Soil science
J. Al-Jomah; A. Halajnia; A. Lakzian; A.R. Astaraei
Abstract
Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing ...
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Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing global food security is a fundamental goal to feed the growing world population, it is necessary to develop suitable and efficient techniques for the rehabilitation of salt-affected soils and their exploitation. Chemical fertilizers are usually used to provide nutrients required for plant growth in order to increase crop yield, but application of these chemical components has negative environmental effects and reduces the quality of soils and agricultural products. The use of beneficial microorganisms (bacteria and fungi) as fertilizers and biological amendments has a high potential to improve productivity in saline soils. The aim of this study was to investigate the effect of using Acidithiobacillus bacteria along with mycorrhiza on the production of some photosynthetic and biochemical metabolites in maize under salt stress and comparing it with control conditions.
Materials and Methods
To perform this experiment, a surface soil sample was collected from a depth of 30 cm from the campus of Ferdowsi University of Mashhad, and some physical and chemical properties of the soil were measured by usual laboratory methods. To prepare saline soil a mixture of four compounds MgSO4.7H2O, Na2SO4, NaCl, and CaCl2. 2H2O were used. The mycorrhizal fungus (Funneliformis mosseae) and mesophilic Acidithiobacillus bacteria species two types of bacteria, Acidithiobacillus thiooxidans PTCC No: 1692 (DSM 504) and Acidithiobacillus ferrooxidans PTCC No: 1646 (DSM 583), were purchased from Turan Biotechnology Company (Semnan Science and Technology Park) and Iran Microbial Scientific and Industrial Research Center (PTCC), respectively. In this research, the effect of biological treatments including: two levels of mycorrhiza (inoculation and non-inoculation), two levels of salinity (0.96 and 6 d/m) and four levels of Acidithiobacillus control (C), Acidithiobacillus thiooxidans (T), Acidithiobacillus Ferrooxidans (F), Acidithiobacillus thiooxidans and Ferrooxidans (T+F) were compared with each other on some photosynthetic and biochemical characteristics of Zea mays under greenhouse conditions in the form of a completely randomized design with factorial arrangement with three replications. 10 gr of salt mixture (this amount of salt was obtained to reach electrical conductivity of 6 in the pre-experiment) was added to 5 kg of soil and the soil moisture of the pots was kept for one month in the field capacity. Bacterial treatments were inoculated with 30 mL of cell suspension per pot (approximately 107 CFU mL-1). In the simultaneous use of two bacteria, 15 ml of each bacterial cell suspension (15+15) was added to each pot. Single-cross 704 variety of maize was grown in pots and soil moisture was maintained during the growth period in the field capacity by weighing. Chlorophyll a, b and carotenoid, concentrations of flavonoids, anthocyanins and proline and electrical leakage were measured in fresh leaf samples (third leaf on the stem).
Results and Discussion
The results showed that salinity decreased the percentage of root colonization and chlorophyll a and b content in leaves. Salinity decreased chlorophyll a, b and carotenoid in leaves by 27.9, 68.42% and 50%, respectively. Salinity increased proline concentration (42.62%), electrolyte leakage (33.30%), anthocyanins concentration (96.36%) and leaf flavonoids (84.73%) compared to control soil. Inoculation with mycorrhiza compared to no inoculation had a remarkable and significant effect on all investigated parameters in both saline and control soils. In saline soil, mycorrhizal inoculation reduces electrolyte leakage (56.75%) and increases chlorophyll a (2.3 times), chlorophyll b (6.6 times), carotenoid (1.3 times), proline concentration (24.39%), anthocyanins amount (24.07) and flavonoids (20.4%) in the plant. The effect of bacterial treatments on the investigated parameters in plants inoculated with mycorrhiza was greater than non-inoculated treatments. The effectiveness of the simultaneous application of both bacteria was greater than the effect of each of them alone. In saline soil, simultaneous inoculation of mycorrhizae with both bacteria species reduces electrolyte leakage (14.72%) and increases chlorophyll a (39.80%), chlorophyll b (106%), carotenoid (50%), proline concentration (10.12%), the amount of anthocyanins (14.17%) and flavonoids (4.06%) compared to mycorrhiza treatment alone. The results showed that these bacteria can probably be considered as helping mycorrhizal bacteria.
Conclusion
The objective of this study was to examine the impact of simultaneous inoculation of mycorrhizae and Acidithiobacillus bacteria on select photosynthetic and biochemical metabolites of maize subjected to salinity stress conditions. Confirming the results of other studies, the results of this research also showed the clear and distinct effect of mycorrhiza on increasing chlorophyll and producing metabolites effective in increasing plant resistance to salt stress. In addition, the results showed that although the use of each species of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans alone was effective on the measured parameters in both saline and control soils, the simultaneous inoculation of both Acidithiobacillus bacteria species and mycorrhiza had the greatest effect on increasing chlorophyll, production of proline, anthocyanins and flavinoids and reducing electrolyte leakage and as a result, increasing tolerance to salt stress. In other words, these bacteria can be considered as mycorrhiza helper bacteria, whose activity can improve the function of mycorrhiza. On the other hand, mycorrhiza symbiosis may have increased the efficiency of these bacteria by changing the soil conditions and the environment around the roots. However, further greenhouse and field experiments with other plant species are necessary to confirm these findings.
