Research Paper
M. Soleimanzadeh; F. Khormali; M. Sohrabi; R. Ghorbani Nasrabadi; M. Kehl
Abstract
Introduction Biological soil crusts are a widespread community of cyanobacteria, green alga, lichens, mosses, and other organisms. These crusts play important roles in arid and semi-arid ecosystems, such as carbon and nitrogen fixation, soil protection against water and wind erosion, and water retention. ...
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Introduction Biological soil crusts are a widespread community of cyanobacteria, green alga, lichens, mosses, and other organisms. These crusts play important roles in arid and semi-arid ecosystems, such as carbon and nitrogen fixation, soil protection against water and wind erosion, and water retention. In arid and semi-arid regions, the biological soil crusts also possess a key role in the global carbon cycle due to the carbon fixation (photosynthesis) and its release (respiration) into the atmosphere. These organisms increase the organic carbon content of the soil in arid and semi-arid regions by performing photosynthesis. Soil organic carbon is a mixture of various components and one of the important characteristics for soil quality evaluation. Biological attributes of soil quality include many soil components and processes related to the organic material cycle, such as total organic carbon and nitrogen, microbial biomass, carbon and nitrogen mineralization, labile fractions of elements, the activity of enzymes, and animals and plants in soil. These biological attributes respond rapidly to natural and human-derived changes, and therefore they are used as indices for quality of soils. Biological soil crusts are the main cover of the loess soil surface in the northern parts of Golestan Province. The region that was selected to be studied in the province was Maraveh Tappeh. This region has arid and semi-arid climate and is attributed to low vegetation, especially on the slopes to the south. In these slopes, biological and physical crusts are dominant. Therefore, a study was conducted to investigate the effect of lichen biological soil crusts on organic carbon and different fractions of labile carbon. Materials and Methods After extensive field studies, two species of lichen biological soil crusts were collected and transferred to the laboratory for identification. The results elucidated that the studied species were Diploschistes Diacapsis (Ach.) Lumbsch, and Fulgensia Fulgens (Sw.) Elenk, based on taxonomical identification. Soil sampling was done from 0-2 and 2-5cm depths under lichen biological and physical crusts. Soil samples were transferred to the laboratory, and then the organic carbon, carbohydrate, permanganate oxidizable carbon, microbial biomass carbon, cold-water extractable organic carbon, and hot-water extractable organic carbon were measured by standard methods. Results and Discussion Results show that lichen biological soil crusts led to the increase in soil organic carbon and different fractions of labile organic carbon related to the physical crust. As a result, the highest values for these traits were observed in soils affected by lichen biological soil crusts. Soil covered by the Diploschistes Diacapsis species had the highest amount of soil organic carbon and different fractions of labile organic carbon in comparison to the Fulgensia Fulgens species in 0-2cm depth, which had a significant difference at 5% probability level. the physical crusts had the least amount of soil organic carbon and different fractions of labile organic carbon related to the lichen biological soil crusts, which was caused by the loss of topsoil and the lack of biological coverage. There was a positive correlation between the measured traits. There was a high correlation between hot water-extractable carbon and carbohydrate. There were high correlation coefficients between organic carbon with microbial biomass carbon, hot water-extractable carbon, and carbohydrate. In general, there was a high correlation coefficient between hot water-extractable carbon with organic carbon and other labile fractions of organic carbon except for cold water-extractable carbon, whereas there was low correlation coefficient between hot water-extractable carbon with organic carbon and other labile fractions of organic carbon. Conclusion According to the results attained from the following study, the presence of biological soil crusts on loessial soils led to the increase in organic carbon, carbohydrate, permanganate oxidizable carbon, microbial biomass carbon, cold-water extractable organic carbon, and hot-water extractable organic carbon. Diploschistes Diacapsis Species have the highest impact on organic carbon and different fractions of labile organic carbon. The High correlations show that the best attributes to evaluate the quality of soil organic carbon in the studied area are microbial biomass carbon, carbohydrate, and hot water-extractable carbon and these may be used as a good indicator to evaluate soil quality. The studied area falls within the arid and semi-arid climate, and given the erosion-prone nature of loess deposits, improper management may lead to severe problems, such as erosion and dust production. Hence, protecting lichen biological loess crusts against human activity and livestock grazing may result in lower water and wind erosion, and increase soil quality in this region.
