Research Article
Soil science
fatemeh jannati; Fereydoon sarmadian
Abstract
AbstractIntroduction:Research and development in high-potential agricultural areas are of great importance for ensuring the food needs of the population and livestock. Neglecting these regions can lead to increased food prices and food shortages, which can have a negative impact on the economy and public ...
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AbstractIntroduction:Research and development in high-potential agricultural areas are of great importance for ensuring the food needs of the population and livestock. Neglecting these regions can lead to increased food prices and food shortages, which can have a negative impact on the economy and public health. Land suitability maps provide essential information for agricultural planning and are vital for reducing land degradation and evaluating sustainable land use. The utilization of modern mapping techniques such as digital soil mapping and machine learning algorithms can significantly improve the accuracy of land suitability assessment and crop performance prediction. These methods have been widely employed as primary tools for mapping and evaluating land suitability in various regions worldwide.Materials and Methods:In this study, a total of 288 soil profiles were utilized to compute the land suitability index for wheat, barley, and alfalfa crops. Various environmental variables were incorporated, including topographic factors derived from the digital elevation model and spectral indices obtained from Landsat 8 satellite imagery. Eight key factors, namely slope percentage, climate, texture, gypsum content, equivalent calcium carbonate, electrical conductivity (EC), and sodium absorption ratio (SAR), were identified as influential in the assessment of land suitability. To quantify the degrees of land suitability for the target crops, a parametric approach based on the square root method was employed. Moreover, the random forest machine learning model was utilized for spatial modeling, zoning mapping, and determining the significance of environmental variables in the land suitability evaluation process. By incorporating these comprehensive methodologies, a more detailed and accurate understanding of the land suitability for wheat, barley, and alfalfa cultivation can be achieved, facilitating informed decision-making in agricultural planning and land management strategies.Results and Discussion:The spatial prediction results demonstrated the effectiveness of the random forest model in classifying land suitability for wheat, barley, and alfalfa. The model achieved high accuracy, with Kappa coefficients of 81%, 84%, and 85% for wheat, barley, and alfalfa, respectively. The overall accuracies were also impressive, reaching 86% for wheat, 88% for barley, and 89% for alfalfa. Analyzing the land suitability assessment results, it was found that barley had the highest land suitability class, covering a significant portion of 40% in class S1. Alfalfa followed closely with 35.5% of the total area, and wheat occupied 32% in the same class. Delving into the predictive environmental variables for barley, Diffuse, SHt, and MrVBF emerged as the most influential factors. These variables played a crucial role in assessing the suitability of land for barley cultivation. Similarly, for wheat, the variables Diffuse, MrVBF, and TWI were identified as significant indicators, contributing to the accurate prediction of wheat performance. Regarding alfalfa, the variables MrVBF, Diffuse, and Valley_depth stood out as the most important variables, providing valuable insights into land suitability for alfalfa cultivation. In general, the limiting factors for irrigated cultivation of these crops were primarily associated with soil properties. In the northern regions, soil texture was identified as a significant limiting factor, impacting the suitability of the land for crop cultivation. On the other hand, in the southern regions, soil characteristics such as the percentage of lime, gypsum, salinity, and alkalinity were recognized as the most influential limiting factors, affecting the suitability of the land for successful crop production. These findings provide valuable information for land planners, farmers, and decision-makers in determining suitable areas for wheat, barley, and alfalfa cultivation. By considering the identified influential factors and addressing the limiting soil properties, agricultural practices can be optimized to maximize crop productivity and ensure sustainable land use.Conclusion:The research aimed to evaluate land suitability for wheat, barley, and alfalfa crops under irrigation. Data selection focused on the most limiting factors for these crops. The model achieved acceptable predictions for wheat, barley, and alfalfa, with Kappa coefficients of 0.81, 0.85, and 0.84, and overall accuracies of 0.86, 0.89, and 0.88, respectively. Barley had the highest percentage of suitable land (40%), followed by alfalfa (39.5%) and wheat (32%). Soil constraints varied across the study area, including texture, stoniness, lime, gypsum, salinity, and alkalinity. The analysis identified 31 soil types, and the random forest model yielded a digital soil map with a Kappa coefficient of 0.76 and overall accuracy of 0.81. The findings support effective land management and agricultural planning.
Research Article
z
Donya Parmah; Hamid Reza Chaghazardi; Farzad Mondani; Ali Beheshti Al Agha; Daniel Kehrizi
Abstract
IntroductionOptimum yield production in rainfed cultivation directly depends on the amount of rainfall and moisture storage in the soil. The tillage system directly affects the moisture storage and the physical and chemical properties of the soil, and choosing the right tillage system affects the yield ...
