Soil science
S. Naseri; Sh. Kiani; H.R. Motaghian
Abstract
IntroductionUrea is one of the nitrogen chemical fertilizers for vegetable production in soil. But it is seldom used in soilless cultures. Leafy vegetables such as Lettuce (Lactuca sativa L.) contain high levels of nitrate and attempts have been made to reduce the nitrate concentration in this crop for ...
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IntroductionUrea is one of the nitrogen chemical fertilizers for vegetable production in soil. But it is seldom used in soilless cultures. Leafy vegetables such as Lettuce (Lactuca sativa L.) contain high levels of nitrate and attempts have been made to reduce the nitrate concentration in this crop for human consumption. Using reduced forms of nitrogen, i.e. urea, is one of the applied strategies for reducing nitrate accumulation in lettuce. Little information is available concerning urea as a source of nitrogen for production of leafy vegetables such as lettuce in soilless culture. This experiment was conducted to investigate the effect of different ratios of urea:nitrate in nutrient solution on the growth indices, yield and nitrate accumulation of red French lettuce (Lactuca sativa L. cv. Lolla Rossa) in soilless culture. Materials and MethodsA hydroponic experiment using completely randomized design was carried out with seven ratios of urea:nitrate in nutrient solution and four replications in the research greenhouse of Shahrekord University. Urea:nitrate ratios in nutrient solution were: 0:100, 10:90, 20:80, 30:70, 40:60, 50:50 and 60:40. Lettuce seedlings were grown in 2 L plastic pots (one plant per pot) containing mixture of cocopeat + perlite at the ratio of 2:1 (v/v) and were manually fertigated with nutrient solutions on a daily basis. Four weeks after transplanting, lettuce plants were harvested and fresh weights of shoot and root were determined. Plant growth indices including of plant height, plant diameter, leaf length, leaf width, leaf number, leaf greenness index and leaf brix level were measured. After measuring the growth indices, the leaves were grouped separately according to leaf numbers 1-10=outer leaves, >11= inner leaves. The samples were dried in an oven at 60 °C and were ground. Nitrate concentrations in samples were determined calorimetrically using a spectrophotometer at a wavelength of 410 nm. Analysis of variance was performed using SAS software version 9.4. Means comparison was conducted using least significant difference test at 0.05 probability level. Results and DiscussionThe results indicated that application of different ratios of urea to nitrate in nutrient solution had not significant effect on the lettuce growth indices including of plant diameter, leaf length, leaf width, leaf number, leaf greenness index and leaf brix level in comparison with 0:100 of urea:nitrate ratio. Also, root and shoot fresh weights were not affected by urea:nitrate ratio in nutrient solution. The greatest quantity of shoot fresh weight (141 g per plant) was obtained with a 50:50 urea:nitrate ratio. However, this was not significantly different from the shoot fresh weight (125 g per plant) observed when urea was not included in the nutrient solution. Shoot nitrogen concentration (except for plants nourished with a 50:50 urea:nitrate ratio) was not affected by increasing the urea:nitrate ratio in the nutrient solution. The results revealed that application of urea in nutrient solution effectively provided the nitrogen requirement of lettuce. This indicates that lettuce plants can efficiently hydrolyze urea and use it efficiently as a nitrogen source. Application of urea in the nutrient solution led to significant decrease in the nitrate concentration of lettuce root (P< 0.05). Moreover, increasing urea:nitrate ratio in nutrient solution resulted in significant decrease of the nitrate concentration of outer leaves, inner leaves and all leaves of lettuce (P< 0.01). The highest and lowest nitrate concentration in inner, outer and all leaves of lettuce were obtained in plants nourished with 0:100 and 50:50 urea:nitrate ratio in nutrient solution, respectively. Application of urea:nitrate ratio of 50:50 led to the meaningful decrease of nitrate concentration in root (43%), outer leaves (41%), inner leaves (44%) and all leaves (43%) of lettuce in comparison with 0:100 of urea:nitrate ratio. Urea had a repressive effect on nitrate influx and decreased its uptake by plants. Also, after urea uptake by plant root, it is first degraded by cytosolic ureases and then ammonium is incorporated via the GS-GOGAT (Glutamine Synthetase- Glutamine α-OxoGlutarate Amino Transferaze) cycle. Therefore, application of urea in nutrient solution can lead to the reduction of nitrate accumulation in plants. ConclusionBased on the shoot fresh weight and nitrate concentration in lettuce leaves, replacing 50% of nitrate in nutrient solution with urea is recommended for red French lettuce production in hydroponic culture under the conditions of the present study. Compared to other nitrogen fertilizers, urea has a lower price and its application in nutrient solution is useful in reducing production costs.