Research Paper
H. Mehregan; Sh. Ghavami Jolandan; M. E. Khorasani Ferdavani
Abstract
Introduction Today, in modern agriculture, the use of agricultural machines is inevitable. the tire is the last part of the power transmission system, which plays an essential role in controlling the tractor and transferring the tractor's reaction to the soil. Tires used in agricultural implements and ...
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Introduction Today, in modern agriculture, the use of agricultural machines is inevitable. the tire is the last part of the power transmission system, which plays an essential role in controlling the tractor and transferring the tractor's reaction to the soil. Tires used in agricultural implements and tractors should be able to transport appropriately and have sufficient adhesion and slip. Several parameters affect these abilities, including tire diameter and width, tire shape, tire tread modulus, tire pressure and load on the tire, with the last two parameters, tire pressure and load on the tire two very important factor is the tire and surface contact, the tire's contact between the tire and the ground, the tire's involvement in the direction of travel, as well as the tensile and fuel consumption of cars and motor vehicles. Given the fact that the tire pressures/load of agricultural machinery are less attractive to the users, Due to the many benefits that the use of electronic control systems. Due to the many benefits that the use of electronic control systems, Today, the use of electronic control technologies is considered as an innovation. the automatic tire pressure control system could ensure the pressure stability. Tire pressure drop is detected, and the system automatically refills the tire according to the tire pressure requirements. Therefore, the main aim of this paper is to set the tire pressure at the optimal value by designing an electronic control system for measuring and controlling tire pressure and evaluating the response speed of the system. Materials and Methods This research work is mainly aimed at designing a tire pressure control the tire pressure. BD pressure sensor, Arduino board, voltage/pressure regulator, 5-volt double-channel relay module was utilized. Moreover, Solenoid valve, rotary joint along with compressor and reservoir was employed for controlling tire pressure. In this paper, a laboratory tire pressure control system was designed which can operate in both manual and automatic modes. In automatic mode, a series of ideal pressure (P1) is defined as the soil type, and the driver selects an ideal pressure for the system. If the tire pressure (P0) differs from the set pressure point (P1), then the control unit determines a time duration (T1) for the decrease/increase the pressure level to achieve the optimal setpoint. Besides, a manual mode allows the system to provide a wide range of pressure for the driver depending on the terrain encountered. It is worthy of mentioning that the operation of the system in manual mode is the same as that of automatic mode. In this work, experiments were performed at three levels of output pressure (43.5, 65.2, 87 psi), two tire pressure reduction levels (20- 16 and 16 -12 psi), and two tire pressure increase levels (8 -12 and 12 -16 psi). The tests were laid out as a factorial in a completely randomized design with three replicates. Results and Discussion The ANOVA results indicated that the effect of reservoir outlet pressure on the timing function and tire pressure was significant at the level of 1% (p-value <0.01), while the dual and triple impacts of the factors were not significant. The results also illustrated an increase in the speed of the system response at the output pressure of the reservoir of 87 psi. Also, two different scheduling functions were conducted to evaluate the speed of the system response to reduce the tire two levels of 20 to 16 and 16 to 12 psi. For this reason, two different scheduling functions were used. The ANOVA results indicate that the timing function and tire pressure level had a significant effect on the output parameters at the level of 1%. Furthermore, an increase in the speed of the system response in the second-order scheduling function was observed. Comparison of system performance with first and second time estimation functions at different reservoir pressures, as shown in Fig. 9, showed that the use of the second-order estimation function in all cases reduced the number of steps to reaching the desired pressure significantly. Conclusion According to the obtained results, it can be concluded that the replacement of the second-order scheduling function to control tire pressure, increased the speed of the system’s response, which results in keeping the right pressure at all times very accurately.
Research Paper
A. R. Jafarnejadi; S. M. H. Mousavifazl; M. javadzadeh
Abstract
Introduction In spite of problems in providing timely and adequate water supply, the inefficient water use efficiency in agriculture as the most important consumer of freshwater is one of the most important challenges and issues in the agriculture. The knowledge of soil physical properties and water ...