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IntroductionOptimum yield production in rainfed cultivation directly depends on the amount of rainfall and moisture storage in the soil. The tillage system directly affects the moisture storage and the physical and chemical properties of the soil, and choosing the right tillage system affects the yield of the product. Oilseeds are particularly important among crops, forming the second-largest food reserves in the world after grains. These products are rich in fatty acids. Today, the oil extraction and production industry is one of the most strategic industries in most countries. Iran has vast arable lands and favorable fields for cultivating oilseeds. Still, according to the available statistics, more than 80% of the country's required oil is supplied from abroad. Considering that our country needs more and better quality oil products on the one hand, and the other hand, is involved in climate issues and problems such as consecutive droughts, it seems that the cultivation and development of plants with fewer water requirements and high resistance and providing management methods and appropriate fertilizer in line with conservation agriculture is a suitable solution to increase crop yields and maintain and increase soil quality in the long term. For this purpose and considering the value of oilseed cultivation, an experiment was conducted to investigate the effect of tillage and fertilization on the yield and components of safflower yield in rainy conditions.Materials and Methods The experiment was carried out as split plots in a basic design of random complete blocks, with three replications in rainfed conditions. The treatments included tillage systems (conventional tillage, reduced tillage, and no-tillage) as the main factor and NPK fertilizer (a mixture of urea, triple superphosphate, and potassium sulfate) at four levels of zero, 33, 66, and 100% as a secondary factor. Potassium and phosphorus fertilization and 50% of nitrogen fertilizer were used at the same time as planting, and the remaining 50% of nitrogen fertilizer was used four months after planting. Each block had three main plots; the distance between each block was 3 meters, and between the main plots was 2 meters. In each main plot, four sub-plots were created, and the distance between the sub-plots was 1 meter. The area of the main plots was 21 × 15 meters, and the area of each sub-plot was 4.5 ×15 meters. The amount of seed used for safflower was 25 kg per hectare. The safflower seeds were sown in 5 rows and planted at a distance of 50 cm and a distance between plants of 10 cm. In all the stages of planting, holding, and harvesting, all agricultural management was carried out based on the traditional management of the studied area and in the farmer's way. The final sampling or harvesting was done manually in the physiological treatment stage. Before analyzing the variance of the data, the normality test of the data was performed. In this research, the LSD test was used to compare the mean at the 5% probability level, Excel software was used to draw graphs, and SAS 9.4 software was used to analyze the data.Results and Discussion The research showed that the traits examined, including leaf area index, dry matter content, thousand seed weight, seed yield, and biological yield, were affected by the tillage system, fertilizer, and their interaction effect. The highest safflower seed yield of 195.6 g/m2 was obtained from the fertilizer ratio of 33% and conventional tillage, and the lowest seed yield of 116.2 g/m2 was obtained from no-tillage and no fertilizer use. The results showed that the conventional tillage system had better results than low-tillage and no-tillage. The results showed that in reduced tillage and no-tillage, the changing trend of safflower plant leaf area index was not much different, and only in safflower, the 100% fertilizer ratio in reduced tillage had a more significant effect than no tillage. Also in the condition of no fertilizer use in no-tillage, the leaf area index was lower. The use of fertilizer increased the biological yield of the plant, but the effect of this use in conventional tillage was higher than in reduced tillage and no-tillage. Consumption of 33% of the fertilizer required by the plant under conventional tillage conditions caused the highest biological yield in the safflower plant. So, the biological performance of safflower increased by 94% compared to the control.Conclusions In most of the examined traits, the application of 33 and 66% of the fertilizer requirement caused the best results, and the 100% fertilizer ratio left adverse effects, which indicates the lower fertilizer requirement of this cultivar in the studied conditions compared to cultivars in other regions. Since the research was conducted in rainy years, conventional tillage was better than low tillage. It is suggested that this plant's production amount be evaluated under different irrigation conditions and moisture limitations so that tillage systems and management methods can be examined and selected more carefully.
Research Article
Soil science
Fatemeh Rakhsh; Ahmad Golchin; Ali Beheshti Ale Agha
Abstract
Introduction
Soil texture is one of the most influential characteristics of soils that affect the decomposition and retention of soil organic matter because it directly or indirectly affects soil's physical, chemical, and biological properties. Soil clays play an important role in soil organic matter ...
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Introduction
Soil texture is one of the most influential characteristics of soils that affect the decomposition and retention of soil organic matter because it directly or indirectly affects soil's physical, chemical, and biological properties. Soil clays play an important role in soil organic matter stability. Organic matter adsorbed on phyllosilicate clays is more resistant to microbial decomposition than organic matter that has not interacted with any mineral. Exchangeable cations with the influence of physical and chemical characteristics of the soil probably cause changes in the absorption and retention of organic matter. In previous studies, the effect of soil texture on organic matter retention has been investigated, but the impact of clay type and exchange cation has not been investigated. This study aimed to examine the effect of different contents of vermiculite and zeolite clays and exchange cations on the mineralization of organic nitrogen.
Materials and Methods
A factorial experiment was conducted in a completely randomized design with three replications to study the effect of the type and content of clay and the type of exchange cations on organic nitrogen dynamics. Experimental treatments include two types of clay (vermiculite and zeolite), four different levels of clay (0, 15, 30, and 45%), and three types of exchangeable cations (Na+, Ca2+, and Al3+). The experiment included 24 treatments and three replications. There were total of 72 experimental units. Artificial soil of 50 grams was prepared separately according to the amount and type of clay and the type of exchange cation. Then, alfalfa plant residues were added to all the samples at 5% w/w. After adding the inoculum and air drying the samples, the humidity of the samples reached 60% of the field capacity (FC) using distilled water (We first air-dried the samples to prevent the excess water from causing an error in the final moisture, and then we added enough distilled water to each sample to reach 60% of FC). They were kept in the dark for 60 days at a temperature of 23 °C. Distilled water was added and sealed to the bottom of the incubation jars to keep the moisture content of the soil samples constant during incubation. The percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were determined in the prepared samples. The data were analyzed using ANOVA, and the means were compared using Duncan's Multiple Range Test (DMRT). Before applying ANOVA, the data's normality and variance homogeneity were checked using Kolmogorov- Smirnov and Levene tests, respectively. The SPSS software (Windows version 25.0, SPSS Inc., Chicago, USA) and SAS software (version 9.4, SAS Institute Inc., Cary, NC) were employed for data analysis.
