mehdi zangiabadi; manoochehr gorji; Mehdi Shorafa; Payman Keshavarz; Saeed Saadat
Abstract
Introduction: Soil physical quality isone of the most important factors affects plants water use efficiency in agricultural land uses. In the literature, some soil physical properties and indices such as S-index, Pore Size Distribution (PSD), porosity, Air Capacity (AC), Plant Available Water (PAW) content, ...
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Introduction: Soil physical quality isone of the most important factors affects plants water use efficiency in agricultural land uses. In the literature, some soil physical properties and indices such as S-index, Pore Size Distribution (PSD), porosity, Air Capacity (AC), Plant Available Water (PAW) content, Least Limiting Water Range (LLWR) and Integral Water Capacity (IWC) were mentioned as the soil physical quality indicators. It has been reported that the soils with the same PAW, LLWR and IWC may have different physical qualities. The index of Integral Energy (EI) of the soil moistureranges may differ between the soils with equal soilmoistureover a defined water content range. This index is defined as the required energy to uptake the unit mass of soil moistureby plants. According to this definition, the soils with low EI would have better physical quality for plants roots growth. In this research, we hypothesized that EI of different soil moistureranges were negatively related to S-index which means the plants required energy to uptake the soil water in the soils with high S-index, is lower than the soils with poor physical quality (less S-index). So we examined our hypothesis in medium to coarse-textured soils of Khorasan-Razavi province (Iran).
Materials and Methods:This research was conducted in Torogh Agricultural and Natural Resources Research and Education Station in Khorasan-Razavi province, north-eastern Iran (59° 37' 33"-59° 39' 10" E, 36° 12' 31"-36° 13' 56" N). Soil textures of this research station, are classified into loam, silt loam, silty clay loam, clay loam, and sandy loam which is as the same in more than 90% of agricultural soils in Khorasan-Razavi province. Thirty points with different soil textures and organic carbon contents were selected. In order to measure different properties of the soil, two soil samples (5 cm diameter × 5.3 cm length core sample and a disturbed soil sample) were collected from 0-30 cm depth of each point. After conducting required laboratory and field measurements using standard methods, the Soil Moisture Release Curve (SMRC) parameters (RETC program), S-index, PAW and LLWR (measured in matric heads of 100 and 330 cm for the field capacity), IWC and EI of mentioned soil moisture ranges were calculated. In this regard, integration calculations were done by Mathcad Prime 3 software. Finally, the relationships between the measured properties and EI values (for PAW100, PAW330, LLWR100, LLWR330 and IWC) were analyzed using Pearson correlation coefficient and stepwise multivariate linear regression by JMP (9.02) statistical software.
Results and Discussion: The S-index of 30 soil samples were between 0.029-0.070 with average of 0.046. These results showed that 90% of studied soil samples had good and very good and 10% had poor physical quality. The lowest average EI values of different soil moisture ranges were observed in sandy loam and silt loam and the highest was observed in silty clay loam soil textures. The EI(IWC) mean value was lower than EI(PAW) and EI(LLWR) mean values which indicated that calculating the EI values based on continuous effects of water uptake physical limitations, resulted in lower required energy for plants to uptake the unit mass of soil moisture . Statistical analysis resulted in significantly negative relations between S-index and two indices of EI(PAW100) and EI(IWC). Multivariate regression analysis showed that EI(PAW100) and EI(LLWR100) could be estimated by shape parameter (n) of SMRC by regression coefficients of 0.95 and 0.22, respectively and the value of EI(IWC) could be estimated by S-index and organic carbon content by regression coefficient of 0.57. The parameter of saturated volumetric water content (θvs) of SMRC and sand percentage were determining factors of EI(PAW330). In this research, it was not obtained the significant relationship between EI(LLWR330) values and measured soil physical properties. According to the results, increment of the shape parameter (n) of SMRC and S-index led to reducing the plants required energy to uptake the unit mass of soil moisture in PAW100 and IWC ranges. We found that EI of different soil moisture ranges could be used to evaluate the soil physical quality between the soils with equal soilmoisture contents.
