نشریه مهندسی زراعی
سال چهل و سوم شماره 3 (پاییز 1399)

Soil digital mapping represents a set of mathematical computations to predict the distribution of soil classes in the landscape. . The digital identification of soils as a tool for creating soil spatial data provides ways to address the growing need for high-resolution soil maps. The use of digital soil mapping technique has been expanded considerably; therefore, new methods of mapping and preparing digital maps have been developed by researchers to eliminate the limitations of traditional methods. This approach relies on statistical relationships between measured soil observations and environmental covariates at the sampling locations. Digital soil data is increasing based on new processing tools and various digital data. The present study was conducted with the purpose of digital soil mapping in Kouhbanan region of Kerman based on a Multinomial logistic regression model.

The study area is located in southeastern Iran, northwest of Kerman city, in Kouhbanan distinct. This study covers a 2000 ha area. In this study, a Latin hypercube sampling design was applied and the sampling was done according to the difference in landforms (geomorphology map), topography (including digital elevation map) and geology. Finally, the geographic locations of 70 profiles were identified. Soil profiles were described according to U.S. Soil Taxonomy (Soil Survey Staff, 2014) and finally, the soil samples were taken from their diagnostic horizons. The collected soil samples were transferred to the laboratory, and some physical and chemical analyzes were performed based on routine standard methods. Environmental data include the parameters derived from the digital elevation model, Landsat satellite images (remote sensing indexes), geology map, geomorphic units (geomorphology map) and legacy soil map of the study area. All environmental variables were derived using ENVI and SAGA software. In this research, a multinomial logistic regression model was used to predict soil classes and the modeling was done in R software using nnet package. It is worth noting that leave-one-out cross validation was used for validation. Estimation of predictive accuracy of soil classes was also done using the overall accuracy index and Kappa coefficient.

The results showed that the soils of the study area were mainly classified in the Aridisols and Entisols orders. The modeling results showed that the terrain attributes were recognized as the effective auxiliary variables in the prediction process of soil classes. This confirms topographic importance on soil genesis in the studied area. After that, geomorphology map was an important tool in soil mapping that helps to increase predictive accuracy. Among the soil classes, the prediction of Haplocambids was accompanied with low accuracy, while Haplosalids great groups were predicted with high accuracy. The low estimation accuracy of the great group of Haplocambids is probably due to the low sample size of this class of soil in the study area. A good identification of the relationships between the predictor variables and the target variable depends primarily on the size and distribution of the sample in the layers. There were only two examples of Haplocambids in the area. Therefore, low accuracy is expected because the model has failed to establish a relationship between this class with environmental variables and makes it difficult to identify threshold values for classifying soil classes and, consequently, a poorly trained model. It is also possible that low prediction accuracy is the result of the conceptual model being incomplete, since there is no characteristic feature that can help model training and ultimately prediction. Among the soil great groups, the best predictions were obtained for the great group of Haplosalids, which demonstrates high values of user accuracy and reliability. Accurate prediction of the class of Haplosalids is highly correlated with the spatial distribution of indices such as wetness index and NDVI. Kappa index and purity map were calculated 0.45 and 0.65 for digital soil map derived from multinomial logistic regression. In the predicted map, six major groups of Haplosalids, Haplocambids, Haplocalcids, Haplogypsids, Calcigypsids and Torrifluvents were identified. The great groups of Haplocalcids, Haplosalids, and Calcigypsids cover most of the area and the great groups Haplocambids and Haplogypsids occupy lowest of the area. The great group of Haplosalids is located in the north of the region and in the piedmont plain landform. Haplocalcids great groups were most commonly found in alluvial fan landform, while Calcigypsids are located in pediments, alluvial fans, and piedmont plain landforms. Haplocambids and Haplogypsids great groups are located more in the geomorphic surface of the alluvial fan and the piedmont plain, respectively. The parts of the region with the most variations or diversity of soil classes are exactly where the geomorphological map has the most segmentation. Therefore, the presence of different soil classes in the least-differentiated and most similar regions is resulted to an inefficient conceptual model and poor prediction results.