Results and Discussion
The results of variance analysis of the data showed that the effect of the type and content of clay and the type of exchangeable cation on the percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were significant (p< 0.01). The results revealed that, regardless of the duration of the samples, with the increase in the amount of clay, the percentage of inorganic nitrogen and the activity of enzymes decreased, but the nitrogen of microbial biomass increased. The highest percentage of inorganic nitrogen was obtained 60 days after incubation of the samples and in clays saturated with calcium, and the lowest amount of these attributes was obtained 15 days after incubation of the samples and in clays saturated with aluminum. The results showed that nitrogen mineralization increased with the samples' incubation time. Also, the highest percentage of mineralized nitrogen, microbial biomass nitrogen, and enzyme activity were observed in soils with vermiculite clay.
Conclusion
The increase in the incubation duration increased the percentage of inorganic nitrogen. The percentage of mineralized nitrogen and microbial biomass nitrogen was higher in soils with vermiculite clay than in soils with zeolite clay. Moreover, regardless of the incubation duration of samples, with increasing clay content, the percentage of mineralized nitrogen and enzyme activity decreased, but with increasing clay nitrogen content, microbial biomass increased. The highest and lowest amounts of mineralized nitrogen and nitrogen of microbial biomass were measured in soils with calcium and aluminum, respectively. The results showed the effect of the clay type and content and the exchangeable cation type on organic nitrogen dynamics.
Research Article
Irrigation
Akbar Khedri; Amir Saberinasr; Nasrollah Kalantari
Abstract
Introduction: The comprehension of the hydrogeological conditions of the aquifer and the determination of its hydraulic characteristics, such as hydraulic conductivity, transmissivity coefficient, and specific storage, are crucial for the management and preservation of groundwater resources. Various ...
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Introduction: The comprehension of the hydrogeological conditions of the aquifer and the determination of its hydraulic characteristics, such as hydraulic conductivity, transmissivity coefficient, and specific storage, are crucial for the management and preservation of groundwater resources. Various conventional methods, including empirical formulas, laboratory techniques (constant and falling head), tracer tests, field tests (Lugeon, Lefranc, slug, flowmeter, and pumping tests), and groundwater inverse modeling, are employed to establish these characteristics, particularly hydraulic conductivity. Empirical formulas are limited to ideal conditions, and in laboratory methods, the sample must be kept undisturbed. Due to the impracticality of measuring large-scale effective factors, the hydraulic conductivity determined through laboratory methods is also the only representative of the hydraulic conductivity at the sampling point. Tracer studies encounter numerous constraints, such as time, cost, porosity determination, and tracer dispersion in multilayered aquifers. It is also difficult to determine the average hydrodynamic properties of the heterogeneous aquifer based on the data obtained from a specific section of the Lefranc and Slug tests. Consequently, pumping tests are commonly selected for hydraulic parameter estimation. Although costly and time-intensive, these tests provide more precise coefficients. Geophysical methods have been greatly developed during the last two decades and have shown a significant correlation with the hydraulic parameters of the aquifer derived from borehole pumping tests or direct laboratory measurements. This approach minimizes uncertainties in numerical model calibration, improves data coverage, and reduces the time and cost of regional hydrogeological investigations. The conventional approach, known as the electrical resistivity method, is still widely used in global and local research projects for evaluating aquifer hydraulic characteristics (Ige et al., 2018; Arétouyap et al., 2019; Youssef, 2020; Ullah et al., 2020; de Almeida et al., 2021; Lekone et al., 2023). Therefore, this study aims to use the integrated approach of the geophysical method and pumping test as a cost-effective and efficient alternative for estimating the hydraulic parameters of the alluvial aquifer in the northeast of Gachsaran city.
Material and Methods: The research area is an alluvial aquifer located 5 km to the northeast of Gachsaran, between coordinates 50-52 to 51-09 E longitude and 30-15 to 30-28 N latitude. Using 86 vertical electrical soundings, Archie's equations, and the IPI2win software, the hydraulic characteristics of the aquifer under investigation were estimated. Subsequently, these characteristics were then compared to the coefficients derived from the data of two pumping test wells, which were calculated using the Aquifer test software and obtained via the Cooper-Jacob and Neuman methods.
Results and discussion: The hydrodynamic coefficients of the aquifer were initially determined using the Cooper-Jacob method in this study. The hydraulic conductivity values for wells one and two are 4.9 m/day and 5.7 m/day, respectively. Correspondingly, the storage coefficient values for wells one and two are 0.015 and 0.021, respectively. Based on the Cooper-Jacob approach, it is deduced that if the storage coefficient values exceed 0.001, the aquifer is classified as unconfined. In this study, the storage coefficient values for both pumping wells suggest that the aquifer is unconfined. Since the vertical flow component and the delayed yield phenomenon should also be taken into account in unconfiend aquifers, the Neuman analytical model has been used in the studied aquifer. The values of specific yield (Sy) for pumping wells one and two, which are related to delayed yield, are 0.05 and 0.04, respectively. These values were calculated by analyzing the first segment of the curve derived from the Neuman logarithmic drawdown-time plot. The storage coefficient values for pumping wells one and two, extracted from the second section of the curve, are 0.015 and 0.021, respectively. Furthermore, the transmissivity value for well number 1 was 323 m2/day, while for well number 2, it was 655.5 m2/day. The vertical electrical sounding (VES) data were subsequently initially analyzed and interpreted using the IPI2win software and the equalization curve method (partial curve matching technique). The coefficients denoted as m and n, indicative of the degree of cementation of the sediments, were determined based on the sedimentary composition prevalent in the area. Archie's equations were employed to calculate the formation factor and porosity parameters. The aquifer exhibits a porosity range of approximately 0.15 in the eastern and southeastern parts (near the outlet of the plain) and around 0.41 in the centeral, northern, and northwestern sections of the area (next to the Asmari Formation). The specific yield (Sy) of the aquifer was calculated using the provided formula:
The minimum and maximum specific yield were estimated as 0.006 (in the eastern and southeastern regions) and 0.089 (in the western and northwestern regions of the plain), respectively, with an average value of 0.04. The transmissivity coefficients for the entire aquifer were then calculated based on the fitted relationship between hydraulic conductivity (K) and formation factor (F):
The range of transmissivity coefficients varies from a minimum of 63 m2/day (in the western and northwestern sections of the plain) to a maximum of 608.9 m2/day (in the eastern and southeastern areas). The average transmissivity coefficient is calculated as 323.7 m2/day.
