نشریه مهندسی زراعی
سال چهل و دوم شماره 2 (تابستان 1398)

Introduction The loess-paleosol sequences in Northern Iran are important archives that represent several cycles of Quaternary climate change and can be used to complete the information gap on loess between Europe and central Asia. Last interglacial soils derived from loess in northern Iran is represented by strongly developed Bt horizons of forest soils. In Golestan and Mazandaran area, soils under the forest are mainly classified as Alfisols or Luvisols. Interestingly, E horizons are generally not found in these soils. In the Caspian Lowlands, a pronounced precipitation gradient is reflected in mean annual precipitation rates decreasing from about 1850 mm at Bandar Anzali in the west to about 435 mm at Gonbad- e Kavoos in the east. The results of the loess climosequence in Northern Iran showed that with increasing precipitation, soil pH and calcium carbonate contents decrease, whereas soil organic carbon, clay content, and cation exchange capacity increase. For years, many efforts to quantify the soil properties led to the provision of indices of soil development. Among these indices are forms and ratios of iron, morphological, and micromorphological indices. Many studies have been carried out on the loess-paleosol sequences and modern loess soils in Northern Iran with focus on micromorphology, mineralogy, and dating but more investigation is needed with an emphasis on the forest soils with well-pronounced clay illuviation as a proxy for paleo-moisture. For this purpose, we used micromorphology and soil color indices to report the effects of precipitation gradient on the variability in the formation of soils under forest vegetation. Materials and Methods The study area is located at the northern slopes of Alborz Mountain Ranges, covered with Caspian or Hyrcanian deciduous forests. Field sampling started in summer 2015. More than ten soil pedons with loess parent material were investigated based on former studies. Finally, six representative modern pedons were selected and dug in an east-west direction on loess deposits. The climate data shows that precipitation varies from 500 mm in Qapan (Pedon 1) to up to 800 mm in Neka. Physiochemical properties of soils were studied using standard methods. Thin section prepared for soil micromorphological studies were studied and interpreted based on Bullock et al. and Stoops guideline using a polarizing microscope. The micromorphological index of soil development (MISECA), suggested by Khormali et al (2003), was calculated. Also, color indices were calculated based on Hurst (1977), Torrent (1983), and Alexander (1985) by using the Munsell color chart. In all color indices, Munsell color hue converts to a single number. Results and Discussion The results showed that the downward decalcification and the subsequent clay illuviation were the main criteria influencing the assessment of soil development in this study. So, all of the soils host argillic and calcic horizons and are classified as Alfisols and Mollisols. Micromorphological studies confirmed the morphology studies in the field and the results of physico-chemical analyses. MISECA index showed pedological changes in different pedons in the studied areas. A significant positive relationship between climate gradient (increasing rainfall) and MISECA index was found. The area and thickness of clay coatings show an increasing trend with rainfall. Occurrence and preservation of clay coatings are more pronounced in more humid regions with illite and vermiculite as the dominant clay minerals. These minerals reduce the shrink/swell potential and increase the number of clay coatings present. In Argillic horizons of all pedons, except Toshan, dominant b-fabric is speckled due to carbonate leaching, while in Toshan, it is striated b-fabric. In calcite horizon, b-fabric is crystallitic. The correlation of various forms of iron with three color indices of Hurst, Torrent, and Alexander showed that Torrent and Alexander indices were better than the other one for the study area. Moreover, there was a good correlation between MISECA and Torrent color index. Conclusion The results showed that the soil evolution in the studied areas is strongly influenced by soil formation factors, especially in a climate which shows a change in the micromorphological characteristics of soils. With increasing the rainfall from the east to the west in this gradient, the amount and thickness of clay coating, as well as secondary calcium carbonate accumulation, change significantly. In addition, the micromorphological and color indices of soil evolution can be used as two indicators for assessing the effects of rainfall gradient on soil formation in northern Iran. On the other hand, knowledge of the development of modern loess-derived soils could help to better understand the paleoenvironment.