Conclusion: This Research investigated the relationship of PAW, LLWR and IWC EI values with soil physical properties and S-Index in medium to coarse-textured soils. The results indicated that increment of S-index led to decreasing EI(PAW100) and EI(IWC) indices. According to the results, the shape parameter of SMRC and S-index could be accounted for determining factors of EI(PAW100) and EI(IWC) indices values.
Mehdi Zangiabadi; manoochehr gorji; Mehdi Shorafa; Saeed Khavari Khorasani; Saeed Saadat
Abstract
Introduction: Soil is the main source of water retention and availability for plant uptake. The supplement of water is completely dependent on soil physical properties. The soils with higher values of available water are generally more productive because they can supply adequate moisture to plants during ...
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Introduction: Soil is the main source of water retention and availability for plant uptake. The supplement of water is completely dependent on soil physical properties. The soils with higher values of available water are generally more productive because they can supply adequate moisture to plants during the intervals between irrigation or rainfall events. Generally according tothe spatial and temporal distribution of precipitation, Iran has an arid climate in which most of the relatively low annual precipitation falls from October through April. Thus, water deficiency along with the lack of organic carbon in the soil justifies the necessity of studying the soil, water and plant relationships that may improve the efficiency of water consumption in agricultural practices. For that reason, this research was conducted to investigate the relationship between some soil physical properties and Integral Water Capacity (IWC) index as one of the soil physical quality indices.
Materials and Methods: This study was conducted in Torogh Agricultural and Natural Resources Research Station in Khorasan-Razavi province, north-eastern Iran during 2013-2014. This station is located in south-east of Mashhad city with a semi-arid climate, annual precipitation of 260 mm and mean air temperature of 13.5 °C. The soil was classified in Entisols and Aridisols with a physiographic unit of alluvial plain that generally had medium to coarse textures in topsoil. Thirty points with different soil textures and organic carbon contents were selected as experimental plots. In order to measure different properties of the soil, two soil cores (8 cm diameter × 4 cm length cylinder for bulk density and 5 cm diameter × 5.3 cm length cylinder for sandbox measurements) and one disturbed soil sample (for other measurements) were collected from 0-30 cm depth of each plot. After conducting required laboratory analysis and field measurements using standard methods, the soil moisture curve parameters (RETC program), Porosity (POR), Air Capacity (AC), Relative Field Content (RFC) and Integral Water Capacity (IWC) index, were calculated. In this regard, integration calculations were done by Mathcad Prime 3 software. Finally, the relationship between the measured properties and IWC index were analyzed using Pearson correlation coefficient and stepwise multiple linear regression by SAS (9.1) statistical software.
Results and Discussion: Laboratory analysis results showed that the soil texture classes of samples were loam (40%), silt loam (23%), silty clay loam (17%), clay loam (13%), and sandy loam (7%). On average, very fine sand particles were dominant between five size classes of sand and the lowest values were devoted to very coarse sand particles. Soil porosity and air capacity calculation results indicated that on average bulk soil porosity (PORt) and bulk soil air capacity (ACt) were 0.46 and 0.20 (cm3cm-3), respectively. According to the results, RFC of 60% of studied soil samples were lower than 0.6, 7% were higher than 0.7 and only 33% were between 0.6-0.7 (optimal range). IWC index calculations were resulted in 0.13-0.25 (cm3cm-3) in different soil textures. The highest IWC were related to Loam and Clay Loam textures, respectively. Statistical analyses indicated that there were no significant relationship between soil particles (sand, silt and clay) and organic carbon content with IWC index. The factors of soil bulk density and RFC were negatively correlated with IWC index that means decreasing the soil bulk density and RFC would lead to the reduction of the effects of water uptake limitation factors by increasing the values of weighting functions (IWC calculations), and improvement of soil physical quality. High significant (P < 0.001) positive correlation coefficients were observed between IWC index and the factors of soil PORt, ACt and soil matrix air capacity (ACf) in this study. Multiple regression analysis results showed that IWC index could be estimated by the factors of ACt and PORt with the determination coefficient of 0.63. The partial determination coefficients indicated that ACt factor accounted for 50% and PORt accounted for 13% of IWC index variations.
Conclusion: The results indicated that in medium to coarse-textured soils, IWC index could be estimated using the bulk soil air capacity (ACt) and bulk soil porosity (PORt) factors that are derived from soil volumetric water content at saturation and field capacity points.
