نشریه ماشین های کشاورزی
سال سیزدهم شماره 3 (پیاپی 29، پاییز 1402)

Adopting new technologies for crop growth has the characteristics of improving disaster resistance and stress tolerance, ensuring stable yields, and improving product quality. Currently, the cultivation of seed trays relies on huge labor power, and further mechanization is needed to increase production. However, there are some problems in this operation, such as the difficulty of improving the speed of a single machine, seedling deficiency detection, automatic planting, and controlling the quality, which need to be solved urgently. To solve these problems, there are already some meaningful attempts. Si et al. (2012) applied a photoelectric sensor to a vegetable transplanter, which can measure the distance between seedlings and the movement speed of seedlings in a seedling guide tube, to prevent omission transplantation. Yang et al. (2018) designed a seedling separation device with reciprocating movement of the seedling cup for rice transplanting. Tests show that the structure of the mechanical parts of the seedling separation device meets the requirements of seed movement. The optimization of the control system can improve the positioning accuracy according to requirements and achieve the purpose of automatic seedling division. Chen et al. (2020) designed and tested of soft-pot-tray automatic embedding system for a light-economical pot seedling nursery machine. The experimental results showed that the embedded-hard-tray automatic lowering mechanism was reliable and stable as the tray placement success rate was greater than 99%. The successful tray embedding rate was 100% and the seed exposure rate was less than 1% with a linear velocity of the conveyor belt of 0.92 m s-1. The experiment findings agreed well with the analytical results.Despite the sharp decline in Iran's water resources and growing population, the need to produce food and agricultural products is greater than ever. In the past, most seeds were planted directly into the soil, and many water resources, especially groundwater, were used for direct seed sowing and plant germination. One way to reduce the consumption of water, fertilizers, and pesticides is to plant seedlings instead of direct seed sowing. Therefore, the purpose of this study was dynamic modeling and fabrication of seed planting systems in seedling trays.

In this experiment, Flores sugar beet seeds (Maribo company, Denmark) were used. The seedling trays had dimensions of 29.5*60 cm with openings and holes of 5.5 and 4 cm, respectively. To plant seeds in seedling trays, first, a planter arm was modeled and its position was obtained at any time. Then, based on dynamic modeling, the arm was constructed and a capacitive proximity sensor (CR30-15AC, China) and IR infrared proximity sensor (E18-D80NK, China) were used to find the location of seedling trays on the input conveyor and position of discharging arm, respectively. To achieve a stable and effective control system, a micro-controller-based circuit was developed to signal the planting system. The seed planting operation was performed in the seedling tray according to the coordinates which were provided through the image processing method. The planting system was evaluated at two levels of forward speed (5 and 10 cm s-1). Moreover, a smartphone program was implemented to monitor the operation of the planting system.

The planting system was assessed for sugar beet seeds using two levels of forward speed (5 and 10 cm s-1). The nominal capacity of this planter ranged from 3579 to 4613 cells per hour, with a miss and multiple implantation indices of 0.03% and 8.17%, respectively, in 3000 cells. Due to its planting accuracy, speed, and low energy consumption (25.56 watt-hours), this system has the potential to replace manual seeding in seedling trays.

In the present study, a seed-sowing system for planting seedling trays was designed, constructed, and evaluated based on dynamic modeling. In the developed system, unlike previous research, planting location detection was conducted through image processing. Additionally, a smartphone program was established to monitor the operation of the planting system without interfering with its performance. This study demonstrates that image processing can successfully detect planting locations and can effectively improve efficiency over time for major producers.

The world today is facing the issue of population growth, which will result in food shortages. One way to supply food to this growing population is to facilitate the production of agricultural products to meet the growing demand. Medicinal plants are an important product of the agricultural sector. In Iran, manual harvesting reduces the productivity of these crops, and the use of manual harvesting poses challenges related to available manpower. The costs and time required for manual harvesting are additional obstacles. Given the importance of developing medicinal plants, designing and constructing a mechanized machine for harvesting them could improve the harvesting process.