The results showed that topographic parameters were the most important and powerful variable in modeling, and confirms that topography or relief is the most important soil forming factor in the study area. Predictive results of soil classes in Kuhbanan area of Kerman province showed that geomorphological map in the study area is very useful and necessary and also is effective in understanding and communicating between soil and landscape. Using this map as a qualitative auxiliary variable can explain much of the variability of soils in the study area. Careful field observation, satellite imagery consideration, study and interpretation of data obtained from soil profiles indicate that the study area has been evolved by geological, geomorphological, and hydrological processes that lead to the formation of various landforms including rock outcrops, hills, pediment , alluvial fan and plain. For the multinomial logistic regression model in the study area, terrain attributes have the most influence on the prediction of soil classes and soil properties than the remote sensing indices. The strong relationship between soil data and environmental parameters is one of the factors influencing model accuracy. Logistic regression models will have great potential in predicting soil classes if a complete understanding of the study area and proper selection of auxiliary variables are carried out.

Soil degradation is a phenomenon which destructs the soil structure and mitigates its capacity for production. Among several processes that cause soil degradation, soil erosion as one of the most common forms of soil degradation leads to loss of soil surface and including on-site and off-site effects. Although soil erosion is a natural process on the earth, but destructive human activities such as burning agriculture residue, deforestation, overgrazing, and lack of proper soil conservation practices; accelerate the soil erosion and enhance the negative outcomes of erosion. Selecting and implementing of management scenarios requires assessment of soil losses from different management operations. Generally, management practices consist of structural and non-structural methods that used to reduce erosion, prevent nutrient removal, and increase soil infiltration capacity. Application of simulation models is an appropriate technique to evaluate erosional conditions. GeoWEPP is a process-based, distributed parameters and continuous simulation model of water erosion in watersheds with the possibility to simulate hillslopes and hydrographical network. Locating problems in real world usually face with a large amount of information and decision space that need to be optimized using evolutionary algorithms due to the variety of aims considered. Considering diversity of evolutionary algorithms, NSGA-II is one of the most common and a usable multiobjective evolutionary algorithm (MOEA) which is very powerful tool for solving problems with conflicting objectives. Development of simulation models along with optimization algorithms that are capable of analyzing very complex systems, have found to be very efficient in real world problems. Simulation-optimization models are powerful tools for solving problems for least cost and best performance.

To predict sediment yield and runoff in the studied watershed, the GeoWEPP integrates WEPP model with TOPAZ (Topography Parameterization), CLIGEN (Climate Generation) and GIS tool (ArcGIS). The GeoWEPP model provides the processing of digital data including DEM ASCII file, soil ASCII file and landcover ASCII file. To generate climate file, the CLIGEN module which is a stochastic weather generation model was utilized. Furthermore in TOPAZ part the CSA (critical source area) and MSCL (minimum source channel length) to delineate streams and also the outlet point of studied watershed were defined using GeoWEPP linked to ArcGIS. Using the basic maps including DEM, slope, soil great groups and soil database the GeoWEPP model simulates and generates the hillslopes automatically; therefore this is an important advantage of GeoWEPP compared to WEPP model which is capable of performing the simulation of watershed components spontaneously. In this study in order to optimize the placement of Gabions, 118 channels and 5110 candidate sites for gabion construction were simulated and evaluated. For optimization process; regarding the number of objectives firstly the AHP technique was used to prioritize the effective factors on the placement of Gabions. Analytical hierarchy process is a structured technique for organizing and analyzing complicated decisions based on mathematical calculations. The AHP depicts the accurate approach for quantifying the weights of criteria and estimates the relative magnitudes of factors through pair-wise comparisons. The AHP technique includes creating hierarchical structure, prioritizing and calculating relative weights of the criteria, calculating the final weights and system results compatibility. The main criteria (objectives) for our study were minimum distance from road, minimum distance from residential area, maximum length of main channel, maximum sediment yield, maximum discharge volume and maximum volume structure. Indeed using the AHP technique it was possible to restrict the decision making space and the number of possible options, therefore simplify the optimization process. Then NSGA-II (Non-dominated Sorting Genetic Algorithm) was applied in order to find the best solutions, i.e. the Pareto front, of alternatives for optimal location of structures based on the two objectives with higher priority and distance constraint.