F. Mohammadi Navchinejad; A. R. Hosseinpur; H. R. Motaghian
Abstract
Introduction: Application of organic fertilizers such as vermicompost to agricultural calcareous soils with low organic matter content is a way to add nutrients to these soils. Different organic fertilizers have different effects on soil nutrient availability. Moreover, the study of nutrients distribution ...
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Introduction: Application of organic fertilizers such as vermicompost to agricultural calcareous soils with low organic matter content is a way to add nutrients to these soils. Different organic fertilizers have different effects on soil nutrient availability. Moreover, the study of nutrients distribution in the soil allows us to investigate their mobility and bioavailability. Zinc (Zn) deficiency is an important problem in many calcareous soils due to its effect on increasing the yield of agricultural products. Organic fertilizers can improve availability of Zn by impact on its fractionation. On the other hand, their interaction with chemical fertilizers requires careful consideration of availability and fractionation of Zn in soils treated with organic and chemical fertilizers. The aim of this research was to investigate the interaction effect of zinc sulphate, and vermicompost on availability and fractions of Zn in a calcareous clay soil.
Materials and Methods: This study was performed as a completely randomized factorial design including two levels of vermicompost (0 and 1% w/w) and three levels of Zn (0, 2, and 5 mg kg-1 as ZnSO4) with three replications. All treated soils were incubated for 120 days at 22 ± 1 0C and constant moisture (17% w/w). Zinc availability (DTPA-TEA) and other fractions (BCR method) were determined at the beginning of experiment, 60 days, and 120 days after incubation. The soil samples were sequentially extracted using an operationally defined sequential fractionation procedure, based on that employed by BCR in which increasingly strong extractants were used to release Zn associated with different soil fractions. Four Zn -fractions were extracted in the following sequence: Step 1: soluble, exchangeable, and associated with carbonates fraction (a 40 ml of 0.1 M CH3COOH for 16 h at room temperature), Step 2: iron-manganese oxides-associated fraction (40 ml of 1 M NH2OH.HCl in 1.5 M HNO3 for 16 h at 22 0C), Step 3: organic matter-associated fraction (50 ml of 1 M CH3COONH4 in 1.5M HNO3 for 16 h at 85 0C) and Finally step 4: residual fraction was determined using 4 M HNO3 (a 12.5 ml volume of 4 M HNO3, for 16 h at 80 0C). Concentrations of Zn in all extractants were determined by Atomic absorption spectroscopy..
Results and Discussion: The results of this study showed that the mean of Zn extracted by DTPA-TEA after vermicompost application increased significantly (P<0.05). The interaction between vermicompost and time on Zn extracted by DTPA-TEA was not significant (P>0.05). Zinc extracted by DTPA-TEA decreased with increasing incubation time. All forms of Zn increased by vermicompost application in soil samples treated with ZnSO4. Soluble, exchangeable, and bound to carbonates Zn and Zn associated to Fe-Mn oxides fractions (except vermicompost with 5 mg kg-1 Zn at 60 days after incubation) increased with increasing incubation time. Zinc associated to organic matter increased 60 days after incubation compared to the beginning of the experiment. However, difference between Zn associated to organic matter at 120 days after incubation and beginning of the experiment was not significant (except vermicompost with 5 mg kg-1 Zn at 60 days after incubation). The results of this study showed that residual Zn decreased with increasing incubation time. Results of this study demonstrated that the fractions of Zn in the soil samples treated with ZnSO4 were modified after vermicompost application and its availability increased. Therefore, the application of chemical fertilizers with organic fertilizers leads to increase Zn in the soil. The results of correlation study showed that the relation between available Zn and Zn associated to Fe-Mn oxides at 1 h (r=0.77 p<0.05), 60 days after incubation (r=0.95 p<0.05), and 120 days after incubation (r=0.95, p<0.05) was significant. There was a significant correlation between available Zn and Zn in forms of solution, exchangeable and associated with carbonates, associated with Fe-Mn oxides, and associated with organic matter, which indicate the effective role of these fractions in supplying the required Zn to plant.
Conclusion: Vermicompost application in calcareous soils increased available Zn and the effect of vermicompost was not dependent on time. Over time, there was a decrease in available Zn in the presence of chemical fertilizer. Vermicompost application in calcareous soils increased all Zn fractions. According to these results, the Zn fractions in the soil treated with zinc sulfate had been changed and its availability increased during incubation time. The results of this study demonstrated that the fractions of Zn in the soils treated with ZnSO4 and vermicompost were modified and its availability increased. Therefore, the application of chemical fertilizers with organic fertilizers can increase Zn in calcareous clay soils.
