Study of Ammonia Gas Emission from Broiler Houses and the Effects of Temperature, Humidity and Age on It

Introduction Iran as one of the largest producers of poultry in Asia and plays major role in feeding the world's population, particularly in the poultry industry. Research about this industry will help to improve the quality and the quantity of products. Increasing of the concentration of toxic gases such as NH3 (ammonia), CO2 (carbon dioxide), SH2 and CH4 in poultry houses comes from bird activity inside the barn is one of the basic problems of the farming. Increasing the amount of these gases more than standard level would cause heavy mortality and reductions in the production. Ammonia is one of the most toxic gases in poultry houses, which must be controlled. Different studies have been carried out on measurement of ammonia emissions from poultry houses to reduce energy consumption and reduce emissions of ammonia. But no specific study has been found on ammonia emissions in Iran and there is no reliable documents of ammonia emissions from poultry in this country. Materials and Methods In this study a poultry house with 18 thousand chickens was used to measure the emission rate of ammonia, the effect of temperature, moisture and age of chickens on emissions of ammonia in Sabzevar city. The barn was equipped with semi-automatic mechanical ventilation. At the first step of this research all sensors was installed for data collection, i.e., air velocity, temperature, humidity and ammonia concentration. Recorded data information were stored in a central computer. Five digital sensors, model AM2303, have been used to measure the temperature and humidity of the ambient air quality. The concentration of ammonia in the air inputs and outputs of the farm was measured using an ammonia sensor model TGS2444 every 10 seconds throughout the study and recorded in the central system. The average speed of the exhaust air was measured using the hot wire anemometer probe for every fan. The outputs of all sensors was converted to digital data and transferred to the central computer using RS485 cable in each module. Converting of the sensors output to digital data reduces changing the data and probable errors. Ammonia emission rates was found by calculating the concentration of ammonia and measuring the rate of input air and fans exhaust air by ammonia gas equilibrium equation. Relation of the ammonia emission rate was achieved using affective factors such as age of the birds and inside air humidity and temperature by regression method. Results and Discussion The average rate of ammonia emission during broiler growing were measured 89 mg per day for each bird. Ammonia emission rates increased until the age of 37 days and then decreased after the age of 37 days. Age of birds has the highest impact coefficient and temperature and relative humidity of the barn have the least impact coefficients on the ammonia emission rate. The ammonia emission rate has also increased by increasing the age of the bird, temperature and relative humidity of the air. Comparing of the ammonia emission rate derived from regression equation with real conditions showed that the regression equation method has a high precision for estimating the ammonia emission rate. Conclusions It is showed that the results of this research can predict the ammonia emission rate in the poultry houses and predict the required ventilation rates to minimize the amount of ammonia concentration. The results of this study can be used for automatic control system to minimize energy consumption in the poultry houses. According to the results, the reduction of temperature and humidity in poultry house can be used to reduce the ammonia level

Engineering Properties of Japanese quail Eggs in Different Levels of Dietary Calcium

The eggshell of birds, as a natural shield and package, protects the tissues inside it from microbial and mechanical damages. Proper intake of calcium, as an important and effective factor in increasing the strength and quality of the eggshell, could reduce complications. In this paper, the effect of dietary calcium at five different levels on engineering features of Japanese quail eggs in a in their first laying period was investigated. The values for an average of mass, volume, specific mass, shell thickness, major diameter, central diameter and rupture force along the longitudinal and transverse axes were measured. Rupture energy or toughness, slope of the rupture curve (hardness), deformation along the longitudinal and transverse axis to the point of rupture as well as longitudinal and transverse deformation of 450 tested quail eggs (3 period of time, 5 treatment of calcium, 5 replication, 6 observation) were measured. The characters of the specific mass, shell thickness, rupture force, and slope of the rupture curve of quail eggs indicate the strength of quail egg. In this study, variations in all parameters indicating shell strength at different levels of dietary calcium were consistent with each other. Five different treatments with 1.5%, 2%, 2.5%, 3%, and 3.5% calcium content were supplied for the study. By increasing the calcium content of the quail diet from 1.5 to 3 wt%, the volume and weight of quail eggs dropped and shell thickness was reinforced. According to the results, the shell strength of quail eggs along the transverse axis was slightly less than the longitudinal axis, but the flexibility and energy required for quail egg rupture were much greater across the longitudinal axis