The results of paired comparison matrix and prioritizing showed that the length of main channel in the watershed is the main effective criterion in locating Gabion structures. The first priority is considered as the most critical channel which produces the highest sediment yield; therefore the most expensive structure is established on that channel. After channel length, the volume discharge was the second priority of effective factors for gabion placement. Using the results of AHP, based on channel length and discharge volume the non-dominated sorting genetic algorithm (NSGA-II) was performed and the priority of critical channels and the specific position was determined from 1 to 35 among 5110 candidate sites for Gabion construction. Using the ArcGIS, slope map and the lowest width of the critical channels the place for gabion construction as a point was determined. Moreover the main output of GeoWEPP is the spatial distribution of sediment yield and based on this map the sediment yield was classified in the watershed. Based on this map the red color was the highest amount of sediment yield (more than 4 ton) in the watershed.

Results confirmed that application of simulation-optimization techniques helps to select the best sites to construct the Gabion as structural best management practice therefore is a cost-effective technique.

Citrus are one of the major agricultural production available in the world and it is one of the popular fruits in the diet. The most well-known varieties of citrus fruits include oranges, lemons, grapefruits and tangerines. Cultivation of sweet lemon requires specific climate situation that it is found in many region of Iran. However, the high quality ones are in Jahrom, Ghsre Shirin, Dezfool, Jiroft and the Sorth of Iran. Two major limitation of long-term storage for citrus fruits are decay caused by pathogens, especially fungi, skin fruit damage and water loss, which can cause wrinkles and reduce product marketability and consumer acceptability. Edible coatings are one of the most effective methods to maintaining the fruit quality. Today edible coatings can preserve citrus quality and provide attractive approach to satisfactory performance. Chitosan is used for film or edible coatings to extend the shelf life of foods such as fruits, meat and fish and foods. The results of several studies indicate the effective role of chitosan in controlling fruit during storage. Wax in the fruit is used to prevent moisture loss and wrinkle of the fruit and also to maintain the appearance of the product and its marketability. So, the final goal of this study is investigate the effect of edible coatings (chitosan-clay Nano composite, Wax coatings and olive oil) on some quality attributes of sweet lemon during shelf life storage.

Sweet lemon's fruits (216 N.) were harvested randomly from a citrus orchard in Dezfool, Iran. The samples immediately sent into the laboratory for storage after necessary treatments. All fruits were disinfected by immersion in 4% chlorox for 3 minutes and then dried. Chitosan with low molecular weight (43 KD) was bought from Sigma Aldrich Company. Clay was purchased from Sefid Sang Aligoodarz Company in Iran and wax coating was provided from Pooshesh Hayat sabz company in Iran. The chitosan-clay coating was prepared by dissolving a mixture of chitosan (3w/v% to solution), clay (5, 10 and 15% wt to chitosan) and glycerol (10v/w% to chitosan) and tween 80(5% v/w to chitosan) in acid lactic solution (2%). Nano structure of chitosan-clay nano-composite was approved by XRD analysis. The chemical parameters of fruit juice such as TSS (%), pH(%) and TA (%) of lemon juice were measured. TSS was determined by digital refractometer (model MA882, made in Japan). pH was measured by pHmeter ( portable p-755 model) and TA was determined by AOAC standard method. The experiment was performed at three levels of chitosan-clay nanocomposite, olive oil, Carnoba wax and uncoated samples during 12 days shelf life storage. The experimental design was factorial based on completely randomized design with three replications. Limon samples were maintained at ambient temperature of 25 ℃ and relative humidity of 80-85%. Chemical characteristics (pH, citric acid, fruit juice TSS, vitamin C) and mechanical characteristics (weight loss percentage, sphericity coefficient, maximum shear force, maximum fracture force and maximum tensile strength of the fruit skin) were measured during storage.