Introduction Material conveying in the industries is carried out in the different ways. Pneumatic conveyors are widely used in industries. The special benefits of these conveyors have led them in the short term to widely used in different industries. Transfer of materials without dust dispersion, the flexibility to choose the vertical, horizontal or diagonal tubing, low maintenance costs and manpower, adequate safety and reliability during conveying at the high amounts of materials, easy and automatic control are the some benefits of the pneumatic conveying systems Materials and Methods The mean aperture and the coefficient of variation of sugar particles were determined by sugar crystal size distribution test. It is done based on the cumulative percentages of remaining sugar content on the sieve. The mean aperture (MA) and the coefficient of variation (CV) are obtained from the chart. 7 sieves are used for testing. The percentage of remaining sugar on each sieve was calculated. The amounts of D50% and D16% were calculated following the plotting the size of the sieves versus the cumulative percentage of the remaining sugar on each sieve graph. The conveying pressure drop includes the total pressure drop required for air alone (ΔPL), the material acceleration pressure drop (ΔPA), the friction and material collision pressure drop (ΔP*z), the pressure drop due to lifting and suspension of materials (ΔPG), and bends' pressure drop (ΔPB) in Pascal. Following determination of required power (293.42 w) to run the system, with a confidence coefficient of 3, a blower with a rated power of 700 w was selected. The amount of pressure produced by the selected centrifuge fan was measured by a pitot tube embedded in the blower outlet. The outlet air velocity was measured by a pressure gauge according to the principles of the pitot tube. Results and Discussion The treatments and their levels consisted of pipe lengths at three levels (2, 4 and 6 m), inlet air velocity at five levels (13, 16, 19, 22 and 25 m/s) and mass flow rate of sugar at three levels (160, 180 and 200 kg/h). The statistical analysis was done as a factorial based on a completely randomized design. Analysis of variance and comparison of means were done using Duncan's test at 5% level in each case. Then, the effects of the factors on pressure drop, mean aperture and coefficient of variation of particle size were investigated. Analysis of variance of data shows that the effect of conveying length, mass flow rate of sugar particles and inlet air velocity as well as their interactions and the interaction of three factors on air and sugar pressure drop is significant at 1%. In all conveying lengths, an increase in air velocity and consequently increased sugar particles' velocity at each mass flow rate causes an increase in frictional pressure drop due to the particle's collision with the wall as well as air collision with the pipe wall at each length and the sugar mass flow rate level. Also, total pressure drop has increased with mass flow rate at any velocity. Analysis of variance of data shows that the effect of conveying length, mass flow rate of sugar particles, inlet air velocity, and the interaction of mass flow rate and air velocity on qualitative properties of sugar is significant at 1% level. Considering the significance of the effects of the main factors and interactions between air velocity and mass flow rate, the effect of every main factors and the interaction of air velocity and mass flow rate on qualitative characteristics of the sample was investigated. With increasing velocity in each mass flow rate, the mean aperture and coefficient of variation significantly decreased and increased, respectively. Also, with increasing mass flow at any velocity, the mean aperture decreased and the coefficient of variation increased. By increasing the mass flow rate, the effect of the air velocity on the mean aperture reduction and increase in coefficient of variation increases, and at higher velocities, the mass flow rate effect is more pronounced. Conclusion The length of the pipe with a reduction by 15% in mean aperture and an increase of 137.5% in coefficient of variations than the initial sugar sample had the least effect on these two qualitative properties of sugar. With an increase in air velocity from 13 to 25 m/s, MA and CV values decreased by 20.27 and increased by 17.22, respectively. The velocity of 13 m/s with a reduction of 5.19% in the mean aperture and an increase of 6.69% in coefficient of variation compared to the initial sugar sample had the least effect on the size and the particle coefficient of variation size of the particles among all 5 velocity treatments. With the increase in particle mass flow rate of 160 to 200 kg/h, MA and CV values decrease by 16.49% and increase by 14.75%, respectively. The particle density increases with the mass flow rate.

Introduction Phosphorus (P) is an essential nutrient for all forms of life on the earth, but in excess concentrations, it can act as a serious water pollutant through eutrophication. Thus, it is very important to remove P from aqueous solutions before their release into natural water resources. Among the various P removal techniques that have been developed, the sorption process is widely accepted to be an effective water treatment technique because of low cost, ease of operation, simplicity of design, and high sorption capacity in dilute solutions. Layered double hydroxides (LDHs) are a type of two-dimensional nanostructure anionic clays with high capacities to sorption of anions. These non-silicate clays consist of positively charged brucite-like octahedral sheets which neutralize by a negatively charged interlayer containing relatively weak bonded anions and water molecules. The positive charges generated by the isomorphous substitution of trivalent cations for divalent cations are balanced by interlayer anions that can be exchanged by other anions making them good anion-exchangers with high selectivity. LDHs have been widely used as environmental sorbents because of their high charge density, large interlayer areas, good thermal stability, and high anion exchange capacities of the interlayer anions. The aim of the present study was to synthesize a Mg-Fe LDH as a sorbent for P removal from aqueous solution. Materials and Methods The Mg-Fe LDH was synthesized using the co-precipitation method. In brief, a mixture solution containing 0.03 mol MgCl2. 6H2O, and 0.01 mol FeCl3. 