Journal of Agricultural Machinery

Abstract In this research the effects of drum speed and feed rate on the amount of wheat grain damages during threshing operation were investigated. A local flail type threshing machine for threshing wheat at three different drum speeds (11, 20 and 36.7 m/s) and at three different feed rates (0.013, 0.025 and 0.05 kg/s) was used. Increasing drum peripheral speed from 11 to 20 m/s has been resulted in increasing visible and invisible damages from 0.01% to 1.95% and from 2.13% to 16.5%, respectively. Increasing drum peripheral speed up to 36.7 m/s the visible and invisible damages observed as 24.3% and 36.85%, respectively. On the other hand, increasing the machine feed rate from 0.013 to 0.025 kg/s and then to 0.05 kg/s, the percent of broken seeds were decreased by 21.17% and 31.8%, respectively. The germination test showed that the both type of germinations (visible and propositional) decreased with increasing drum speed and increased with increasing feed rate. The electrical conductivity of the threshed seeds had a direct relationship with increasing the drum speed and decreasing the feed rate. The Slids10 and Sohag10 varieties were the toughest and the most weakened varieties, respectively in this investigation.

Abstract In this paper, a low-cost dynamometer for rolling, steered wheels is described. The dynamometer was constructed to determine whether such an instrumented mechanism was practical. Four S-beam load cells, an Opto-counter and a potentiometer were used to obtain all moments, and forces using dynamic and kinematic analysis. Minimal simplifying assumptions considered for the required calculations. Overturning, aligning and rolling resistance moments besides vertical force are directly measured by the load cells. The Opto-counter detects wheel angular velocity and the potentiometer was used to measure the steering angle. The results showed that the mechanism was very well calibrated with a coefficient of determination of over 0.99 and can be used to define wheel dynamic behavior.

Abstract Water scarcity is today’s world biggest challenge which requires different countries to manage their water resources in the most efficient way. Sprinkler irrigation increases water consumption efficiency due to more uniform distribution of water across the field. Precision farming is based on the site-specific use of inputs according to soil characteristics and plant needs. One of the main inputs for agricultural production is water. Thus, efficient use of water resources based on variable rate irrigation is considered to be a basic approach of precision irrigation. The main purpose of this study was to simulate and fabricate a variable flow sprinkler, applicable in solid set sprinkler irrigation system. The preliminary drawing of the proposed sprinkler, which equipped with a flow and pressure control plunger, was simulated using Fluent software. The actual sprinkler was then fabricated and evaluated in a field. The performance of the sprinkler was evaluated at three pressure levels, three plunger positions (at the points of the least and biggest sprinkler’s cross section for water passage) and three diameters of outlet nozzle opening. Results showed that the plunger had the capability of varying outlet flow and pressure in the sprinkler and trends in flow and pressure variation as affected by the plunger position was very complicated. The Fluent model for conditions with fully open of the plunger and half opened was effectively efficient. However, as the plunger closed the water passage more than the half of cross section, the model did not show an acceptable efficiency.

Abstract In conventional cultivation of sugar beet the weeding and crust breaking are mostly performed manually. The objectives of this research were to design, fabricate and evaluate a soil crust breaker and weeding implement equipped with a detecting sensor. Each unit consisted of a distance detecting sensor and a hydro-motor for driving the blades and pneumatic valves for moving the blades. The hydro-motor was activated by the sensors. To avoid damaging the plants, a command signal was sent to the pneumatic valves to move the blades up and down and pass safely. Three configurations of cutting blades were considered which could be mounted to the crust breaker. The field evaluation was conducted with two tractor forward speeds (0.4 and 1 km h-1) and four plant-to-plant spacings within rows (20, 25, 30 and 40 cm) all with three different blade shapes. For field evaluation split plot experiments arranged in a completely randomized block design with three replications. The number of plants damaged (evaluated only for four-lobe blades) and size of broken crusts (evaluated for all blade shapes) for various treatments were recorded and compared. The results of analysis indicated that the higher the inter-row spacing the lower the injury to the plant. The highest and the least damage to the plants occurred for within-row plant spacings of 20 and 40 cm, respectively. The forward speed was also significantly affected the percent of plant damaged. The forward speed of 1 km h-1 at 20 cm spacing had the most (59%) and the speed of 0.40 km h-1 at 40 cm spacing had the least effect (3.3%) on the percent of plant damage. The two-lobe blade could result in the maximum surface area broken.