ویژگی‌های مهندسی تخم بلدرچین ژاپنی در سطوح مختلف کلسیم جیره غذایی دوره10 شماره1 سال1399

The eggshell of birds, as a natural shield and package, protects the tissues inside it from microbial and mechanical damages. Proper intake of calcium, as an important and effective factor in increasing the strength and quality of the eggshell, could reduce complications. In this paper, the effect of dietary calcium at five different levels on engineering features of Japanese quail eggs in a in their first laying period was investigated. The values for an average of mass, volume, specific mass, shell thickness, major diameter, central diameter and rupture force along the longitudinal and transverse axes were measured. Rupture energy or toughness, slope of the rupture curve (hardness), deformation along the longitudinal and transverse axis to the point of rupture as well as longitudinal and transverse deformation of 450 tested quail eggs (3 period of time, 5 treatment of calcium, 5 replication, 6 observation) were measured. The characters of the specific mass, shell thickness, rupture force, and slope of the rupture curve of quail eggs indicate the strength of quail egg. In this study, variations in all parameters indicating shell strength at different levels of dietary calcium were consistent with each other. Five different treatments with 1.5%, 2%, 2.5%, 3%, and 3.5% calcium content were supplied for the study. By increasing the calcium content of the quail diet from 1.5 to 3 wt%, the volume and weight of quail eggs dropped and shell thickness was reinforced. According to the results, the shell strength of quail eggs along the transverse axis was slightly less than the longitudinal axis, but the flexibility and energy required for quail egg rupture were much greater across the longitudinal axis.پوسته تخم پرندگان، به‌عنوان یک بسته‌بندی طبیعی، از مواد موجود در تخم در برابر آسیب‌های میکروبی و مکانیکی محافظت می‌کند. مصرف مقادیر مناسب کلسیم در جیره عذایی پرنده، به‌عنوان یک عامل مهم و مؤثر در افزایش قدرت و کیفیت پوسته تخم می‌تواند عوارض ناشی از مشکلات پوسته را کاهش دهد. در این مقاله، تأثیر کلسیم جیره غذایی در پنج سطح مختلف بر ویژگی‌های مهندسی تخم بلدرچین ژاپنی در گله بلدرچین مادر در اولین دوره تخم‌گذاری آن‌ها بررسی شده است. مقادیر میانگین جرم، حجم، جرم مخصوص، ضخامت پوسته، قطر بزرگ، قطر میانی و نیروی شکست در امتداد محورهای طولی و عرضی اندازه‌گیری شد. انرژی شکست یا چقرمگی، شیب منحنی پارگی (سختی)، تغییر شکل در امتداد محور طولی و عرضی تا نقطه شکست و همچنین تغییر شکل طولی و عرضی 450 عدد تخم بلدرچین مورد آزمایش بررسی و اندازه‌گیری شد. پارامترهای جرم مخصوص، ضخامت پوسته، نیروی شکست و شیب منحنی شکست تخم بلدرچین همگی بیانگر استحکام پوسته تخم بلدرچین بوده و در مقالات مختلف از هرکدام از این پارامترها برای نشان دادن استحکام و تغییرات استحکام پوسته استفاده شده است. در مطالعه‌ی حاضر تغییرات تمام پارامترهای بیانگر استحکام پوسته تخم در سطوح مختلف تغذیه‌ی کلسیم با یکدیگر همسو بوده و یکدیگر را تایید کردند. با افزایش مقدار کلسیم جیره غذایی بلدرچین از 5/1 به 3 درصد وزنی، حجم و وزن تخم بلدرچین کاهش یافته و ضخامت پوسته تقویت می‌شود. طبق نتایج به‌دست آمده، مقاومت پوسته تخم بلدرچین در امتداد محور عرضی کمی کمتر از محور طولی است، اما انعطاف‌پذیری و انرژی شکست تخم بلدرچین در محور طولی بسیار بیشتر است

Effect of Calcium Chloride Concentration on Some Mechanical Properties of Apple during Storage