6H2O was added dropwise into a flask containing 100 ml of 1 M NaOH solution under vigorous stirring at pH=10. The obtained slurry was filtered and washed repeatedly with DW until the filtrate pH reached neutral. Mg-Fe LDH particles were then obtained by drying the filtrate at 70 °C in an oven overnight. The crystallinity of the sample was studied using X-ray diffraction (XRD) analysis. In order to investigate the performance of the synthesized LDH as a P sorbent, batch experiments were carried out in polyethylene centrifuge tubes. The suspensions were shaken for 24 hours at 250 rpm, and the supernatant was then separated by centrifugation at 4000 rpm for 10 minutes and were filtered by Whatman ashless grade 42 filtration papers. Equilibrium P concentration was determined according to the ascorbic acid method using UV-vis spectrophotometer at the wavelength of 880 nm. The effects of pH, initial P concentration, and contact time on P sorption were investigated in the ranges of 2-10, 0-300 mg/L and 0-1440 min, respectively. Results and Discussion The XRD pattern of the LDH sample showed typical structure of hydrotalcite-like compounds with sharp and reflection peaks corresponding to the (003), (006), (012), (015), and (110) crystal planes which are characteristic planes of hydrotalcite-like compounds. The efficiency of LDH to remove P decreased with the increasing of initial P concentration and the maximum removal efficiency of LDH occurred in the range of 5-20 mg/L of initial P concentration. With increasing of initial P concentration from 20 to 300 mg/L, the P removal efficiency of LDH decreased from 98.7 to 24.6 %. The P removal efficiency was increased with time and reached equilibrium at 60 min. The P removal rate of LDH in this time was about 66 % and no significant decrease in residual P concentration was observed after 60 min. The sorption of P on LDH was highly pH dependent, and the maximum P removal was found at pH of 4. The sorption kinetic and isotherm data were well described by pseudo-second-order and Langmuir equations, respectively. According to the Langmuir equation, the maximum P sorption capacity (Qmax) of LDH was obtained as 13.96 mg/g. Conclusion It was found from the results of this study that the mechanisms involved in the P sorption onto LDH included electrostatic attraction, ligand exchange, and surface complex formation. In addition, the results suggested that the synthesized Mg-Fe LDH can be potentially used as an effective sorbent for the removal of P from aqueous solutions. Further research is needed on the regeneration of the LDH after P sorption and the evaluation of desorption behavior of P from LDH under different conditions.

Introduction The Lamiaceae is a chief medicinal and aromatic plant family. It is a family of extensive diversity and variety with international distribution. It is known that most of their properties are due to the essential oils they contain as products of their secondary metabolism. The metabolic performance of living organisms can be distinguished into primary and secondary metabolisms. Secondary metabolites represent features that can be expressed in terms of ecological, taxonomic, and biochemical differentiation and diversity. The antioxidant properties of the volatile oils are not as robust as that of water-soluble constituents. Oregano, a member of the family is an herb that has been cultivated for centuries in the Mediterranean region, although now it can be found in most continents. Because of variability in composition and origin of different Origanum spp, the antioxidant capacity reported can vary substantially. In one study, oregano had the highest total antioxidant capacity and phenolic content compared with other Lamiaceae herbs, thyme, sage, rosemary, mint, and sweet basil. Istanbul oregano (Origanum vulgare ssp. hirtum (Link) Ietswaart)is a perennial plant with dense indumentum, white and pink flowers, strong fragrance, and flowering in July and August. It grows widelyin the Thrace, Marmara, and west and southern regions of Turkey. The plant is richer in oil and carvacrol content than O. onites and if improved, agronomic affairs would offer a better alternative. The environmental and social reasons indicate that conventional agriculture constitutes a continuous pressure contributing to the progressive worsening of environmental conditions. In this matter, the increasing use of saline irrigation water is one of the main factors resulting in salt accumulation in the plant rhizosphere. In this situation, soil degradation emphasized the need to develop strategies of salt affected soil reclamation. One of the possible solutions is to use humic substances. Micronutrients are essential elements that are used by plants in small quantities. Yield and quality of agricultural products increased with micronutrients application; therefore, human and animal health is protected with a feed of enrichment plant materials. Each essential element only can perform its role in plant nutrition properly when other necessary elements are available in balanced ratios for the plant. The aim of this trial was to study the effects of some micronutrients and humic substances on the antioxidant activity of the plant. Materials and Methods The trial was conducted at the experimental fields (37.53° N, 45.08° E, and 1320 m) and the greenhouse of the Agronomy Department, Faculty of Agriculture and the Lab of Biology Department, Urmia University, during 2015-2016, prepared in a randomized complete block design in three replications, using Fe, Zn, Cu, humic acid and their incorporation (3 g Lit-1) spray as treatments. The land was plowed at the optimum moisture level (field capacity) and leveled. Phosphorus and Potassium fertilizers were applied at pre-sowing time in autumn, according to soil analysis and farrowed in 50 cm. The seeds for sowing were obtained from Turkey. Sowing was done in green house at the Department of Horticulture, Faculty of Agriculture, Urmia University, during the period from 21. 03. 2015 till 06.05.2015. The seeds were sowed in plastic pots filled with soil, sand, and peat moss substrate as a material for germination. After that sowing was irrigated regularly depending on weather conditions and development stage of plants. Seedlings were harvested and planted in the experimental field. Nitrogen fertilizer was used in planting time, and vegetative phase according to soil analysis. Irrigation was conducted depending on plants need. Harvestings were done in 50% flowering. Physical and chemical characteristics of the field soil were determined by the standard method. Total phenolic content, flavonoid content, DPPH radical scavenging activity, nitric oxide radical scavenging activity, and Chain-breaking activitywere determined. Results The aim of this study was to increase the amount of oregano essential oil, and the use of micronutrients and humic substances increased the essential oil content of the plant. According to the results, the highest and lowest leaf dry weight was related to Zn+Cu+HA+Fe and Cu treatments, respectively. The highest essential oil content (3.50%) was recorded in Zn+Cu+HA and the lowest (2.28%) in Fe+HA treatments. The highest amount of total phenol in the plant leaves (72.7 g gallic acid/ 100 g DW) in Zn, flavonoid content (88.8 g quercetin/ 100 g DW) in HA and DPPH radical scavenging activity (74.1%) were observed in Fe+Cu+Zn+HA sprayings. In addition maximum nitric oxide radical scavenging (50.3%) and Chain-breaking activity (70.7 -Abs-3/min/mg extract) were observed in Zn and Fe+Zn treatments, respectively. In conclusion, the type of micronutrients and humic substances can affect the quality traits such as essential oil and antioxidant activity and according to the use target of the plant, combined and non-combined consumption of micronutrients, and humic substances can be recommended.