In designing the machine for harvesting medicinal plants in cultivation rows, different scenarios were examined regarding the position of the machine relative to the tractor. The advantages and disadvantages of each scenario were listed separately, and finally, the continuous placement of tractors, harvesters, and trailers was defined. One of the goals of designing this machine is to perform harvesting operations for two row spacing’s - 80 and 160 cm. To achieve this goal, mechanisms were added to the machine that allow for changing the position of the harvesting head, as well as the cutting height. Moreover, due to the sensitivity of the harvested product to soil contact, the plants should be transferred immediately after cutting. Therefore, a transfer mechanism was designed and built to move the cut products to the trailer. Independent variables, including forward speed at two levels, type of reel in two types, and cutting blade in two types, were considered. Dependent variables also included harvesting efficiency, percentage of damaged plants, and harvesting capacity.

The results of variance analysis for different treatments show that the forward speed, type of reel, and cutting blade type have an effect on harvest efficiency. The difference in harvest efficiency is significant at a 1% probability level. A star cutting blade provides higher efficiency than a 40-teeth cutting blade. The rubber reel prevents plants from falling to the ground by creating a closed space in front of the blade. However, the inner parts of the rods reel are empty, and the plant can fall to the ground. Additionally, the plant may get wrapped around the rods, causing a decrease in harvesting efficiency. Another essential parameter when identifying and evaluating a harvesting machine is crop damage. Some plants get crushed and torn due to the impact on metal components. This situation reduces the quality of the harvested product, leading to a decline in the final product's price. The star-cutting blade causes more leaf rupture. In contrast, the teeth in the 40-teeth blade are continuous, making it unlikely for the leaf to get caught between the two teeth. However, with the star blade, the distance between the two blades is large, allowing the plant to get stuck in between and re-cut.

Based on tests conducted for eight different positions of the harvester, it was observed that the G test outperformed the other tests with 85.88% harvesting efficiency, a capacity of 344.8 kg h-1, and only 1.34% peppermint leaf damage. Therefore, for harvesting similar peppermint products, we recommend using a combination of a star blade, rubber carousel, and a forward speed of 1.2 meters per second. However, new tests should be conducted on other products like lavender and those with strong stems.

In the poultry industry, reducing energy consumption is essential for reducing costs. Energy requirements in the poultry industry include heating, cooling, lighting, and power line energy. Identifying factors that increase energy usage is crucial, and providing appropriate solutions to reduce costs and energy consumption is inevitable. One of the major and expensive factors in the poultry industry is the use of fossil fuels, which also causes pollution. Energy costs directly impact the cost of production and increase the per capita cost of production in the meat and egg sectors. In Iran, poultry farms are among the most widely used energy consumers, especially for heating breeding halls, making them a significant subset of the agricultural sector.

The problem under study is the thermal simulation of a meat poultry farm located in Ardestan city, Isfahan province. Ardestan city is situated in a desert region in the north of Isfahan province, at a latitude of 33 degrees and 23 minutes north, and a longitude of 52 degrees and 22 minutes east. The dimensions of the poultry hall floor are 5 meters by 8 meters, and it has a capacity of 300 poultry pieces. There are two inlet air vents (windows), each with dimensions of 1.90 by 1.6 meters. The roof has an average height of 2.5 meters and is sloping, made from a combination of plastic carton, fiberglass, and sheet metal.To reduce energy consumption in this poultry farm, a solar heating system is designed and studied in this research. The farm is one of the functions of Isfahan province, with dimensions of 8 meters in length and 5 meters in width. The simulation is performed using TRNSYS software.

The results demonstrate that a collector surface area of 26 m2 is necessary to reach the technically optimal point, where the sun's maximum production is achieved with no energy dissipation. Furthermore, the findings indicate that a balance of 16 m2 is required to align the solar system with the auxiliary system.

By installing 2 square meters of solar collectors, 5.2% of the total energy demand can be met with solar energy. To fully meet the energy demand using solar energy, a collector area of 30 square meters is required. As the solar fraction increases, the system's ability to extract solar energy also increases. The maximum production of solar energy without any wastage is achievable with a collector area of 26 square meters. Moreover, to maintain a balance between the use of solar energy and the auxiliary system, a collector area of 16 square meters is needed.