Soil science
A. Nosrati Miandoab; H. Emami; A. Astaraei; M.R. Mosadeghi; H. Asgarzadeh
Abstract
IntroductionSoil salinity has a negative effect on physical, chemical and biological properties of soil. Salinity also affects the relationships between soil and plants, which in turn has a significant effect on plant growth. One of the solutions used to reduce the effects of salinity and improve the ...
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IntroductionSoil salinity has a negative effect on physical, chemical and biological properties of soil. Salinity also affects the relationships between soil and plants, which in turn has a significant effect on plant growth. One of the solutions used to reduce the effects of salinity and improve the physical properties of the soil is application of organic and chemical conditioners. Organic matter as well as calcium improve the structure and physical condition of the soil. Conditioners in saline soils include soluble calcium salts such as gypsum (CaSO4.2H2O), calcium chloride (CaCl2.2H2O) and phosphogypsum (phosphorous gypsum), and acids such as sulfuric acid, sulfur, pyrite, Aluminum sulfate and sulfur lime (calcium polysulfide). Strategies aimed at evaluating and ameliorating the structural quality of soils should be developed to ensure the sustainable use of lands. The least limiting water range (LLWR) attempts to incorporate crop-limiting values of soil strength, aeration, and water supply to plant roots into one effective parameter (on the basis of soil water content). The LLWR can be a useful indicator of soil quality and soil physical constraints on crop production. Therefore, the objective of this research was to study the effects of organic and inorganic conditioners on some structural and hydraulic indices of saline sodic soils.Material and MethodsIn this study, the effect of two types of organic and chemical conditioners and the simultaneous application of them on modifying the physical properties of 5 saline soils around the lake of Urmia were investigated. Treatments included algae, salfit and algae+salfit. The soil samples were transferred to culture boxes (40 × 40 × 40) according to the bulk density of the sampling site. The soil samples were wetted and dried several times. Conditioners treatments including application of calcium and organic compounds. After reaching the field capacity, wheat seeds were sown and irrigated with water (electrical conductivity 0.28 dS/m and pH= 7.78). It should be noted that irrigation was done at intervals of 8 days. Two months after the beginning the experiment, irrigation was stopped and soil moisture was allowed to reach a permanent wilting point. At this stage, undisturbed soil samples were prepared from the treated soil of each box and the mean weight‐diameter of dry (MWDdry) and wet (MWDwet) aggregates were measured. Then the values of least limiting water range in two suctions of 330 and 100 cm and water integral capacity of samples were measured.Results and DiscussionAccording to the initial analysis, all soils used were saline and the amount of calcium carbonate was high in two soils (number 3 and 5). Soil organic carbon content was also low. The results of salfit analysis also showed that the dissolved calcium and sulfur content were 8 and 3.9%, respectively. The results showed that soil 1 had the highest amount of MWDwet and soil 5 had the lowest amount of MWDwet. The highest and lowest aggregate stability values were obtained in soils 3 and 5, respectively, where soil 5 was very saline soil. The studied soils differed in terms of soil water relations. The highest amount of LLWR330 was found in soil 5, while the lowest amount of LLWR100 and IWC parameters was also obtained in same soil. The results of this study showed that salfit treatment caused the highest increase in aggregate stability (74.9%) LLWR330 (14.5%) and integral water capacity (26.2%) compared to the control and the highest mean weight‐diameter of aggregates in both wet and dry conditions was obtained in salfit-algae treatment (52.4% and 40.4% increase, respectively). The results of correlation analysis among the measured parameters showed that the highest correlation was found between aggregate stability and MWDwet. Among the measured parameters, aggregate stability had the highest correlation with other parameters and the correlation of this parameter with LLWR330, LLWR100, IWC and MWDwet were 0.36, 55, 75 and 88 %, respectively. Soil water integral capacity also had a significant correlation (p < 0.01) with LLWR330 (0.84) and MWDwet (0.7).ConclusionThe effect of initial soil properties on studied parameters was significant and the use of conditioners improved studied parameters, and use of conditioners increased indices structural and hydraulic of saline soils. In general, the results of this study showed the positive effect of conditioners on physical properties of the studied soils, in which salfit and salfit-algae have a better effect on studied parameter, and they could be useful to improve soil physical condition. It seems that the application of different rates of conditioners as well as their interaction with each other should be considered according to the basic properties of the soil.
S. Sangsefidi; A. Lakzian; A.R. Astaraei; M. Banayan; M. Mazhari
Abstract
Introduction: Nitrification inhibitors are compounds that slow biological oxidation of ammonium to nitrite by reducing the activity of Nitrosomonas bacteria, without affecting the subsequent oxidation of nitrite to nitrate, either by inhibiting or interfering with the metabolism of nitrifying bacteria. ...