To ensure the precision of the geoelectric method's coefficients, a comparative analysis was conducted with the hydrodynamic coefficients obtained from the two pumping test wells, as presented in the table below:
Conclusion: The evaluation and comparison of the hydrodynamic coefficients derived from the aforementioned methods indicate that the geoelectric method coefficients exhibit acceptable agreement with the pumping test coefficients. In other words, the analysis of the pumping test conducted using the Neuman technique in the unconfined aquifer revealed that well number two displayed a greater transmissivity coefficient, while well number one presented a higher specific yield. These findings are confirmed by the geoelectric approach. Consequently, such hybrid approaches, which include simultaneous analysis of geophysical methods (such as VES) and pumping tests will be a great alternative to multiple costly pumping tests for evaluating the hydrodynamic coefficients of an aquifer. Moreover, employing this hybrid technique enables the generation of dense hydrodynamic coefficients in an aquifer for use as inputs in the groundwater model.
Research Article
Soil science
zahra movahedirad; Mohsen Hamidpour
Abstract
Introduction
Recently, layered double hydroxides (LDH) have attracted considerable attention. LDHs have found applications in numerous cases particularly slow-release fertilizers for essential nutrients for plants. Several studies have reported the release of nitrate and phosphorus from LDHs. The metal ...
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Introduction
Recently, layered double hydroxides (LDH) have attracted considerable attention. LDHs have found applications in numerous cases particularly slow-release fertilizers for essential nutrients for plants. Several studies have reported the release of nitrate and phosphorus from LDHs. The metal hydroxide layer can structurally incorporate micronutrients such as Zn, Cu, and Mn. According to recent research, LDHs have a suitable potential for releasing micronutrients. No information regarding ratios M2+/M3+ in LDHs and the influence of malic acid on the release of Zn, Mn, and Mg from LDHs is available. This study aimed to investigate the effects of malic acid and the ratio of divalent cation (M2+) to trivalent cation (M3+) on the kinetics release of Zn, Mn and Mg from Mg-Zn-Mn-Al-LDH intercalated with nitrate.
Materials and Methods
All chemicals used in this study including malic acid (C4H6O5), KCl, Zn (NO3)2.6H2O, Mn(NO3)2.4H2O Mg(NO3)2.6H2O and Al(NO3).9H2O were of analytical grades, purchased from Chem-Lab or Merck Chemical Corporations. The solutions were made with the decarbonated ultrapure water (electrical resistivity = 18 MΩcm). The LDHs were synthesized by co-precipitation method at constant pH = 9.2-9.6. Two types of LDHs were synthesized with varying the M+2(Zn+Mn+Mg)/M+3(Al) 3:1 and 4:1 in the precursor solution while being stirred vigorously in a nitrogen atmosphere. The pH was kept at 9.2-9.6 by adding volumes of 3 M NaOH. The crystals of LDH were ripened in the mixture for 2 h and after that, the precipitates were centrifuged at 3000 rpm for 20 min and washed several times with distilled water and placed in an oven at 70 °C for 8 hours to dry. The chemical composition of the synthesized LDHs was determined by furnace atomic absorption spectrophotometry (SavantAA, GBC) after acid digestion. The physical, chemical, and morphological characteristics of the LDHs were determined using X-ray diffraction analysis (Panalytical x Pert ProX-ray diffractometer), Fe-SEM (Sigma VP), FT-IR (Nicolet iS10 spectrometer), and BET (BELSORP Mini II) techniques.
A batch study was done to determine the effect of different ratios of M2+/M3+ in LDHs and the effect of malic acid on release of Zn, Mn, and Mg from LDH (3:1) and LDH (4:1). Briefly, 0.01 g of synthesized LDH were put in a centrifuge tube mixed with 10 ml background electrolyte (KCl 0.01 M) and 1.25 mM malic acid in initial pH=6-7 and constant temperature (25±0.5 °C). Blank samples (without ligand) were also considered. Suspensions were shaken at periods ranging from 5 to 720 min agitation (180 rpm). Then, the supernatant solution was separated using a centrifuge at a speed of 4000 rpm for 20 minutes. Zn, Mn, and Mg concentrations in supernatant solutions were determined by graphite furnace atomic absorption spectrophotometry. The effect of pH in the range of 5 to 10 on the release of Zn, Mn, and Mg from LDH was also studied. Two equations (pseudo-second-order and Elovich) were used to fit the kinetics data.
