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F. Zarei, M.r. Nouri Emamzadehei, A.r. Ghasemi Dastgerdi, A. Shahnazari,
Volume 26, Issue 4 (3-2023)
Volume 26, Issue 4 (3-2023)
Abstract
The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification.
M. Farzamnia, M. Miran Zadeh,
Volume 26, Issue 4 (3-2023)
Volume 26, Issue 4 (3-2023)
Abstract
The present study was carried out in the Mahyar region of Esfahan Province to determine optimum drip tape spacing for the wheat crops on a silty clay loam soil respecting grain yield as well as yield components, water use efficiency, and variations in the salinity within the soil profile. The experiment was performed for three years from 2017 to 2019 with a randomized complete block design with three replicates and four treatments. The treatments consisted of three tape spacings (A) at 45, (B) at 60, (C) at 75 cm, and the Control (D) was irrigated with the basin method. The same volume of irrigated water was applied to the drip treatments, A, B, and C in every irrigation interval, whereas for treatment D, the local farmers’ practice was followed. Based on the results from compound variance analysis, the treatment effect on both grain yield and biological yield, and on water use efficiency and harvest index was significant at 1% and 5% level of confidence, respectively. The mean water use efficiency in treatments A, B, C, and D was measured as 0.79, 0.79, 0.73, and 0.78 kg m-3; thus, treatments A, B, and D outperformed treatment C. A comparison between the salinity of the soil profile at the beginning and the end of the growing season revealed that the basin irrigation method was more effective on salt leaching than the drip tape system. The results of this study indicated that concerning water use efficiency and crop yield, drip tapes spaced at 45 or 60 cm outperformed those which were 75 cm apart. On the other hand, the work required for irrigation system installation as well as the amount of drip tape residues left on the field at the end of the growing season is larger for tapes spaced at 45 cm compared to those which are 60 cm apart. This will have a significant impact on farmers’ budgets and environmental issues. Therefore, it is recommended to lay the tapes 60 cm apart for the irrigation of wheat crops on silty clay loam soils.
N. Moradian Paik, S. Jafari,
Volume 26, Issue 4 (3-2023)
Volume 26, Issue 4 (3-2023)
Abstract
Changes in land quality factors were investigated according to the change in land use of two conventional cropping systems in Khuzestan (Dimcheh region, periodic cultivation system, sugarcane, forest, and deforesting in Zaras region). The results showed that by the change of forest land use, organic carbon from 0.93 to 0.55%, cation exchange capacity (CEC) from 19.6 to 13.3 cmol/kg, C/N from 7.4 to 3.8%, the mean weight diameter of aggregate (MWD) from 1.7 to 1.3%, and microbial respiration from 0.11 to 0.06 mg of CO2 /gr of soil per day decreased and in contrast, the dispersible clay from 4.6 to 19.3% increased. PCA analysis for the parameters showed that five factors justified more than 90% of the variance in the values of FC, PWP, AW, and AF. In the Dimcheh region, the average volumetric moisture content of FC from 31.3% to 27.3%, available water from 12.9% to 9.8%, dispersible clay from 56.1% to 12.3%, and bulk density reduced from 1.6 to 1.4%, organic carbon from 0.45 to 0.78%, C/N from 6.3 to 10.0%, microbial respiration from 0.01 to 0.04 mg of CO2 /gr soil per day and MWD of aggregates increased from 0.77 to 1.3 mm. Five factors including FC, AW, BD, DC, and OM explained more than 90% of the variance.