The results of experiments showed that the trend of changes in vitamin C content decreased during storage. But this decrease was slower in the different percentages of chitosan-clay, olive oil coating and carnoba wax than in the control samples. The results showed the significant differences at 1% and 5% levels between different coatings at maximum fracture force, percent weight loss and pH. In addition, the effect of storage times on TSS, pH and maximum fracture force was significant. The lowest and highest percentage of weight loss for uncoated samples and olive oil coating were 12.3% and 10.23%, respectively. Results showed that the coated fruits had the better performance in preserving the quality of properties than the uncoated samples and 5% chitosan-clay nanocomposite coatings were higher performance than the other coatings.

In this study, the effect of chitosan-clay nanocomposite, olive oil, Carnoba wax and uncoated samples during 12 days shelf life storage on Chemical characteristics (pH, citric acid, fruit juice TSS, vitamin C) and mechanical characteristics (weight loss percentage, sphericity coefficient, maximum shear force, maximum fracture force and maximum tensile strength of the fruit skin) were investigated. The results of this study showed that 5% chitosan-clay nanocomposite coatings were higher performance than the other coatings.

Today, with advances in all sciences, we must always look for a way to make the best use of plant residues and turn them into valuable products. A consequence of improving family life standards and consistent industrial development is a higher demand for energy usage. Nowadays, agricultural residues are produced in huge quantities and could be considered as a promising source for renewable energy generation. Bagasse is one of the major sources of sugarcane production. The production of valuable products from Bagas, in addition to having economic benefits, can reduce the environmental damage caused by burning them. In recent years, there has been an increasing trend in the utilization of sugarcane bagasse as a major by-product of the sugarcane industry. Another very valuable substance produced from sugarcane bagasse, which we will discuss in this study, is bio compressed coal. Valorization of sugarcane bagasse to engineered biochar using hydrothermal carbonization (HTC) presents a perspective source to substitute conventional fossil fuels. HTC process offers the benefits of converting the sugarcane bagasse into biochar and bio-oil. In this process, biomass is usually conducted in the temperature range of 180–250 ◦C. HTC technique is promoted as one way of reducing carbon dioxide (CO) emissions, which mostly generated through open burning of crop residues. Besides the utilization for power/heat generation for sugarcane industries, Bagasse may find other potential applications, for instance: electricity generation, biogas production, livestock feed/compost production, and also bioethanol production. The unique features of biochar generated through HTC process are its portability, high volumetric energy density, hydrophobicity, and wear ability.

In this research, sugarcane waste was obtained from Hakim Farabi Sugarcane Cultivation and Industry Company in Ahvaz. The hydrothermal carbonization process was performed in a batch reactor at Shahid Chamran University of Ahvaz. The parameters studied in this study include the retention time of the material inside the reactor (30, 75, and 120 minutes), bagasse mass to water ratio (0.15, 0.20, and 0.30) and the pressure inside the reactor (10, 12.5 And 15 bar). In order to measure the pressure, a Nuova FiMa barometer was used, which was able to measure the pressure values up to 25 bar. A temperature control system model HANYoung ED6 was used, which was equipped with a ceramic heater with a diameter of 230 mm and a height of 230 mm to provide heat for the process. The PARR1266 calorie bomb device was employed to measure the calorific value of the samples. The moisture content of the samples was also measured using ASTM-2010a standard. In this experimental work, the response surface method was employed to investigate the effect of input parameters (i.e., pressure, residence time, and water-to-biomass) on the response parameter (i.e., HHV and energy consumption). Design Expert ver.10 software was used to predict the corresponding models. The obtained models provided a good relationship between the independent/dependent parameters.