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Introduction: Nitrification inhibitors are compounds that slow biological oxidation of ammonium to nitrite by reducing the activity of Nitrosomonas bacteria, without affecting the subsequent oxidation of nitrite to nitrate, either by inhibiting or interfering with the metabolism of nitrifying bacteria. The first step of nitrification is inhibited (i.e., the activity of Nitrosomonas bacteria) by the nitrification inhibitors, while the second step for oxidation of nitrite (NO2-) to nitrate (NO3-) is normally not influenced. In recent years, numerous compounds have been identified and used as nitrification inhibitors, particularly in agricultural soils. They are chemical compounds that slow the nitrification of ammonia, ammonium-containing, or urea-containing fertilizers, which are applied to soil as fertilizers, such as thiourea, carbon Sulfide, thioethers, ethylene, 3-amino-1,2,4-triazole, dicyandiamide (DCD), 2-amino-4-chloro-6-methyl pyrimidine, ammonium thiosulphate and 3,4-dimethylpyrazole phosphate (DMPP). These inhibitors reduce the losses of nitrogen in soil. Some nitrification inhibitors are very effective in the efficiency of the nitrogen fertilizers. Recently, a lot of attention has been paid to nitrification inhibitors from an environmental point of view. Some nitrification inhibitors are very expensive and not economically suitable for land application. Nonetheless, many farmers and researchers apply these compounds for many purposes in some specific places. On the other hand, there are many inexpensive natural nitrification inhibitors such as Artemisia powder, Karanj (Pongamia glabra), neem (Azadrachta indica) and tea (Camellia sinensis) waste which can compete with the artificial nitrification inhibitors such as 3, 4-dimethylpyrazole phosphate (DMPP), dicyandiamide (DCD) which are very common nitrification inhibitors. Applying 1.5 kg ha-1 of DMPP is sufficient to achieve optimal nitrification inhibition. 4-dimethylpyrazole phosphate (DMPP) can significantly shrink nitrate (NO3) leaching. 4-dimethylpyrazole phosphate (DMPP) may also decrease N2O emission and the use of DMPP-containing fertilizers can improve yield. The aim of this study was to compare the effect of 3, 4-dimethylpyrazole phosphate (DMPP), Dicyandiamide (DCD) and powder Artemisia (ART) at the presence of Urea, cow manure and Vermicompost.Material and Methods: Effects of three nitrification inhibitors, (3, 4-dimethylpyrazole phosphate (DMPP), Dicyandiamide (DCD) and powder Artemisia (ART)) at the presence of three nitrogen sources (Urea, cow manure and Vermicompost) were investigated in a calcareous soil under lettuce cultivation in a greenhouse condition. The changes in the soil mineral nitrogen (nitrate and ammonium), plant nitrogen, nitrate accumulation in leaves and some of growth characteristics such as lettuce chlorophyll content, leaf area index, leaf dry weight and root dry weight were determined. The experiment was carried out in a completely randomized factorial design with three replications. Soil ammonium and nitrate concentration were measured during the experiment. The growth characteristics of lettuce were also measured at the end of experiment. Nitrogen and nitrate contents were also determined in lettuce leaves. Results and Discussion: The results of the experiment showed that soil nitrate decreased at the presence of three nitrification inhibitors but the soil nitrogen ammonium increased significantly. Application of nitrification inhibitors also reduced the concentration of nitrate in the lettuce leaves during two harvesting times. Moreover, the nitrogen concentration in the plant increased at the presence of nitrification inhibitors. The application of nitrification inhibitors influenced the plant growth characteristics and changed the lettuce growth characteristics. Chlorophyll content increased significantly in lettuce leaves. Leaf area index, leaf and root dry weight of lettuce increased notably when 3, 4-dimethylpyrazole phosphate (DMPP) and powder Artemisia (ART) nitrification inhibitors were applied to the soil samples. These growth characteristics, however, reduced significantly when dicyandiamide nitrification inhibitors was applied to the soil samples. In addition, the symptoms of toxicity were observed in lettuce plant when dicyandiamide nitrification inhibitors were applied to the soil samples. In general, the highest efficiency of nitrification inhibitors was recorded at the presence of urea fertilizer source and the greatest efficiency was observed initially for powder Artemisia (ART) and then for 3, 4-dimethylpyrazole phosphate (DMPP) and dicyandiamide, respectively, when urea fertilizer was applied to the soil samples. There was a positive correlation between soil nitrogen content and plant nitrate in the first and second harvest. The correlation between soil ammonium and plant nitrate (in the first and second harvest) and soil nitrate was negative.
zahra sharifi; Alireza Astaraei; A Fotovat; mojtaba baranimotlagh; Hojat Emami
Abstract
Introduction: Zinc is one of the essential micronutrients for plants, mining and industrial activities leading to pollution of heavy metals, including zinc metal contamination in soils. In addition to the total concentration, knowledge of the Zinc fractions is necessary to assess the mobility of zinc ...
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Introduction: Zinc is one of the essential micronutrients for plants, mining and industrial activities leading to pollution of heavy metals, including zinc metal contamination in soils. In addition to the total concentration, knowledge of the Zinc fractions is necessary to assess the mobility of zinc in the soils. One of the sequential extraction methods is Tessier method. sequential extraction with plant cultivation simultaneously, is the appropriate approach for assessing the mobility of toxic metals. Therefore this study was conducted to evaluate the chemical forms and determine their relationship to the physical and chemical properties of soils in some fields under cultivation in Khorasan Razavi province.