Introduction One of the medical plants is lemon verbena with the scientific name of Lippia citriodora Kunth. It belongs to the family of Verbenaceae. The essential oil of lemon verbena has different compositions, which the most important of them are Geranial, Limonene, and Neral. The most important and commonly used physiological method after harvesting medicinal plants is the drying of plant organs which have high energy consumption. The temperature and the method of drying of these plants affect drug quality. The aim of this study was to investigate the effect of different drying methods on essential oil extraction efficiency and the drying time of lemon verbena leaves in a continuous flow dryer system and traditional drying method. Materials and Methods An amount of 150 g of lemon verbena leaves were dried in a continuous flow dryer equipped with the solar pre-heating system at three temperatures of 30, 40, and 50 °C, and three air velocities of 1, 1.5, and 2 m/s. To determine the significant difference between the effects of different air velocities and air temperatures in the dryer method, a factorial experiment was used in a completely randomized design with three replications for each treatment. The required heat for product drying was supplied by the combination of a gas water heater and a solar water heater. In the first stage, the gas water heater was off and the required thermal energy was provided only by the solar water heater. The radiation of solar energy heated the water in the solar water heater tank. After the water temperature reached the desired level, warm water was entered into the heat exchanger through an electric valve and a water pump. The air flow generated by the centrifugal blower was passed through the heat exchanger, and it was heated by the warm water. The warm air was then entered into the drying chamber through the air inlet pipe. If the temperature of the water in the solar water heater tank was lower than the desired level, the electric valve was actuated and made to direct the water flow to the inlet of the gas water heater before entering the water into the heat exchanger. At the same time, the gas water heater was turned on and provided the required thermal energy for warming up the water. In order to compare the quality of the dried product with the traditional drying method, 30 g of dried leaves from each treatment were submitted to hydrodistillation with a Clevenger-type apparatus and extracted with 450 ml of water for 3 h. A completely randomized design was used to determine the significant difference between the essential oil extraction efficiency of each method. Data were analyzed in SAS (Version 9.00) Software and the mean comparison was performed using Duncan's multiple range test. Results and Discussion The results showed that with increasing the air temperature and air velocity, the drying time of lemon verbena in the dryer significantly decreased. Also, with increasing airspeed to the dryer, moisture transfer from the product was performed faster. Finally, the drying time of the product was reduced. The highest essential oil extraction efficiency was obtained at 40 °C and 2 m/s (0.61%), while the lowest essential oil extraction efficiency was 0.23% in the sun drying method. The minimum drying time was obtained at 50 °C and the air velocity of 2 m/s in the dryer (110 min) and the maximum drying time was obtained in the (shade) traditional method (720 min). In this research, a new system was introduced in order to increase the uniformity and quality of the product in the process of drying the lemon verbena. In addition, by comparing the quality of dried product with traditional methods, it was found that the essential oil extraction efficiency in this dryer system was significantly (at 1% level) more than traditional drying methods. Also, the drying time in this system is much shorter than traditional drying methods. Conclusion In general, the results indicate that the drying methods in this study have a significant effect on the essential oil extraction efficiency and drying time of lemon verbena leaves. According to the results of this study, the use of this system for drying lemon verbena has advantages, such as increasing the quality of the product and reducing the drying time compared with the traditional methods. The most important advantages of using this system include: providing a considerable part of the required energy free, the use of warm water in a circulated circuit and the adaptation of the solar pre-heating system to the environmental objectives, the uniformity of product drying due to the continuous flow drying system, shorter drying time and the better quality of the product than traditional drying.