The HTC process has been analyzed using a Response Surface Method to derive predicted models for the HHV and energy parameters. The results obtained showed that all models provided could successfully predict the HTC process. According to the results, the models developed were statistically significant at the level of 1%. The multi-regression models between the input/response variables were obtained as second-order quadratic equations. The F-value for the residence time, and water-to- bagasse, and pressure were 2417, 286, and 1185, respectively. The value of F-value of each derived model indicates the significance of the studied parameters. The parameters of water-to-bagasse and pressure had a more significant effect compared to the residence time factor. The R-square value for this study was achieved as 0.0996, indicating that the proposed model was able to evaluate the experimental data thoroughly. A multi-objective optimization technique was used to achieve an optimal HTC process condition with the maximum possible amount of desirability value.

The optimum amount of water-to-bagasse, pressure, and residence time was calculated using the response surface techniques. A pressure of 11 bar, the residence time of 38 min, and water-to-bagasse of 0.15 were found to be optimal values. The findings of this study indicate that at optimal input variables, the value of calorific value and used energy was 21 Mj/kg and 0.09 kWh, respectively. Keywords: Hydrothermal carbonization, Sugarcane bagasse, Response surface method, Optimization

Traditional organic manure can be potentially beneficial for soil physical, chemical and biological properties by improving organic matter of soils. Recently, biochar, a carbon rich product of biomass produced by thermochemical conversion under oxygen-limited conditions, has been studied for its effects as a soil amendment. The use of a modified form of manure as manure biochar for soil improvement reduces some environmental, food safety and disposal problems of manures. However, biochar application has been shown to have a positive and negative effect on soil fauna such as earthworm depending on the type of feedstock for its production. Since earthworm function affects physical properties and amount of organic carbon of soils and because of the different effect of biochar and its feedstock on earthworm activity, this study hypothesizes that earthworm may differently alter soil physical properties and aggregates associated carbon in the biochar and its feedstock amended soils. The purpose of this study was to investigate the effect of cow manure and its biochar in the presence and absence of earthworm on bulk density, total porosity, saturated hydraulic conductivity, aggregate stability and content of organic carbon in soil aggregates during 30 and 90 days incubation.

A completely randomized design with 2×4×2 factorial treatment combination was used in triplicates. Treatment variants examined in this study included the following: (i) 2 levels of amendment type (cow manure and its biochar), (ii) 4 levels of applied amendment rate (0, 1, 2 and 5%), (iii) 2 levels of earthworm (with and without earthworm). The biochar was produced from cow manure (passed through 2 mm mesh) by slow pyrolysis at 450 °C. For this experiment, the soil sample was passed through 4 mm mesh. Then, amended soil and the control were moistened up to 70% water holding capacity. Then 5 adult Eisenia fetida with fully-developed clitellum and similar weight were added to half of them. Treatments were then incubated at laboratory temperature and constant moisture for 30 and 90 days. Based on evaporation loss, the soil moisture was kept constant by regular weighing of each pot. At the end of each time (30 and 90 days), samples were taken from different treatments to determine bulk density, total porosity, saturated hydraulic conductivity. Also, soil aggregates were separated by wet sieving, then aggregate size distribution was determined and mean weight diameter (MWD) was calculated, also organic carbon content in each aggregate size fraction was determined.

The results showed that the application of both organic amendments was effective in decreasing soil bulk density, increasing total porosity, saturated hydraulic conductivity and aggregate stability, but the effects of organic amendments on these physical properties were more pronounced in cow manure- than biochar-amended soils. Further reduction in bulk density following manure application is attributed to a dilution effect, resulting from mixing of the lighter material of manure with denser mineral fractions of the soil. In addition, cow manure has more content of organic carbon than its biochar which can increase total porosity by promoting aggregation. The greater porosity and aggregation of soils as affected by the application of organic amendments are apparently responsible for the increased saturated hydraulic conductivity. The results showed that the effect of cow manure on the soil physical properties reduced with time more rapidly than its biochar. It might be attributed to lower stability of manure to degradation than biochar in soils because manure contains higher content of labile organic compounds compared to biochar. Our results also showed that application of organic amendments led to increase organic carbon in soil aggregates, especially in 4-2 mm aggregates, indicating that the large macro-aggregates can be considered as a susceptible indicator to organic carbon managements in soil. Also, the organic carbon content of 4-2, 2-0.25 and 0.25-0.05 mm aggregates was 42.8, 27.8 and 20.8% (in 30 days incubation) and 27.2, 28.6% and 20.6% (in 90 days of incubation) higher in cow manure- than biochar-amended soils. The results also showed that earthworm reduced soil bulk density, increased total porosity, saturated hydraulic conductivity and aggregate stability regardless of soil amendment but such effect on bulk density and total porosity was more pronounced in cow manure- than biochar-amended soils. It means that type of organic amendments can influence on earthworm activity, thereby altering some soil physical properties. Also, earthworm led to increase carbon content in soil aggregates, especially in smaller aggregates.