Materials and Methods: The experiment was conducted in a completely randomized design with factorial arrangement includes 4 levels of contamination (0, 500, 1000 and 1500 (mg/kg)) and 10 soil types from different regions of Khorasan Razavi province of 0-30 cm depth in the range of electrical conductivity 1 up to 15 ds/m, with three replications at Research greenhouses of Ferdowsi University of Mashhad. An example of mining waste was prepared as a source of pollution. The soil samples were kept at field capacity moisture for 6 months. Then air-dried soil samples were used for planting borage and determine the Zinc fractions. Then soil samples were air dried and used for planting borage and determining the Zinc fractions. Texture, cation exchange capacity, organic carbon, electrical conductivity, pH and Available phosphorus and potassium were measured in the saturation extract. DTPA-extractable Zinc was measured by atomic absorption spectrometry. Borage was planted in greenhouses in 3 kg pots with three replications. During flowering, the plants were harvested and dry digestion method was used to measure the concentration of Zinc. Chemical forms and Pseudo total concentration of zinc in the samples were determined using Tessier and digestion by HCl and HNO3 acids (3:1) methods respectively. The concentration of the extracts was measured by atomic absorption spectrometry. Statistical analysis was done using Minitab and Excel softwares.
Results and Discussion: Chemical Forms Average of zinc in soils was as follows:
Exchangeable < iron and manganese oxides < organic < carbonate < residual
Despite the low percentage of organic matter in these soils, in high levels of Zinc contamination a large amount of zinc was saved. Lack of organic Zinc, in addition to the low amount of organic matter soil is related to the dominance of iron oxides. In high levels of soil contamination, increased concentrations of zinc in all fractions, especially organic and carbonate which leads to an increase in the availability of zinc, is a serious threat to environment. The amount of exchangeable zinc was insignificant. Also the exchangeable, forms a small part of total amount of metal in the soils. The correlation between the chemical forms with each other and with the pseudo total, absorbed by plant roots and shoots and extracted with DTPA together, was significant. Absence of correlation between the exchangeable and iron and manganese oxides is probably indicative of the fact that the main supplier of soluble and exchangeable zinc normally after carbonates are iron and manganese oxides, that have little role in these soils. There is a significant positive correlation between different fractions of zinc with each other and this indicate a dynamic relationship between the zinc chemical forms in the soil. Correlation coefficients between plant available and chemical forms of zinc showed that plant available zinc derived from all fractions. A higher correlation coefficient between the plant available with carbonate and organic zinc was obtained, which indicates that carbonate and organic are the major suppliers for available plants zinc.
Conclusion: In this study, the residual, carbonate and organic fractions are dominant form of zinc in soils, respectively. With increasing level of contamination, percentage of residual zinc decreased and percentage of other fractions increased, particularly organic and carbonate. Increasing the availability of zinc, is a threat to the environment. There is a high correlation coefficient between different fractions of Zinc with each other and with the pseudo total, amount of plant and available plant zinc showed that there is a dynamic relationship in the soil systems. There is a higher correlation coefficient between the available zinc and carbonate and organic fractions of soils, which indicate available plant zinc, are mainly derived from carbonate and organic fractions.
Setareh Sharifi; Amir Lakzian; Alireza Astaraei; nasrin ghorbanzadeh
Abstract
Introduction: Iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. Ferric iron oxides are the most abundant forms of iron in soils and sediments. Ferric iron is highly insoluble at circumneutral pH. Present investigations have shown that the ...
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Introduction: Iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. Ferric iron oxides are the most abundant forms of iron in soils and sediments. Ferric iron is highly insoluble at circumneutral pH. Present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. Anaerobic bacteria reduce ferric iron which bound to soil clay minerals under anaerobic conditions. They have the ability to use ferric iron as a terminal electron acceptor. Many studies presented that dissimilatory iron reducing bacteria (DIRB) mediate the transfer of electrons from small organic molecules like acetate and glucose to various humic materials (electron shuttles) which then pass electrons abiotically to ferric iron oxyhydroxide and phyllosilicate minerals. Electron shuttles like AQDS, a tricyclic quinone, increase the rate of iron reduction by iron reducing bacteria on sites of iron oxides and oxyhydroxides. By increasing the rate of bioreduction of ferric iron, the solubility and availability of iron enhanced meaningfully. Royer et al. (2002) showed that bioreduction of hematite (common iron mineral in soils) increased more than three times in the presence of AQDS and Shewanella putrefaciens comparedto control treatments. Previous works have mostly used synthetic minerals as electron acceptor in bioreduction process. Furthermore, the effect of quinones as electron acceptor for microorganisms were studied with poorly crystalline ferric iron oxides . The main objective of this study was to study the effect of AQS, humic acid and fulvic acid (as electron shuttle) and Shewanella sp. and Pseudomonas aeruginosa, on bioreduction of native ferric iron in two acidic and calcareous soils.
Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in vitro condition. The soil samples collected from locations in Mashhad and Guilan cities, Iran, in 2015. The soil samples were air dried in a glasshouse and later subjected to general analysis. Some part of the soil samples were kept at 4 oC as fresh soil samples for bioreduction assay. In that part of experiment, all soil samples were treated with glucose (10 mM) as electron donor. Native ferric iron considered as electron acceptor. Then soil samples were treated with AQS, humic acid and fulvic acid (as electron shuttles) and inoculated with bacterial cells (Shewanella sp. and P. aeruginosa) and they were incubated for 30 days in an incubator at 30 and 37 oC according to the optimum temperature for bacteria in an anaerobic condition. At the end of incubation time, ferrous and acid extractable iron were determined with Ferrozine assay by spectrophotometer in 562 nm (8, 25).
Results and Discussion: Results showed that the AQS had a noticeable effect on ferrous iron concentrations in both acidic and calcareous soils. In these cases ferrous iron concentrations were 8 and 15.7 times higher compared to initial concentration in acidic and calcareous soils, respectively. The Shewanella sp. intensified ferrous iron concentration 7.2 and 16.3 fold in acidic and calcareous soils, respectively but P. aeruginosa increased it 5.6 and 12.1 fold compared to initial concentration of ferrous iron. In acidic soil, in the presence of Shewanella sp. and AQS, ferrous and acid extractable iron concentrations were 1.45 and 4.50 mg g-1, respectively. Results showed that 11.7 fold enhancements occur in the presence of Shewanella sp. and AQS compared to initial (0.385 mg g-1) concentration of iron in acidic soil. When P. aeruginosa was inoculated in acidic soil in the presence of AQS, soluble ferrous iron concentration was 1.27 mg g-1. The acid extractable iron in this treatment was 2.85 mg g-1. The concentration of soluble ferrous iron in calcareous soil was 0.81 mg g-1, when AQS was added to Shewanella sp. treatments. That value was 0.54 when P. aeruginosa was added. The acid extractable iron was 3.90 mg g-1 in the presence of AQS and Shewanella sp. By adding P. aeruginosa, acid extractable iron was 2.84 mg g-1 compared to control treatments.
Conclusions: Dissimilatory ferric iron reduction is a potentially important process in controlling contaminant fate. It has the potential for being particularly useful in the remediation of metals and radionuclides. Means for stimulating ferric iron reduction will be useful in enhancing bioremediation process. Results illustrated that the Shewanella sp. and P. aeruginosa were enhanced the bioreduction of ferric iron in the presence of AQS, humic acid and fulvic acid in soils. When soil samples were inoculated with Shewanella sp., and AQS was added to the soil samples (in acidic and calcareous soil samples) the concentration of ferrous iron increased intensively.
V. Feiziasl; A. Fotovat; A. Astaraei; A. Lakzian; M.A. Mousavi Shalmani; A. Khorasani
Abstract
Introduction: Nitrogen (N) is one of the most important growth-limiting nutrients for dryland wheat. Mineral nitrogen or ammonium (NH4+) and nitrate (NO3−) are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. Nitrogen fertilization in dryland area can increase ...
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Introduction: Nitrogen (N) is one of the most important growth-limiting nutrients for dryland wheat. Mineral nitrogen or ammonium (NH4+) and nitrate (NO3−) are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. Nitrogen fertilization in dryland area can increase the use of soil moisture, and improve wheat yields to some extent. Many researchers have been confirmed interactions between water stress and nitrogen fertilizers on wheat, especially under field conditions. Because of water stress affects forms of nitrogen uptake that leads to disorder in plant metabolism, reduction in grain yield and crop quality in dryland condition. On the other hand, use of suitable methods for determining nitrogen requirement can increase dryland wheat production. However, nitrogen recommendations should be based on soil profile content or precipitation. An efficient method for nitrogen fertilizer recommendation involves choosing an effective soil extractant and calibrating soil nitrogen (Total N, NO3− andNH4+) tests against yield responses to applied nitrogen in field experiments. Soil testing enables initial N supply to be measured and N supply throughout the season due to mineralization to be estimated. This study was carried out to establish relationship between nitrogen forms (Total N, NO3− andNH4+) in soil and soil profile water content with plant response for recommendation of nitrogen fertilizer.
Materials and Methods: This study was carried out in split-split plot in a RCBD in Dryland Agricultural Research Institute (DARI), Maragheh, Iranwhere N application times (fall, 2/3 in fall and 1/3 in spring) were assigned to the main plots, N rates to sub plot (0, 30, 60 and 90 kg/ha), and 7 dryland wheat genotypes to sub-sub plots (Azar2, Ohadi, Rasad and 1-4 other genotypes) in three replications in 2010-2011. Soil samples were collected from 0-20, 20-40, 40-60 and 60-80 cm in sub-sub plots in shooting stage (ZGS32). Ammonium measurement in the soil KCl extracts was down by spectrophotometry method and colorimetric reaction at 655 nm. Also, Absorption spectrophotometry method was used for determination of nitrate in soil extract based on its UV absorbance at 210 nm. In this method two measurements were carried out; one before (by Zn coated by Cu) and second after reduction of nitrate). Using the difference between these two measurements, concentration of nitrate in the extracts was determined. Soil water content was also measured with Diviner 2000 after calibration in 0-20, 20-40, 40-60 and 60-80 cm soil profile in sub-sub plots. After wheat harvest, the most suitable regression model between soil mineral nitrogen (Nm) and soil moisture (θ) was fitted with wheat grain yield by DataFit version 9.0 software.