Results and Discussion
. The results showed that the calculated molar ratio of divalent cation to trivalent cation is similar to their molar ratio in the solution prepared for the synthesis of LDH samples. The X-ray diffraction patterns of LDH (3:1) and LDH (4:1) samples show the existence of strong and sharp peaks for 003 and 006 plates. Accordingly, the reflections of the 003 and 006 plates reveal the layered structure of the synthesized LDH materials. Two bands of FT-IR spectrums around 3480 and 1620 cm-1 for all synthesized LDH materials designate stretching vibrations of the O-H group of hydroxide layers and the interlayer water molecules. The sharp characteristic band around 1382 cm−1 in LDH (3:1) and band around 1354 cm-1 in LDH (4:1) is attributed to the antisymmetric stretching mode of nitrate anion in LDH. The specific surface area of LDH (3:1) and LDH (4:1) were 5.50 m2g-1 and 16.54 m2g-1 respectively. The average pore diameters in LDH (3:1) and LDH (4:1) were 1.92 nm and 2.55 nm, respectively.
Time-dependent cumulative release of Zn, Mn, and Mg from LDH (3:1) and LDH (4:1) in the presence and absence of malic acid was investigated. Time-dependent Zn, Mn, and Mg release from LDH (3:1) and LDH (4:1) was accelerated in the presence of malic acid. The Zn, Mn, and Mg release from the LDHs was likely to be separated into two stages. In the initial stage from 0 to 60 min, the release rate of Zn, Mn, and Mg was rapid, then either remained constant or slightly enhanced during 60–720 min. In this research, among the non-linear models used to determine the release kinetics of Zn, Mn, and Mg, the result with the highest R2 values was chosen. The R2 values were 0.91–0.99, 0.93–0.99, 0.93–0.99, 0.89-0.99, and 0.55–0.86 for pseudo-first-order, pseudo-second-order, Elovich, power function, and parabolic diffusion, respectively. So, pseudo-second-order and Elovich models were used to analyze kinetic data. The amounts of release of Zn, Mn and Mg were higher from LDH (4:1) than from LDH (3:1) because of greater specific surface area, volume, and pore diameter in LDH (4:1). On the other hand, the presence of divalent cations in this structure has increased its instability. A comparison of metal release versus time profiles exhibited that dissolution was greatly dependent on the pH.
Conclusions
The results of this research showed that the release of Zn, Mn, and Mg from LDHs was dependent on time, ligand, solution pH, and the type of LDH. Based on the results of fitting the kinetics models to the experimental data, the release rate of Zn, Mn, and Mg from LDH (4:1) was higher than LDH (3:1). In both types of LDH, the presence of malic acid led to an increase in the rate and amount of release of Zn, Mn, and Mg compared to the absence of malic acid. Although the results of this research showed that it is possible to influence the amount and rate of release of Zn and Mn by synthesizing these compounds in different ratios of divalent to trivalent cations, to confirm the efficiency of LDH as a slow-release fertilizer in calcareous soils, greenhouse studies are needed.
Research Article
Irrigation
mostafa fallahi khoshhi; parasto Hamezadeh; Ali Reza karbalaee; zahra beygam hejazizadeh
Abstract
Introduction:
Precipitation is a key climate variable that is very difficult to predict in numerical weather models. Since precipitation in mountainous areas may vary greatly in the spatio-temporal dimension, accurate spatially distributed data are very important for assessing water resources in mountainous ...
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Introduction:
Precipitation is a key climate variable that is very difficult to predict in numerical weather models. Since precipitation in mountainous areas may vary greatly in the spatio-temporal dimension, accurate spatially distributed data are very important for assessing water resources in mountainous areas.The large temporal and spatial changes of precipitation, especially in mountainous areas, have turned it into a controversial variable in climate models. Measuring precipitation (rain and snow) along with its distribution and changes is very important to improve our understanding of global water cycle and energy, water resources monitoring, hydrological modeling. Lack of reliable data is one of the most important challenges in rainfall analysis. Since precipitation in mountainous areas varies greatly in the temporal-spatial dimension, accurate spatially distributed data is very important for water resources assessment and management. However, in many mountainous regions, few rain gauge stations are available. Today, satellite products are used as a tool to measure precipitation in these areas, but the difference between the existing products challenges their accuracy for mountainous areas. On the other hand, the quality of different satellite products varies from one product to another and from one climatic region to another Therefore, there is a need to fully evaluate them before using them.
Method:
The purpose of this research is to evaluate the precipitation data of two satellite products (GPM, PERSIAN) and reanalysis data (ECMWF) in the estimation of precipitation in mountainous areas without stations in Lorestan province. In the present study, the rainfall data of 24 synoptic and rain gauge stations with appropriate distribution in Lorestan province were selected with emphasis on the stations located or close to the mountainous areas. from rainfall data (daily, monthly and yearly) of GPM and PERSIANN satellites and reanalysis data (ECMWF) (period 2021-2015) and synoptic and rain gauge stations (period 2021-2015) in Lorestan province to evaluate satellite precipitation algorithms and estimate The amount of precipitation in the areas without statistics was used.
To evaluate the accuracy of the products, R-squared correlation (R2), root mean square error (RMSE), standard deviation (MAD), correlation coefficient (R), error deviation (MBE) and Nash-Sutcliffe coefficient (NS) were used. Also, the probability of detection (POD), false alarm ratio (FAR), and critical success index (CSI) indices were used to validate the data.