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Introduction In spite of problems in providing timely and adequate water supply, the inefficient water use efficiency in agriculture as the most important consumer of freshwater is one of the most important challenges and issues in the agriculture. The knowledge of soil physical properties and water retention have main rolled on soil water application management. This research was conducted to determine the soil physical and chemical properties affecting the soil water retention capacity in calcareous soils series in Khuzestan province. Materials and Methods From the nine dominant series in the different regions, five disturbed soil samples and the same number of undisturbed soils were collected from 0-20 cm depth. Soil physical properties including soil texture, bulk density were measured. Moreover, soil water characteristic curve was measured at five points (0, 330, 1000, 5000 and 15000 cm) using pressure plate and pressure membrane devices. The van Genuchten equation was fitted on the measured soil water characteristic curve data. In addition to soil physical and hydrological properties, soil salinity as electrical conductivity (EC), pH and lime (TNV) were also measured. Results and Discussion The results showed that the soil pH varied in the range of 7.1 - 7.6, EC variation range was 2.43 - 47 dS m-1, sand, silt and clay contents varied in ranges of 18 - 40%, 32 - 50% and 20 - 44 %, respectively, TNV was 48 – 60 % and the values of soil bulk density were in the range of 1.14 - 1.52 g cm-3. The studied soils were calcareous (TNV value of all studied series was more than 45 %) and had moderate to heavy texture including loam (55 % of studied soil series), silty clay loam (23 %), clay loam (11 %) and clay (3 %). The water content at field capacity (corresponding of soil suction of 330 cm) and permanent wilting point (corresponding of soil suction of 15000 cm) varied from 32 to 56 % and 16 to 26 %, respectively. There are significant correlation between clay content with the soil moisture at both field capacity and permanent wilting point. The most salinity was observed in south east of Ahvaz (loam), south Ahvaz (loam), Khoramshahr 2 (clay) and Khoramshahr 1 (loam) series. The values of soil available water in studied calcareous series were varied as Khorramshahr 2 (0.30 cm3 cm-3) > Ahvaz-Hamidiyeh (0.22 cm3 cm-3) > Khorramshahr 1 (0.189 cm3 cm-3) > Ramhormoz-Rustamabad 1 (0.177 cm3 cm-3) > Ramhormoz-Bazidi (0.165 cm3 cm-3) > South of Ahwaz (0.16 cm3 cm-3) > South east of Ahwaz (0.134 cm3 cm-3) > Ramhormoz- Rustam Abad 2 (0.119 cm3 cm-3) > Shadegan (0.102 cm3 cm-3). The results showed that van Genuchten equation had suitable fit on studied soils of dominant calcareous series. The studied soil samples from the south of Ahvaz with the highest bulk density (1.55 g cm-3) and high salinity (33.5 dS m-1) had the highest value of the van-Genuchten parameter (n) which indicates more uniform distribution of the soil pore volume. In spite of the high ability of Khorramshahr 2 series in soil water retention, based on the coefficients of van Genuchten equation and measured soil water characteristic curve, it can be argued that this soil probably has severe aeration limitation. Conclusion The result showed that salinity and bulk density were important properties that affect the ability of soil water retention and availability in the studied soil series. Extensive water retention capacity in the soil (10 to 30 %) indicates the need for different irrigation management operations in each of the studied soil series. The highest value of soil densities were observed in south of Ahvaz, Ramhormoz-Bazidi and Khorramshahr series, indicating soil degradation in studied areas due to inappropriate cultivation management practices. Moreover, the results showed that the experimental parameters of the van Genuchten equation have a physical concept and can be found useful information on the soil ability to water retention and some other soil physical properties. The results of this research confirmed that there is a significant difference in the ability of soil water retention in the dominant calcareous soils series of Khuzestan province which indicates the necessity of proper understanding of soil hydraulic properties for irrigation management in farms, increasing water use efficiency.
Research Paper
M. Hejazi-Mehrizi; A. Saadatfar
Abstract
Introduction Salinity is one of the common stresses in agricultural lands of arid and semi-arid regions in Iran. Furthermore, excessive CaCO3, high pH, nutritional disorders have been known as limited factors for plant growth and productivity in such soils. The cultivation of salt tolerant plants such ...