Today, the use of coatings is common to maintain the quality of fruits in storage period. Previous studies have shown that the calcium compounds can improve and preserve the strength of fruit’s cell wall. In this research, the effect of calcium chloride dehydrate (CaCl2*2H2O) concentration on two varieties of apple (Golden Delicious and Red Delicious), was studied. The apples were immersed in the calcium chloride dihydrate solution and then transferred to a cold storage. The effect of three concentration levels: 0, 3 and 6 percent, and three storage durations: no storage, one month and two months, were investigated on the apples mechanical properties such as failure stress, failure strain, modulus of elasticity and toughness. Statistical factorial experiments in the form of completely randomized design were used to analyze the obtained results. The ANOVA results showed that the effect of calcium chloride concentration was significant on the modulus of elasticity (

Effect of electrostatic field on dynamic friction coefficient of pistachio

Introduction: Separation and grading of agricultural products from the production to supply, has notable importance. The separation can be done based on physical, electrical, magnetic, optical properties and etc. It is necessary for any development of new systems to study enough on the properties and behavior of agricultural products. Some characteristics for separation are size (length, width and thickness), hardness, shape, density, surface roughness, color, speed limit, aerodynamic properties, electrical conductivity, elasticity and coefficient of static friction point. So far, the friction properties of agricultural products used in the separating process, but the effect of electrostatic charging on static and dynamic coefficients of friction for separation had little attention. The aim of this study was to find out the interactions between electrostatic and friction properties to find a way to separate products that separation is not possible with conventional methods or not sufficiently accurate. In this paper, the separation of close and smiley pistachios by electrostatic charging was investigated. Materials and Methods: Kallehghoochi pistachio cultivar has the top rank in production in Iran. Therefore, it was used as a sample. The experimental design that used in this study, had moisture content at three levels (24.2, 14.5 and 8.1 percent), electric field intensity at three levels (zero, 4000 and 7000 V), speed of movement on the surface at three levels (1300, 2500 and 3300 mm per minute), friction surface (galvanized sheet iron, aluminum and flat rubber) and pistachio type at two levels (filled splits and closed) that was measured and analyzed in completely randomized factorial design. A friction measuring device (built in Ferdowsi University of Mashhad) used to measure the friction force. It has a removable table that can move in two directions with adjustable speed. The test sample put into the vessel with internal dimensions of 300 × 150 × 25 mm and with wall thickness of 5 mm placed on trolleys. In the bottom of the container a separate aluminum plate was installed as the negative pole of the electric field. The friction plates as a positive pole placed on top of the sample. There were no contact between friction plates and walls of vessel (samples were about 2 to 3 mm higher from the edges of wall). Frictional force changes due to movement of table, measured and recorded by an accurate load cell. From force-displacement curves, the coefficient of dynamic friction and static coefficient of friction calculated. In general, according to the experimental design, 486 tests were performed. Results and Discussion: According to the results of statistical analysis, there is significant interaction affect between pistachios type and electrical field, as well as, the interaction between electrical field and speed, on dynamic coefficient of friction. It means two pistachio types can be separated by electrical charging. Different physical properties of surface of filled non-splits pistachio nuts (such as corners and edges) and filled splits ones, caused differences in the distribution of electric charge and as a result, its interaction with the electric field were significant. Changes in dynamic coefficient of friction according to the electric field intensity at different levels of moisture content and speed on the friction surfaces of iron, aluminum and rubber, was drawn in Fig.4, 5 and 6, respectively. These figures reflected the reduction of dynamic coefficient of friction by increasing the movement speed of table. According to Fig.7, increasing the intensity of the electric field increases the dynamic coefficient of friction. Because this leads to build the opposition charge on samples and galvanized iron sheets, and with increase of electrical field, these charges will rise. Fig.9 shows different trends of variation of dynamic coefficient of friction against moisture on rubber surface. This chart shows the higher coefficient of friction of filled non-splits samples than filled splits in all cases and shows an increasing trend with increasing humidity. Conclusions: Table 2 presents the dynamic coefficients of friction in different states on different levels of moisture content. According to this table, the maximum difference was achieved in moisture content of 8% (which is close to the product storage moisture) in rubber surface with field strength of 7000 V and 1300 mm per minute speed. On 14 percent moisture content, the maximum difference was achieved on aluminum surface by 2500 millimeter per minute speed and 7000 V field strength. By the results, on 24 percent moisture content (the moisture close to peeling process) the maximum difference between filled non-splits and filled splits pistachios friction was achieved on aluminum surface, 7000 V electric field strength and 2500 millimeter per minute table speed. Thus, to have a separation system, the aluminum surface, 7000 V electric field strength and adjustable speed between 1300 to 2500 mm per minute is recommended