The results of the review of all three products (GPM, PERSIAN, ECMWF) showed that in general all three products are not accurate enough in estimating daily rainfall, although a few stations have medium to low correlation coefficients, but the ability to estimate rainfall due to the existence of other There are no errors. In general, ECMWF products are more reliable than other products on a daily scale. Precipitation estimation using satellite data on a monthly scale indicated that these products provide favorable results for estimating precipitation on a monthly scale. Among the three products, with different data, the GPM satellite product has better accuracy with regard to the amount of errors and also the spatial pattern of the estimated precipitation. On an annual scale, considering the amount of statistical errors as well as the spatial patterns of average annual precipitation, GPM satellite has a better ability to estimate the amount of precipitation. Also, according to the results of the MBE index on a daily and monthly scale, ECMWF products are overestimated and PERSIAN and GPM products are underestimated in precipitation estimation. In the annual scale, GPM and ECMWF products are overestimated and PERSIAN products are underestimated.. Based on the observed rainfall of the studied stations, the highest rainfall occurs in the west and center of the studied area, and the eastern parts of the area have the lowest amount of rainfall. In the ECMWF satellite product, the spatial pattern of the amount of precipitation has changed with the displacement of precipitation cores to the west and east of the region, which is different from the climatic reality of the studied region. In the product of the PERSIAN satellite, the precipitation cores are closer to the reality by moving towards the center and north, but it is still different from the climatic reality of the region. In the GPM satellite product, the spatial pattern of the annual rainfall amount is almost similar to the spatial pattern of observed rainfall, and the precipitation cores are identified in the center and west of the region; Therefore, according to the spatial pattern of annual rainfall, GPM satellite products have better accuracy than other products.
Research Article
Soil science
Zeinab Barati; Hamidreza Owliaie; ebrahim adhami; Mahdi Najafi Ghiri
Abstract
Introduction
Zagros oak forest ecosystem is one of the largest forest ecosystems under destruction in Iran, which is of great importance in terms of water and soil protection. Moisture stress in recent years has caused the deterioration of these forests in a wide area. Iranian oak (Quercus brantii Lindlb.) ...
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Introduction
Zagros oak forest ecosystem is one of the largest forest ecosystems under destruction in Iran, which is of great importance in terms of water and soil protection. Moisture stress in recent years has caused the deterioration of these forests in a wide area. Iranian oak (Quercus brantii Lindlb.) is the main tree species forming these forests. Potassium (K) is considered to be the most important nutrient cation in terms of its quantity in plant tissue and its physiological and biochemical functions. Soil tests measure the quantity of a nutrient element that is extracted from soil by a particular extracting solution. Over the years, many different soil testing methods and extracting solutions were evaluated to identify a technique that provides the most reliable prediction of crop yield response to nutrient application. It was determined that some soil testing procedures are best suited for particular soil types and climatic regions. There has been no research on the general status of K in the soil of Zagros forests, related to oak trees. It is important to introduce appropriate K extractants for extracting available K in these soils. Therefore, this research was carried out to achieve the mentioned goals in some forest areas of this Province.
Materials and Methods
Ten forest areas with dominant coverage of oak trees were selected in different parts of Kohgiluyeh and Boyerahmad Province. The physiochemical properties of the soil samples were determined based on standard methods. Soil pH, texture, electrical conductivity, calcium carbonate equivalent (CCE), organic carbon, and cation exchange capacity (CEC) were identified. The content of K present in different forms was determined by standard methods. Solution K was measured in the saturated extract. Exchangeable K was determined by extraction of 5 g soil sample with 20 mL 1 M NH4OAc (pH 7) for 5 min. Nitric acid-extractable K was measured by extraction of 2.5 g soil sample with 30 mL of boiling 1.0 M HNO3 for 1 h. Non-exchangeable K was calculated as the difference between HNO3-extractable K and NH4OAc-extracteable K. Total K was determined following digestion of 0.5 g soil sample with 10 mL of 48% HF and 1 mL of aqua regia. The 12 extracting solutions were 1M NaCl, 2M NaCl, 0.01M CaCl2, Morgan, AB-DTPA, 1M NH4OAC, 0.25M NH4OAC, 1M MgOAC, 1M NaOAC, 2M HCl, 0.1M HNO3, and 0.025M H2SO4. The K content of leaf samples was determined in 1g of each sample. The samples were dried and then ashed in 450°C for 4 h. 2M HCl was used to digest the samples. Potassium was measured on all filtrated extracts using a Corning 405 flame photometer.
Results and Discussion
The soils are all calcareous (average of 42.9 and 44.7% CCE in surface and subsurface, respectively), with pH in range of 7.0-7.8. The textural classes were sandy clay loam, clay loam, and clay. The range of soluble potassium is between 4.8 to 32.7 with an average of 15.4 mgkg-1, exchangeable potassium from 65.1 to 364 (with an average of 247 mgkg-1, non-exchangeable potassium from 106 to 876 with an average of 515 mgkg-1, structural potassium was from 761 to 7322 with an average of 4026 mgkg-1and total potassium was from 1051 to 8110 with an average of 4493 mgkg-1. Soluble, exchangeable, non-exchangeable, and structural potassium were 0.49, 9.6, 12.1, and 77.8%, of the total K, respectively. Among the 12 tested methods, 1.0 mol/L NH4OAC extracted the highest amount of K (mean 229.3 mgkg-1, ranging 64.9-384.2 mgkg-1) and 1.0 mol/L MgOAC removed the lowest amount of K (mean 53.0 mgkg-1, ranged 19.1-88.0 mgkg-1). Correlation coefficients between K extracted by 12 extractants were positive and significant. Maximum correlation between K leaf and extracted soil K was noticed in AB-DTPA, 0.25M NH4OAC, 1M NaCl, and Morgan-Wolfe (r=0.60, 0.59, 0.56, and 0.55, respectively) and the minimum correlation was noticed in 2M HCl and 0.025 M H2SO4 (r= 0.41 and 0.44, respectively). The amount of potassium in oak leaves (in the range of 0.65% to 1.18%) showed a significant correlation with exchangeable potassium in the soil. The amount of potassium in 50% of the oak leaf samples was less than the critical limit (1%). As a general result, 1M NaCl and 0.25M NH4OAC extractants are recommended for extracting potassium, due to greater correlation, simplicity of the method, and economic considerations.