In conventional combine harvesters, wheat chaff is typically removed from the end of the machine and deposited on the field surface. Depending on the wheat cultivar, cultivation method, and growing conditions, the amount of chaff produced can range from 0.8 to 1.5 times the amount of grain harvested per hectare (Tavakoli, 2012). On average, this translates to an annual production of approximately 14 million tons of chaff, which is valued at around $240000000 based on regional prices in 2018-2019 ($1000 per kilogram). If collected, these chaff residues could be used as animal feed for livestock. Additionally, the long stems protruding from the back of conventional combine harvesters can interfere with subsequent cultivation efforts. Chaff combine harvesters have a similar structure to conventional machines, but feature a modified end that includes a tank and blower for collecting and depositing crushed chaff. Apart from the threshing unit, all other components of the harvester remain unchanged.

This study was conducted in 2019 in dryland wheat fields to determine the performance of Chaff combine harvesters in Kurdistan province. The study used 15 combine harvesters, including John Deere models equipped with chaff threshers from Shiraz, Bookan, and Hamedan, as well as the Hamedan Barzegar specific chaff collector combine. These combines were evaluated and compared based on natural losses, head and chaff storage losses, field capacity, purity percentage, and yield in field conditions in Kurdistan province. The total number of combines evaluated was 15, using a completely randomized design. Among these, 33% belonged to Shiraz company (5 samples), 33% to Bookan (5 samples), 20% to Hamedan (3 samples), and 14% to Hamedan Barzegar (2 samples). Sampling included measurement of natural losses, header losses, threshing tank losses (losses of the threshing unit, separating unit, and cleaning unit), and quality losses (broken grains and impurities) in the combine tank.

The results showed that the average yield, natural loss, and combine loss were 1,698.14 kg.ha-1, 2.39%, and 4.92%, respectively. In terms of the loss rates in different parts of the combine, 43.49% was related to the chaff storage of the combine, and 56.50% was related to the combine head.The natural loss rate in this province was 2.39%. The total combine loss was 5.18%, with 40.44% of that related to chaff storage and the rest related to the combine head. The results also showed a significant difference between the treatments in terms of field capacity, chaff storage loss, and purity percentage at a probability level of 5%.The total loss of the Hamedan Barzegar combine was 6.67%, which was higher than the other combines. The chaff storage loss of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combines were 0.87%, 2.64%, 0.78%, and 4.28%, respectively, showing a significant difference at a 5% level. There was also a significant difference between the treatments in terms of total grain loss.Based on these results, it is recommended to use the Hamedan, Bookan, Shiraz, and Hamedan Barzegar combines, with total losses of 4.33%, 4.33%, 4.52%, and 6.56%, respectively.

The average purity of harvested grains was 96.62%, and there was no significant difference between the combine harvesters in this regard.There was a significant difference between the combines in terms of field capacity at a probability level of 5%. The field capacity of the Bookan, Hamedan Barzegar, Hamedan, and Shiraz combine harvesters were 0.83, 0.87, 0.83, and 0.73 hectares per hour, respectively.In Kurdistan province, the average grain combine loss in dryland wheat harvesting with chaff combine harvesters was 4.92%, which is higher than in other provinces.The loss in the chaff tank of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combine harvesters was 0.87%, 2.64%, 0.78%, and 4.28%, respectively. Regardless of head losses, the loss in the Hamedan combine was less than other combine harvesters.The total losses of the Hamedan Barzegar, Bookan, Shiraz, and Hamedan combine harvesters were 6.56%, 4.32%, 4.52%, and 4.30%, respectively, with the Hamedan Barzegar and Hamedan combine harvesters having the highest and lowest losses, respectively.Based on the results obtained from this study, using the Hamedan combine is recommended in the dryland conditions of Kurdistan due to its low losses, high purity, and field capacity.

Cotton, as one of the most widely used products in various industries, has always been considered by leading countries in agriculture. The applications of this plant range from the food industry to the military industry, as well as the textile and animal nutrition industry. It is predicted that by 2025, the area under cotton cultivation in the world will reach more than 33 million hectares (FAO, 2017). Based on the growing population, it is necessary to use machines in industries and other sectors to accelerate production and increase efficiency. Cotton is no exception to this rule. The use of a machine can play an effective role in reducing harvest costs and decreasing losses from frost and early fall rainfall by enabling timely harvesting.