Morteza Bahmani; jahangard mohammadi; Isa Esfandiarpour Borujeni; Hamidreza Mottaghian; Keramatollah Saeidi
Abstract
Introduction: The importance and the presence of spatial variability in soil properties is inevitable, however, the understanding of causes and sources of the variability is not complete. Spatial variation of soil attributes can affect the quality and quantity of plants. Investigation of the soil variability ...
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Introduction: The importance and the presence of spatial variability in soil properties is inevitable, however, the understanding of causes and sources of the variability is not complete. Spatial variation of soil attributes can affect the quality and quantity of plants. Investigation of the soil variability at the small scale can be evaluated by classic statistics and geospatial statistics. The present study was conducted to investigate the spatial variability of yield characteristics of rose (Rosa Damasceneea Mill) and soil characteristics in two main cultivated fields of rose (Negar- Golzar) with different climatic and topographic characteristics located in Bardsir city, Kerman Province.
Materials and Methods: In order to achieve the objectives of the present study, 100 soil and plant samples were collected from each farm. The soil samples were taken from 0 to 25 cm depth and analyzed. The measured soil properties at each location were including fragment, clay, silt, sand, and organic matter contents, CEC, calcium carbonate equivalent, EC, pH, total nitrogen, available phosphorus, and available potassium. Moreover, some plant characteristics (yield, plant height, and plant crown diameter) were measured at each point. Then, maps of soil properties and plant induces were prepared using Geoeas, Variowin, and surfer software. Descriptive statistics were applied using Statistica software (version 20). Kolmogorov-Smirnov test was also used to test the tolerance of variables distribution.
Results and Discussion: The results of Kolmogorov-Smirnov test showed that all characteristics of the plant and soil in both farms follow the normal distribution. Statistical analysis showed that coefficient of variation of soil properties was as follows: total nitrogen (54.47%) and pH (3.16%) in Negar farm, and EC (46.09%) and pH (35.3%) in Golzar farm. The variability of nutrients in both farms had similar trends, so that total nitrogen, phosphorus and potassium have the highest to lowest coefficients of variation, respectively. Analysis of variograms indicated that all of the variables in both fields have a strong and moderate spatial variability. Ranges for variograms were from 122.16m (for yield) to 218.46 m (for silt) in Negar farm and from 115.1m (for available K) to 228 m for (total nitrogen) in Golzar unit. The distribution conditions and spatial variations of the soil properties in the study area were not uniform due to variation of the range of the variograms. The results also showed that the yield characteristics of the rose with some soil characteristics have a closer spatial relationship. About this, in the Negar farm, the range of the rose flower yield was close to the clay, available potassium and calcium carbonate contents. In the Golzar farm, the range of rose flower yield was close to the range of clay, silt, fragments and available phosphorus contents. The spatial correlation ratio showed that all plant characteristics including plant yield, plant height and plant diameter had a strong spatial correlation in the Golzar farm, and all characteristics of the soil were in the medium spatial correlation. Also, in the Negar farm, the product yield characteristics were in a strong spatial correlation class, and all other characteristics were in the medium spatial correlation. Kriging maps showed that soil characteristics and product yield in the study area had spatial distribution. The similarity of the spatial distribution pattern of some variables was one of the important features that these maps showed.
Conclusion: The results of this study showed the characteristics of plant yield and soil characteristics have a moderate to strong spatial dependency even in small scales. Kriging maps illustrated that the pattern and distribution of soil properties even within a farm can be varied. However, the spatial pattern of some soil characteristics such as organic matter and total nitrogen with the spatial pattern of plant characteristics and the dimensions of the farms showed conformity. This indicates that the variability of these characteristics is mainly under the management of farmers, and in order to optimize the use of nutrients, inputs should be re-evaluated by farm managers. In general, the results of this study indicated geostatistical method can be used to recognize of control factors of plant production and use its information in order to improve management.
Mina Nazarizadeh; Fayez Raiesi; Hamid reza Motaghian
Abstract
Introduction: Salinity and pollution are two environmental stresses that individually influence the population, growth and activity of earthworms as soil bioengineers. It is well-known that the population and activity of these organisms are mostly reduced or even their activity and growth can be stopped ...
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Introduction: Salinity and pollution are two environmental stresses that individually influence the population, growth and activity of earthworms as soil bioengineers. It is well-known that the population and activity of these organisms are mostly reduced or even their activity and growth can be stopped in polluted and saline soils. The individual effects of these abiotic stresses on earthworms, however, depend on the level of salinity, pollution and organic matter. Nonetheless, the joint or combined effect of these stresses on earthworms, especially in arid and semi-arid areas, is poorly known. Because of the importance of earthworms in soil ecosystem, the study of salinity and pollution interactions on earthworm population and activity to reduce their detrimental effects using organic materials is essential. The aim of this study was to examine how salinity and lead (Pb) stresses simultaneously affect the earthworms in soil ecosystem.