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Introduction Salinity is one of the common stresses in agricultural lands of arid and semi-arid regions in Iran. Furthermore, excessive CaCO3, high pH, nutritional disorders have been known as limited factors for plant growth and productivity in such soils. The cultivation of salt tolerant plants such as rosemary (Rosmarinus officinalis L.) is important from the point of view land reclamation. Rosemary is a woody plant, evergreen, perennial herb belonging to Lamiaceae family. It is native to Mediterranean but it can tolerate undesirable conditions such as drought and salinity stresses. Zinc (Zn) and copper (Cu) are essential micro-nutrients that play important roles in plant metabolic processes and can increase plant tolerance to salinity. Zn is vital for protein synthesis, protein stability, and different enzyme activities such as Zn/Cu superoxide dismutase and carbonic anhydrase. On the other hand, chlorophyll production, photosynthesis and enzyme activities are the most important role of Cu in plants. Superoxide dismutases (SOD) are metalloproteins that catalyze superoxide radicals (O2-) produced under salinity stress into oxygen molecules and hydrogen peroxide, resulting to increased tolerance of plants to salinity. The most abundant superoxide dismutase isozyme in plants is Cu / Zn SOD, in which the role of Zn is structural and copper plays a catalytic role. Materials and Methods There is limited information about the effect of micronutrient application on the growth and salinity tolerance of rosemary. This study was conducted to investigate the effect of Zn and Cu co-application on some physiological and biochemical characteristics of rosemary under saline condition. For this purpose, a completely randomized design was carried out in a factorial experiment. The factors consisted of four types of fertilizer treatments (T1: control, T2: control + zinc, T3: control + copper and T4: control + copper + zinc) and three levels of salinity stress (S0: 0, S1: 60 and S2: 120 mM as NaCl) in four replications in a calcareous soil under greenhouse conditions. After 90 days, the plants were harvested and some growth characteristics including shoot and root fresh and dry weight were measured. Some physiological and biochemical properties such as leaf relative water content (LRWC), membrane permeability (MP), malondialdehyde (MDA), shoot and root Na concentration, and shoot and root K concentration were also measured. Results and Discussion The results showed that salinity had no significant effect on fresh weight of shoots, while shoot dry weight of rosemary decreased as 60% in control treatment, 44% in zinc treatment, 38% in copper treatment and 27% in zinc + copper treatment. Leaf relative water contents of rosemary decreased in response to salinity stress, and the only co application of zinc and copper under 120 mM NaCl stress resulted to a significant increase of LRWC (9%). Salinity stress increased the membrane permeability of rosemary leaves. In contrast, at all salinity treatments, addition of Zn and Cu caused a significant decrease in membrane permeability of rosemary leaves. However, there was no significant difference between fertilizer treatments. Salinity stress induced a significant increase in the malondialdehyde content of rosemary. For example, MDA content increased by 39% in control and by 24% in Cu treated plants when salinity level reached from 0 to 120 mmol L-1. Based on the results, in soil treated with 60 mmol L-1, addition of Zn and Cu and at the higher salinity level (120 mmol L-1) addition of Zn to soils had a significant effect on leaf and root Na concentration and thereby improvement of plant salt tolerance. Also, the result showed that co-application of Zn and Cu could reduce the undesirable effect of salinity on shoot and root K concentration and thereby improving plant tolerance to salinity stress. Conclusion In conclusion, zinc and copper, especially in combination form, increases the tolerance of rosemary to salinity by reducing of cell membrane damage, malondialdehyde content, shoot and root plant Na concentration and increasing of LRWC and shoot and root K concentration.
Research Paper
M. R. Kamandar; J. Masah; M. Khanali
Abstract
Introduction Now cities are not comparable to the past for many problems such as air and sound pollution of factories and vehicles. Some natural systems such as parks help to keep the stability of cities and improve the life quality of urbanites. Privet with the scientific name of Ligustrum Ovalifolium ...