E. Javiz, A. Jalalian, M.r. Mosaddeghi, E. Chavoshi, N. Honarjoo,
Volume 26, Issue 4 (3-2023)
Volume 26, Issue 4 (3-2023)
Abstract
One of the most significant environmental crises in arid, semi-arid, sub-humid, and even humid regions is the destructive phenomenon of desertification and in the arid and semi-arid regions is wind erosion. These problems exist in large areas of Iran and it is necessary to use an environmentally friendly and economic method to solve this problem. In this study, calcium bentonite clay was used for the first time in Iran and perhaps in the worlds in the critical region of Sajzi, which covers an area of 65 hectares. Experiments were performed on the crusts after one year of mulching with bentonite clay. The results showed that wind erosion has a negative and significant correlation with the mean weight diameter and geometric weight diameter of aggregate, aggregates with diameters greater than 0.25 mm, shear strength, and penetration resistance. On the other hand, the results of the permeability test using double-ring and by three models (Kostiakov, Horton, and Philip) showed that the lowest mean square error (SSE) and the highest coefficient of determination (R2) belonged to the Kostiakov model in the mulch-applied and control samples. This result indicated the superiority of the Kostiakov model compared to Horton and Philip's models. Wind erosion intensity was also measured in situ using a portable wind tunnel at 20 points in the Sajzi region. The findings showed that mulch application has controlled more than 95% of soil erosion.
H. Ghazvinian, H. Karami,
Volume 26, Issue 4 (3-2023)
Volume 26, Issue 4 (3-2023)
Abstract
Runoff is formed by spending some time after rain and significantly depends on rainfall intensity, soil moisture, and slope. One of the fundamental questions about runoff is the time that it starts to create. In this research, the runoff start time in sandy loam soil was evaluated experimentally under different conditions using a precipitation simulator machine. The rainfall intensity parameters of (60, 80, and 100 millimeters per hour) and the slope of (0 and 5 percent) were investigated. The rainfall was created in the three soil treatment types completely dry (Sdry), the dry soil that had been saturated 24 hours before the test (S24hrlag), and the dry soil that had been saturated 48 hours before the test (S48hrlag). Eighteen tests were conducted on this soil. At the end of each test, the soil moisture was measured. The experimental results were compared with the numerical model of Green-Ampt. According to the Kendall and Spearman correlation test results, as the rainfall be intense, the start time of the runoff is lower. Also, the runoff starts at a faster time in the slope of 5 percent for every three types of soil. Also, the results of starting time of the runoff in the soil with a delay of 48 hours in the rain compared to the soil with a delay of 24 hours in the rain are closer in all of the rainfall intensity and slopes compared to the case of dry soil. Therefore, in the experiments related to a delay of 24 hours, the time of the start of runoff decreases. While in tests with a delay of 48 hours, it was not much different from completely dry soil. Also, the Green-Ampt results are close to the experimental results (R2=0.9775), and the maximum difference between the two mentioned methods is 4.8 minutes. Therefore, it can be used with the Green-Ampt method to calculate the start time of runoff in sandy loam soil in different states of rainfall intensity and bed slope.
J. Abedi Koupaei, Z. Iravani,
Volume 27, Issue 1 (5-2023)
Volume 27, Issue 1 (5-2023)
Abstract
Water pollution with petroleum products is one of the serious environmental problems in Iran. According to the importance of this issue, refining benzene by bio-absorbent has attracted much attention in recent years. The maximum permissible limit assigned by World Health Organization (WHO) for benzene in drinking water is 0.001 mg/L. In recent years, attempts made to develop inexpensive adsorbents utilizing abundant natural materials. Agricultural waste materials often employed as adsorbent may have potential marketing preference for wastewater treatment among other adsorbent types due to the low cost, environmentally friendly, naturally accessible, and efficiency. The objective of this study was to investigate the removal of benzene by batch and continuous techniques. In this study, the ash cone pine (APC) was used for the removal of benzene from aqueous solutions and its ability as an adsorbent, while the variable initial concentration of benzene, the amount of adsorbent, contact time, temperature, and pollutant's solution pH were investigated. Langmuirand and Freundlich Isotherm models were fitted to benzene adsorption equilibrium data. Kinetic models including pseudo-first order, pseudo-second order, intra-particle diffusion, and power function were used to describe kinetic data of benzene adsorption. The results showed that optimum benzene adsorption was observed at pH=7, and the optimum amount of adsorbent was 0.1 g. The observed equilibrium time was 10 minutes. The equilibrium adsorption capacities were 366 mg/g at 2000 mg/L initial benzene concentration. Linear and non-linear isotherm studies showed that equilibrium data better fitted the Langmuir isotherm model. Kinetic studies showed better applicability of the pseudo-second-order kinetics model. Column adsorption experiments were performed to check the absorbent performance during continuously injecting benzene solution into the adsorbent column until the adsorbent has been saturated to complete the studies on the introduced adsorbent. The results for columns with continuous inflow indicated that the maximum capacity of adsorption of benzene for the adsorbent column with a diameter of 3cm, and input concentration of 1000 mg/L, and an input rate of 100 mL/h for ash cone pine (APC) was 295 mg/g. The results of this experiment showed that APC has a high capability for the removal of benzene from aqueous solutions.