Materials and Methods: In this research, the interaction effect of salinity stress using sodium chloride (NaCl) and Pb stress using lead nitrate (PbNO3) on the population, weight and activity of the earthworm Eisenia fetida was studied under greenhouse conditions. This factorial experiment was carried out using 3 factors, including Pb pollution (control and 30 mg kg-1 Pb), salinity (control, 4 and 8 dS m-1) and cow manure (control and 4% by weight) arranged in a completely randomized design with four replicates. The experiment lasted 13 weeks and earthworm’s population and activity including the number of adult worms, total earthworms, wet and dry weights, and wet and dry weights of casts produced by earthworm were measured at the end of the experiment. Concentration of DTPA (di-ethylene-triamine-pentaacetic acid) extractable Pb was also determined to assess how salinity influences the accessibility of this metal in the soil. The Fisher’s least significant difference test was used to determine the significance of any difference between the means values at 5% level with the STATISTICA 8 software. The Bliss Independence Model was used to determine the type of interaction between salinity and Pb pollution for each manure treatment.
Results and Discussion: The current results showed that increasing salinity level enhanced the accessibility of Pb and subsequently its toxicity for earthworms. In contrast, addition of cow manure reduced the accessibility of Pb by 22-50% at all salinity levels. Earthworm population, wet and dry body weights, and wet and dry weights of casts produced by worms were all significantly (p
Parvin Kabiri; hamid reza motaghian; Alireza Hosseinpur
Abstract
Introduction: Anthropogenic activities have transformed the global geochemical cycling of heavy metals. Mine tailings are of great concern due to the detrimental effects of toxic inorganic elements causing environmental risks. Zinc (Zn) as an essential element is required in small amounts for various ...
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Introduction: Anthropogenic activities have transformed the global geochemical cycling of heavy metals. Mine tailings are of great concern due to the detrimental effects of toxic inorganic elements causing environmental risks. Zinc (Zn) as an essential element is required in small amounts for various biochemical reactions and physiological functions. However, high concentrations of Zn can induce oxidative stress. Applying an organic amendment is a promising, in situ phytostabilization approach to alleviate the phytotoxic effects of heavy metal in contaminated soils. The application of biochar as an amendment may be a solution to reduce the risk of pollutant diffusion. Biochars is a fine-grained biological residue combusted under low oxygen conditions, resulting in a porous, stable carbon-based material. The potential biochar applications include carbon sequestration, soil fertility improvement, and pollution remediation; therefore, it can reduce pollutants mobility and bioavailability.
Materials and Methods: Results of this research indicated that biochars decreased Zn concentration in maize shoots and roots. They reduced Zn concentration in the shoot/root of maize. Zinc concentration in shoots and roots of maize (Zea mays L.) harvested at 60 days after sowing, decreased with increasing thermochemical temperature and application rate of biochar. In treated soil with 2% (w/w) biochar prepared at 600 °C, Zn concentration in shoots and roots decreased by 21.6 and 33.0 % respectively (p
Mohamad Rahmanian; AliReza Hosseinpour; Ebrahim Adhami; Hamidreza Motaghian
Abstract
Introduction: Rhizosphere is commonly defined as the zone where root activity significantly influences the biological and chemical properties of the soil. Biological, physical and chemical characteristics of rhizosphere, especially metal availability and metal chemical forms are different than the bulk ...
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Introduction: Rhizosphere is commonly defined as the zone where root activity significantly influences the biological and chemical properties of the soil. Biological, physical and chemical characteristics of rhizosphere, especially metal availability and metal chemical forms are different than the bulk soil. Plant roots continuously release compounds such as sugars, amino acids, and carboxylic acids. Plant roots have the ability to transform metal fractions for easier uptake through root exudation in the rhizosphere. This study was conducted to investigate change in availability and fractions of Copper in the rhizosphere of sunflower (Helianthus annuus L.) in a sandy contaminated soil treated with chelators (EDTA, citric acid and poultry manure extract (PME)) in greenhouse condition.
Materials and Methods: In this study, EDTA and citric acid were used at concentrations of 0, 0.5 and 1 mmol kg-1 soil and PME was used at concentrations of0, 0.5 and 1 g kg-1 soil. Three seeds of sunflower were planted in the rhizobox. After 10 weeks, plants were harvested and rhizosphere and bulk soils were separated. Dissolved organic carbon (DOC), microbial biomass carbon (MBC), available Cu (by using 7 chemical procedures including DTPA-TEA,AB-DTPA, Mehlich1, Mehlich3, CaCl2 0.01 M, rhizosphere-based method and distilled water) and Cu-fractions were determined in the rhizosphere and bulk soils.