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Introduction Now cities are not comparable to the past for many problems such as air and sound pollution of factories and vehicles. Some natural systems such as parks help to keep the stability of cities and improve the life quality of urbanites. Privet with the scientific name of Ligustrum Ovalifolium is the evergreen plant, and widely cultivated at all of the parks in Iran. Privet stems are pruned by manual or gasoline -powered hedge trimmer. The knowing of the cutting properties of privet stalk have important role in the design and fabricate of privet pruning machine. A series of laboratory test was conducted to measure the shear force, shear consumption energy and shear strength of stem internodes of privet stalk under quasi-static and impact cutting at different loading rate, different internode position and moisture level 58% wet base. In the quasi-static cutting test, the stalk specimens were cut in the quasi-static process by using a computer aided cutting test apparatus at four loading rates: 5, 10, 15 and 20mm/min and three internode positions: fifth, tenth and fifteenth downward from the terminal bud. In impact test, the stalk specimens were served in impact process by using a cutting test apparatus was designed, fabricated, and calibrated at four loading rates: 1, 2, 3 and 4m/s and three internodes: fifth, tenth and fifteenth. Materials and Methods The study was performed to investigate the effect of quasi-static and impact shear on shear force, shear consumption energy and shear strength. The measured initial moisture content of the samples was 58% on wet base. The privet stalk diameter decreases towards to the top of the plant stalks. Thus, the stalks equally was divided into three regions downward from the terminal bud: (a) fifth internode, (b) tenth internode and (c) fifteenth internode. The quasi-static tests were conducted using the universal testing machine (SMT-5, SANTAM Co, Iran). The shear tests were carried out at four rates of speeds 5, 10, 15 and 20 mm/min. To determine the shear force of privet stalk, an impact cutting tester was designed, fabricated and calibrated. It was similar to an Izod impact cutting tester for metals. A cutting blade with sharpened angel of 23 degree and oblique angle of 60 degree was attached to end of pendulum's arm. The shear tests were carried out at four rates of blade speeds 1, 2, 3 and 4 m/s. A data acquisition system was attached to pendulum arm and it includes 4 strain gages and a digital indicator to show the real-time shear force. Four strain gages were contacted to each other by Wheatstone bridge circuit and were mounted on two sides of pendulum. After calibration, the impact shear force was applied to the privet samples by releasing the pendulum arm in the testing machine up to the sample failure. The real-time applied force and cutting time were measured by data acquisition system and chronometer.Results and Discussion In quasi -static cutting of the stalk specimens, the analysis of variance (ANOVA) indicated that the loading rate and interaction of loading rateinternode position have significant effect on the shear consumption energy and shear strength in probability level of 5% and 1% respectively. However, the effect of internode position on shear force, shear strength and shear consumption energy was significant in 1% probability levels. In impact cutting of the stalk specimens, the analysis of variance showed that, the effect of the loading rate and their interaction of loading rateinternode position on the mentioned parameters were significant (P<0.01) but the effect of internode position on shear force and shear consumption energy was significant in 1% probability levels. The average values of shear force, shear strength and shear consumption energy were deeply decreased with increase in loading rate level from 1 to 4 m/s and internode position from fifteenth internode to fifth internode.Conclusion In quasi-static cutting, the increment proportion of energy consumption at blade velocity of 20mm/min to 5mm/min is about 2.2 at fifth internode, 2.6 at tenth internode and 2.9 at fifteenth internode respectively. Also in quasi-static cutting process, the increment proportion of shear strength at blade velocity of 20 mm/min to 5mm/min is about 1.5 at fifth internode, 1.4 at tenth internode and 1.2 at fifteenth internode respectively.In impact cutting, the reduction proportion of energy consumption at blade velocity of 1m/s to 4m/s is about 1.44 at fifth internode, 1.6 at tenth internode and 3 at fifteenth internode respectively. Also in impact cutting process, the reduction proportion of shear strength at blade velocity of 1m/s to 4m/s is about 5.2 at fifth internode, 29.4 at tenth internode and 53.8 at fifteenth internode respectively.
Research Paper
A. Rahimi; B. Doulati; S. Heydarzadeh
Abstract
Introduction Lamiaceae, formerly called Labiatae, the mint family of flowering plants with 236 genera and more than 7,000 species, the largest family of the order Lamiales and many species are cultivated for their fragrant leaves and attractive flowers. Thymus daenensis is native to Iran and growing ...