R. Mousavai, M. Rasouli Sadaghiani, E. Sepehr, M. Barin,
Volume 27, Issue 1 (5-2023)
Volume 27, Issue 1 (5-2023)
Abstract
can provide useful information about P adsorption and the factors affecting it. A batch experiment was performed with phosphorus concentrations (0 to 35 mg/L) in two soils with different electrical conductivity (EC) (2 and 15 dSm-1) by a variety of biochar treatments including simple apple-grape biochar (BC), rock phosphate- biochar (BC-RP), enriched-biochar (BC-H3PO4-RP), enriched-biochar (BC-HCl-RP), triple superphosphate (TSP ), and control (Cont). The results indicated that phosphorus sorption capacity varied between the soils. Biochar treatments were effective in reducing the phosphorus adsorption of both soils. Due to BC-H3PO4-RP and BC-HCl-RP treatments, the maximum phosphorus adsorption of soils decreased in S1 soil by 14 and 23 % and in S2 soil by 26 and 19%, respectively. Also, the use of these treatments decreased the parameters of Langmuir absorption intensity (KL) of S1 soil to 0.085 and 0.066, respectively and S2 soil to 0.11 and 0.15, L/mg respectively, and Freundlich absorption capacity (KF) of S1 soil decreased to 19.2 and 22.5 and S2 soil to 28.2 and 28.1 L/kg, respectively. Enriched biochars significantly reduced the buffering indices of both soils indicating phosphorus adsorption decreased and increased the availability of phosphorus for the plant. The standard phosphorus requirement of S2 soil was lower than S1 soil by both equations. Therefore, enriched biochar can be an effective strategy to increase phosphorus availability and reduce the use of chemical fertilizers in saline and non-saline conditions; however, more field studies are needed for a clear understanding of the potential of P-enriched biochar as a fertilizer alternative.
S. Falahati, E. Adhami, H. Owliaie,
Volume 27, Issue 1 (5-2023)
Volume 27, Issue 1 (5-2023)
Abstract
Due to the importance of nickel (Ni), and the effect of common soil additives on Ni fractions distribution, the present study was conducted to evaluate the effect of zeolite and vermicompost on nickel fractions over time. The experimental design consisted of a factorial combination of two levels of vermicompost (zero and 2% by weight), three levels of zeolite (zero, 4% by weight of Firoozkooh zeolite, and 4% by weight of Semnan zeolite), and two soil texture (clay and sandy loam) in a completely randomized design in triplicates. Treatments were contaminated with 50 and 100 mg nickel/kg soil. Ni fractions were extracted and measured at 20 and 60 days. The results showed that in initial soils, Car-Ni in sandy loam soil was higher than in clay soil, while the content of Fe, Mn- Ox Ni, OM-Ni, and Res-Ni in the clay soil was higher. In sandy loam soil, more nickel was recovered in Exch- and Car-fractions, while nickel recovery was higher in Mn, Fe-Ox Ni, OM-Ni, and Res-Ni in the clay texture. Zeolite addition caused a significant decrease of Exch- and Car-Ni in the clay soil on 60d and 100 mg/kg Ni level. Exch-Ni was reduced due to vermicompost application. Vermicompost application caused the decrease in Fe, Mn Ox-Ni in both studied soils and times, and OM-Ni increased by vermicompost application. Aging generally reduces the Exch-Ni but changes in Car-Ni over time depending on the soil texture. Aging did not affect Mn, Fe-Ox Ni, and Res-Ni, while OM-Ni increased over time in clay soil.