A.A. Zolfaghari; Mehdi Shorafa; M.H. Mohammadi; A. Liaghat; A. Hoorfar; manoochehr gorji
Abstract
Quantitative knowledge of soil hydraulic properties such as the soil moisture characteristics curve (SMC) is crucial for flow and transport modeling supporting hydrologic and agricultural engineering. However, many laboratory and field methods are currently available for direct measurement of the soil ...
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Quantitative knowledge of soil hydraulic properties such as the soil moisture characteristics curve (SMC) is crucial for flow and transport modeling supporting hydrologic and agricultural engineering. However, many laboratory and field methods are currently available for direct measurement of the soil hydraulic properties but, most or all of direct methods are too time consuming and costly. Thus developing of physically-based methods for predicting SMC is essential. In this study, an analytical method was developed to estimate Brooks-Cory model parameters using horizontal infiltration data. The new method was compared with Wang et al (2002) method. Sixteen soils with wide range of hydraulic properties were used to test the new method. The results showed that the new method estimates n and hd parameters smaller than those experimental values. Although, results showed that the new method properly predicts the measured SMC data. High coefficient of determination (R2=0.93) and low root mean square error (RMSE =0.03) confirmed the accurate predictability of new method. Mean RMSE of Wang et al (2002) method was 0.049. Therefore, results indicated that the new method is more accurate than Wang et al (2002) method for predicting soil moisture characteristics curve. The sensitivity analysis indicated that, for a given soil, the accurately estimation of SMC depends mainly on sorptivity parameter.
H. Aryanpour; Mehdi Shorafa; A. Liaghat
Abstract
As far as soil moisture is a function of soil structure and texture any changes on these properties changes the soil moisture content. In this study for finding the soil moisture content at field capacity and permanent wilting point for cultivated soil, point pedotransfer functions of non cultivated ...
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As far as soil moisture is a function of soil structure and texture any changes on these properties changes the soil moisture content. In this study for finding the soil moisture content at field capacity and permanent wilting point for cultivated soil, point pedotransfer functions of non cultivated of the same soils were used. For this purpose 64 soil samples from cultivated and non cultivated were chosen in Abyek Qazvin area. Then available soil properties such as particle size distribution, bulk density, organic carbon, calcium carbonate, cation exchang capacity and PH of soils were measured. The soil moisture at FC and PWP. For non cultivated soil were determined by peresure plates. After that point pedotransfer functions were established. With using these functions the moisture of cultivated soils were predicted and compared with the measured ones. The results showed that this functions had overestimated moisture for FC and underestimated moisture for PWP. In fact cultivation reduses soil ability in moisture preservation. Correlation coefficient between measured and predicted moisture for cultivated soils at PWP was more than FC.
S. Seyed Alikhani; M. Shorafa; A. Tavassoli; S.S. Ebrahimi
Abstract
Abstract
Petroleum pollution is one of the most common and dangerous pollutions that is due to petroleum industries such as refineries, and consequently of oil pipes and tanks leak causing environmental pollutions. One of the newest born technologies in this area is phytoremediation, in which plants ...
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Abstract
Petroleum pollution is one of the most common and dangerous pollutions that is due to petroleum industries such as refineries, and consequently of oil pipes and tanks leak causing environmental pollutions. One of the newest born technologies in this area is phytoremediation, in which plants are used for decreasing of petroleum pollution. This technology is used for remediation of soil, underground and waste water pollution, because of low expenses and simple application. In this research bioremediation system by three plants barley, vetch and bean at three levels of density, with three replications in factorial experiments, randomized complete block design (RCBD) was used. In three steps of plant growth, concentration of total petroleum hydrocarbons (TPHs) of soil was measured. Statistical analysis showed that the amount of soil remediation had a direct relation with increasing plant density levels. The maximum remediation belonged to barley which in it's maximum density level, it reduced the amount of pollution up to 45.78%. Generally, because of high resistance of barley to petroleum pollution and it’s ability for remediation of pollution, barley was recognized as the best plant among the evaluated treatments for remediation of petroleum polluted soils.