Abstract Grain loss monitors are installed on combine harvester and make it possible to measure grain loss on different parts of the combine. The instrument permits the operator to adjust a proper ground speed to keep grain loss within an acceptable range. In this study a loss monitoring system was implemented to measure grain losses continuously on straw walker and sieves. Two grain loss monitors (KEE and TeeJet) were installed behind the straw walker and the sieves of JD-955 and JD-1165 combine harvesters. Harvesting performance parameters such as combine total and processing losses were then measured. To evaluate the precision and accuracy of the instruments, the measured and monitored losses were compared and investigated. The results of a two-year research showed that the average processing loss of the combine harvesters with 10-12% grain moisture content and 750 rpm drum speed was 0.82% which is whitin the acceptable range recommended by ASAE Standard No. S343.3. Furthermore, there was no significant difference between the measured and monitored values of processing loss.

Abstract For planting fine seeds in cellular trays, an automatic pneumatic seeder was designed, constructed and evaluated. CATIA software was used to design and analysis the system parts of the seeder. Different parts of the seeder, including vibrating seed hopper, vacuum boom, seed picking nozzles, seed tube, pneumatic system and electronic control unit for automation of the seeder, were designed and constructed. The area of nozzle orifice was used to calculate the required pressure of nozzle tip. The seeder was evaluated using two sizes of trays. Experiments were performed with five replications and the error of planting the seeds in the 105 and 390-cellular trays were 1.9 and 0.46 percent, respectively. The time of planting for 105 and 390 cellular trays reduced from 20 min (for manual seeding) to 35 s and from 90 min to 160 s, respectively.

Abstract Equipment availability is necessary in the development of Agriculture mechanization. Crop thinning is one of the most important stages in row crop production which is laborious and costly. The objective of this project is design and construction of a row crop thinning machine. Four main system units are plant sensors, ground sensors, control and thinning platforms. In this machine the unwanted plants on the rows are randomly removed by employing a pneumatically system. A blade on a vertical arm with pendulum motion removes the plant from the rows. The machine control system consists of an arm and a blade which is activated by a double acting cylinder and equipped with a relay and a timer. The pneumatic cylinder is controlled via a solenoid valve. Laboratory tests were conducted to validate the machine performance. Some other preliminary tests also were performed for optimization of parameters such as cinematic index and cutting length of blades. The laboratory tests (totally 9 tests) were performed with a constant forward speed and three levels of plant density, using artificial plants. The data were analyzed using SPSS software. The results show that satisfactory performance of the machine is achieved when the plant density is moderate i.e. the thinning performance reduces with higher plant distance in the row. The other effective variable on machine performance is the adjustment of sensor sensitivity, which is used to distinguish between week and strong plants. In general the machine performance is sensitive to plant shape and morphology, plant distribution pattern in the field, growing stage of the plants, time of thinning and the effectiveness of previous weeding operations

Abstract Farmers are now more interested in application of weed control methods and tools with less environmental side effects. Flame weeding using propane gas is an approach with almost no any chemical residue on the soil and plant surfaces or underground water. In this research, a flame weeding machine with the ability of uniform and also discrete flaming was developed and evaluated in laboratory and field scales. In this apparatus, machine vision technology successfully discriminates between soil and weeds (plants grown in between the corn rows are considered as weeds) under natural illumination. In the laboratory tests, the effect of three forward speeds (0.5, 0.7 and 0.9 m s-1) on flam leading or lagging was investigated. The feasibility of using this technology for site-specific weed control of a corn field in comparison with conventional continuous flaming was investigated. The field trials were conducted with both continuous and discrete flaming approaches. The system performance and weed response to flaming treatments were evaluated by measuring the fuel consumption, counting the number of and weighting the survived and dead weeds one and three days after each flaming treatment. The results of laboratory tests showed that the effect of forward speed on system accuracy was significant and the system performance was more accurate at forward speeds of 0.5 and 0.7 m s-1 than 0.9 m s-1. According to the field experiments, continuous and discrete flaming methods exhibited similar results in eradication of weeds (both number and weight-based), while the fuel consumption of the discrete flaming was lower than the continuous one. The results also showed that discrete flaming by employing machine vision technology could be an efficient substitute for continuous flaming due to its lower fuel consumption and potential reduction of air pollution as well as other benefits of flame weeding.