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Introduction Lamiaceae, formerly called Labiatae, the mint family of flowering plants with 236 genera and more than 7,000 species, the largest family of the order Lamiales and many species are cultivated for their fragrant leaves and attractive flowers. Thymus daenensis is native to Iran and growing in many parts of Iran, the plant is extensively used in folk medicine and has a wide variety of essential oils. Medicinal and aromatic plants have antioxidant compounds such as polyphenols which decrease oxidative stress in cells of plants and animals. In recent decades, excessive use of chemical fertilizers in order to increase the yield of agricultural products has caused many problems in economic and environmental aspects. The biofertilizer plays an important role in nitrogen fixation, iron sequestration, and phosphate solubilization, thus making these complex organic molecules available for utilization by the plants. Biofertilizers are the microbial inoculants that colonize the rhizosphere and improve plant growth by enhancing nutrient accessibility to plants. However, biofertilizers perform more than one mechanism for accomplishing plant growth enhancement. These abilities are of great agriculture importance as far as crop yield and soil fertility improvement is concerned, thus decreasing the ill effects of chemical-based fertilizers in our environment. For instance, excessive use of chemical N fertilizers causes soil acidifcation and, thus, groundwater and atmospheric pollution. Nonetheless, synthesis of chemical fertilizers is highly energy-consuming processes. Chemical based fertilizers impose long-lasting effects on the atmosphere in terms of carbon footprint, eutrophication, and soil fertility decline. However, the control of chemical and biological properties of soil is important in the quantity and quality of agricultural crops. Few reports reveal that in case of controlled soil conditions, signifcant enhancement in crop production was achieved through biofertilizer applications. Thus, this research was carried out with the aim of studying the effect of independent and combined use of biological and chemical fertilizers on quantitative and qualitative properties of thyme. Materials and Methods The aim of this study was to investigate the effect of biofertilizers (phosphate Barvar-2 and Azotobacter), manure (cow manure), and chemical (NPK) on quantitative and qualitative characteristics of Thymus daenensis. Physicochemical properties of study soil (calcium carbonate equilibrium, pH, OC, EC, micro and macro elements, soil texture) and was determined by standard methods. A factorial experiment based on randomized completely design was carried out with eight treatments including chemical fertilizer (100%), biofertilizers (phosphate Barow-2 and Azotobacter) (100%), cow manure (100%), combined treatment: chemical + biofertilizer 50%, chemical + cow manure 50%, biofertilizer,+ cow manure 50%, biofertilizer + chemical + cow manure 50% and control at three replications. Seeds of Thymus daenensis were treated before cultivate with biofertilizers (phosphate Barvar-2 and Azotobacter) with 100 g ha-1 based on the recommended guidelines (10^8 active bacteria g-1 of biofertilizer). Seeds were cultured in perlite and pit moss culture beds. Transplant was transmitted to the farm at the end of April. Thymus product was harvested at flowering stage. Economic performance of thymus including leaf and inflorescence weight was calculated after drying of bushes. Essential oil content was measured using clevenger. Physiological and antioxidant propertiese including chlorophyll a and b, total chlorophyll, cartenoids, total phenolic content and flavnoieds were measured (Lichtenthaler and Wellburn, 1987; Horwist, 1984). Essential oil yield was obtained from essential oil percentage in dry matter yield of thymus. Results The results showed that the integrated application of biofertiliizers was significant in qualitative and quantitative characteristics of Thymus daenensis. Based on the results, shoot dry yield (156.26 g m-2), essential oil yield (5.36 g m-2) and economic yield (74.72 g m-2) in 50% chemical fertilizer + biofertilizer + cow manure treatment were higher as compared to other treatments. Integrated application of organic and chemical fertilizers improved the content of photosynthetic pigmentation and increased the concentration of iron (Fe), zinc (Zn) and copper (Cu) in thymus. Aso, combined application of 50% chemical fertilizer + biofertilizer + manure increased total phenol (30.12%), flavonoids (22.26%) and antioxidant activity (15.95%) of thymus compared to control treatment. Conclusion The results showed that the chemical fertilizers to start production and compensate for the fertilizer source and biofertilizers for the continuous of the presence of nutrients in soil are important. Consequently, the combination of chemical fertilizer (NPK) and biofertilizers could be recommended as a suitable nutrition source for plant as well as the improvement of soil physical and chemical properties. Accordingly, chemical fertilizers consumption are hazardous for human severely affect ecological balance in the environment. Therefore, the success related to biofertilizers depends on inventions of innovative strategies which are related to the functions of different beneficial bacteria and their proper application to the fields through advanced and improved techniques.
Research Paper
N. Monjezi
Abstract
Introduction Currently, musculoskeletal disorders are one of the most common occupational diseases and one of the most common causes of absenteeism, which leads to a decrease in productivity. Postural assessment methods are considered pivotal in the investigation of the risks of developing job-related ...