Results and Discussion: The best model between soil N forms (nitrate, ammonium and mineral nitrogen) was calibrated between mineral nitrogen (Nm) and soil moisture (θ) with crop response (Y=a+bN_m+c ln〖(θ)〗+dN_m^2+eln〖(θ)〗^2+fN_m ln〖(θ)〗) that explained 80% of dryland wheat yield variations. In this model, the contributions of mineral nitrogen (NO3− +NH4+) were 26%, soil moisture 50% and their interactions 24%. According to this model, the effect of soil moisture on production of grain yield was 2.3 folds greater than the mineral N. These results are most suitable for sampling and calibration of mineral nitrogen in 0-40 cm in dryland wheat stem elongation (ZGS32). Critical value of soil mineral N was 41 kg/ha, equal to 18.0 mg Nm/kg in this layer for obtaining higher grain yield (over 2500 kg/ha). According to regression model, application of 50 kg N/ha in autumn was able to provide Nm critical level in 0-40 cm layer for dryland wheat genotypes under experimental conditions. Also simulation model showed that nitrogen fertilizer increased grain yield and it is more than the soil mineral nitrogen. If the soil mineral nitrogen is 20 kg/ha or less in 0-40 cm soil layer, there may be increase of grain yield up to 4000 kg/ha through the application of nitrogen fertilizers. Therefore, increasing of mineral nitrogen in the soil profile up to 20 kg/ha is not appropriate for wheat production in Northwest of Iran drylands.
Conclusion: It can be concluded that, there is a relationship between soil nitrogen and moisture content with dryland wheat response and suggested model can be used for nitrogen recommendations for dryland wheat. According to the model, the effects of nitrogen fertilizer application on grain yield were much more than the effect of soil mineral nitrogen. Therefore, the increasing of soil nitrogen storage is not recommended in dryland conditions.
P. Mirhoseini Moosavi; A. Astaraei; Ali reza Karimi; Gh. Karimi
Abstract
Montmorillonite is the major mineral of Bentonite with many applications in industrial fields but some impurities decreases the quality of the bentonite. The main objective of this study was to investigate the suitable method for purification of Ghaen mine bentonite. A combination of methods was considered ...
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Montmorillonite is the major mineral of Bentonite with many applications in industrial fields but some impurities decreases the quality of the bentonite. The main objective of this study was to investigate the suitable method for purification of Ghaen mine bentonite. A combination of methods was considered including wet sieving and sedimentation, centrifuge and ultrasound. The efficiency of purification methods was determined based on X-ray, particle size, cation exchange capacity (CEC) and ratio peak of the Quartz/Montmorillonite analysis before and after experiments. The results showed that such methods were efficient for preparing of the materials having high quantity of montmorillonite with less than 2 microns particle sizes. Cristobalite was the only mineral remained in samples, however many of particles were exempted from the samples. Cristobalite was the main impurity remained with montmorillonite. Chemical treatment is the only way for its complete removal. The results of this study revealed that by using easy, cheap and fast methods, it is possible for acceptable purification of bentonite.
M. J. Pajand; H. Emami; Alireza Astaraei
Abstract
Introduction: Topography is an important and effective property affecting the soil quality. Some researchers demonstrated that degree and aspect of land slope may influence the particle size distribution and gravel. Slope degree affects the surface and subsurface run-off, drainage, soil temperature, ...
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Introduction: Topography is an important and effective property affecting the soil quality. Some researchers demonstrated that degree and aspect of land slope may influence the particle size distribution and gravel. Slope degree affects the surface and subsurface run-off, drainage, soil temperature, stability of soil aggregates and soil erosion. This research was carried out to determine the spatial variation of soil properties in different slope degrees of northern and southern slopes in Khorasan Razavei province, Iran.
Material and Methods: This study was performed in Sanganeh research station (longitude 60o 15ʹ60ʺ and latitude 36o 41ʹ 36ʺ), of north-eastern, Khorasan Razavi province of Iran. In order to study the effects of topography on some soil physical and chemical properties, a topo-sequence with the same slope length, parent materials and cover crops was selected. 30 soil samples (0-30 cm depth) were collected from different slopes of less than 5, 5-15, 15-30, 30-50 and more than 50 percent of both southern and northern aspects. In this study, the soil particle size distribution (texture) was measured by hydrometer method, organic carbon and calcium carbonate were determined by wet oxidation and titration with HCl 6 M, respectively and soil structural stability index, aggregates mean weight diameter and particles fractal dimension were calculated by related equations. Finally, the studied soil properties of 5 slopes (less than 5, 5-15, 15-30, 30-50, and more than 50%) and 2 aspects (north and south) with 3 replicates were compared by nested experimental design and Tuky test in JMP statistical software.