Keywords: Barley, Bean, Petroleum, Pollution, Soil, Vetch
E. Entezami; M. Shorafa; Gh.R. Savaghebi
Abstract
Abstract
Soil pollution with heavy metals like zinc causes increasing concerns about environment. According to distribution in soil, this study was conducted to compare zinc concentration between aggregate exteriors and interiors of some contaminated soils. Aggregates were collected from 5 depths of ...
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Abstract
Soil pollution with heavy metals like zinc causes increasing concerns about environment. According to distribution in soil, this study was conducted to compare zinc concentration between aggregate exteriors and interiors of some contaminated soils. Aggregates were collected from 5 depths of 4 soil profiles with different textures and were separated mechanically into exterior and interior fractions. Soluble and exchangeable and also bonded to carbonate fractions of zinc from both aggregate interiors and exteriors, were extracted and measured. The concentrations of zinc in both above fractions were high in the exterior part. Concentration of soluble and exchangeable zinc showed high correlation coefficient with soil pH and total concentration of soil zinc, also bonded to carbonate fraction of zinc showed high correlation coefficient with total concentration of zinc and low correlation coefficient with percentage of soil CaCO3.
Keywords: Aggregate, Contaminated soil, Forms of zinc
M. Zangiabadi; A.S. Rangavar; H. Gh. Rafahi; M. Shorafa; M. R. Bihamta
Abstract
چکیده
فرسایش خاک یک معضل برای کشاورزی در نواحی استوایی و نیمه خشک میباشد و به علت اثرات دراز مدتش بر روی حاصلخیزی خاک و کشاورزی پایدار، از اهمیت زیادی برخودار است. فرسایش ...
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چکیده
فرسایش خاک یک معضل برای کشاورزی در نواحی استوایی و نیمه خشک میباشد و به علت اثرات دراز مدتش بر روی حاصلخیزی خاک و کشاورزی پایدار، از اهمیت زیادی برخودار است. فرسایش همچنین با رسوبگذاری، آلودگی و تشدید سیلابها باعث وارد آمدن صدمات محیطی میشود. این مطالعه به منظور بررسی و تعیین میزان مقاومت یا سستی خاک در برابر فرسایش آبی و همچنین تعیین عوامل تأثیرگذار بر این فرآیند انجام گرفت. اندازهگیریها در کرتهای آزمایشی مجهز به مخازن رواناب و رسوبگیر که در مراتع شمال شرق استان خراسان رضوی و با اقلیم نیمه خشک قرار داشتند، صورت پذیرفت. در این مطالعه تعداد زیادی از ویژگیهای فیزیکی و شیمیایی خاک، درصد تراکم پوشش گیاهی و شیب منطقه اندازهگیری و در نهایت رابطه این عوامل با میزان خاک فرسایش یافته بر اثر 43 رخداد بارندگی رسوبزا با استفاده از نرم افزارهای آماری بررسی گردید. رگرسیون خطی چند متغیره نشان داد که سه عامل درصد تراکم پوشش گیاهی، درصد سنگریزه درشت (75-13 میلی متر) در لایه سطحی خاک و همچنین درصد شیب زمین به ترتیب مهمترین عوامل تعیینکننده میزان فرسایش خاک میباشند. بنابراین مدیریت پوشش گیاهی و همچنین مدیریت شیب مرتع مورد مطالعه که از مراتع شاخص منطقه به حساب میآید اولین گام در جهت کاهش پتانسیل خاک منطقه نسبت به فرسایش میباشد.
واژههای کلیدی: فرسایش خاک، کرتهای آزمایشی، مرتع نیمه خشک، پوشش گیاهی، سنگریزه
D. Namdar Khojasteh; M. Shorafa; M. Fazeli Sangani
Abstract
Abstract
Time domain reflectometry (TDR) is a widely used method for measuring the dielectric constant (Ka) and bulk electrical conductivity (σa) in soils. The TDR-measured σa and Ka can be used to calculate the soil solution electrical conductivity, (σp). A theoretical model describing a linear ...