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Introduction Currently, musculoskeletal disorders are one of the most common occupational diseases and one of the most common causes of absenteeism, which leads to a decrease in productivity. Postural assessment methods are considered pivotal in the investigation of the risks of developing job-related musculoskeletal disorders. Various approaches are presented to assess the risk of injury in inappropriate postures. Agriculture is one of the most crucial sectors in both the developing and the developed countries since it ensures the food security of the country. In the process of producing sugarcane, a significant part of the stages of cutting, planting, and harvesting is done manually. A low level of knowledge about the correct condition of the body during work is one of the problems of farmers. Therefore, body status assessment methods are considered as the basis for assessing the risk of musculoskeletal disorders associated with work. Materials and Methods This research was carried out with the aim of analyzing the risk factors of occupational skeletal musculoskeletal injuries in sugar cane farmers using QEC method and Nordic questionnaire. The quick exposure checklist (QEC) quickly assesses the exposure to risks for work-related musculoskeletal disorders (WMSDs). QEC is based on the practitioners’ needs and research on major WMSD risk factors. The Nordic body map is given to the participants to be filled out with the assist of a student research assistant when needed. However, due to practical reasons, most participants are interviewed using the semi-structured method by a student research assistant. The Nordic body map consists of 28 parts of the body that must be rated based on the symptoms. Examples of the body parts are the right shoulder, upper arm, etc. The postures of 50 cutting workers, 200 planting workers, and 50 harvesting workers were selected by random sampling and analyzed using QEC2003 software. Results and Discussion According to the results of the Nordic questionnaire in manual cutting sugarcane, the most prevalent signs of musculoskeletal disorders were in the waist (80%), wrists and hands (78%), knees (74%), and feet (70%). In manual planting sugarcane, the most prevalent signs of musculoskeletal disorders were in the areas of the waist (89%), back (86.5%), and knee (84.5%), respectively. The findings also indicate that in the manual harvesting operations, the most prevalent signs of musculoskeletal disorders were the wrist and hand (88%), waist (84%), and foot (80%). The results of the Nordic questionnaire show that most disadvantages of cutting, planting, and harvesting in workers are visible in the lower back (80%), lower back (89%), and wrist/hand (88%), respectively. The prevalence of skeletal musculoskeletal disorders, especially in the waist, was observed among a high number of sugarcane producers. The results also showed that in the QEC method, in cutting, planting, and harvesting 44, 62, and 59 percent of workers’ postures were placed in the most critical group. In manual cutting of sugarcane, 30 percent of the workers were at the high-risk level and 44 percent of workers were at high risk, indicating the high risk of this operation, and that better preventive measures should begin as soon as possible. In the QEC method for manual planting of sugarcane, 7% of the postures of workers is acceptable and their risk is very low. Work posture for 9.5% of people requires more research and attention, and 21.5% of workers must be treated fairly fast. 62% of the postures of workers need to be corrected promptly. In the QEC method for manual harvesting of sugarcane, the posture requires 14% more research and attention, and 28% of workers should be treated fairly quickly. For 59% of postoperative workers, work should be promptly corrected. The QEC analysis showed that some of the work postures posed greater risks of MSDs to the workers with QEC scores. QEC helps to prevent many kinds of WMSDs from developing and educates users about WMSD risks in their workplaces. Conclusion The study has identified the body parts and tasks of the workers exposed to ergonomic risks through the Nordic questionnaire and the QEC method, respectively. Results from the study showed that the majority of the workers were having WMSDs.The physical condition of sugar cane production workers needs to be corrected. The ergonomic training course can have an impact on improving the working conditions of workers, but it is not enough, and it is a must-have for the sugar agro-industry to move towards all mechanized operations.
Research Paper
N. Asgari; S. Ayoubi; A. Dematte; H. Khademi
Abstract
Introduction Carbonates are an essential and prominent constituent of soil chemical properties particularly in arid and semiarid regions, in regards with soil productivity and conservation. The conventional techniques for assessing soil properties rely on direct laboratory measurements which are expensive, ...
