of this evaluation was strategic, aiming to showcase the diverse conditions of the study area based on land cover/land use, climatic, and topographical parameters. Various variables, including climate parameters, topographic components, and remote sensing subscale indices, were investigated in conjunction with SAR data and optical images. Nonlinear machine learning algorithms, specifically SVM, RF, and BRT, were employed to predict total soil nitrogen status by modeling complex relationships between soil properties and environmental variables. R software, utilizing the CARET package for parameter input, was employed to implement the algorithm.

The results indicated the following: RF and BRT algorithms outperformed SVM and were effective in monitoring total soil nitrogen values. Multi-temporal SAR images showed higher accuracy in monitoring total soil nitrogen content compared to optical remote sensing data, facilitating more realistic predictions in paddy soils. The integration of environmental variables led to an increase in the accuracy of algorithms, where remote sensing variables played a crucial role, contributing to 61% and 51% effects in RF and BRT algorithms, respectively. The comparison of SVM and RF algorithms revealed that RF ranked second after the BRT algorithm, and the accuracy of total soil nitrogen estimation was not achieved with the SVM algorithm. However, both BRT and RF algorithms were able to monitor changes in total soil nitrogen. BRT performed better, accurately recording 58% of changes, as evidenced by a higher R2 value (0.58) and lower RMSE (0.25 mg/kg) and MAE (0.19 mg/kg) values.

In conclusion, the following key points were extracted from this research: 1) RF and BRT algorithms outperformed SVM in effectively monitoring total soil nitrogen levels; 2) multi-temporal SAR images demonstrated higher accuracy in tracking total soil nitrogen compared to optical remote sensing, enabling precise predictions in paddy soils; 3) the incorporation of environmental variables enhanced algorithmic accuracy; and 4) remote sensing variables contributed 61% and 51% to RF and BRT algorithms, respectively.

Contamination of soils with heavy metals is one of the most serious environmental problems increasing the risk of the entry of heavy metals into food chains. Rhizosphere soil is distinct from the bulk soil and is defined as the volume of soil around living roots which is influenced by root activities. Enzymes are produced by both roots and soil microorganisms to alter nutrient availability in rhizosphere soil. Soil enzymes promote the transformation of matter and energy in the soil, and their activity has a close relationship with soil nutrient availability. Detection of microbial enzymes in a natural environment is important to understand biochemical activities and to verify the biotechnological potential of microorganisms. However, there are few reports to indicate the biotechnological potential of plant growth promoting rhizobacteria (PGPR) and their effects on the activity of bacterial enzymes in rhizosphere soils under the stress of heavy metals. Thus, in the present study lead and cadmium contaminated rhizosphere soils were inoculated with PGPR species to investigate the influence of these bacteria on the activity of some enzymes.  A factorial pot experiment with completely randomized design base and three replications was performed in the greenhouse conditions. The factors examined were (a) rhizosphere soils of three varieties of cabbage [Brassica oleracea var. acephala L. (Ornamental cabbage), Brassica oleracea var. italica L. (Broccoli cabbage) and Brassica oleracea var. capitata L. (Cabbage)] and (b) five species of PGPR, consisting Pseudomonas putida PTCC 1694, Bacillus megaterium PTCC 1656, Proteus vulgaris PTCC 1079, Bacillus subtilis PTCC 1715 and Azotobacter chroococcum, used to inoculate the rhizosphere soils. There was also a control treatment (without rhizobacteria). The experiment had 18 treatments and there were 54 experimental units. To study rhizosphere soils, several rhizoboxes were used and three seedlings of cabbage were planted in the central part of each rhizobox (rhizosphere area). In treatments inoculated with rhizobacterial species, 2 ml of a bacterial suspension with 107-108 (cfu ml-1) was used to inoculate the soil of rootzone. After three months, cabbage varieties were harvested and the activity of alkaline phosphatase, acid phosphatase, urease, and dihydrogenase were measured in rhizosphere soils. The data obtained from this study were statistically analyzed by SPSS statistical software package (Version 9.4) and the variance of the data was analyzed by one-way ANOVAs (Duncan’s test) range test at 1 and 5 percent probability levels. The analysis of variance of the data (ANOVA) showed that the cabbage varieties, inoculation with PGPR species and their interactions had significant effects (p < 0.01) on the activity of alkaline phosphatase, acid phosphatase, urease, and dihydrogenase in rhizosphere soils. The results showed that inoculation of the rhizosphere soils with PGPR species increased the activity of soil enzymes. The highest activity of alkaline phosphatase (1529.28 µg pNP.g-1 dm.h-1) was measured in rhizosphere soils of the broccoli inoculated with Pseudomonas putida PTCC 1694. But, the highest activity of acid phosphatase (497.92 µg pNP.g-1dm.h-1) was obtained in rhizosphere soils of cabbage inoculated with Pseudomonas putida PTCC 1694. Also, the highest activity of urease (208.36 µg N-NH4+.g-1dm.2h-1) was observed in rhizosphere soils of the cabbage inoculated with Azotobacter chroococcum and the highest activity of dihydrogenase (8.71 µg TPF.g-1dm.16h-1) was observed when rhizosphere soils of the cabbage were inoculated with Bacillus subtilis PTCC1715. From the results of this study, it may be concluded that inoculation of Pb and Cd contaminated soils with PGPR species could modulate the toxic effects of heavy metals on plant and increase the activity of some key enzymes for plant growth in rhizosphere soils.