Abstract The main method of rice planting in Iran is transplanting. Due to poor mechanization of rice production, this method is laborious and costly. The other method is direct seeding in wet lands which is performed in the one third of rice cultivation area of the world. The most important problem in this method is high labor requirement of weed control. In order to compare the different rice planting methods (direct drilling, transplanting, and seed broadcasting) a manually operated rice direct seeder (drum seeder) was designed and fabricated. The research was conducted using a randomized complete block design with three treatments and three replications. Required draft force, field efficiency, effective field capacity, yield, and yield components were measured and the treatments were compared economically. Results showed that there were significant differences among the treatments from the view point of rice yield at the confidence level of 95% i.e. the transplanting method had the maximum yield. A higher rice yield was obtained from the direct seeder compared to the manual broadcasting method but, the difference between these two methods for crop yield was not significant even at the confidence level of the 95%. The coefficient of variation of seed distribution with direct seeding was more than 20%. The labor and time requirements per hectare reduced to 7 and 20 times, respectively when comparing the newly designed direct seeder with the transplanting method. The direct seeding method had the highest benefit to cost ratio in spite of its lower yield. Therefore, this method could be recommended in the rice growing regions.

Abstract Due to the importance of weed control and the limitations of mechanical methods in some places, in this research the water jet cutting for weed control was investigated. The cutting tests were performed on camel thorn weed in Shahid Bahonar university of Kerman. The water jet pressure of 90 bars was achieved with the aid of a suitable pump. The cutting time was studied in a completely randomized factorial design experiment (CRD) with five replications. Factors of experiments are: stem diameter in 2 levels (smaller and larger than 5 mm), distance of spraying jet from weeds in 3 levels (10, 20 and 30 cm) and two types of plant holders: blade and plate. The results showed that stem diameter and jet distance from the weed stem had significant effects on cutting time (at the 1%). The mean comparison of parameters showed that with increase of stem diameter the cutting time increased and any increase in jet distance from the weeds decreased the cutting time linearly with R2=0.96 and R2=0.99 for small and large diameter weeds, respectively. The minimum cutting time was measured at 30 cm of the jet from small diameter of stems. A multivariate linear regression model was also proposed for cutting weed parameters. It can be concluded that due to the flexibility of water jet cutting for restricted places, hydrodynamic control of weeds is proposed as a complementary method and sometimes a competing substitute method.

Abstract Increasing demand for food production in the recent years has raised the usage of granular fertilizers. Consequently, the growing use of fertilizers has reduced the quality and quantity of crop production. In addition pollution problems such as soil and water (surface and subterranean water) contaminations has increased. Consistent spreading of fertilizers in the farmlands is of fundamental rules in conventional framings. In present study, the effects of the number and the arrangement (position) of blades of a single disk fertilizer distributer and for two different fertilizers were investigated in order to obtain optimized distribution of fertilizer. The tests were conducted in factorial arrangement and in a completely randomized model. The variables were the number of blades in three levels of 4, 6 and 8, the blade position angles (in two patterns of radial and non-radial) and the type of fertilizer (phosphate and nitrate). Statistical analysis of results indicated that the number of blades on the disk and type of fertilizer are not effective parameters in order to reach a consistent distribution pattern of fertilizer while the position of blades on the disk has significant influence for this purpose. The best pattern of distribution was obtained from the disk with four non-radial blades and nitrate fertilizer.