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Introduction Carbonates are an essential and prominent constituent of soil chemical properties particularly in arid and semiarid regions, in regards with soil productivity and conservation. The conventional techniques for assessing soil properties rely on direct laboratory measurements which are expensive, time consuming and labor intensive. Hence, it is required to develop fast and cost-efficient techniques for evaluation of mentioned parameters. The Koppen climatic classification generally categorizes Iran among the arid and semi-arid climates. About 90 % of its lands are arid or semiarid. According to Soil Survey Staff (2014), calcareous soils contain 5% or more volumes of inorganic carbon (or carbonate calcium equivalent), which are the prevailing formation in arid and semi-arid areas. These soils are typical of areas where minerals cannot be leached away from the soil profile due to low precipitation. Based on the reports of FAO.UNDP (1972), approximately 12% of soils all over the world and 65% in Iran are calcareous. Therefore, carbonate is a key component that physically and chemically influences soil properties, as well as its fertility and productivity. One of the fast, easy-to-use, cost-effective and non-destructive methods of soil analysis is the visible to near-infrared (Vis-NIR) and mid-infrared (mid-IR) spectroscopy, that can partly be employed for the optimization of traditional techniques. Therefore, the reflectance spectroscopy is considered as one of relatively inexpensive and fast techniques to evaluate these features. The purpose of the present study was to evaluate the capability of the reflectance spectroscopy technique in Vis-NIR (250-2500 nm) and mid-IR (400-400 cm1-) ranges to estimate soil carbonates content as one of the key components affecting the physical and chemical properties of soils (especially in arid and semi-arid regions). Materials and Methods The study area is located in Juneqan District, Chaharmohal and Bakhtiari Province, southwest of Iran. 272 soil samples were collected from a depth of 0-10 cm, air dried and passed through a 2 mm sieve. The carbonates value of each sample was determined by standard laboratory method. The spectral reflectance of soil samples was extracted in the Vis-NIR (250-2500 nm) and mid-IR (400-400 cm1-) ranges using a spectroradiometer FieldSpec 3 (ASD-Analytical Spectral Devices, Boulder Colorado, USA) and Nicolet 6700 Fourier Transform Infrared (FT-IR) (Thermo Fisher Scientific Inc., Waltham, MA), respectively. In the next step, seven preprocessing methods included absorbance transformation (log [1/reflectance]) (Abs), multiplicative scatter correction (MSC), standard normal variate transformation (SNV), Savitzsky-Golay derivation (SGD), Continuum removal transformation (CR), Normalization in range <-1,>1 (Nor) and Detrend (Det), were performed over original spectra for correcting light scattering in reflectance measurements and data improvement before using data in calibration models. Afterward, The dataset (272 samples) for each spectra range was randomly divided in calibration (70%) and validation (30%) datasets. Four different calibration models were fitted over Vis-NIR and mid-IR spectra to develop carbonates prediction models including: Partial Least Squares Regression (PLSR), Support Vector Machine (SVM), Random Forest (RF) and Gaussian Process Regression (GPR). The evaluation of soil predicting models was done according to the value of R2, RMSE and RPD. According to some researches, RPD values more than 2 shows that the models provide precise predictions, values of RPD between 1.4 and 2 are considered to be reasonably representative, and values less than 1.4 indicate poor predictive value. Results and Discussion The carbonates content in studied samples ranged from 1 to 76% with an average value of 24.7%. Overall, carbonates content promoted increase of spectral reflectance intensity on several region of spectrum in both spectral ranges. The specific absorption wavelength in Vis-NIR spectra used to indicate the presence of soil carbonates was 2338 nm and in the mid-IR range were 714, 850, 870, 1796, and 2510 cm1. The results showed that the best performance of the used models in the Vis-NIR spectral range was related to the SVM model (R2=0.81, RMSE=5.36) and in the mid-IR range allocated to PLSR model (R2=0.86, RMSE=4.5). Both of these models showed great accuracy in carbonates estimating (RPD>2). Besides, the results showed that the mid-IR spectral range in the prediction of carbonates provided better performance than the Vis-NIR range. This can explained by the fact that the fundamental molecular vibrations of soil components occur in the mid-IR range, while only their overtones and combinations are detected in the Vis-NIR range. Conclusion It seems that the reflectance spectroscopy technique can be considered as a precise substitute for the conventional methods of measuring carbonates, which are sometimes costly, time consuming and destructive. However, due to the spatial and temporal variability of soil properties as well as the huge variety of models and spectral preprocessing methods, it is necessary to examine the capability of this technique in other areas with other preprocessing methods and regression models.
