Potential of indigenous microbes as helping agents for phyto-restoration of a Pb-contaminated soil

The aim of this study was to assess the effects of heavy metal tolerant soil microbes inoculation on growth and metal uptake of pearl millet, Pennisetum glaucum, couch grass,Triticum repens and alfalfa,Medicago sativa in a soil spiked (and subsequently aged) with increasing concentrations of Pb. A soil sample (soil 1) was spiked with increasing (0 to 1500 mg/kg) concentrations of Pb and incubated for a seven months period. Another soil sample with a historical background of metal contamination (soil 2), having heavy metals-resistant microbial communities, also was taken and used as inocula. The plants were grown in pots containing contaminated soils. At the end of growth period, plants shoots were harvested, washed, oven-dried, ground and analyzed for Pb. The results showed a significant reduction (p < 0.05) in plants yield by increasing soil Pb concentration and inoculation of stress-adapted microbes further increased this reduction. This could be attributed to the increased access of plants to the relatively immobile Pb existed in the studied calcareous soil as well as to more metal contaminant absorption caused by soil microbial activity. In general, introduction of the microbes also resulted in lower Pb uptake by the studied plants

Comparing the Goodness of Different Statistical Criteria for Evaluating the Soil Water Infiltration Models

Introduction: The infiltration process is one of the most important components of the hydrologic cycle. Quantifying the infiltration water into soil is of great importance in watershed management. Prediction of flooding, erosion and pollutant transport all depends on the rate of runoff which is directly affected by the rate of infiltration. Quantification of infiltration water into soil is also necessary to determine the availability of water for crop growth and to estimate the amount of additional water needed for irrigation. Thus, an accurate model is required to estimate infiltration of water into soil. The ability of physical and empirical models in simulation of soil processes is commonly measured through comparisons of simulated and observed values. For these reasons, a large variety of indices have been proposed and used over the years in comparison of infiltration water into soil models. Among the proposed indices, some are absolute criteria such as the widely used root mean square error (RMSE), while others are relative criteria (i.e. normalized) such as the Nash and Sutcliffe (1970) efficiency criterion (NSE). Selecting and using appropriate statistical criteria to evaluate and interpretation of the results for infiltration water into soil models is essential because each of the used criteria focus on specific types of errors. Also, descriptions of various goodness of fit indices or indicators including their advantages and shortcomings, and rigorous discussions on the suitability of each index are very important. The objective of this study is to compare the goodness of different statistical criteria to evaluate infiltration of water into soil models. Comparison techniques were considered to define the best models: coefficient of determination (R2), root mean square error (RMSE), efficiency criteria (NSEI) and modified forms (such as NSEjI, NSESQRTI, NSElnI and NSEiI). Comparatively little work has been carried out on the meaning and interpretation of efficiency criteria (NSEI) and its modified forms used to evaluate the models. Materials and Methods: The collection data of 145 point-data of measured infiltration of water into soil were used. The infiltration data were obtained by the Double Rings method in different soils of Iran having a wide range of soil characteristics. The study areas were located in Zanjan, Fars, Ardebil, Bushehr and Isfahan provinces. The soils of these regions are classified as Mollisols, Aridisols, Inceptisols and Entisols soil taxonomy orders. The land use of the study area consisted of wheat, barley, pasture and fallow land.The parameters of the models (i.e. Philip (18), Green and Ampt (3), SCS (23), Kostiakov (6), Horton (5), and Kostiakov and Lewis (11) models) were determined, using the least square optimization method. All models were fitted to experimental infiltration data using an iterative nonlinear regression procedure, which finds the values of the fitting parameters that give the best fit between the model and the data. The fitting process was performed using the MatLab 7.7.0 (R2008b) Software Package. Then, the ability of infiltration of water into soil models with the mean of coefficient of determination (R2), root mean square error (RMSE), efficiency criteria(NSEI) and modified forms (such as NSEjI, NSESQRTI,NSElnI and NSEiI) were determined and goodness of criteria was compared for the selection of the best model. Results and Discussion: The results showed the mean of RMSE for all soils cannot always be a suitable index for the evaluation of infiltration of water into soil models. A more valid comparison withNSEI, NSEjI, NSESQRTI, NSElnI indices indicated that these indices also cannot apparently distinguish among the infiltration models for the estimation of cumulative infiltration. These indices are sensitive to the large amount of data. The NSEiI index with giving more weight to infiltration data in shorter times was selected as the most appropriate index for comparing models. According to the NSEiI index, Kostiakov and Lewis, Kostiakov, SCS, Philip, Horton, and Green and Ampt models were the best models in approximately 72.42, 44.83, 26.9, 53.11, 11.73 and 1.0 percent of soils, respectively. Conclusion: The results of this study indicated that the ability of modified forms of NSE indices in evaluation of infiltration of water into soil models depend on the influence of models from infiltration data values in different time series. This encourages us to be cautious on the application and interpretation of statistical criteria when evaluating the models. Keywords: Error, Statistical criteria, Infiltration water into soi