Abstract The tire-mechanics models have been developed for the study of wheel movement on the road or soil surface while these models are unlikely to describe the motion of wheels on uneven surfaces. Due to dynamical complexity of this phenomena and the importance of this subject for farm conditions and the wheel carrier devices, the present research aimed to investigate the effects of several parameters on the wheel passing the obstacle. The experiments were carried out using single wheel tester in soil bin condition. The results indicated a relatively linear relationship between the impact force applied on tire and forward speed of wheel and also the height of rectangular obstacle. The effect of inflation pressure was inversed in the range of complete formed tire’s body on impact force and in low levels of tire inflation pressure; tire’s body damps the maximum impact forces. The medium levels of pressure (about 150-200 kPa) resulted in less horizontal force that applied on the wheel for different levels of forward speed and obstacle’s height. Tractive force for passing obstacle was increased by raising forward speed and the obstacle’s height.

Abstract Soil compaction can occur as a result of a number of factors. One of the most important factors is soil response to pressures imposed by wheels and soil engaging tools. This research investigated the effect of tyre load and inflation pressure on soil compaction-related factors. These factors include rut width, rut depth, cone index and horizontal force in different layers of soil profile. In this research a stiff carcass tyre has been used and a soil compaction profile sensor in controlled soil bin laboratory conditions. This sensor consisted of eight flaps, each equipped with strain gauges, installed on a subsoiler leg face with working depth of 45 cm. Studies were conducted using a factorial experiment at two levels of axle load of 6.3 kN and 23.9 kN and three levels of inflation pressure of 324 kPa, 524 kPa and 724 kPa with three replications in a randomized complete design. Duncan test and F test were applied to compare the means of pressure and axle load, respectively. The soil compaction profile sensor measured soil compaction at different layers from soil surface to 45 cm depth at 5 cm interval. The results of experiments indicated that vertical load significantly affected the horizontal force at different tyre inflation pressures on the soil profile. The tyre inflation pressure exhibited greater effects on shallow depths than those of higher depths. The amount of rut width, rut depth and cone index increased with an increase in vertical load. Increasing of the inflation pressure decreased rut width and increased rut depth and cone index.

Abstract This study was carried out to evaluate the effects of tillage practices (with different depths) on soil penetration resistance, technical parameters and grain yield of wheat crop. The experiment was conducted as a randomized complete block design with three replications for two years. Treatments included: moldboard plow fallowed by two passes of disc harrow and leveler (CT), two passes of disc harrow plus leveler (RT), subsoiler fallowed by two passes of disc harrow and leveler (S1D) and subsoiler fallowed by rotivator (S1R). The results showed that soil compaction and penetration resistance increased at the end of growth stages because of irrigation operations and cohesion force of soil particles. However due to increasing of cumulative infiltration, it can be concluded that subsoiler caused the formation of micro cracks in different depths of soil. From technical indices viewpoint comparing to CT treatment, S1D and S1R treatments saved fuel consumption up to 2.2 and 10.44 lit ha 1 and tillage operation time up to 0.58 and 1.54 h ha-1, respectively. The result of grain yield assessment showed an increase of 8.5% in grain yield after replacing moldboard plow with annual subsoiling. Subsoiling has advantages such as, good technical indices, elimination of preplanting irrigation and fewer operations in planting time. Finally, subsoiling increased grain yield by 22% as compared to reduced tillage practice