Results and Discussion: Rhizosphere soils properties were different with bulk soils. The results showed that the mean of DOC and MBC in the rhizosphere soils were higher than the bulk soils, but this difference was significant in some treatments. The mean value of pH in the rhizosphere soils was significantly (p
Akram Farshadirad; Alireza Hosseinpour; Shojae ghorbani; hamidreza motaghian
Abstract
Introduction: In recent years, because of the presence of industrial factories around the Isfahan province of Iran and high concentrations of heavy metals in the vicinity of them, and the gradual accumulation of heavy metals from various sources of pollution in urban areas over time, including gasoline ...
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Introduction: In recent years, because of the presence of industrial factories around the Isfahan province of Iran and high concentrations of heavy metals in the vicinity of them, and the gradual accumulation of heavy metals from various sources of pollution in urban areas over time, including gasoline combustion, and use of urban waste compost and sewage sludge as fertilizer, there has been widespread concerned regarding the human health problems with increasing heavy metals in soils around the Isfahan city. The variation of composition in the soil matrix may lead to variation of composition and behavior of soil heavy metals. Soil is a heterogeneous body of materials and soil components are obviously in interaction. Studies tacking this complexity often use aggregate measurements as surrogates of the complex soil matrix. So, it is important the understanding soil particle-size distribution of aggregates and its effects on heavy metal partitioning among the size fractions, the fate of metals and their toxicity potential in the soil environment. Therefore, the present study aimed to determine the Cu release potential from different size fractions of different polluted soils by different extractants and their availability for corn plant.
Materials and Methods: Five soil samples were collected from the surface soils (0–15 cm) of Isfahan province, in central of Iran. The soil samples were air-dried and ground to pass a 2-mm sieve for laboratory analysis. Air dried samples fractionated into four different aggregate size fractions 2.0–4.0 (large macro-aggregate), 0.25–2 (small macro-aggregate), 0.05–0.25 (micro-aggregate), and
hamid reza motaghian; alireza hosseinpuor; Shahram Kiani
Abstract
Introduction: Use of organic fertilizers such as vermicompost in agricultural soils with low organic matter content is almost considered as a one way for adding nutrients in these soils. However, application of these fertilizers may affect micronutrient release characteristics. Micronutrient release ...
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Introduction: Use of organic fertilizers such as vermicompost in agricultural soils with low organic matter content is almost considered as a one way for adding nutrients in these soils. However, application of these fertilizers may affect micronutrient release characteristics. Micronutrient release Kinetics in soils especially in amended soils give information about potential of amended soils to release these elements into solution. Although it is important to study kinetics of micronutrient release from soils to identify soil micronutrients buffering capacity, little attention has been paid to micronutrients desorption rate studies especially in amended soils. The rate of release micronutrients from soil solid phase by considering micronutrients as adsorbed ions or in mineral forms is an important parameter in nutrition of plants by microelements and a dynamic factor that regulates its continuous supply to growing plants; nonetheless, little attention has been paid to micronutrients kinetics inrelease studies.
Material and Methods: In this study, kinetics of zinc (Zn) and copper (Cu) were compared in one calcareous soil amended with 0, 0.5, and 1% (w/w) of manure and vermicompost in a completely randomized design and then amended and un-amended soils were incubated at field capacity, for 30 days. After incubation period, amended and un-amended soils were air-dried and were prepared to kinetics study. Kinetics of Zn and Cu release were studied by successive extraction with DTPA-TEA solution. Two grams of the amended and un-amended soils, in triplicate, suspended in 20 ml DTPA-TEA solution were equilibrated at 25±10C for 1, 8, 24, 48, 72, 96, 120, 144, 168, 336 and 504 h by shaking for 15 min. before incubation and 15 min. before the suspensions were centrifuged. Seven drops of toluene were added to each 1000 ml of extractant to inhibit microbial activity. Zinc and copper desorption with time was fitted by using different equations (Zero-order, First-order, Parabolic diffusion, Simplified Elovich, and Power function).
Results and Discussion: Results showed that released Zn in soils amended with manure and vermicompost compared to control soil significantly increased (p0.05) and released Cu in soil amended with vermicompost decreased significantly (p
Alireza Hosseinpur`; hamid reza motaghian
Abstract
Introduction: Application of organic fertilizers in agricultural soils with low organic matter content is one of the best ways of nutrientsaddition to these soils. Different organic fertilizers have different effects on nutrient availability in soil. Moreover study of the distribution of nutrients in ...