Results and Discussion: The maximum and minimum clay contents as well as fractal dimension and organic carbon contents were found in less than 5% and more than 50% of south slopes, respectively. Clay content and fractal dimension in north aspect were also significantly (P
H. Emami; A.R. Astaraei; A. Fotovat
Abstract
Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, ...
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Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, and 60 ton/ha) of different organic compounds including municipal waste compost, sewage sludge, cattle manure, and wheat straw to gether with control treatment in three replications were applied into loamy soil. The treated soils were kept for 6 months at 70% of field capacity moisture in greenhouse condition. Then soil quality determined based on non-linear score function by using of 14 physical and chemical indicators. The results showed that the score of control treatment was 52.7, which it belong to class 4, i.e. low quality. Addition of different organic matter into studied soil led to improve soil quality score and soil quality class was increased one to 2 degrees. Among the studied treatments, the highest score of soil quality was obtained in 60 ton/ha sewage sludge and 30 and 60 ton/ha compost. Also, addition the other organic treatments cause to increase the quantitative soil quality score in relation to control, and soil quality class increased one degree. Among the studied indicators, iron (Fe), Manganese (Mn), zinc (Zn) micro-nutrients, aeration porosity (AC), and mean weight diameter of aggregates (MWD) were the important limiting indictors in degrading the soil quality in control treatment, and applying the compost and sewage sludge increased their scores.
M. Ghaemi; A. Astaraei; M. Nassiri Mahalati; S.H. Sanaeinejad; H. Emami
Abstract
Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to ...
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Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to identify intercorrelations among soil properties (chemical, physical and biological) using principal component analysis (PCA) and their relationships with maize yield variability in field. Site variables (18) and maize yield were measured in selected parts of Astan Quds agricultural fields in Mashhad city. The principal component analysis was used to reduce the site variables numbers and remove multicollinearity among variables. The first four PCs with eigenvalues>1 accounted for > 67% of variability in measured soil properties. Soil properties were grouped in four PCs as: (PC1) Soil highly descriptive fertility potential, (PC2) Soil moderately descriptive fertility potential, (PC3) Soil permeability potential, (PC4) Soil aggregation potential. The results showed that the factor of soil highly descriptive fertility potential explained 43% of variance and accounted for 77% of the yield variability in the field. Principal component analysis allows explaining a major part of crop yield variability by removing the multicollinearity.
V. Feiziasl; A. Fotovat; A. Astaraei; A. Lakzian; M.A. Mousavi Shalmani
Abstract
In order to determination of water stress threshold and dryland wheat genotypes water status in different nitrogen managements, this experiment was carried out in split split plot RCBD design in three replications in 2010-2011 cropping year. Treatments included: N application time (whole fertilization ...
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In order to determination of water stress threshold and dryland wheat genotypes water status in different nitrogen managements, this experiment was carried out in split split plot RCBD design in three replications in 2010-2011 cropping year. Treatments included: N application time (whole fertilization of N at planting time , and its split fertilization as 2/3 at planting time and 1/3 in early spring), N rates (0, 30, 60 and 90 kg ha-1) and 7 wheat genotypes. Also these genotypes were grown in supplemental irrigation condition for calculation of crop water stress index (CWSI) parameters. Canopy temperature (Tc) was measured in flowering and early milking stages. Crop water stress index (CWSI) was calculated. A non-water stressed baseline (lower baseline) were fitted as Tc-Ta=4.523-3.761×VPD; R2=0.92 and non-transpiring baseline (upper baseline) determined 6 ºC for rainfed wheat genotypes. Water stress threshold was 0.4 and crossing of that occurred 8 days before heading stage. In water stress threshold boundary, was depleted 60 mm available water from 0 to 50 cm soil depth. There was negative significant relationship (p >0.01) between CWSI and grain yield in all treatments and different nitrogen rates. Nitrogen application reduced water stress and increased grain yield of rainfed wheat genotypes. Ohadi and Rasad genotypes showed highest resistance to water stress and high grain yield production for N30 in split and planting time application, respectively. Cereal4 and Rasad genotypes were suitable for N60 application in split and planting time application, respectively.
A. Lakzian; M. Fazeli Sangani; Alireza Astaraei; A. Fotovat
Abstract
This study was conducted to evaluate using terrain attributes derived from digital elevation model (DEM) as ancillary data to predict soil organic carbon (SOC) by implementing different statistical and geostatistical techniques. A linear regression model (LR), Artificial Neural Network model (ANN), ordinary ...