Abstract A three-year field experiment (2004-2007) was conducted on a silty clay loam soil at Tajarak Research Station of Hamedan to determine proper grain drill for wheat in Hamedan dryland areas. In this study, three grain drills including: Hamedani Barzegar; Sahalan Kesht; and Kesht Gostar with wheat seed broadcasting and disking were used. The experiment was a randomized complete block design with four replications. In laboratory, the precision of metering device and the amount of seed damage by metering mechanism were measured. At the end of growth season (harvesting time), crop yield and the associated parameters (spike per m2, number of grain per spike, wheat kernel) were determined. Results showed that planting methods did not affect wheat grain yield significantly. However, wheat grain yield was significantly higher for Kesht Gostar grain drill than the other two machines in two drier years. Mean wheat grain yield was 1224 kg ha–1. Mean wheat grain yield was the greatest (1275 kg ha-1) for Kesht Gostar and the least (1174 Kg ha-1) for Hamedani Barzegar grain drill. Mean straw yield was not affected by planting methods. Mean wheat straw yield was the greatest (2349 kg ha-1) for Hamedani Barzegar grain drill, and the least (2009 Kg ha-1) for the combination of seed broadcasting and disking. The amounts of rainfall during growing season strongly influenced wheat grain and straw yields. Mean wheat grain yield was 1572 Kg ha-1 and 1026 Kg ha-1 in wet year and dry years, respectively. This study showed that a wide range of grain drills is adaptable for dryland wheat cropping system for the semiarid Hamedan areas.

Abstract Disk plows are one of the most important tillage tools. Two way (reversible) disk plows can perform continues plowing. So they can save time and costs and hence improve overall efficiency. In this study, a “two-way” disk plow was designed based on a λ-formed straight-line, four-bar linkage (Daniel mechanism). This design contains disk and rear wheel reversing mechanism, stabilization mechanism of the plow, a disk angle adjustment tool and transport condition for safe operation of the mechanism. Disk reversing mechanism was designed based on a geometrical analysis considering working condition of the disk plow. The suitable displacement of the plow’s frame was achieved by dimensional analysis of Daniel mechanism and a derived mathematical equation. The rear wheel mechanism was made by means of adding a slotted link to the previous four-bar linkage. The synthesized five-bar linkage was then analyzed for its kinematical and force conditions. For each analysis, related diagrams were plotted and discussed. This innovation has the advantages of low production cost and maintenance as well as easy operation, because of its design simplicity with minimum mechanical auxiliaries. The modeling and analysis was done by the aid of CATIA software.

Abstract In recent decades, canola has been considered as the most important oilseed. Harvesting is the most major problem of canola cultivation, since canola pods are very sensitive to shocks and vibrations. Large amount of produce will fall on the ground especially when the combine's head is not adjusted properly. When canola harvested with a combine, the losses may reach up to 50%. The yields can be improved by decreasing seed losses during the harvesting operation. The objective of this study was to determine the optimal harvesting conditions of combine platform to minimize grain losses. In order to achieve this, a laboratory test stand platform was designed and built in the Department of Mechanics of Agricultural Machinery in Shiraz University. Three factors which are more effective on the losses were assessed to determine the best adjustments. These factors were combine forward speed at three levels; 1.5, 2 and 2.5 km h-1, cutter bar speed at three levels; 800, 1100 and 1400 cycles per minute and the relative linear speed of reel in respect of forward speed also at three levels; 1, 1.3 and 1.5. Desired experiment were accomplished on Talaeie variety at 16% m.c) d.b(. The grain losses were measured at each level, with three replicates. By considering the interaction of factors, results showed that the effect of these factors at 5% level was significant, and the minimum loss occurred at 2 km h-1 for forward speed, 1400 cut per minute for cutter bar speed and 1.5 for relative reel speed to forward speed.

Abstract This experiment was conducted to study the effect of nozzle types and the time of herbicide incorporation in soil on weed control, using split plot design by randomized block design. The main plots were soil and herbicide mixing time and the subplots were nozzle types with three replications. This study was performed in Karaj station of Seed and Plant Improvement Institute, located 25 km west of Tehran, in 2008. Treatments were including: T-Jet standard nozzle, Flood-Jet nozzle and Air induction nozzle as well as mixing with the soil immediately, three, six and nine hours after spraying. The parameters were measured includes: the number of weeds before spraying, 15 days and 30 days after spraying; dry weed at two stages of 15 and 30 days after the spraying; and yield of corn. The results revealed that the spraying quality coefficient was greater for T-jet nozzle compared to the other types. However Flood-jet nozzle had a wide range of corn weeds control in comparison to other treatments. Regardless of the nozzle type, the immediate incorporation of herbicide in soil after spraying significantly increased the yield. The time of herbicide incorporation in soil and poison intermixture with soil, from zero to 4.5 hours after spraying was superior to the other times. This was mainly due to different weeds reactions to the times of herbicide incorporation in soil after spraying, and also treatments effect on yield and weed dry weight. Combined data analysis showed that treatment combination of T-Jet nozzle (with time of herbicide incorporation in soil immediately and three hours after spraying), Flood-jet nozzle (with time of herbicide incorporation in soil immediately after spraying) and air induction nozzle (with time of herbicide incorporation in soil immediately, three and six hours after spraying) produced the highest yield than the other treatment combinations.