Introduction Nitrogen is one of the essential elements for plants and is consumed more than other elements in plant nutrition. Nitrogen is an important component of the chlorophyll molecule and is present in the chlorophyll structure as a protein. Without nitrogen, plant growth decreases significantly. This research was carried out to estimate the amount of nitrogen and chlorophyll of sugarcane leaves from color indices extracted from digital aerial images taken by a quad-copter at two 5 and 10 m altitudes in the fields of Debal Khozaie sugarcane agro-industry company, Khuzestan, Iran. The images used for this research are from three farms with different growth stages. Materials and Methods The imaging was carried out using a quad-copter, the Phantom 3 professional model, at two heights (5 and 10 meters) from the specified points in the fields. After taking the photos from all marked points by the quad-copter camera, four healthy cane branch - with 45 cm distance from each other - were picked at each point and placed in plastic bags. Then, samples were immediately transferred to the laboratory to measure the leaf chlorophyll value, moisture content and the amount of nitrogen. Using a hand-held chlorophyll meter (SPAD-502 model), the leaf chlorophyll index was measured and recorded at each point. After drying the samples, the nitrogen levels were measured using the manual Kjeldahl method. The designed image processing algorithm, to extract color indices from sugarcane fields' images, had these steps: image transfer, preprocessing, image smoothing, noise, and background removal, extracting and selecting of image attributes. After using the image processing algorithm, the color indices of the fields' images were obtained; then the relationship between color indices and nitrogen and chlorophyll content of sugarcane leaves were determined using multivariate regression. The preparation of the data was done in Excel 2013 software and the development of multiple regression equations in SPSS v.21 software. The student t-test was used to compare the performance of regression models in the prediction of nitrogen and chlorophyll content with real values. Results and Discussion Based on the results of the measurements, the dispersion of nitrogen was not uniform throughout and between the fields. The least nitrogen dispersion was in the first growth period and the greatest one in the second growth period. None of the fields had uniform dispersion in the chlorophyll content. The least dispersion was observed in the second growth period and the highest dispersion in the third growth period. Based on the Pearson correlation statistical analysis - from 48 features extracted by image processing including mean, variance, skewness, and peak value of each image color indices in RGB, HSV, HIS, and Lab color spaces - only 24 features were selected to determine the regressions equations. These indices had a correlation with the amount of nitrogen in sugarcane leaves. In the images of 5 meters height, the obtained regression equation for nitrogen estimation was significant at 1% probability level and had a 74.3% determination factor. The determination factor of the five regression equations presented for the images taken from 10 m height were 71, 74, 77, 79, and 82 percent. Also, all the regression equations were significant at 1% probability level, so these relationships are valid and can be used to estimate the amount of nitrogen in sugarcane from 10 m height. By increasing the number of color indices, the accuracy of the regression model in the estimation of nitrogen levels was increased. Accuracy of the 10 m regression model for estimating the amount of nitrogen in sugarcane was higher than the 5 m regression model. All four regression models presented for estimating the chlorophyll of leaf based on color indices of images taken from 5m height were significant at 1% probability level. The obtained determination coefficients for these models were 26, 45, 55, and 62%. By increasing the number of color indices, the accuracy of the regression model was increased for the estimation of chlorophyll content of the leaf. Also, the presented regression model for the estimation of leaf chlorophyll based on color indices obtained from 10 m height images was significant at 1% probability level. The determination factor for this model was 69%, which is more than the determination factor of the most accurate regression model presented for 5m height images. The regression model presented for estimating the sugarcane nitrogen content from leaf chlorophyll was significant at 1% probability level. The amount of determination factor for this model was 68%, which is very close to the amount reported by the Debal Khozaie sugarcane agro-industry company, Khuzestan, Iran. Conclusion Thecomparison of the results of regression equations with real values showed that nitrogen prediction with regression model for 5 m height images and two regression models for 10 m height images had no significant difference with each other. Also, the results of sugarcane nitrogen estimation using the leaves chlorophyll was not significantly different from the actual nitrogen content of leaves. On the other hand, chlorophyll prediction was performed by two regression models for 5 m height images and the regression model for 10 m height images were not significantly different from the actual amount of leaves chlorophyll. Therefore, the presented regression equations are valid and reliable and using these relationships can help know the state of nitrogen and chlorophyll in sugarcane fields.