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Abstract
Time domain reflectometry (TDR) is a widely used method for measuring the dielectric constant (Ka) and bulk electrical conductivity (σa) in soils. The TDR-measured σa and Ka can be used to calculate the soil solution electrical conductivity, (σp). A theoretical model describing a linear relationship between bulk electrical conductivity, σa, and dielectric constant, Ka, in moist soil was already presented. By using this linear relationship, the pore water electrical conductivity, σp, can be estimated in a wide range of soil types without soil-specific calibration. The objective of this study was to evaluate the linear model presented previously for TDR. The previous study was on light texture soils but in this study we used clay, clay loam, loam, silty clay and silty clay loam textures. The results showed that the linear model performed well for light texture soils but not for heavy textures. Such poor result for heavy texture is mainly due to this fact that dielectric constant pore water was lower than 80 which was proposed as default by model. This study showed that for heavy texture soils dielectric constant of pore water is smaller than light textured soils.
Keywords: Time-domain Reflectometry, Electrical conductivity, Dielectric constant
M.R. Neyshabouri; M. Shorafa; A. Liaghat
Abstract
Abstract
Tillage properties at optimum moisture after irrigation or rainfall have a great influence on prevention of soil structure destruction. Soil sampling was carried out on spring of 1384 from Karaj and Varamin plains of Iran. The water content at inflection point of retention curve (θi) was used ...
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Abstract
Tillage properties at optimum moisture after irrigation or rainfall have a great influence on prevention of soil structure destruction. Soil sampling was carried out on spring of 1384 from Karaj and Varamin plains of Iran. The water content at inflection point of retention curve (θi) was used to determine the optimum water content for tillage. So, the soil moisture was measured in matric pressure heads 0, 1.5, 2.5, 5.5 kPa by hanging water column and in 10, 20, 30, 50, 100, 200, 300, 500, and 1000 kPa by pressure plate for 140 samples. The particle size distribution (clay, silt and sand) and bulk density data of soils with measured moisture contents in above suctions were input to RETC software and parameters of Van Genuchten equation (1980) and θi were determined for any samples. The results of this study showed that the range of θi was 0.17-0.77 and its mean was 0.52 cm3cm-3 in all 140 soil samples. Also there was a positive and significant correlation between θi and percentage of Clay, Calcium carbonate and saturated water content (P
F. Vahabbi; H. Mirseyed Hosseini; M. Shorafa; S. Hatami
Abstract
Abstract
Spent mushroom compost (SMC) is a by-product of the mushroom industries. It is made from straw, manure, gypsum and horse-bedded straw, hay and poultry manure. SMC has been used as a soil amendment, particularly for intensive horticultural production. In this study the effects of various SMC's ...
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Abstract
Spent mushroom compost (SMC) is a by-product of the mushroom industries. It is made from straw, manure, gypsum and horse-bedded straw, hay and poultry manure. SMC has been used as a soil amendment, particularly for intensive horticultural production. In this study the effects of various SMC's types (fresh, one year old, two years old) on changes of chemical characteristics of a loamy soil was studied for 12 weeks in a laboratory column incubation under controlled conditions. Different rates of each SMC (0, 15, 30, 60 t ha-1) were mixed with a loamy soil. The columns were leached with deionized water every week. Leachates were collected and analyzed for EC, pH, soluble cations (Sodium, Potassium, Calcium, and Magnesium), and anions (Chloride, Bicarbonate, Nitrate) content. Similar data collection was conducted on the soil samples at the beginning and at the end of the test. The results showed that EC and concentration of nutrients was the lowest in two years old SMC. It is probably due to the amount of salts leached out during the weathering of SMC. The leachate contained a higher amount of Calcium and Magnesium over the 12 week period. Two years old SMC had less Cl and Na and had less effect on soil salinity and sodification. Since the slow inorganic-N release rate from SMC-amended soil is predominantly the result of the slow mineralization of recalcitrant organic-N in SMC, therefore, nitrate content in two years old SMC can provide the primary requirements of plants. Comparison of different levels of SMC showed that using 30 t ha -1 is more favorable as compared with other levels. The 60 t ha -1 level caused higher EC and salinity in the soil. As a general rule if SMC with proper aging is used at an appropriate level it can affect the chemical and physical characteristics of the soil and can be used as a soil amendment.
Key words: Spent Mushroom Compost (SMC), wastage mushroom, Composting, Soil amendment, Columns leaching