Contamination of soils by heavy metals is one of the most serious environmental problems that increases the risk of toxic metal entry into the food chains. When heavy metals enter the soil, they are progressively converted to the insoluble form by reactions with soil components. A variety of mechanisms such as absorption, ion exchange, co-precipitation and complexation incorporates heavy metals into soil minerals or bounds them to various soil phases. Organic acids are natural compounds that are secreted from the root of the plant and can affect the solubility and uptake of heavy metals.

To evaluate the effects of plant growth promoting rhizobacteria (PGPR) on organic acids production and heavy metal uptake by different cabbage varieties, a factorial pot experiment with completely randomized design and three replications was performed under the greenhouse conditions. The factors included (a) rhizosphere soils of three varieties of cabbage [Brassica oleracea var. acephala L. (Ornamental cabbage), Brassica oleracea var. italica L. (Broccoli cabbage) and Brassica oleracea var. capitata L. (Cabbage)] and (b) five species of PGPR consisting of Pseudomonas putida PTCC 1694, Bacillus megaterium PTCC 1656, Proteus vulgaris PTCC 1079, Bacillus subtilis PTCC 1715 and Azotobacter chroococcum and control (without rhizobacteria) used to inoculate the rhizosphere soils. The experiment had 18 treatments and there were 54 experimental units and three seedlings of cabbage were planted in each pot. In all treatments inoculated with rhizobacterial species, 2 ml of a bacterial suspension with 107-108 (cfu ml-1) were used to inoculate the soil of root area. The data obtained in this study were statistically analyzed by SAS software (version 9.4) and the mean comparison was performed by Duncan’s multiple range test at 1 and 5 percent probability levels.

The analysis of variance (ANOVA) showed that the cabbage varieties, bacterial inoculation and their interactions had significant effects (p < 0.01) on organic acids concentration, fresh and dry biomass of plant, concentrations of Pb and Cd in root and shoot of cabbage plant. The results showed that inoculation of the rhizosphere soils with PGPR species increased organic acids concentration of rhizosphere. The highest concentration of malic and citric acids in rhizosphere soil (9.59 and 118.34 mg dl-1, respectively) was obtained when the rhizosphere soils of the broccoli were inoculated with Pseudomonas putida PTCC 1694 and the highest concentration of acetic acid in rhizosphere (233.88 mg dl-1) was determined when the rhizosphere of broccoli were inoculated with Bacillus megaterium PTCC 1656. Inoculation of the rhizosphere with PGPR species also increased the fresh and dry biomass of plant, and Pb and Cd concentrations in cabbage root and shoot. The highest fresh and dry biomass of cabbage (416.77 and 76.96 g in the plot, respectively) were obtained when the rhizosphere soils of cabbage were inoculated with Bacillus megaterium PTCC 1656, the highest concentration of Pb in the root and shoot and Cd in the root of cabbage (12.20, 90.77 and 9.01 mg kg-1, respectively) were obtained when the rhizosphere soils of the ornamental cabbage were inoculated with Pseudomonas putida PTCC 1694. Inoculation of the rhizosphere soils of the ornamental cabbage, broccoli and cabbage by B. megaterium PTCC1656 caused an increase in the DOC concentration by 137, 150 and 120%, respectively, compared to uninoculated rhizosphere soils. Bacterial inoculation also increased the concentrations of available phosphorus in the rhizosphere soils and the highest concentration of phosphorus was measured in the treatments inoculated by P. putida PTCC1694. Furthermore, the concentrations of available phosphorus in the rhizosphere soils of the ornamental cabbage, broccoli and cabbage increased by 79, 71 and 111%, respectively, relative to uninoculated rhizosphere soils.

