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1

Pedotransfer function capability to simulate behaviour of smectitic soils in estimation of various soil water retention curve models

100%
Zadeh G. E., Bayat H.
Polish Journal of Soil Science
|
2012
|
tom 45
|
nr 2
For modelling the flow transport in unsaturated conditions, we can use hydraulic properties which are expensive and time-consuming to be obtained directly because of high variability and complexity of soil systems. Few studies have been done about pedotransfer functions (PTFs) in smectitic soils. Moreover, the utility of fractal parameters in the prediction of soil water retention curve (SWRC) have not been investigated in these soils. In this study, PTFs have been made for estimating the parameters of van Genuchten (VG) and Dexter models by regression and artificial neural networks methods. Therefore, 69 soil samples were collected from Guilan Province, Iran. Fractal and non-fractal models were fitted to the particle size distribution (PSD) and micro-aggregate size distribution (ASD) and their parameters were calculated. To create PTFs, the parameters of PSD and ASD models were used as estimators. The comparison of the results of the two models of Dexter and VG shows the priority of Dexter model for the purpose of testing of smectitic soils. The results showed the superiority of Fredlund et al. PSD model parameters and fractal parameters of ASD, in the estimation of Dexter and VG SWRC models, respectively. This outcome may be related to the higher accuracy of Fredlund et al. PSD model in the description of the PSD data in the clayey soils. However, the higher number of parameters in comparison to the number of fractal model parameters may be another reason.
2

Drought effects on growth, water status, proline content and antioxidant system in three Salvia nemorosa L. cultivars

100%
Bayat H., Moghadam A. N.
Acta Physiologiae Plantarum
|
2019
|
tom 41
|
nr 09
Plant growth and yield are influenced by various environmental stresses, especially drought. An experiment was done to study the comparative effects of water stress on growth, physiology and antioxidant systems in three Salvia nemorosa L. cultivars (‘Isfahan’, ‘Violet Queen’ and ‘Rose Queen’). The cultivars were treated as control or water stress by stopping irrigation for 10 days. The results showed that the highest number of leaves per plant, leaf area, dry weight of root and shoot and total biomass were obtained from native cultivar ‘Isfahan’ under water shortage. Relative water content, chlorophyll a, b and total chlorophyll reduced in all studied cultivars under drought; but the rate of reduction was the lowest in ‘Isfahan’. Drought stress increased total soluble sugar in the root and leaf tissues in all cultivars and the highest values were obtained from native cultivar ‘Isfahan’. Drought stress also increased proline content, total phenols and flavonoids in all tested cultivars; but the rate of increase in ‘Isfahan’ was higher than the other cultivars. The activities of catalase and peroxidase enzymes enhanced in all cultivars under drought stress conditions; however, their activities were higher in ‘Isfahan’ than the other cultivars. Among the cultivars studied, it was found that ‘Isfahan’ was more tolerant which was revealed by physiological and biochemical characteristics.
3
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Content available

Seed priming with selenium improves growth, water relation and antioxidant activity of pot marigold (Calendula officinalis L.) under drought conditions

100%
Bayat H., Aminifard M. H.
Acta Scientiarum Polonorum. Hortorum Cultus
|
2021
|
tom 20
|
nr 1
4

Fitting soil particle-size distribution (PSD) models by PSD curve fitting software

81%
Rastgou M., Bayat H., MansoorizadehM. M.
Polish Journal of Soil Science
|
2019
|
tom 52
|
nr 2
This paper describes a particle-size distribution (PSD) curve fitting software for analyzing the soil PSD and soil physical properties. A better characterization of soil texture can be obtained by describing the soil PSD using mathematical models. The mathematical equations of soil PSD are mainly used as a basis to estimate the soil hydraulic properties. Until now, many attempts are made to represent PSD curves using mathematical models, but selecting the best PSD model requires fitting all models to the PSD data, which would be difficult and time-consuming. So far, no specific program has been developed to fit the PSD models to the experimental data. A practical user-friendly software called "PSD Curve Fitting Software" was developed and introduced to program a simultaneous fitting of all models on soil PSD data of all samples. Some of the capabilities of this software are calculating evaluation statistics for all models and soils and their statistical properties such as average, standard deviation, minimum and maximum for all models, the amount of models’ fitting parameters and their statistical properties for all soil samples, soil water retention curve by Arya and Paris (1981) and Meskini-Vishkaee et al. (2014) methods, soil hydraulic conductivity by Arya et al. (1999) method, different textural and hydraulic properties, specific surface area, and other descriptive statistics of PSD for all soil samples. All calculated parameters are presented in an output Excel file format by the software. The software runs under Windows XP/7/8/10.
5
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Content available

Prediction of CEC using fractal parameters by artificial neural networks

81%
Bayat H., Davatgar N., Jalali M.
International Agrophysics
|
2014
|
tom 28
|
nr 2
The prediction of cation exchange capacity from readily available soil properties remains a challenge. In this study, firstly, we extended the entire particle size distribution curve from limited soil texture data and, at the second step, calculated the fractal parameters from the particle size distribution curve. Three pedotransfer functions were developed based on soil properties, parameters of particle size distribution curve model and fractal parameters of particle size distribution curve fractal model using the artificial neural networks technique. 1 662 soil samples were collected and separated into eight groups. Particle size distribution curve model parameters were estimated from limited soil texture data by the Skaggs method and fractal parameters were calculated by Bird model. Using particle size distribution curve model parameters and fractal parameters in the pedotransfer functions resulted in improvements of cation exchange capacity predictions. The pedotransfer functions that used fractal parameters as predictors performed better than the those which used particle size distribution curve model parameters. This can be related to the non-linear relationship between cation exchange capacity and fractal parameters. Partitioning the soil samples significantly increased the accuracy and reliability of the pedotransfer functions. Substantial improvement was achieved by utilising fractal parameters in the clusters.
6

Effects of active and passive modified atmosphere packaging on the vase life and quality of narcissus (Narcissus tazetta L.) 'Shahla' cut flowers

81%
Moradinezhad F., Bayat H., Dorostkar M.
Journal of Horticultural Research
|
2023
|
tom 31
|
nr 2
7

Parametric estimation of water retention using mGMDH method and principal component analysis

61%
Neyshaburi M. R., Bayat H., Rastgou M., Mohammadi K., Gregory A. S., Nariman-Zadeh N.
Polish Journal of Soil Science
|
2016
|
tom 49
|
nr 1
Performing a primary analysis, such as principal component analysis (PCA) may increase accuracy and reliability of developed pedotransfer functions (PTFs). This study focuses on the usefulness of the soil penetration resistance (PR) and principal components (PCs) as new inputs along with the others to develop the PTFs for estimating the soil water retention curve (SWRC) using a multi-objective group method of data handling (mGMDH). The Brooks and Corey (1964) SWRC model was used to give a description of the water retention curves and its parameters were determined from experimental SWRC data. To select eight PCs, PCA was applied to all measured or calculated variables. Penetration resistance, organic matter (OM), aggregates mean weight diameter (MWD), saturated hydraulic conductivity (Ks), macro porosity (Mp), micro porosity (Mip) and eight selected PCs were used as predictors to estimate the Brooks and Corey model parameters by mGMDH. Using PR or OM, Ks and MWD, improved the estimation of SWRC in some cases. Using the predicted PR can be useful in the estimation of SWRC. Using either the MP and Mip or the eight PCs significantly improved the PTFs accuracy and reliability. It would be very useful to apply PCA on the original variables as a primary analysis to develop parametric PTFs.
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