Introduction Conservation and improvement the soil structural stability play a key role in soil management in agro ecosystems especially in arid and semiarid region with high erosion potential. Soil structure is an important soil physical property and has many effects on other soil physical, chemical and biological behaviors such as retention and movement of water, nutrients and pollutions, soil hydraulic and mechanical properties, soil aeration and erosivity. Wetting and drying cycles are one of important environmental factor affecting soil structural stability. Previous studies showed inconsistent results about the positive or negative effects of wetting and drying cycles on soil stability. This study was conducted to investigate the effect of wetting and drying cycles on the soil structural stability in the presence of safflower residues. Materials and Methods The agricultural soil was collected from the soil surface layer (0–20 cm) of Shahrood in Semnan province and passed through a 4 mm sieve. An experiment was conducted including two treatments i.e. number of wetting and drying cycles (0, 1, 2, 4, 8 and 10 cycle) and amount of safflower residues (0, 1 and 2 g 100 g-1 soil ). Plant residues were collected from safflower fields and after drying, milled and passed through a 1 mm sieve. Then crop residues were mixed into soil. The wet and dry cycles were applied during 2 month. In wetting periods the soil was kept in filed capacity and in dry periods the soil was kept in electrical oven in 40°C. The soil organic carbon and soil diluted acid carbohydrate concentration were measured at the end of the experiment. The soil structural stability was measured using high energy moisture curve. The soil drainable pores, soil suction at inflection point, stability index, stability ratio and Dexter's S index were calculated. Results and Discussion The greatest soil organic carbon was observed in control treatment (0 wet and dry cycle) and then it was decreased by increment of cycles in all crop residues levels. These cycles improve the microbial activity during the rewetting process and increase decomposition of crop residues. The soil organic carbon and diluted acid carbohydrate were highest in treatments including 2 g residues 100g-1 in all studied wet and dry cycles. The greatest soil drainable pore volume and the lowest soil suction at inflection point were found in treatment including 4 wet and dry cycles. The results showed that 2 and 4 cycles increased the soil drainable pore volume by 58 and 106 % compared to the control treatment (no applied cycle). More increment of wet and dry cycles decreased the soil drainable pore volume and this factor was declined by 40 % in 10 cycles treatment compared to 4 cycles. It means that wet and dry cycles can improved the soil structure because of rearrangement of soil particles and improvement of soil particle contact points. However, the high number of wet and dry cycles destructed the aggregate and decreased their stability. In addition, the physical protection of soil aggregates from soil organic matters declined through aggregate breakdown. This phenomenon provided fresh organic matter for decomposers and consequently the aggregate stability decreased. Appling only one wet and dry cycle could not significantly improve the stability ratio. This ratio improved considerably when 2 and 4 cycles were used. Following the aggregate breakdown in treatments including more than 4 cycles, the stability ratio decreased in all crop residue levels. Our results showed that the greatest and the lowest volume of coarse and medium pore were observed in 4 and 10 wet and dry cycles treatments but the greatest and the lowest volume of fine pores were observed in 10 and 4 wet and dry cycles treatments. It means that the structural stability improvement during 0-4 cycle changed the pore distribution and made larger pores but the aggregate breakdown with more than 4 cycles changed the pore volume again and increased the portion of finer pores. Conclusion Our results showed that the low number of these cycles can improve the soil aggregation and aggregate stability but the high number of these cycles has negative effect on aggregate stability. However, the presence of organic matter in soil can decreased the negative effect of wet and dry cycles. These results confirmed the importance of incorporating crop residues in to the soils after crop harvest.

Introduction Recently, due to the enhancement of industrialization, urbanization, and disposal of wastes, fertilizers, and pesticides the concentration of heavy metals in agricultural soil has increased. Heavy metals are a serious threat to the environment due to their hazardous effects. Heavy metal contamination of the soil is of particular attention due to food security issues and several reported health risks to both human and living organisms. In addition, large areas worldwide are polluted by lead (Pb). One of the major problems in the process of Phytoremediation is the low solubility of heavy metals, such as lead in the contaminated soil. Phytoextraction is a solar-driven remediation technology which greatly reduces the costs and has minimum adverse side effects. Lead (Pb) is among the highly toxic and most common heavy metals at contaminated sites. It originates from various anthropogenic sources and causes a variety of health, environmental, and ecological problems. The weed plant species are usually of the quickly growing nature and have higher biomass under unfavorable environments. Their phytoremediation potential could be more effective in reducing food chain contamination and consequently the risk to human health. Therefore, the objective of this study was to assess the Pb remediation potential of Artemisia (Artemisia absinthium L.) and Xanthium (Xanthium strumarium L.) in contaminated calcareous soil. Materials and Methods This study was carried out under a greenhouse condition as a factorial experiment based on a randomized complete block design with two factors, including Pb concentration in four levels (0, 250, 500, and 1000 mg Pb kg-1 soil) and plant type in two levels of Artemisia (Artemisia absanthium L.) and Xanthium (Xanthium strumarium L.) and in three replications. In this study, the soil was selected and was spiked with 0, 250, 500, and 1000 mg Pb kg−1 soil.  