Conclusion
The results of this research showed that the range of the values of different forms of potassium in different parts of the province had a relatively large difference (6 and 8 times difference in exchangeable and non-exchangeable potassium values). The amounts of available forms of potassium in the western regions of the province with less rainfall were in most cases higher than the more humid eastern regions. The average amount of exchangeable potassium in 60% of the studied areas was less than the critical limit of 250 mgkg-1 soil. Also, the average amount of leaf K in 50 percent of the samples was less than the critical level. Considering the great importance of potassium in the nutrition of oak trees and dealing with environmental stress, especially the shortage of soil moisture, it is recommended to pay more attention to the conditions of this element in the soil of the forest areas of the province. Also, fertilizing and foliar spraying of trees in some forest areas should be considered.
Research Article
Irrigation
Mohammad Reza Alashti; Mojtaba Khoshravesh; Fardin Sadegh-Zadeh; Hazi Mohammad Azamathulla
Abstract
Introduction
The rapid growth and development of urban communities, coupled with the increased industrial and economic activities in recent years, have led to the production and release of various pollutants into the environment. These pollutants have adverse effects on human health, living organisms, ...
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Introduction
The rapid growth and development of urban communities, coupled with the increased industrial and economic activities in recent years, have led to the production and release of various pollutants into the environment. These pollutants have adverse effects on human health, living organisms, and the overall environment. With limitations in water resources, insufficient rainfall, the looming risk of water crises in many countries, and the escalating pollution of surface and underground water, there is a pressing need for environmental solutions to mitigate these issues. It is important to acknowledge that wastewater often contains pollutants that may render it unsuitable for certain applications. The utilization of biochar derived from cost-effective materials and innovative technologies such as ultrasonics is one avenue that warrants exploration for enhancing water quality. In this approach, a nitrate solution is exposed to both an adsorbent and ultrasonic waves. This dual treatment induces changes in the physical and chemical properties of water, thereby offering potential improvements in water quality.
Materials and Methods
This study aimed to explore the impact of utilizing biochar derived from rice straw, which was coated with iron (III) and zinc cations, and subjected to ultrasonication, on the nitrate adsorption process from aqueous solutions. In order to produce biochar, cheap materials of rice straw were used. The chopped straw was placed in the electric furnace and heated for one hour to reach the desired temperature. Then it was kept at that temperature for 2 hours. After that, the obtained biochar was washed three times with distilled water at a ratio of 1:20 and dried in an oven at 70°C for 24 hours. In this research, two different temperatures of 350°C and 650°C were used for the production of biochar, which according to the results obtained in the pre-tests of the research that nitrate removal efficiency is higher in biochars made at 650°C. These biochars were used for the continuation of the experiments. In this research, after conducting pre-tests to optimize the adsorbent dose in the proportions of 0.1, 0.3, 0.5, 0.8 and 1 gram of the adsorbent and 40 ml of nitrate solution, concentrations of 20, 45, 80, 100, 150 and 200 ppm of nitrate solution was investigated. The research involved conducting experiments to determine the optimal parameters for each treatment, with three repetitions conducted in the water quality laboratory of Sari agricultural sciences and natural resources university during the years 2021 and 2022. The treatments comprised biochar (B), biochar and ultrasonic (BU), biochar with iron (III) coating (BF), biochar with iron (III) coating and ultrasonic (BFU), biochar with zinc coating (BZ), and biochar with zinc coating and ultrasonic (BZU). In this investigation, Langmuir and Freundlich adsorption isotherms were examined.
Results and Discussion
The results indicated that the BF and BFU treatments exhibited a higher maximum adsorption capacity. The Freundlich isotherm demonstrated higher correlation coefficients for BF, BFU, BZ, and B, suggesting a superior fit of the Freundlich model in these treatments. The better fit of the Freundlich adsorption isotherm indicates the heterogeneity of biochar surface adsorption sites, which means that the adsorption process is not confined to a single constituent layer. Nitrate adsorption on biochar surface is probably influenced by electrostatic adsorption and ion exchange. Conversely, the BZU and BU treatments showed a better fit with the Langmuir model. In the analysis of the Freundlich isotherm, nf values revealed that BF, BFU, and BZ treatments exhibited a favorable adsorption state with a desirable curve shape. The B treatment displayed a normal adsorption state with a linear curve shape, while BU and BZU treatments showed a weak adsorption state with an unfavorable curve shape. The elevated values of adsorption capacity (KF) obtained for BF, BFU, and BZ, namely 1909.414, 1484.22, and 386.63 ((mg/g)(L/mg)1/n), respectively, underscore the high nitrate adsorption capacity of these treatments. Also, biochars coated with iron (III) and with iron solution concentration of 10000 mg/L had a very good performance in removing nitrate from aqueous solutions. The new ultrasonic technology was able to improve the performance of the tested adsorbents in a period of 5 minutes without the need to stir the mixture of biochar and nitrate solution in the obtained equilibrium times, which were between 60 and 120 minutes. The use of this technology can be effective and useful in increasing the economic benefits of using limited water resources and increasing the efficiency of water consumption.