Armaghan cultivar is an early-maturing cotton cultivar with high yield potential and good compatibility, introduced for conventional and secondary crops in Golestan, North Khorasan, Ardabil, and the central regions of Iran. The early maturity of this cultivar provides the possibility of cotton cultivation after wheat harvest in different regions of Iran. It reduces pests and diseases through the escape mechanism and completes the growth period in delayed planting. In this research, two types of picker machines were compared. One of the harvesting machines used in this study is a two-row self-propelled spindle picker machine, and the other picking machine is a two-row tractor semi-mounted dentate picker. Before harvesting with a machine, it is necessary to use a defoliator. This allows for seed cotton harvest with less trash and more cleanliness. About ten to fifteen days after spraying the defoliator, the leafless plants are ready for machine harvesting. In this study, the number of leaves was counted before spraying and before harvest, and the percentage of defoliation in each treatment was calculated and evaluated. The harvesting efficiency of machines, machine losses, and fiber qualities for each harvester was measured.

The results showed that the type of machine has a significant effect on plant residues and machine performance. However, the loss on the ground is not affected by the type of machine and remains almost the same for both machines. The mean comparisons revealed that the spindle harvesting machine leaves more than twice the amount of residues on the plant compared to the dentate harvesting machine. In terms of fiber quality, no significant difference was observed in any of the qualitative properties, and both machines perform at the same level.

The results of this research on the functional characteristics of picker machines and the cultivar and field conditions demonstrate that a higher percentage of leaves on the plant yields better performance from dentate picker machines compared to spindle pickers. Spindle pickers are sensitive to leaves due to the teeth on their needles, causing reduced efficiency in such fields. In contrast, dentate picker machines work well and perform better under these conditions. Based on this study, the dentate harvesting machine is more suitable than the spindle picker machine for harvesting Armaghan cotton cultivars.

Sugarcane is one of the strategic products of Khuzestan province, which is cultivated in 10 active agro-industrial sites and covers an area of about 110,000 hectares of irrigated farms in the province. Sugarcane harvesting, like most crops, is done by special sugarcane harvesters. Due to the life of machines and also the amount of heavy machine operations in each season of sugarcane harvest, the loss is inevitable. On the other hand, in Khuzestan province, due to lack of studies, there is little information in this area. Therefore, the aim of this study is to investigate the extent of losses during sugarcane harvesting operations, taking into account factors such as cultivars, age of sugarcane, and reaping speed of the Astaf 7000 model. The study will be conducted at the sugarcane agro-industrial site of Dehkhoda in 2021.

The experiment was conducted as a factorial split-plot design based on randomized complete blocks (RCBD) with three replications. The first factor included four levels of cultivars (IRC-12, CP48-103, CP 73-21, and CP69-1062), the second factor included three levels of harvest age (plant, Ratoon 1, Ratoon 2), and the third factor included three levels of speed (3, 5, and 7 km h-1). Sampling was carried out under the same and constant conditions with respect to soil moisture content, harvester operator, harvester characteristics, harvester settings, and crop density in each field.

The results of analysis of variance of the data obtained from measuring sugarcane losses showed that the effect of cultivar on yield, full-length sugarcane, chopped sugarcane and splinter sugarcane had a significant effect at a probability level of one percent. The effect of age had a significant effect on yield, full-length sugarcane, chopped sugarcane with a probability level of one percent, but had no significant effect on the amount of splinter sugarcane. The interaction between cultivar and age had a significant effect on yield, chopped sugarcane, and full-length sugarcane with a probability level of one percent and on splinter sugarcane with a probability level of five percent. The effect of machine speed had a significant effect on full-length sugarcane, chopped sugarcane and splinter sugarcane with a probability level of one percent, but had no significant effect on yield. The interaction of cultivar and machine speed had a significant effect on yield, full-length sugarcane, chopped sugarcane and splinter sugarcane with a probability level of one percent. The interaction effect of age and machine speed on yield had a significant effect on full-length sugarcane and splinter sugarcane with a probability level of one percent and on the amount of splinter sugarcane with a probability level of five but had no significant effect on yield. Also, the interaction of cultivar, age and machine speed had a significant effect on yield, full-length sugarcane and chopped sugarcane with a probability level of one percent, but had no significant effect on the amount of splinter sugarcane. The results showed that the highest yield in CP69-1062 variety was observed in the plant farm with average machine speed (144.33 tons per hectare). Also, the highest amount of sugarcane losses in cultivar CP48-103 in Raton II and with 7 km h-1 machine speed (3.32 tons per hectare), the highest amount of chopped sugarcane losses in cultivar CP48-103 in plant farm and with average speed (1.78 tons per hectare) was observed. According to the results under the interaction of cultivar and device speed, the highest amount of sugarcane losses in CP69-1062 cultivar and high speed (0.314 tons per hectare) as well as IRC-12 cultivar and high speed (0.308 tons in Hectares), and under the interaction of farm age and speed of the harvester, the highest amount of sugarcane losses was observed in Ratoon farm and the high speed of the harvester (0.300 tons per hectare).