Then plants were grown in pots containing the contaminated soil. At the end of the growth period, the dry weight of root and shoot, Pb concentration in the root and shoot of plants, and soil bioavailable Pb were measured. Also, the tolerance index (TI) of root and shoot was calculated by dividing the dry biomass of plant in each treatment by dry biomass in the control treatment at Pb0 mg kg-1 of the soil. Moreover, the stabilized Pb in roots (MS) and extracted Pb by shoots (ME) were calculated. For evaluating the ability of plants on uptake and shoot and root accumulation of Pb, mBCF (Modified bioaccumulation factor) and mBAF (bioconcentration factors) of shoot and root were calculated by dividing the Pb concentration in plant dry matter to bioavailable Pb concentration in soil and dividing the Pb accumulation in the plant fraction bioavailable metal content in the soil. In addition, the modified translocation factor (mTF) was calculated by dividing the Pb concentration in shoot dry matter by Pb concentration in root dry matter.   Results and Discussion Results of this study indicated that with increasing soil Pb contamination, the root and shoot dry weight and tolerance index of plants decreased, while shoot and root Pb concentration, stabilized Pb in roots and the extracted Pb from shoots increased. The highest and lowest relative shoot and root dry weight were observed in Pb0 and Pb1000 treatments, respectively. There was no significant difference in the tolerance index (TI) of plants. In this study, roots and shoots mBCF, obtained for both plants and different levels of Pb in soil, were above unity, indicating that the plant is able to take up and accumulate Pb. A. absanthium PGPR had higher mTF than X. strumarium plant at every concentration of soil Pb. The assessment of the phytoremediation performance clearly revealed that the amounts of all phytoextraction indices in A. absanthium were higher than X. strumarium, while all phytostabilization indices in X. strumarium were higher than X. strumarium.  In general, maximum Pb accumulation for root was recorded for X. strumarium (average of root mBAF, mBCF, and mTF 1.65 %, 5.48 and 0.97, respectively) and maximum accumulation of Pb in shoot was observed for A. absantium (average of shoot mBAF, mBCF, and mTF 2.79 %, 2.86, and 1.84, respectively). Conclusion It could be concluded that X. strumarium and A. absanthium, with high biomass in native condition, might be effective in phytostabilization and phytoextraction of Pb, respectively, especially in low levels of soil Pb contamination (250 and 500 mg kg-1).

Introduction Increasing the yield and, consequently, increasing the concentration of macro and micro nutrients in the plant is one of the important aspects of agriculture. The improvement of the quality and quantity of some elements, such as potassium, zinc, and iron in the soil can cause an increase in the yield of the crop and the concentration of these elements in plant tissues. The increase in the concentration of these elements in plants can be effective in the health of livestock and consequently the health of humans. One of the new approaches that can be used in this field is the use of magnetic water. Magnetic water is obtained by passing water from a magnetic field. An  externally  applied magnetic field causes  changes  in  the atomic, molecular, and electronic structure of the treated water, such as changes to its solidifying and boiling points, viscosity and the dielectric  constant,  the  formation  of  clustering  structures from linear and ring hydrogen-bound chains of molecules, the magnetic interaction between these clustering structures, and  increasing the polarization effects of water molecules. The biological effects of magnetic field or electromagnetic field treatments depend on the strength and exposure period of water conditioning, in particular, the ion content, quality, and the volume of water. Materials and methods For this purpose, a field experiment was conducted in a factorial arrangement with two main treatments, adding and without adding potassium and zinc fertilizers, and five sub-treatments (magnetic field strengths, including a 0.4 Electromagnetic Coil (EC), 0.3 magnet, 0.3 EC, 0.1 EC, and the control treatment) in four replications at Research Station of Goran University of Agricultural and Natural Resources. The size of each experimental plot was 2 m × 2.5 m. Corn was planted in each plot with the distances of 15 cm from each other and rows with distances of 70 cm from each other. An electromagnetic coil and a permanent magnet were used to create a magnetic field. Water was passed from the middle of this magnetic field through a hose and the plots were irrigated with this magnetic water. The irrigation was conducted based on soil moisture content and continued until the harvest and drying of the plants. Soil and plant samples were taken at two flowering and harvesting stages and were transferred to the laboratory for analyzation. Concentrations of K, Zn, and Fe in the soil and plant tissues were measured. Statistical analysis was performed using the SAS software. Results The results of this study showed that all the plots that were irrigated by magnetic water had corn plants with greater height and more yield was obtained than the control treatments. This could be due to the ease of absorbing water from the soil. Magnetic water has lower surface tension than untreated water, so the plant needs less force to absorb water from soil particles. Also, the plants that were irrigated by magnetic water had higher concentrations (P <0.01) of elements, such as potassium, zinc, and iron in their grains. Magnetic water can increase the availability of the elements in the soil. So, more concentration of elements can be absorbed by the roots and transferred to the aerial parts of the plants. Among the magnetic water treatments, 0.4 Tesla strength treatment had the highest effect on the yield and corn height, as well as potassium, zinc, and iron concentration in grain (P <0.01). Higher strengths of the magnetic field (0.4 T) had more effect on the availability of elements in the soil and their absorption by the plants. The yield of corn in 0.4 EC, 0.3 M, 0.3 EC, and 0.1 EC treatments that potassium and zinc fertilizers were added to them increased as 164, 131, 107, and 45 percent, respectively, than the control. So, increasing the strength of the magnetic field had more effects on some soil properties. The treatments that K and Zn fertilizers were added to them had more yield than other treatments that these fertilizers were not added to them. This could be attributed to the fact that magnetic water has increased the solubility of K and Zn fertilizers. In fact, magnetic water has been able to increase the uptake of K and Zn from the soil.  Conclusion These results indicate that the magnetization of water can be used as an appropriate approach to increase the quantity and quality of product yield and the concentration of the elements in the crops.