The results showed that although application of cow manure improved soil physical properties more than cow manure biochar at both incubation times, it seems that cow manure biochar has a more stable effect on the soil physical properties over time. Also, application of organic amendments can lead to increase soil organic carbon by further increasing C in larger aggregates. Other results indicated that the improving effect of earthworm on soil physical properties (except for bulk density and total porosity) did not depend on the type of applied organic amendment in soil. The effect of earthworm on bulk density and total porosity was more pronounced in soils amended with cow manure than its biochar. Also, it is thought that earthworm increases organic carbon in soil by physical stabilization of organic carbon in soil aggregates, especially in smaller aggregates.

Salinity is one of the most important environmental stresses limiting agricultural production in arid and semi-arid regions, which occupies a relatively large area of arable land. Nutrient availability is decreased in saline conditions in soil solution and plant nutrient balance is changed. Nitrogen fertilizer management as an essential nutrient for plant growth is very important under salinity stress. Also, salicylic acid is a plant growth regulator involved in defense mechanisms of plants against biotic and abiotic stresses. Therefore, the aim of this study was to investigate the effect of salinity on the concentration of nutrients in wheat in response to salicylic acid consumption at different levels of nitrogen.

In order to investigate the effects of salicylic acid and nitrogen fertilizer application rates at different salinity levels on nutrient concentration of wheat cv. Morvarid, an experiment was conducted as a split plot factorial based on a randomized complete block design with four replications in the fields of Mazraeh-E-Nemooneh located in Anbarolum, Aq Qala city, Golestan province. The main factor included three soil salinity levels (3-4 below wheat tolerance threshold (control), 9-11 and 13-15 dS.m-1) and sub factors included two levels of salicylic acid (0 and 1.5 mM) and three levels of N fertilizer (from urea source, 46% N) were 1) N based on soil test recommendation, 2) 30% N more than soil test recommendation and 3) 30% N less than soil test recommendation, respectively. Salicylic acid was foliar applied twice for about 2 weeks in the tillering stage and 10 days after the second stage spraying, content in them was determined. Nitrogen treatments were applied in three stages - one third before planting with ammonium sulfate (21% N) and remains top-dressed with urea (46% N) at tillering and stem elongation stages. At the emergence stage of the cluster or the beginning of flowering of wheat, the amount of nitrogen in the flag leaf was measured. The concentrations of nitrogen, potassium and sodium in grain and straw were also measured by standard methods.

The results showed that by increasing salinity, the flag leaf N concentration, N and K concentration of wheat staw and seed decreased. However, Na concentration of straw and seeds increased. With increasing N and salicylic acid consumption, the concentration of N flag leaf, the seed and straw N and K concentrations increased, but the concentration of Na in seed and straw decreased. The interaction of salinity, salicylic acid and nitrogen on seed N and K concentrations and also on flag leaf N concentration was significant but there was no significant effect on other measured elements. Comparison of the mean of simple effects of salinity on the evaluated elements indicates a significant reduction of all studied elements due to salinity treatment. Also, comparison of the mean of simple effects of nitrogen fertilizer showed that all elements were affected by the treatment. The results of mean comparison showed a positive and significant effect of salicylic acid on the leaf N concentration of the flag leaf, so that the N concentration in the flag leaf in a 1.5 mM salicylic acid treatment was significantly increased compared to the non-use treatment.