Abstract For measuring the draft forces exerted by implements into tractor, we use the dynamometers that are divided into pull type or three-point hitch type. For measuring the forces between the tractor and the mounted implements, three-point hitch dynamometers are used. In this research, an adjustable three-point hitch dynamometer with a draft capacity of 25 kN was designed and built which is made up from two frames that one of them placed inside the other. The force sensing elements were comprised of a loadcell that was installed between the frames. All mounted tillage implements were able to be tested by this measuring device excluding mounted implements which are powered by PTO and by using this dynamometer, the variations of implements draft force in the different tillage conditions consist of the various work depths and different forward speeds would be studied. After design and construction steps, dynamometer was calibrated, tested and evaluated. Field tests were done by using of four mounted tillage implements and obtained data were compared by obtained data from ASAE D497.5 standard formula. So with these data, the design of tines, their stems, equipment frames and the selection of the optimal size of the tillage equipments in regard of the soil type of the region and the power of the available tractors will be more scientific and reasonable.

Abstract Farm management needs creative methods to success. FMEA (Failure Modes and Effects Analysis) is a new method to analyze potential reliability problems in the development cycle of the project, making it easier to take actions to overcome such issues, thus enhancing the reliability through design or process. Anticipating these failure modes, being the central step in the analysis, needs to be carried on extensively, in order to prepare a list of maximum potential failure modes. Risk is measured in terms of Risk Priority Number (RPN) that is a product of occurrence, severity, and detection difficulty. This study attempted to improve clod mean weight diameter and soil inversion as indicators of tillage quality by FMEA methodology. The results showed that low soil moisture, slow speed of ploughing and great depth of ploughing is the most important factors that increase clod MWD with 900, 630 and 560 RPN, respectively. Also for soil inversion the slow speed of ploughing, not using coulter, low soil moisture and great depth of ploughing are important factors with 720, 648, 490 and 420 RPN. Using a split - split factorial experiment with 16 treatments and three replications also acknowledged the results of this method. After reforming the conditions and re-testing the experiment, results showed that clod MWD was reduced 20% and soil inversion increased 2% approximately. This study proposes the use of this technique in agricultural management.

Abstract In recent years using rototillers in orchards and small fields especially in northern areas of Iran has been increased. In this study, a multi-function rototiller was developed and its performance was analyzed and evaluated in the field conditions. The specifications of this machine were determined according to the standard and operational situation. The calculations were performed for determining the rotor speed at different gears and then power transmission system was designed. Theoretical analysis was conducted to investigate the machine forward speed and blade rotational speed on the quality of rototilling operation. Results indicated that the forward speed and blade rotational speed affected the thickness of soil cut layer and soil crushing rate. Field tests were performed to determine the thickness of soil cut layer and soil crushing rate for orchard and paddy field conditions. In addition, some physical properties of soil such as composition, moisture content, weeding height, and DENSITY at 15 cm depth were measured. Data analysis was performed by Completely Randomized Design (CRD) with factorial test 3×3 at three replications. Duncan test presented the best combinations of forward speed and blade rotational speed for thickness of soil cut layer were 0.4 ms-1 and 50 rpm, respectively. Also, the best combinations of these two factors for soil crushing rate lower than 40 mm were 0.2 ms-1 and 110 rpm, between 40-80 mm; 0.3 ms-1 and 50 rpm and higher than 80 mm; 0.4 ms-1 and 50 rpm, respectively.