The effect of slicing type on drying kinetics and quality of dried carrot

Introduction: Carrot is one of the most common vegetables used for human nutrition because of its high vitamin and fiber contents. Drying improves the product shelf life without addition of any chemical preservative and reduces both the size of package and the transport cost. Drying also aidsto reduce postharvest losses of fruits and vegetables especially, which can be as high as 70%. Dried carrots are used in dehydrated soups and in the form of powder in pastries and sauces. The main aim of drying agricultural products is decrease the moisture content to a level which allows safe storage over an extended period. Many fruits and vegetables can be sliced before drying.because of different tissue of a fruit or vegetable, cutting them in different direction and shape created different tissue slices. Due to drying is the exiting process of the moisture from internal tissue so different tissue slices caused different drying kinetics. Therefore, the study on effect of cutting parameters on drying is necessary. Materials and Methods: Carrots (Daucus carota L.) were purchased from the local market (Kerman, Iran) and stored in a refrigerator at 5°C. The initial moisture contents of the Carrot samples were determined by the oven drying method. The sample was dried in an oven at 105±2°C about 24 hours. The carrots cut by 3 models blade at 3 directions. The samples were dried in an oven at 70°C. Moisture content of the carrot slices were determined by weighting of samples during drying. Volume changes because of sample shrinkage were measured by a water displacement method. Rehydration experiment was performed by immersing a weighted amount of dried samples into hot water 50 °C for 30 min. In this study the effect of some cutting parameters was considered on carrot drying and the quality of final drying product. The tests were performed as a completely random design. The effects of carrot thickness at two levels (3 and 6 mm), blade in 3 models (flat blade, wavy blade and Ridged blade) and the cutting direction at 3 levels (linear, lateral and diagonal) were evaluated on drying kinetics, drying rate, shrinkage and rehydration. Statistic analysis done by SPSS software. Results and Discussion: The results of analysis of variance showed that the effects of cutting parameters were significant on studied parameters (p<0.01) (Table 1). Thin layers dried faster than thick layers because of firmness of surface which it causes slow moisture transfer. The least drying time was 200 minutes at the samples that cut by a wavy blade at the lateral direction with a significant difference (p<0.05) given Fig.3. In these samples surface evaporation is more, because of more surface. The compare means showed drying rate at thick layer is fewer because of the longer distance moisture removal (Fig.6). Also the most drying rate was 0.74 gmin-1 at cutting by flat blade on linear direction with a significant difference (p<0.05).The least shrinkage was obtained on this treatment was 36.7% given Fig.8. The most of tissue of linear slices is woody part that is dense compare with other parts therefore shrinkage decrease at during drying. The most rehydration was 3.96 and 3.88 for cutting by flat blade in diagonal and linear direction with significant difference to other treatments. Rehydration depends on cell damage greatly. Since the slices of carrot that cut by flat blade were damaged fewer than other treatments therefore rehydration was more. Conclusions: The drying behavior of carrot slices was studied at different methods in slicing carrot. The results showed a significant effect of the cutting variables on drying kinetics, drying rate, shrinkage and rehydration. The carrot moisture content decreases continuously over the drying and the fastest drying occurred at thin layers sliced by wavy blade. The slices that were cut by flat blade at linear direction caused the best quality. The results show cutting parameters are significant effect on quality of dried fruits and vegetable. There for the study of drying behavior is necessary for fruits with different tissue because of more quality of production and high efficiency at drying. Also the study of cutting parameter suggest on other fruits and vegetables with different tissue. The results help to manufactures for improvement of production of drying equipment

Desigining of Computer Vision Algorithm to Detect Sweet Pepper for Robotic Harvesting Under Natural Light