M. Dehghanian, H. Tabatabaee, H. Shirani, F. Nikookhah,
Volume 27, Issue 1 (5-2023)
Volume 27, Issue 1 (5-2023)
Abstract
In sustainable agriculture, cow manure is used for greater productivity, a rich source of E-Coli pathogenic bacteria. The objective of this research was to investigate the simultaneous effect of the fractionation size of cattle manure and irrigation water salinity on the retention of E-Coli bacteria in the depths of the sand column with a height of 10 cm under saturated flow. Four different particle fractions of cow manure (1-2, 0.5-1, 0.25-0.5, and smaller than 0.25 mm) were added to the surface of the sand column at the scale of 30 tons per hectare, then leaching was done with different salinities (0, 0.5, 2.5, 5, and 10 dS/m) up to 10 pore volumes, then samples were taken from the depths of 0, 3, 6, and 12 cm. The number of bacteria in each sample was determined by the live counting method. The results showed that the effect of all sources of change and their interaction effects on the retention of bacteria in the soil is significant at the level of 5%. Salinity had a negative effect on the retention of bacteria, and the highest and lowest values of the relative concentration of bacteria (the result of dividing the number of bacteria in each soil depth by the initial number of bacteria in the desired manure treatment) were in 0 dS/m and 10 dS/m salinity of leaching water, respectively. By decreasing the size of cow manure particles due to the increase in hydrophobicity and blocking of preferential pores, the retention of bacteria decreased in all investigated soil depths. The highest and lowest retention of bacteria in the soil were investigated in the largest cow manure particle size (1-2 mm) and the smallest cow manure particle size (less than 0.25 mm), respectively. In addition, the highest relative concentration of bacteria in the soil was seen in the depth of 0-3 cm, and no significant difference was seen in other soil depths.
A.r. Eftekhari, M. Mirmohammad Sadeghi, A. Jalalian,
Volume 27, Issue 2 (9-2023)
Volume 27, Issue 2 (9-2023)
Abstract
The use of biotechnology-based methods in the field of geotechnical engineering has led to the birth of new knowledge of biogeotechnology and several studies have been conducted using this new knowledge in various geotechnical issues including reducing permeability and increasing shear strength, especially in sandy soils and the desired results have been obtained. Nevertheless, little research has been done using biogeotechnology in the field of improving the mechanical properties of clay soils, especially in reducing the swelling of expansive soils, which is considered one of the types of problematic soils. The main cause of swelling of expansive soils is the presence of montmorillonite clays in these types of soils. Using chemical additives to stabilize expansive soils such as lime and cement is a common practice. However, environmental concerns related to greenhouse gas production caused by the production of chemical substances and the destructive effects of these substances on the environment and soils have encouraged researchers to use other sustainable stabilization alternatives. Microbial Induced Carbonate Precipitation (MICP) is a technique that can be a promising solution to solve this problem. The objective of the present study was to investigate the effect of the MICP method on the swelling of expansive clay soils and its effect on the mechanical strength of this type of soil. One-dimensional swelling tests, uniaxial compressive strength tests, and Atterberg limits tests were performed on clay soil with a liquid limit of 53 using Sporosarcina pasteurii bacteria, calcium chloride, and urea as nutrients. Taguchi's method was used for the design of the experiments and the statistical analysis of the results. This method designs experiments through partial factorial and reduces their number without a significant effect on the results. Bacterial concentration, nutrient molarity ratio, treatment time, and soil moisture were selected as four factors with Four levels of variation. The results showed that the (MICP) method was effective in reducing the swelling potential of expansive soils and also caused a significant increase in the unconfined compressive strength of the soil and its undrained shear strength.