It is concluded that inoculation of Pb and Cd contaminated soils by PGPR species, especially Bacillus megaterium PTCC 1656 and Pseudomonas putida PTCC 1694, enhances the tolerance of host plants, metal uptake performance and thus phytoremediation process by increasing the metal bioavailability and biomass production of the plant. As the distribution and accumulation of heavy metals in plant tissues are important factors for evaluation of plant role in phytoremediation of polluted soils, the PGPR inoculation of rhizosphere soils can be used as a biotechnological tool to enhance biomass production and plant uptake and thus the efficiency of phytoextraction.

Responses of olive self-rooted cuttings of Zard cultivar (Olea europaea L. cv. Zard) to different levels of soil compaction and irrigation water salinity at the field capacity under greenhouse condition were studied. A loamy sand soil passed through a 4.76mm sieve, was poured into the PVC cylinders with diameter of 15cm and then they were compacted to be achieved the desired compaction levels. One-year-old rooted olive cuttings were transplanted into the PVC cylinders. After stabilization of cuttings, cylinders were irrigated by waters having different electrical conductivities at three days intervals, for five months. Some morphological and physiological properties of the olive plants were measured. As the salinity levels of irrigation water increased transpiration, stomatal conductance, photosynthetic rate, relative water content, water potential of stem, temperature difference between leaf and the environment and chlorophyll index decreased, for preserving plant internal water balance. Instantaneous WUE, electrolyte leakage and Na concentration of leaves increased as the salinity levels of irrigation water increased because of the decrease in transpiration and due to the plant’s salinity tolerance mechanisms. The relative water content of leaf, water potential of stem and temperature difference between leaf and environment decreased as the soil compaction increased due to decrease in water uptake. Photosynthetic indices of olive cuttings of Zard cultivar significantly decreased beyond the EC of 8 dS m-1.

Tuberose is one of the most important cut-flowers in Iran and the world. Since nutrition is an important factor in growth and quality of ornamental plants، a factorial experiment was conducted، based on completely randomized blocks design، with 12 treatments and 3 replications، in Zanjan province، in 2011، to assess the effects of nitrogen (N) fertilizer and phosphate solubilizing bacteria (PSB) on growth and quantitative traits of tuberose (Polianthes tuberose L.). N from urea fertilizer source at 4 levels (0، 50، 100 and 200 kg/ha) and PSB at 3 levels (0، 5 and 10 kg/ha microbial fertilizer) were applied to soil. Soil was inoculated with PSB before planting and N was applied in two splits (after emergence of the bulbs and 20 days after the first application). In this experiment، the plant height، length of florescence، stem and floret diameter، number of leaves and florets، and fresh and dry weights of aerial parts and roots were measured. The results of ANOVA of data showed that application of N fertilizer increased significantly all measured traits، except stem and floret diameters. All growth parameters، except dry weight of aerial parts، were increased significantly by soil inoculation with PSB. Based on the results of this study، application of 200 kg/ha N and 10 kg/ha microbial fertilizer containing PSB resulted in the highest yield and quantitative traits for tuberose.

In this paper firt of all we introduce a generalization of torsion freeness of acts over monoids, called -torsion freeness. Then in section 1 of results we give some general properties and in sections 2, 3 and 4 we give a characterization of monoids for which this property of their right Rees factor, cyclic and acts in general implies some other properties, respectively.

The ability of earthworms in recycling a wide range of organic solid wastes is well established. Only a few earthworm species are suitable for commercial vermicomposting. Two species, Eisenia foetida and Lumbricus rubellus, are common in temperate regions. Samples of earthworms were collected from manure pills and forest litter in North and Northwest of Iran. The samples were maintained in pots under greenhouse conditions. External morphological characteristics of mature worms were used in identifying earthworm species. These characteristics included: total number of body segments, numbers of clitellum and tubercula pubertatis (TP) segments, dorsal and external body color, body size, prestomium and prostomium shape, number of first segment with dorsal pore and patterns of clitellum and TP. All collected samples belonged to the species Eisenia foetida. Under incubation conditions in manure substrate (a moisture of 70% saturation at 24±2oC), each worm produced 1-2 cocoons daily and each cocoon contained 2-7 worm embryos. The collected earthworm samples showed a good ability in vermicomposting of manure, plant residues, and some organic industrial refuses. The C:N ratio decreased during the vermicomposting process, which indicates the improved stage of decomposition and the vermicompost stability.