Therefore, in order to reduce the amount of losses in sugarcane fields, it is recommended to use resistant and somewhat later cultivars for cultivation, because early cultivars are more fragile during harvest due to stem fragility and the rate of losses increases. Also, Harvester speed optimization reduces the amount of losses, and due to the increase in the rate of losses in reclaimed farms, it is recommended to create more resistant stem tissue by proper plant nutrition and more care to reduce the rate of losses in ratoon farms.

Peanut (Arachis hypogaea L.) is an annual plant of the legume genus that is cultivated in 109 countries due to its high-quality oil and seed protein. In Iran, this crop is cultivated on an area of 3000 hectares, with an average yield of 4 tons per hectare. Threshing performance significantly affects seed loss and physical damage, including cracking and crushing of seeds during harvest. Therefore, over the last century, extensive research has been conducted on different types of threshing methods, as well as the design and development of various threshing machines.Research on seed crops such as cereals and seeds suggest that factors such as the rotational speed of the thresher, threshing-concave distance, feeding rate, and shape of threshing teeth play a crucial role in determining the threshing efficiency and quality of the threshed seeds. Although limited research has been conducted on peanut threshing, there are currently no combine-machines available for this crop on global markets. Therefore, this study aims to investigate several working parameters of an experimental peanut thresher, including the effect of sieve angle, sieve range of movement, and suction speed on the separation unit.

The relevant experiments were conducted in the Parsabad Moghan region of Ardabil province (latitude 39.65 North, longitude 47.91 East). To conduct the experiments and separate the seeds from the pods, we used a peanut threshing machine cultivar Nc2, which is commonly cultivated under agricultural conditions in Ardabil and Gilan Agricultural Research Centers.To achieve the aims of this research, we investigated several effective parameters in the performance of the machine, including sieve angle, sieve movement range, and fan suction speed, to obtain the best settings for maximum threshing performance and separation efficiency. It is worth noting that the average seed weight per kilogram of peanut plant was between 300-400 grams, and the moisture content of the seeds in the tested cultivar was 45%. Before using the machine, workers must first dig up the plants and place them on the ground in a coupe, after which another worker must feed the plants into the machine through the feeder.

The study found that changes in sieve angle, sieve movement range, and suction speed significantly affect the separation efficiency and peanut loss rate at a 1% significance level. Increasing the sieving angle leads to a higher speed of material movement on the sieve, which results in insufficient time for separating straw from the seed. Similarly, increasing the sieve movement range causes a rapid decrease in cleaning efficiency. To achieve better straw-seed separation, it is necessary to apply impact shocks to the products located on the sieve within a short period. However, as the range of movement increases, the time interval between impact shocks also increases, which disrupts the straw's separation from the seed.The study found that increasing the sieve range and suction speed leads to a higher rate of peanut loss. This is due to the fact that when the suction speed and sieve movement range are increased, the product spends less time on the sieve, which results in insufficient time for proper separation. Additionally, high speed may exceed the limit of peanut seed and cause it to move out of the machine with the straw. Increasing the sieve movement range leads to a more uniform movement of straw and seed on the sieve; however, achieving better separation of straw from the sieve requires dynamic shocks and sudden acceleration, which decreases as the sieve movement range increases. The optimal farm capacity and material capacity were achieved with a 5-degree slope at 0.55 hectares per hour and 509 kilograms per hectare, respectively, using a sieve range of 3.5 centimeters and a fan suction speed of 8 meters per second.