D. Khatibi Roudbarsara, A. Khaledi Darvishan, J. Alavi,
Volume 27, Issue 2 (9-2023)
Volume 27, Issue 2 (9-2023)
Abstract
Soil erosion followed by sediment production is the most important phenomenon that causes soil and environment degradation in many areas and is increasing. Sediment fingerprinting is a method to identify sediment sources and determine the contribution of each source to sediment production. The present research was carried out to evaluate the relative erosion sensitivity of lithological units and to determine the contribution of each unit in bed sediment production using geochemical properties in the Vaz River located in Mazandaran province. The 33 soil samples were taken from the whole watershed and one sediment sample at the outlet of the watershed. Then, five tracers of B, Al, Sc, Mo, and Sn were selected as the optimal combination using three statistical tests range tests, Kruskal-Wallis, and discriminant function analysis. Finally, using optimal tracers and a combined multivariate model, the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were obtained using FingerPro statistical package and R software. The results showed that the contribution of lithological units with very high (A), high (B), medium to high (C), and medium (D) sensitivity in bed sediment production were 24.23, 50.77, 15.62, and 9.36%, respectively. Then, the specific contribution of each sensitivity class was also calculated to remove the effect of area on the results. The Qal lithological unit including the Quaternary sediments in the river bed and banks with very high sensitivity to erosion (A) and a specific contribution of 0.0807 % per hectare had the maximum contribution in bed sediment production in Vaz River.
Y. Gateazadeh, H.a. Kashkuli, D. Khodadadi Dehkordi, A. Mokhtaran, A. Assareh,
Volume 27, Issue 2 (9-2023)
Volume 27, Issue 2 (9-2023)
Abstract
To monitor and compare the changes of salts in the soil profile around the roots of the corn plant, the plant yield, and the productivity of corn water, an Experimental was conducted in a completely randomized block of three repetitions in two crop years 2017-2018 and 2018-2019 at Ahvaz Agricultural Research Station. Experimental treatments included two subsurface drip irrigation systems with a working depth of 30 cm from the soil surface and tape irrigation and two irrigation intervals of 2 and 4 days. The results of monitoring soil solutes obtained from sampling depths (0-25, 25-50, and 75-50 cm) showed that soil salinity in the second year in both systems as a result of improving the quality of irrigation water from 3.61 dS/m to 2.01 dS/m, it was reduced by two times. The results of soil salinity monitoring showed the highest ratio of salinity reduction with a 2-day irrigation interval in both irrigation systems. The most leaching was done at the irrigation depth of 25-50 cm in the subsurface drip irrigation system and at the depth of 0-25 cm in the tape system. The highest yield of corn dry fodder was 9.13 and 7.13 tons per hectare, respectively, and the best water efficiency based on dry corn fodder at the rate of 13.74 kg/m was obtained in the strip drip irrigation system (tape) with a two-day irrigation interval and in the second crop year. Also, the results of the soil salinity measurement showed that the implementation and exploitation of the drip irrigation system can be the basis for improving the quality of the soil as the most important non-renewable resource of agriculture.
F. Meskini-Vishkaee, A.r. Jafarnejhadi, M. Goosheh, B. Delsooz Khaki, M. Javadzadeh,
Volume 27, Issue 3 (12-2023)
Volume 27, Issue 3 (12-2023)
Abstract
One of the most common approaches for farm irrigation management is using soil readily available water and allowable depletion coefficient. The objective of this study was to determine wheat crop response coefficients, critical moisture content, and soil allowable depletion coefficient using a physically based method in three dominant soils under wheat cultivation in Khuzestan province. Treatments included full irrigation and water stress at three levels low, moderate, and high. The highest and lowest values of wheat crop response coefficient were related to silty clay loam (Ky=1.26) and clay loam (Ky=0.96), respectively. Critical soil moisture content was observed in loam soil (0.25 cm3cm-3)> silty clay loam (0.23 cm3cm-3)> clay loam (0.22 cm3cm-3), respectively. Despite the higher critical moisture content in loam, the most soil allowable depletion coefficient was also calculated in loam (0.54). Soil allowable depletion coefficient in silty clay loam and clay loam were 0.44 and 0.42, respectively. The results confirmed the simultaneous effects of soil and plant properties on the availability of soil water for the plants.