Ring diameter effects on determination of field-saturated hydraulic conductivity of different loam soils

Establishing ring diameter effects on the field-saturated soil hydraulic conductivity, Kfs, determined with ponding infiltrometer methods can help to find a compromise between the need to sample a large area with an individual measurement and the impracticality of using large rings in the field. Five ring sizes (diameter, D = 5.5, 10.9, 16.0, 27.8 and 31.8 cm) were used to determine Kfsby the simplified falling head (SFH) technique in four loamy soils with different salinity (electrical conductivity of saturated extract, ECe= 0.9\ue2\u80\u9329.4 dS/m) and sodicity (exchangeable sodium percentage, ESP = 2.7\ue2\u80\u9381.3%) levels. According to USDA classification, two soils were non-saline, non-sodic (NN1 and NN2), a soil was saline-sodic (SS) and another soil was non-saline and sodic (NS). Ring diameter did not have in general a statistically detectable influence on the mean Kfsof a given soil. The only exception was for the NS soil but also in this case the effect was negligible for many practical applications since Kfsincreased by 2.3 times as D increased from 5.5 to 31.8 cm. However, smaller rings implied either higher or lower estimates of Kfsvariability as compared with larger rings, depending on the soil. The former result probably occurred when only a part of total heterogeneity was sampled with a small ring. The latter result was probably obtained when insertion of small rings altered or even destroyed the fragile macroporosity and also when using small rings increased the probability to only sample relatively homogeneous soil volumes. As compared with the largest rings, those with a diameter in the range 10.9 to 27.8 cm yielded a similar information on the differences between the soil hydraulic conductivity of the four considered soils. More discrepancies were detected for the smallest rings (D = 5.5 cm). Even small rings appear usable to obtain a mean value of Kfsfor the sampled soils, perhaps with the exception of the smallest ones. However, as large as possible rings should be used if Kfsvariability has also to be determined

Social Capital of Parents of Children and Adolescents and Its Relation to Psychiatric Disorders; A Population-Based Study

Social capital is a complex concept that is considered an effective factor in the development of societies. Considering the importance of burdens of psychiatric disorders in Iran, we studied the relationship between various dimensions of social capital of parents of children and adolescents and psychiatric disorders among them. In this cross-sectional study, 18,940 parents of children and adolescents aged 6 to 18 years old were randomly selected from all provinces of Iran and were evaluated by the Millon clinical multiaxial inventory-III (MCMI-III) and a modified version of Nahapiet and Ghoshal questionnaire. MCMI-III was designed as a self-report tool for investigating psychiatric clinical disorders and personality traits in the general population. Modified Nahapiet and ghoshal questionnaire has 20 items and measures four components of social capital included trust, values, communication, and collaboration. Validity and reliability of both questionnaires have been approved in Iran. In the regression model, the relationship between social capital components and clinical and sever clinical syndromes, in the form of regression weight and standard weight for trust was � 0.558 and � 0.062 with p value less than 0.0001, and for values was � 0.466 and � 0.057, respectively, with p value less than 0.0001. There was a reverse correlation between social capital components of parents of children and adolescents and psychiatric disorders in Iran. In regression statistical models, the two components of values and trust were negative predictors of psychiatric disorders. Considering the high prevalence of psychiatric disorders in Iran, it seems that the strengthening of cognitive and structural aspects of social capital of parents of children and adolescents is one of the effective factors in reducing the prevalence of these disorders among them. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Social Capital of Parents of Children and Adolescents and Its Relation to Psychiatric Disorders; A Population-Based Study

Social capital is a complex concept that is considered an effective factor in the development of societies. Considering the importance of burdens of psychiatric disorders in Iran, we studied the relationship between various dimensions of social capital of parents of children and adolescents and psychiatric disorders among them. In this cross-sectional study, 18,940 parents of children and adolescents aged 6 to 18 years old were randomly selected from all provinces of Iran and were evaluated by the Millon clinical multiaxial inventory-III (MCMI-III) and a modified version of Nahapiet and Ghoshal questionnaire. MCMI-III was designed as a self-report tool for investigating psychiatric clinical disorders and personality traits in the general population. Modified Nahapiet and ghoshal questionnaire has 20 items and measures four components of social capital included trust, values, communication, and collaboration. Validity and reliability of both questionnaires have been approved in Iran. In the regression model, the relationship between social capital components and clinical and sever clinical syndromes, in the form of regression weight and standard weight for trust was - 0.558 and - 0.062 with p value less than 0.0001, and for values was - 0.466 and - 0.057, respectively, with p value less than 0.0001. There was a reverse correlation between social capital components of parents of children and adolescents and psychiatric disorders in Iran. In regression statistical models, the two components of values and trust were negative predictors of psychiatric disorders. Considering the high prevalence of psychiatric disorders in Iran, it seems that the strengthening of cognitive and structural aspects of social capital of parents of children and adolescents is one of the effective factors in reducing the prevalence of these disorders among them