according to the results, more nitrogen consumption at moderate salinity can have a positive effect on plant nutrition, and vice versa, at high salinity levels, it is better to reduce nitrogen consumption. The interactions of salicylic acid and nitrogen showed that in general nitrogen treatments with salicylic acid increased the N concentration of seed and straw. Nitrogen fertilization at higher and medium salinity levels increased the concentration of N and K in straw and seeds; However, at high salinity, less nitrogen fertilization improved the concentration of N and K. Also, nitrogen application with salicylic acid improved these traits under saline conditions. Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity. Key words: Salicylic acid, salinity stress, wheat, Nitrogen fertilizer management

Low rainfall, lack of irrigation water of good quality, high water level and high annual evaporation in the southwestern region of Khuzestan, has led to the emergence of saline soils. Various environmental factors, such as low production of soil organic matter, high salt content, high concentration of sodium ions, high pH and quality and depth of groundwater, have significant effects on the qualitative indicators of saline soils in arid and semi-arid regions. Soil quality indicates the ability of the soil to provide biological services to living organisms. These services include food production, water treatment, pollution absorption, carbon dioxide absorption, and the production of a variety of medicinal and industrial plants. Soil quality is an important indicator of agricultural and environmental sustainability and is used to assess soil quality. Each soil quality index must have biological characteristics, be sensitive to environmental and managerial changes, and be effective in measuring measurable and quantitative processing. The present study was conducted to determine the soil quality index in a part of the southwestern lands of Khuzestan province with three land use of agriculture and industry, traditional agriculture and barren lands in a part of the southwestern region of Khuzestan province. In this study, using systematic networking method as well as the characteristics of the study area, a total of 180 soil samples were selected and 22 physical, chemical and biological parameters were determined in each sample. The parameters studied in this study were: electrical conductivity, pH, ions such as sodium, calcium, magnesium, chlorine, bicarbonate, sulfate, SAR, CEC, exchangeable potassium, ozone-absorbable phosphorus, percentage of organic matter, activated carbon, Percentage of clay, silt and sand, average soil diameter, water permeability coefficient in saturated state, specific apparent weight and surface soil hardness. After the laboratory results were determined, using statistical method of factor analysis (FA) and principal component analysis (PCA) in SPSS statistical software, among all the characteristics affecting soil quality (TDS), five characteristics of electrical conductivity, sodium concentration, Chlorine, sulfate, and SAR were identified as the most important characteristics affecting soil quality (MDS). The selection of these factors as MDS indicates the high impact of soluble salts and the low depth of ground water on soil quality indicators of the study area, so that the accumulation of salts on the surface and depth of soil, mainly affects soil quality. To evaluate the lands, two models of cumulative soil quality index (IQI) and Nemro quality index (NQI) were used in two sets of MDS and TDS. Then, in order to compare the performance of soil quality index methods, common methods of secondary root and maximum limitation were used. The results showed that in general, the lands of the region were at different levels in terms of soil quality indicators and land suitability assessment methods, so that the lands of cultivation and industry showed maximum quality, lands under traditional cultivation with medium quality and barren lands showed minimum quality. The Kappa coefficient calculated between the Cumulative Soil Quality Index (IQITDS) and the second and maximum rootstock methods was 0.83 and 0.37, respectively, indicating a high and moderate level of coordination between the data obtained from the various methods tested. The calculated correlation between the results obtained from IQITDS and IQIMDS is equal to 88.43% and also between the results of NQITDS and NQIMDS is equal to 80.59%, which are statistically significant. This suggests that a well-prepared MDS set can be used to represent the TDS set. Therefore, MDS can be used instead of TDS to reduce the time and cost of implementing similar research projects. The results of this study show that soil leaching and leaching of salts from the surface and depth of soil profiles, especially in barren lands and under traditional agriculture has been observed and this is the main cause of differences between these lands and lands under agricultural management and industry. In cultivation and industrial lands, due to leveling, drainage and leaching, additional salts have been washed from the soil profile as much as possible and the conditions for plant growth have been provided. It seems continuity of agricultural and industrial land management, especially in the field of adding low-consumption elements, organic matter and improving physical properties, should be done in such a way that soil quality indicators are closer to the optimal range.