A.r. Vaezi, S. Rezaeipour, M. Babaakbari, F. Azarifam,
Volume 27, Issue 3 (12-2023)
Volume 27, Issue 3 (12-2023)
Abstract
Improving soil physical properties and increasing water retention in the soil are management strategies in soil and water conservation and enhancing crop yield in rainfed lands. This study was conducted to investigate the role of tillage direction and wheat stubble mulch level in improving soil physical properties in rainfed land in Zanjan province. A field experiment was done at two tillage directions: up to the downslope and contour line, and five stubble mulch levels: zero, 25, 50, 75, and 100% of land cover equal to 6 tons per hectare. A total of 30 plots (2 m×5 m) were created. The results indicated that water infiltration and water content were considerably affected by tillage direction, whereas its effect on water holding capacity was not significant. This physical property of the soil was influenced by the inherent properties of the soil, including particle size distribution. The change of up to down tillage direction to the contour line increased soil infiltration to 11% and water content to 6%. The physical soil properties were wholly influenced by mulch consumption. Soil water content increased in mulch treatments along with water holding capacity and infiltration rate. The highest volumetric water content was at 100% mulch level (10.62%) which was 11% more than the control treatment. However, there was no significant difference between 100% and 75% mulch treatment. This revealed that the application of 75% stubble mulch in contouring tillage is a substantial strategy for improving soil physical properties and controlling water loss in rainfed lands of semi-arid regions.
Miss S. Bandak, A.r. Movhedei Naeani, Ch.b. Komaki, M. Kakooei, J. Verrlest,
Volume 27, Issue 3 (12-2023)
Volume 27, Issue 3 (12-2023)
Abstract
Soil organic carbon (SOC) is one of the most important components of soil physical and chemical properties that have an important role in sustainable production in agriculture and preventing soil degradation and erosion. Data mining approaches and spatial modeling besides machine learning techniques to investigate the amount of soil organic carbon using remote sensing data have been widely considered. The objective of the present study was the evaluation of SOC using the remote sensing technique compared with field methods in some areas of the Gonbad Kavous and Neli forests of Azadshar. The soil samples were collected from the soil surface (0-10 cm depth) to estimate the SOC. Data were categorized into two categories: 70% for training and 30% for validation. Three machine learning algorithms including Random forest (RF), support vector machine, extra tree decision, and XGBoost were used to prepare the organic soil carbon map. In the present study, auxiliary variables for predicting SOC included bands related to Lands 8 OLI and sentinel 2 measurement images, topography, and climate. The results showed that the extraction of the components related to the bands along with the calculation of indicators such as normalized vegetation difference, wetness index, and the MrVBF index as auxiliary variables play an important role in more correct estimation of the amount of soil organic matter. Comparison of different estimation regressions showed that the Sentinel 2 random forest model and in Landsat8 with the values of coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MEA) of 0.64, 0.05, and 0.17, respectively, was the best performance ratio compared to other approaches used in the study to estimate the organic carbon content of surface soil in the study area. In general, the results of this study indicated the ability of remote sensing techniques and learning models in the spatial estimation of soil organic carbon. So, this method can be used as an alternative to laboratory methods in determining soil organic carbon.
M. Naderi Khorasgani, T. Azarbeig, J. Mohammadi,
Volume 27, Issue 3 (12-2023)
Volume 27, Issue 3 (12-2023)
Abstract
Soil pollution by heavy metals is a significant issue that threatens human health directly and indirectly. The objectives of this research were to map the extension of some heavy metals in soils of a part of Sirjan Plain, Kerman province, to study the role of natural agents on the distribution of heavy metals, and to assess the risk of soil heavy metal concentration for human health. 120 surficial (0-15 cm) compound soil samples were collected during fieldwork. Soil characteristics like soil texture components, pH, electrical conductivity, organic matter, and total soil heavy metal (Fe, Cu, Zn, Cd, and Pb) concentrations were measured using standard protocols. The mapping of soil texture components and heavy metals was done by the usual Kriging method. Results indicated significant correlation coefficients between soil texture components (silt and clay) and total soil Fe and Cu concentrations. Dominant wind direction and spatial distribution of Fe, Cu, and Zn strongly induced the possible dust-born origin of such elements. Results revealed that the sources of Fe, Cu, and Zn were different from those of Cd and Pb. Maximum soil Fe, Cu, and Zn concentrations were in the southern part of the study area, increasing in an upwind direction while for Cd and Pb, maximum soil concentrations were in the northern part of the study area. The Nemerow integrated pollution index revealed that soils were clean for Cd, lowly polluted for Fe, Pb, and Cu, and moderately polluted for Zn.