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Introduction: Application of organic fertilizers in agricultural soils with low organic matter content is one of the best ways of nutrientsaddition to these soils. Different organic fertilizers have different effects on nutrient availability in soil. Moreover study of the distribution of nutrients in the soil allows investigating their mobility and bioavailability. The nutrients availability and kinetics of nutrients desorption into the soil solution is often closely related to the distribution of nutrients to different fractions in the soil. It has been assumed that the factors influencing metal fractionation and availability in soil include rate of amendment application, amount of nutrients in amendment, root-induced pH changes, metal binding by root exudates, root-induced changes of microbial activities, and metal depletion because of plant uptake.
Materials and Methods: In this study, availability and fractionation of Zinc (Zn) and Copper (Cu) were compared in one calcareous soil amended with 0, 0.5, and 1% (w/w) of cow manure and vermicompost in a completely randomized design. Also, wheat was planted in treated and untreated soils in greenhouse condition.Available Zn and Cu were determined using different methods (DTPA-TEA, AB-DTPA, and Mehlich 3). For Zn and Cu fractionation, the soil samples were sequentially extracted using an operationally defined sequential fractionation procedure, based on that employed by Tessier et al. (1979) in which increasingly strong extractants were used to release Zn and Cu associated with different soil fractions. Five Zn and Cu -fractions were extracted in the following sequence: Step 1: exchangeable fraction (a 8 ml volume of 1.0 MNaOAc (pH= 8.2) for 120 min. at room temperature)., Step 2: carbonate-associated fraction (a 8 ml volume of 1.0 MNaOAc adjusted to pH 5.0 with acetic acid for 6 h at room temperature, Step 3: iron-manganese oxides-associated fraction (20 ml of 0.04 M NH2OH.HCl in 25% (v/v) HOAc for 6 h at 96 0C)., Step 4: organic matter-associated fraction (3 ml of 0.02 N HNO3 adjusted to pH 2 and 5 ml 30% H2O2 (adjusted to pH 2.0 with HNO3) and at 85 0C for 2 h in sequence, followed by 3 ml of 30% H2O2 (adjusted to pH 2.0 with HNO3) the sample was heated to 85 0C for 3 h with intermittent agitation. After cooling, 5 ml of 3.2 M NH4OAc in 20% (v/v) HNO3 was added and agitated continuously for 30 min. Finally step 5: residual fraction was determined using 4 M HNO3 (a 12.5 ml volume of 4 M HNO3, for 16 h at 80 0C). Concentrations of Zn and Cu in all extractants were determined by AAS.
Results and Discussion: The results showed that the effect of treatments on amount of extracted Zn by different methods were significant (P0.05). The minimum and maximum of extracted Zn by DTPA-TEA were in untreated soil (0.73 mg/kg) and treated soils with 1% manure (1.30 mg/kg) and treated soils with 1% manure (1.17 mg/kg), respectively. The results showed that the effect of treatments on Zn associated with Fe-Mn oxides and Zn associated with organic matter was significant (P0.05). The correlation between extracted Zn and Cu by DTPA-TEA and AB-DTPA with Fe-Mn oxides fraction were significant (P
Y. Ostovari; K. Asgari; H. R. Motaghian
Abstract
Introduction: Estimation of cation exchange capacity (CEC) with reliable soil properties can save time and cost. Pedotransfer function (PTF) is a common method in estimating certain soil properties (e.g. CEC) that has been wieldy used for many years. One of the common techniques that have been used ...
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Introduction: Estimation of cation exchange capacity (CEC) with reliable soil properties can save time and cost. Pedotransfer function (PTF) is a common method in estimating certain soil properties (e.g. CEC) that has been wieldy used for many years. One of the common techniques that have been used to develop PTFs is multiple linear regressions. In this method, all easily obtained soil properties are linearly related to certain soil properties. In addition to multiple linear regressions method, more complex techniques such as artificial neural networks and regression tree have been used to develop PTFs. The regression tree method is a well-known method for analyzing the environmental science which determines optimal separation point of independent variables.The purposes of this study were to evaluate and compare tree and multiple linear regressions in estimating cation exchange capacity with reliable soil properties.