Algae have demonstrated to be an efficient bio energy source because in contrast to sugarcane, soybean, canola and oil palm, algae are not edible, they are less expensive to produce, grow faster, allow higher yield and production rate per hectare, do not require clean water to grow, and have the potential of reducing carbon emission. Because of their small size (typically a few micrometer) and low concentration in the culture medium (0.5–2 gL-1), harvesting microalgae biomass is a major challenge. The main goal of this study was to demonstrate the proof of principle for harvesting of microalgae using electro-coagulation-flocculation and to investigation the influence of several important variable on the efficiency of the electro-coagulation-flocculation in harvesting and separating Dunaliella salina microalgae from the culture medium. This is a native species and halophyte microalgae with a different culture medium from the fresh water in terms of salinity and electrical conductivity.

In order to investigate the effects of five control variables (independent) was included: material of the electrodes on both levels of aluminum and iron; current intensity in the range of 300 to 1000 mA; time for electro-coagulation-flocculation, 5 to 20 minutes; the electrode gap, 1 to 3 cm; stirring speed between 0 to 400, on the recovery efficiency as the response variable (dependent) experiments based on multi factors response surface method (combining categorical with numeric factors) was designed. In this study, the experiments were made inside a batch reactor with an effective volume of 250 mm which is made of Pyrex glass. Two electrodes with dimensions of 5 × 5 cm and a surface area of 25 cm2 with distance 2 cm from bottom of the reactor in vertically state and in different stages were placed inside the reactor with distance of 1, 2 and 3 cm. The Voltage and required current in the reactor were provided with a digital DC power supply. The main pilot in shape of cubic rectangular which is made of plexiglass with dimensions 35 × 28 × 18 cm and the effective volume of 14 liters was designed and built, in order to test the results of optimal experiments. For designing an experiment, statistical analysis and optimization was used from the software Design-Expert.

In this study, the modified quadratic model was used to fit the microalgae recovery efficiency data obtained from each batch test. The coefficients of determination (R2), adjusted and predicted were respectively more than 0.98, 0.96 and 0.90, which indicated that the modified quadratic model could describe the microalgae recovery efficiency in the batch tests of this study successfully. The results indicated that the linear effect of control variable on the recovery efficiency is very statistically significant. Moreover with increasing the electric current intensity variable and ECF time, or reduce the distance between the electrodes, the recovery efficiency has increased significantly. Also by increasing stirrer speed from 0 to 200 rpm the amount of recovery efficiency is increased, and by increasing stirrer speed from 200 to 400 rpm the amount of recovery efficiency has decreased. The results showed that aluminum electrodes on the recovery of microalgae from the culture medium are more efficient than iron electrodes. In this study, were searched the optimal operating conditions with aims of maximization of the microalgae recovery efficiency. The maximum microalgae recovery efficiency of 98.06% was obtained at the current intensity of 999 mA, the time of 20 min, the electrode gap of 1.39 cm, the stirring speed of 222 rpm and with aluminum as electrode material .

In this study was examined the effect of five control variables (independent) including: current intensity, electrode gap, ECF time, stirring speed and electrode material on the response variable (dependent) the recovery efficiency of Dunaliella salina microalgae from the culture medium. The modified quadratic model was used to fit the microalgae recovery efficiency data obtained from each batch test. The experimental results in different stages of our study indicated that the harvesting efficiency of the ECF process could be improved with optimized settings in different stages. If you want to achieve the maximum efficiency with considering economic factors, energy and environment, the second part of an article by the same research group that focuses on this topic is recommended. However, as the ECF process is complicated on a large scale, a pilot study is required to further adjust the harvesting efficiency and make alterations in current density and electrode plate distance in the ECF harvester so as to develop such technology and make commercial use of it in the future.