Conclusions
The utilization of cost-effective biochars derived from rice straw, along with the application of ultrasonic technology, can substantially decrease nitrate levels in aqueous solutions. In the case of biochar with iron (III) coating, biochar with iron (III) coating combined with ultrasonic treatment, and biochar combined with ultrasonic treatment, there is a notable affinity for nitrate to be adsorbed onto the surface of the adsorbent.
Research Article
Agricultural Meteorology
خدیجه Javan; Alireza Movaghari
Abstract
Introduction
The most important effect of global warming is the increase in extreme weather events. According to AR5 reports, between 1951 and 2010, the number of warm days and nights increased and the number of cold days and nights has declined globally. In addition, the duration and frequency of hot ...
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Introduction
The most important effect of global warming is the increase in extreme weather events. According to AR5 reports, between 1951 and 2010, the number of warm days and nights increased and the number of cold days and nights has declined globally. In addition, the duration and frequency of hot periods, including thermal waves, has increased since the middle of the twentieth century. The trend analysis of temperature extreme indices is important in estimating the trend of global warming. Temperature Changes are affected by many complex factors. A significant part of these changes is due to the elements of the general circulation of the atmosphere and the sea surface temperature. Given that extreme weather events are one of the most devastating natural hazards and have harmful effects on different parts of society, therefore, many researchers have studied the changes in the past and future of extreme events and the mechanisms that trigger these changes. This research attempts to study the trend of changes in extreme temperature indices in North-West of Iran, and also their relation with general circulation of atmosphere.
Data and methods
At first, diurnal data of minimum and maximum temperature of 20 synoptic stations of the Northwest of Iran, which have long-term and reliable statistics, extracted for the period of 1986-2010 and quality control and data homogeneity of them were investigated. afterwards, 16 Extreme temperature indices introduced by ETCCDMI were applied. In general, these indices are categorized into five categories of absolute indices, based on percentiles, based on thresholds, periodic, and amplitudes that measure the frequency, severity and duration of the temperature. These indices are estimated by RClimDex software and the trend rate of the changes in indices was shown as maps. To measure the changes in the general circulation of atmosphere the annual mean circulation composites extracted for the periods of 1961-1985 and 1986 -2016 based on the reanalysis data of the NCEP / NCAR. Then the difference maps plotted using grads software.
Results
The regional trend of extreme indices and the percentage of stations with a positive and negative trend were identified and the spatial distribution of the gradient of each of the indices was mapped. The results show that all absolute temperature indices have an increasing trend. On average, the maximum temperature (TXx and TXn) has increased by about 0.04 degrees over the decade. The Increase rate of TNx is about 0.03 degrees, while the TNn increased about 0.1 degrees Celsius per decade during the study period. Therefore, in the north-west of Iran, temperature increase has mainly occurred at night. The values of cold days (TX10) and cold nights (TN10) decreased with a gradient of -0.46 and -0.42 days in the decade. The warm days (TX90) and warm nights (TN90) have an increasing trend in 95% of the stations in the area. Frost days (FD) and icing days (IDs) have a decreasing trend, whereas, summer days (SU25) and tropical nights (TR20) have an increasing trend. The number of frost days with a gradient of -0.95 and the number of icing days with a gradient of -0.63 days in decade are decreasing. While, the number of summer days with a gradient of 0.81 and the number of tropical nights with gradient of 0.31 days in decade are increasing. In the northwest of Iran, all stations have been experiencing the increasing trend in Warm spell duration index (WSDI), but the cold spell duration index (CSDI) in 70% of the stations in the region has decreased. Growing season length, as an effective index especially in agriculture, is increasing by an average of 1.1 days per decade. Based on the results of research carried out globally and at the Iran, the trend of Daily temperature range (DTR) is negative, while this index has a positive and increasing trend in 65% of North-West stations in Iran. Except TNx and TNn indices that have positive trend in most stations in the region, Comparison of warm and cold extreme indices indicates that warm indices have a positive and incremental trend, while cold indicators show a decreasing trend. The positive gradient of these indices also corresponds to the decreasing trend of cold day and night indices, which indicates an increase in temperature and a decrease in cold days and nights. The study of large-scale changes in atmospheric circulation shows that the study area has been warmer in the spring and summer and colder in autumn and winter.
Conclusion
In this study, the trend of temperature extreme indices in North-West of Iran and its relation with the large-scale general circulation of the atmosphere have been investigated. The results show that all absolute temperature indices (TXx, TXn, TNx and TNn) are incremental. The indices of cold days (TX10) and nights (TN10) decreased with a gradient of -0.46 and -0.42 days in the decade and the indices of warm days (TX90) and warm nights (TN90) are increasing in 95% of the stations in the area. Frost days and icing days (IDs) show declining trend and summer days (SU25) and tropical nights (TR20) have an increasing trend. In the north-west of Iran, all stations have experienced an increasing trend in Warm spell duration index (WSDI), but the cold spell duration index (CSDI) has been decreasing in 70% of the stations in the area. Growing season length (GSL) is increasing by an average of 1.1 days in every decade. Daily temperature range (DTR) has a positive and increasing trend in 65% of stations in north-west Iran. Comparison of warm and cold extreme indices indicates that warming indices have a positive and incremental trend, while cold indices show a decreasing trend. Study of the general circulation of atmosphere of the region by drawing and analyzing difference maps indicates that the study area has been warmer in spring and summer and colder in autumn and winter.
Keywords: Climate Change, Temperature Indices, Atmosphere Circulation, Northwest of Iran.