Materials and Methods: For this work, 106 soil samples of Unsaturated Soil hydraulic database (UNSODA), which contain a wide range of soil texture classes, were used. The examples were divided into 2 sets including 81 and 25 soil samples for developing and validating multiple linear regression and tree regression, respectively. For estimating CEC with tree and multiple regressions, soil texture properties, organic matter, pH and bulk density were used. To develop multiple linear regressions and create the tree structure, at first, correlation between cation exchange capacity with other soil properties were evaluated; then, soil properties that had significant correlation were chosen to introduce software. As well, the suggested linear function and tree structure were compared with 2 famous pedotranser functions including Bell and Van-kolen and Breeuwsma et al., which have been used for estimating CEC.For investigating the performance of multiple linear regression and tree regression to estimate CEC 1:1 lines, determination coefficient (R2), mean error (ME), root mean square error) RMSE), and geometric mean error (GMER) were used. Statistica 8.0 software that was developed by ESRI was used to develop multiple linear regressions and generate tree structure.
Results and Discussion: The results showed for developing multiple linear regression model to estimate CEC among all inputs parameters (sand, silt, clay, organic matter, pH and bulk density) only just two parameters including organic (with r=0.70) and clay percentage (with r=0.59) had a significant coefficient, so organic and clay percentage appeared, and suggested multiple linear regression models based on this two parameters, with coefficient of 3.183 and 0.274, respectively, were developed. Also, only organic matter and clay percentage from inputs parameter in tree were shown. In tree structure most nods were divided into 2 Childs nods based on organic matter and only in the left side of tree structure in the second level clay percentage was appeared. Regression tree in two data sets (validation and development) based on R2, RMSE, ME and GMER had a high quality for CEC estimation than regression methods. Proposed linear regression model had high performance than Bell and Van-kolen and Breeuwsma et al. to estimate CEC.
Conclusions: The main aim of this study was to investigate the efficiency of multiple linear regression model and regression tree to predict cation exchange capacity (CEC) based on relationships between CEC and easily measurable soil properties. For this work, 106 soil samples of UNSODA data set were used. Results showed that just clay percentage and organic matter that had higher correlation with CEC appeared in suggested linear regression and tree structure. Based on 1:1 lines, R2 ,RMSE, ME and GMER, tree regression model had higher performance than all linear regression models (suggested function , Bell and Van-kolen and Breeuwsma et. al.) to estimate cation exchange capacity. As well, suggested function had more efficiency than Bell and Van-kolen and Breeuwsma to predict CEC.
H.R. Motaghian; A. Hosseinpour
Abstract
Change in microorganism activity and chemical properties can be affect on availability and fractionation of Copper (Cu). This research was conducted to investigate the availability and fractionation of Cu in the bean rhizosphere and bulk soils in 10 calcareous soils using rhizobox at greenhouse. Total ...
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Change in microorganism activity and chemical properties can be affect on availability and fractionation of Copper (Cu). This research was conducted to investigate the availability and fractionation of Cu in the bean rhizosphere and bulk soils in 10 calcareous soils using rhizobox at greenhouse. Total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), pH, available Cu (by using 7 chemical extractants) and Cu-fractions were determined in the rhizosphere and bulk soils. The results indicated that in the bean rhizosphere soils, TOC, DOC and MBC increased significantly (p
alireza hosseinpuor; H.R. Motaghian
Abstract
The amount of available micronutrients such as zinc (Zn) is a primary concern in treated soils with sewage sludge. This study was performed to evaluate Zn availability (DTPA-TEA, Mehlich 1 and Mehlich 3) and its fractionation in soils before and after treated with sewage sludge (1% w/w) and after wheat ...
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The amount of available micronutrients such as zinc (Zn) is a primary concern in treated soils with sewage sludge. This study was performed to evaluate Zn availability (DTPA-TEA, Mehlich 1 and Mehlich 3) and its fractionation in soils before and after treated with sewage sludge (1% w/w) and after wheat plantation in greenhouse conditions. The results of this study showed that mean of Zn extracted by using chemical extractants after sewage sludge application increased significant (P0.05). The results of fractionation showed that residual Zn, exchangeable Zn, Zn associated with organic matter, Zn associated with iron-manganese oxides, and Zn associated with carbonates increased 11, 26, 94, 172, and 279% respectively. The results of mean comparison showed that different between mean of Zn fractions (except Zn associated with iron-manganese oxides) before and after planting was significant (P
H.R. Motaghian; A. Hosseinpour
Abstract
Sewage sludge uses as a low coast fertilizer to rectify deficit of elements such as zinc (Zn). A suitable extractant for estimation of bean-available Zn in calcareous soils amended with sewage sludge has not yet been introduced. The aim of this research was to assess several chemical extractants for ...