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This study was conducted to evaluate using terrain attributes derived from digital elevation model (DEM) as ancillary data to predict soil organic carbon (SOC) by implementing different statistical and geostatistical techniques. A linear regression model (LR), Artificial Neural Network model (ANN), ordinary kriging (OK), ordinary co-kriging (OCK), regression kriging (RK) and kriging with an external drift (KED) were performed to predict spatial distribution of SOC in an area of 2400 km2 in mashhad, iran. The SOC was measured for 200 soil samples of the study area and their corresponding Terrain attributes value was extracted from derived from 10-m resolution DEM. correlation between measured SOC and individual terrain attributes was determined, the number of 160 data were used for model development and 40 as validation data set. Resulting maps of different interpolation methods were compared to evaluate map quality using MAE and R2 criteria calculated from plotting measured versus estimated data. The results showed that there is a significant but not strong correlation between SOC and terrain attributes. The comparison of estimation techniques showed that the KED technique with wetness index as ancillary data has the best performance (MAE=0.18 %, R2=0.67) of all, but no significant difference with RK. There were modest differences between maps created with geostaistical technique but sensible difference with LR and ANN ones. The results of this study propose that although there is a significant correlation between SOC and terrain attributes therefore It can be use for enhancing the quality of map, but it is not able to express the spatial variability of SOC as it is necessary for detailed soil map. Because there is other factors controlling SOC spatial distribution
F. Akbarnejad; A. Astaraei; A. Fotovat; M. Nasiri Mahalati
Abstract
Recently Application of municipal solid waste compost and sewage sludge on the farm land had received considerable attention. These organic wastes provides a valuable source of organic matter and enhances crop yield and soil fertility by improving soil physical, chemical and biological properties. To ...
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Recently Application of municipal solid waste compost and sewage sludge on the farm land had received considerable attention. These organic wastes provides a valuable source of organic matter and enhances crop yield and soil fertility by improving soil physical, chemical and biological properties. To evaluate the influences of municipal solid waste compost (MSWC) and sewage sludge (SS) on chemical properties of soil an experiment was conducted with Municipal solid waste compost at 0, 15, 30 ton/ha (C0, C15 and C30) and sewage sludge at 0, 15, 30 ton/ha (S0, S15 and S30) in a factorial experiment based on completely randomized design with three replications in greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad. Results showed that municipal solid waste compost and sewage sludge and their interaction effects had significant effects on soil chemical properties. With increasing amounts of municipal solid waste compost and sewage sludge, organic carbon and electrical conductivity of soil increased. Portion of Sewage sludge compared to municipal solid waste compost in increasing of organic nitrogen is lower. The most amount of soil organic nitrogen was observed in municipal solid waste treatments. Also use of these wastes together decreased soil acidity.
M. Mohammadi San; A.R. Astaraei; A. Fotovat; A. Lakziyan; M. Taheri
Abstract
Abstract
With increasing population, Mine activities for metal proceeding are also increasing, so environment will be influenced by contaminant especially heavy metals. In situ immobilization of heavy metals using inexpensive amendments is considered as a simple and cost-effective approach for reducing ...
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Abstract
With increasing population, Mine activities for metal proceeding are also increasing, so environment will be influenced by contaminant especially heavy metals. In situ immobilization of heavy metals using inexpensive amendments is considered as a simple and cost-effective approach for reducing heavy metal contamination. In this research we used sequential extraction for assessing reduction in availability of heavy metal in lead and zinc mine waste (bama mine around Isfahan). The effects of chemical amendments consist of 3 level of Zeolite 0 (Z1), 5% (Z2) and 10% (Z3) and 3 level of Triple Super Phosphate 0 (P1), 0.25% (P2) and 0.5% (P3) on speciation of Pb, Zn and Cd was investigated by sequential extraction based on tesier method. Total concentration of Pb, Zn and Cd were 2300, 16500 and 27.4 mgkg-1 d.m. Result showed that TSP transform heavy metal specially Pb from exchangeable and carbonate fractions to residual and organic, sulfides fractions. Zeolite also transformed Pb and Zn from carbonate fraction to residual fraction. But eth effect of phosphorous was superior to zeolite. There was no interaction between Zeolite and TSP.
Keywords: Soil pollution, Heavy metals, Fractionation, In situ immobilization
B. Ghahraman; K. Davary; A.R. Astaraei; M. Majidi; S. Tamassoki
Abstract
Abstract
Irrigation planning and management requires continious monitoring and measurements of soil moisture content. Application of Gypsum blockes (GB) are common in soil moisture measurements. GB readings are subjected to its geometry and soil solution concentration. This study was carried on 90 ...
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Abstract
Irrigation planning and management requires continious monitoring and measurements of soil moisture content. Application of Gypsum blockes (GB) are common in soil moisture measurements. GB readings are subjected to its geometry and soil solution concentration. This study was carried on 90 GB in research greenhouse of Faculty Agricultural, Ferdowsi University of Mashhad. At the begining, all GB were calibrated in distilled water. Further, readings were collected in four solutions of 2, 6, 10 and 18 dS/m salinity. Then, three soil media with different textures (sandy loam, loam, clay loam) at 5 levels of salinity rate (trace, 2, 6, 10 and 18 dS/m of saturated extract) were studied, as 15 treatments. GB readings, at different soil moisture contant, were made by ELE-5910A. For each treatment, readings vs. soil moistures were plotted. These curves were compared with that of standard (same soil texture with trace salinity). Finally, some corrector functions were developed to eliminate the salinity effects from GB readings.
Key words: Gypsum block, Salinity, Salinity effect correction, electrolytic concentration of soil solution