S. Jalinousi, E. Joudaki, A. Moghadassi, M. Mahdieh,
Volume 27, Issue 4 (12-2023)
Volume 27, Issue 4 (12-2023)
Abstract
This research presents the application of phytoremediation to remove ammonia from effluent possessing high ammonium content and alkalinity in one of the most complex refineries in Iran. The objective of this research was to find new methods to protect and preserve water resources. At first, the algae distribution was investigated. After purifying the samples, Chlorella Vulgaris was selected as resistant algae in the areas that experienced ammonia shocks. A 10-liter container and an airlift photobioreactor with similar laboratory conditions were developed to control biomass production. Experiments were conducted over 20 days and maximum biomass production occurred in the first 16-17 days. Cell density was expressed as dry cell weight in ammonia concentration from 10 mg/L to 500 mg/L. It was also observed that when the Nitrogen content of the culture medium was less than 50 mg/L, ammonia was completely removed in both methods. At a concentration of 10 mg/L, total ammonia in both methods was removed in the first week. At 50 mg/L to 100 mg/L concentrations, about 94% of ammonia was removed in the glass container and about 95% in the bioreactor. In these concentrations, with high ammonia content, the final cell density, and absorption power were significantly low and this was evident at 500 mg/L. Prevention of water evaporation and biomass settling, better control of some vital parameters including pH, temperature, light, and energy intensity, effective mass and heat transfer, and carbon dioxide concentration led to better efficiency of the airlift photobioreactor. A noteworthy point in this result was the extraordinary performance of Chlorella Vulgaris in removing toxic pollutants such as ammonia and possibly using it in the biological systems of sanitary, refineries, and petrochemicals.
S. Ghasemi Pirbaloti, S. Soodaee Moshaee,
Volume 28, Issue 1 (5-2024)
Volume 28, Issue 1 (5-2024)
Abstract
Since the long-term sustainability of garden ecosystems is dependent on maintaining the soil quality, knowing the condition of the soils and investigating the effects of the activities on the soil properties is very important and effective in ecosystem management. To investigate the soil quality index of almond (Prunus dulcis) orchards under different managed methods in ChaharMahal va Bakhtiari province, soil samples were collected from three points in each orchard and finally classified into 6 groups (Saman, Ben, Shahrekord, Kiar, Ardel, and Farsan). To determine the soil quality index, soil characteristics including pH, EC, total and water-soluble organic carbon, basal and substrate-derived respiration, rhizosphere microbial population, and available soil P and K were analyzed. The results showed that almond orchard management in different regions affected the soil characteristics and the processes evaluated in this study. The monitoring of soil properties showed that pH 7.05 - 8.48, EC 0.23 - 2.91 dS/m, microbial respiration 0.44 - 8.57 mg CO2.100 g-1.day-1, organic carbon 2.09 - 44.79 g/kg, available phosphorus 1.5 - 122.3 mg/kg, and available potassium were between 91.2 - 3038 mg/kg. Soil quality index components including chemical components, microbial activity, microbial population, and soil organic carbon were determined. The contribution of soil salinity to soil quality obtained using factorial analysis was the highest (31%), followed by microbial carbon mineralization coefficient (27%), rhizosphere microbial population (24%), and water-soluble organic carbon (18%). The soil quality index values for Saman, Ben, Shahrekord, Kiar, Ardal, and Farsan almond orchards were 0.46, 0.40, 0.51, 0.67, 0.54, and 0.37, respectively. These values showed that the evaluated soils are suitable for almond production in Shahrekord, Kiar, and Ardal, and for Saman, Ben, and Farsan, there is a need for serious management measures to improve soil quality and increase the sustainability of these agricultural ecosystems.