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Sewage sludge uses as a low coast fertilizer to rectify deficit of elements such as zinc (Zn). A suitable extractant for estimation of bean-available Zn in calcareous soils amended with sewage sludge has not yet been introduced. The aim of this research was to assess several chemical extractants for the estimate of available Zn in sewage sludge-amended calcareous soils. For amended soils, 1% (w/w) of sewage sludge was added to 10 calcareous soils, and the soils (amended and un-amended) were incubated at field capacity for 30 days. At the end of incubation, soils were air-dried and available Zn was determined using 7 chemical extractants (DTPA-TEA, AB-DTPA, Mehlich 1, Mehlich 2, Mehlich 3, 0.1 N HCl and 0.01 M CaCl2). Zinc concentration in shoots, Zn uptake, and shoot dry weight of bean were determined in a pot experiment in amended and un-amended soils. The results show that Mehlich 3 and Mehlich 1 extractants extracted the highest and the lowest concentrations of Zn in both amended and un-amended soils, respectively. Furthermore, all three studied indices and Zn extracted by using different methods increased in amended soils. In addition, results indicated that significant correlations were found between extracted Zn using AB-DTPA, DTPA-TEA and Mehlich 3 and plant indices in un-amended soils. On the contrary, in sewage sludge-amended soils only the correlation between extracted Zn using DTPA-TEA and Mehlich 1 with Zn uptake and shoot dry weight and Mehlich 2 with Zn concentration was significant. The results of this study showed that DTPA-TEA could estimate bean-available Zn in the sewage sludge-amended and –un-amended calcareous soils.
H.R. Motaghian; A. Hosseinpour; jahangard mohammadi; Fayez Raiesi
Abstract
Rhizosphere is a small zone and has quite different chemical, physical and biological properties from bulk soil. This research was conducted to investigate the availability and fractionation of copper in the wheat rhizosphere and bulk soils by using rhizobox at greenhouse conditions. Three seeds of wheat ...
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Rhizosphere is a small zone and has quite different chemical, physical and biological properties from bulk soil. This research was conducted to investigate the availability and fractionation of copper in the wheat rhizosphere and bulk soils by using rhizobox at greenhouse conditions. Three seeds of wheat were plant in the rhizobox. After 8 weeks, plants were harvested and rhizosphere and bulk soils were separated. Total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and available Cu (by using 7 chemical procedures) and Cu-fractions were determined in the rhizosphere and bulk soils. The results indicated that TOC, DOC and MBC in the rhizosphere were increased significantly (p
H.R. Motaghian; J. Mohammadi
Abstract
Abstract
The effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a ...
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Abstract
The effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. In this research investigated the effect of different land uses on soil physical quality indices. Three land uses including a natural pasture, dryland farming and irrigated farming were selected. From natural pasture 54 samples, dryland farming 40 samples and irrigated farming 17 samples were collected in the surface soil (0-15cm). Saturated hydraulic conductivity, infiltration rate, bulk density, soil distribution size, soil erodibility index, organic carbon and water aggregate stability (three classes) were determined for each land use. The results showed that mean, minimum and maximum of saturated hydraulic conductivity in irrigated farming land use is more than others land uses. Water aggregate stability index the macroaggregates (>2 mm) in irrigated farming land use is lower than others land uses. In the among studies variables, saturated hydraulic conductivity, clay percentage, soil erodibility index and water aggregate stability in macroaggregates in different land uses are significant differences in 5% level. Soil erodibility index and water aggregate stability for macroaggregates seems to be the most reliable soil quality indices for the area.
Keywords: Water aggregate stability, Soil quality index, Soil erodibility index
H.R. Motaghian; A. Karimi; J. Mohammadi
Abstract
Abstract
Analysis and interpreting spatial variability of soil hydraulic and physical properties on a catchment scale is important in hydrological modeling and decision making. This study was conducted to analyze and interpret spatial distribution of selected soil hydraulic and physical properties including ...
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Abstract
Analysis and interpreting spatial variability of soil hydraulic and physical properties on a catchment scale is important in hydrological modeling and decision making. This study was conducted to analyze and interpret spatial distribution of selected soil hydraulic and physical properties including clay, silt, and sand content, bulk density (BD), infiltration rate (IR) and saturated hydraulic conductivity (Ks) in Marghmalek watershed. In this research, 111 soil samples were collected in a regular spaced grid pattern of 1 km from 0-30 cm depth in order to determine the soil size distribution. In addition, at each sampling site undisturbed soil samples were obtained from the topsoil using cylinder method to determine soil bulk density and consequently the saturated hydraulic conductivity. Saturated hydraulic conductivity was determined using the falling head method. Infiltration tests were conducted on all 111 sample sites using double-ring infiltrometers. Maximum coefficient of variation (CV) was found for IR (72%) and Ks (67%). In contrast, the minimum CV value of 8% was found for BD. Statistical analysis illustrated that there was a significant difference (P