Introduction With limited arable land available around the word, some ways can be used to increase the production per unit area to meet the increasing human need for food. In addition to quantity, consideration of quality of products can lead to improve communities’ health. So, in the last few decades, application of organic and bio fertilizers has been taken into account in order to increase quantity of products as well as their quality. Mycorrhiza fungi are the most abundant microorganisms in the soil and are considered as essential factor in sustainable soil-plant system. The use of existing organic and inorganic fertilizers may stimulate the Mycorrhiza-plant root symbiosis and ensure the supply of nutrients to the plant for sustainable production. Filtercake is a main byproduct of sugarcane industry which is obtain during the processing of sugarcane syrup. Filtercake can be transformed into the valuable source of nutrients by biodegradation processes. Many studies have suggested that the use of fertilizers along with Mycorrhiza, especially phosphorous fertilizers, has negative effects on fungi symbiosis with plant root. Regarding this issue, the question arises that due to richness of Filtercake of organic matter, nutrients and microorganisms, is the Mycorrhiza interdependency affected by the addition of this organic manure to the soil? In order to answer this question, the present study was conducted to investigatethe interaction effect of Mycorrhiza(Glomus Intraradices)andFiltercake on coriander (Coriandrum Sativum L.) production. Materials and Methods In order to study the interaction effect of Filtercake and Mycorrhiza on the coriander production, a pot experiment was conducted in factorial completely randomized design with consideration of Mycorrhiza fungi (Glomus Intraradices) treatments at two levels of non-inoculation (m1) and inoculation with Mycorrhiza (m2), Filtercake in three levels of zero (f1), 1.5 (f2) and 3 wt.% (f3) with coriander (Coriandrum sativum L.) as experimental plant in 4 replicates in the greenhouse of Agricultural Sciences and Natural Resources University of Khuzestan during 2017-2018. Twelve weeks after sowing plants were harvested and considered parameters were measured. Data analysis was performed using SAS. Comparison of the meanings was performed using Duncan's test at 5% level. Excel were used to draw charts and graphs. Results and Discussion The highest plant height and root length were observed in treatment consist of Mycorrhiza and 3% Filtercake. Same trend was observed in case of aboveground (cilantro) and root dry weight. The presence of organic matter, increasing of quasi-hormonal activity and improvement of physical, chemical and biological properties of soil are among the factors that provide favorable conditions for vegetative growth and, as a result, increase plant yield. The application of Mycorrhiza increases concentrations of phosphorus, potassium, calcium and magnesium in cilantro, at about 103, 40, 16 and 12 percent, respectively, which are about 11, 105 and 31 percent in case of iron, zinc and copper. Mycorrhiza has a positive effect on the nutrients content in plant, which can be attributed to increased absorption through the fungal hyphae and also to the enrichment of the plant's rhizosphere. The concentration of nutrients in cilantro was significantly increased due to increase in Filtercake level. Since most of the nutrients in the soil are immobilized, the addition of Mycorrhiza fungi can help to improve nutrient uptake by increasing the volume of root access and stimulating the mineralization processes. Application of Filtercake along with Mycorrhiza improves the biological status of the fungi. Increasing the level of the Filtercake from 0 to 3 percent increases colonized Root length, Mycorrhiza interdependency and colonization percent by 51, 22 and 28 percent, respectively. According to the results, the use of Filtercake not only does not reduce the Mycorrhiza indices, but also increases them and act as a key factor for encouraging symbiosis of fungi and plant, so contribute to the enhancement of plant growth parameters. Conclusion In most of the studied characteristics, the maximum amount were observed in the treatment containing 3% Filtercake and Mycorrhiza. So, the simultaneous application of Filtercake and Mycorrhiza increased the growth parameters of the coriander. Although both of treatments (Filtercake and Mycorrhiza) have been effective in increasing the concentration of essential elements in aboveground part of plant, the effect of Mycorrhiza on increasing the concentration of phosphorus and zinc is greater than its effect on other elements, which is for iron and copper in case of Filtercake. The use of organic manure, such as Filtercake, even with high nutrient content, cannot affect the Mycorrhiza interdependency and other colonization indices due to the low release rate of these elements into the soil environment. It seems that the combination of Mycorrhiza and Filtercake by increasing the microbial and enzymatic activities in the soil and the separate application of Mycorrhiza and Filtercake by improving the access ability of the nutrients leads to provide better growth of the plant.