The study concluded that the sieve movement range has the most significant impact on cleaning efficiency, while the sieve angle has the least effect. Similarly, the sieve movement range has the most significant influence on the rate of peanut loss, while the sieve angle has the least effect.

Due to the disadvantages of using chemical materials as pretreatment before grape drying, the application of non-chemical methods that not only take the environmental issues into account but also increase the drying rate and improve the quality of the produced raisins is vitally important. The high-humidity hot air impingement blanching (HHAIB) is one of the non-chemical methods that can be used as a suitable alternative for chemical pretreatment in grape drying. In this research, the design, construction, and evaluation of a high-humidity hot air impingement blanching system are discussed in terms of the drying kinetics of white seedless grapes. The results are compared against the control and chemical pretreatment.

High-humidity hot air impingement blanching (HHAIB) system
The HHAIB system is composed of the steam generator, steam transfer pipes, side channel pump, closing and opening valves, air recycling channel, electric air heater, hot-humid air transfer channel, pretreatment chamber, hot-humid air distribution chamber, nozzles, temperature and humidity sensors and controllers. The performance of the system depends on the humid air temperature, the output fluid velocity from the nozzle, the distance of the nozzles from the product surface, as well as the diameter and arrangement of the nozzles. In order to achieve optimal design of the nozzle array, the relationships existed for the heat transfer coefficient, air mass flow, and blowing power were considered.Application of the HHAIB pretreatment and evaluation of its effect on the grape drying processExperiments were conducted to investigate the effect of temperature and duration of HHAIB pretreatment on the kinetics of grape drying. A two-factor completely randomized factorial design with three replications was used to analyze the data.According to the studies, the air at temperatures of 90, 100, and 110°C, a velocity of 10 m s-1, and relative humidity in the range of 40-45% was applied to the product. Pretreatment durations of 30, 60, 90, 120, and 150 s were also considered. Experiments were conducted with three replicates and control treatment and acid pretreatment were used to compare the drying process. Due to the high quality of shade-dried raisins, this method was used to study the process.The effect of the pretreatment duration on the drying kinetics of white seedless grapes was assessed by observing variations in moisture ratio and drying rate over time, as well as determining the effective diffusivity of water.For the color evaluation of the produced raisins, chroma (C), hue angle H°, and total color difference (ΔE) parameters were calculated after measuring L*, a*, and b* values.

The comparison of the drying process among the control, chemical, and HHAIB showed the positive efficacy of HHAIB on the drying rate of grapes. Compared to fresh grapes, the increase in drying rate under the influence of HHAIB varied from 8% for a duration of 30 s at 90°C to 68% for a duration of 150 s at 110°C. The values of the diffusion coefficient of grapes for the HHAIB pretreatment at temperatures of 90, 100, and 110°C and durations of 30, 60, 90, 120, and 150 s, as well as for the control and chemical pretreatments were determined. The values of the coefficient changed from 2.28×10-10 m2 s-1 for 30 s of applying pretreatment at 90°C to 3.53×10-10 m2 s-1 for 150 s of applying the pretreatment at 110°C. The highest value of this coefficient (7.46×10-10 m2 s-1) was associated with the chemical pretreatment. The value of the diffusion coefficient increased with increasing temperature and duration of the HHAIB pretreatment. In general, this increase in the drying rate and the diffusion coefficient can be attributed to the effect of the HHAIB pretreatment on the texture and destruction of the cell wall, as well as the microcracks created on the skin of the grapes. Moreover, the findings reveal that, in comparison with the hot air temperature, the duration of the HHAIB pretreatment was more effective in enhancing the drying rate. Additionally, based on the color analysis, a temperature of 110°C and a duration range of 90-150 s were achieved as suitable conditions for applying pretreatment.

The HHAIB pretreatment, which combines the benefits of hot air blanching with jet technology, affects the texture and skin of grapes, accelerates the drying process, and increases the quality of the produced raisins. However, the correct application of this pretreatment depends on the proper design of the system and appropriate conditions, including duration, temperature, and relative humidity. The results of drying kinetics showed that the drying rate increased with an increase in the temperature and duration of the pretreatment. The findings indicate that the HHAIB pretreatment could improve the color indices of the raisins, resulting in an increase in the drying rate and acceptable quality of the final product. This provides a basis for the use of HHAIB on larger and industrial scales.