F. Gholamzadeh, H. Asgarzadeh, H. Khodaverdiloo, M.r. Mosaddeghi,
Volume 28, Issue 1 (5-2024)
Volume 28, Issue 1 (5-2024)
Abstract
This study was conducted in the summer of 2021 to evaluate and validate the gravimetric soil water content measurements using a field oven. Ten soil types with a salinity of saturated paste (ECe) less than 4 dS m-1 and three saline soils were studied around Urmia Lake. Plots with dimensions of 1 m × 2 m were prepared for the selected soils to measure gravimetric soil water content and soil physical and chemical properties. The gravimetric water content (θm) values measured using the field oven (i.e., θmFO), were compared with those measured by a standard lab oven (i.e., θmLO). The soil water content values measured in the lab, regarded as a benchmark, were measured at 105 °C for 24 h. Temperatures of 120, 140, and 160 °C with three durations of 10, 15, and 20 min were used to dry the soil samples in the field oven. There was very good compatibility between the values of θmFO and θmLO when the soil samples were dried in the field oven for 15 or 20 min at all three temperatures. Significant linear relations were obtained between the θmFO and θmLO values as the slopes of linear relations were close to 1, the intercepts of relations were negligible and the distributions of measured data around the line 1 to 1 were unbiased. The minimal effects of soil organic matter content, clay content, salinity, and bulk density on water content measurements by the field oven indicate an important advantage of this method. These results confirm the high efficiency of the field oven for fast and reliable measurements of water content in different soils.
E. Karamian, M. Navabian, M.h. Biglouei, M. Rabiei,
Volume 28, Issue 1 (5-2024)
Volume 28, Issue 1 (5-2024)
Abstract
Cultivation of rapeseed as the second crop requires drainage systems in most of the paddy fields of the Guilan province. Mole drainage, as a low-cost and shallow drainage method that is suitable for rice cultivation conditions and easier to implement than pipe drainage, can be a solution in the development of second-crop cultivation. The present study was conducted to evaluate the drainage of mole drainage and nitrogen fertilizer management on the quantity and quality of drainage at Guilan University. In this regard, an experiment was conducted under two treatments including drainage and nitrogen fertilizer (i.e. traditional mole drainage and sand-filled mole drainage), and 180 and 240 kg of nitrogen fertilizer per hectare in three replications. After each rainfall during the plant growth period, water samples were taken from the drains, and parameters of electrical conductivity, pH, total suspended solids, total phosphorus, turbidity, concentrations of ammonium, chloride, nitrite, nitrate, and phosphate were measured. Also, the outflow from the drains and the water table level were measured by piezometers during the rain and after that. The results of the mean comparison of pH and total suspended solids showed that most of them were obtained with 7.49 and 281.25 mg/liter, respectively, in the mole drain filled with sand and the traditional mole drainage and 180 fertilizer treatment. The highest mean of electrical conductivity and turbidity was observed as 651 micro mohs/cm in the traditional mole drainage and 240 fertilizer treatment and with 67.76 NTU in the traditional mole drainage and 180 fertilizer treatment. The statistical analysis showed that the effect of drainage treatment on the amounts of ammonium, nitrite, nitrate, phosphate, and total phosphorus was not significant. The outflow from the traditional mole drainage was 49% lower than the sand-filled mole drainage. The traditional and sand-filled mole drains were able to drain excess water with average reaction coefficients of 0.8 and 0.83 per day during the growth period, respectively. Considering the speed of water discharge, drain discharge, and the main non-significance of qualitative parameters among drainage treatments, mole drainage filled with sand is recommended for the development of rapeseed cultivation in paddy fields.
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