In recent years, automation in agricultural field has attracted more attention of researchers and greenhouse producers. The main reasons are to reduce the cost including labor cost and to reduce the hard working conditions in greenhouse. In present research, a vision system of harvesting robot was developed for recognition of green sweet pepper on plant under natural light. The major challenge of this study was noticeable color similarity between sweet pepper and plant leaves. To overcome this challenge, a new texture index based on edge density approximation (EDA) has been defined and utilized in combination with color indices such as Hue, Saturation and excessive green index (EGI). Fifty images were captured from fifty sweet pepper plants to evaluate the algorithm. The algorithm could recognize 92 out of 107 (i. e., the detection accuracy of 86%) sweet peppers located within the workspace of robot. The error of system in recognition of background, mostly leaves, as a green sweet pepper, decreased 92.98% by using the new defined texture index in comparison with color analysis. This showed the importance of integration of texture with color features when used for recognizing sweet peppers. The main reasons of errors, besides color similarity, were waxy and rough surface of sweet pepper that cause higher reflectance and non-uniform lighting on surface, respectively

The Effect of Compression Ratio and Alternative Fuels on the Performance of Turbocharged Diesel Engine by GT-POWER Software

Introduction Today, maximizing the efficiency of fuels and increasing the output power of diesel engines is considered inevitable due to the increasing need for energy resources, the reduction of fossil fuel resources, the need to maintain the environment, reduce air pollution, and limit the electricity supply and fuel supply. In the large cities of Iran, the problem of vehicle pollution is one of the main problems. The lack of proper fuel, soot filters, and absence of requirement for a technical inspection of diesel vehicles have led to an increase in mortality and the growth of lung cancer due to pollution. All of studies indicate that fossil fuels, despite the low cost of production, will increase the cost of both living and environment. A solution for this crisis is to reduce the sources of pollutant-producing sources from the source of these pollutants. In the internal combustion engines, the compression ratio and alternative fuels are two important factors affecting engine performance and exhaust emission. Materials and Methods In this research, a one-dimensional computational fluid dynamics solution with GT-Power software was used to simulate a six-cylinder diesel engine to study the performance and exhaust emissions with different compression ratios and alternative fuels. The compression ratio was chosen to be 15:1 to 19:1 with an interval at unity. Alternative fuels such as (as base diesel), methanol, ethanol, diesel and ethanol, biodiesel and decane were selected. To modeling engine, first, all parts of the engine were introduced as a real six-cylinder engine, and then the required data were entered according to the actual engine conditions at the atmospheric pressure of one atmosphere. Before this investigation was carried out, a validation model for evaluation was done by experimental and simulation data. The validation results showed that software model error is acceptable and the model has a good capability of fitting and predicting. Results and Discussion The engine performance was evaluated in terms of engine power, engine torque, and specific fuel consumption at different engine compression ratio and fuel. The results showed that with increasing the compression ratio, brake power and brake torque increased. Among the fuels used in this engine, the maximum brake power and brake torque in the compression ratio of 19 with the decane fuel were 3.86% higher than that the base fuel and the lowest value was awarded in the compression ratio of 15, with methanol fuel and it was equal with 56.04%. The results indicated that by increasing compression ratio, the brake specific fuel consumption was reduced due to more power than the fuel consumed in the engine. A fuel with lower heating value should be injected more mass to the engine. This will increase the brake specific fuel consumption. In this research, the decane fuel with a compression ratio of 19 with a reduction of 3.72% had the lowest brake specific fuel consumption among other fuels. The CO emission from the engine largely depended on the fuel's properties, the availability of oxygen, the fuel mix with air, temperature, and turbulence inside the combustion chamber. The results highlighted that by increasing compression ratio, CO emission increased and CO emission in biodiesel fuel, with a compression ratio of 15, was decreased by 82.37% compared to the base. CO2 emissions are not too harmful to humans, but they increase the potential for ozone depletion and global warming. With increasing compression ratio, CO2 and HC emissions increased for all fuels, CO2 emissions have risen up the base. The fuel heating mechanism, combustion temperature, oxygen content, and gas fuel availability are the most important factors in the formation of NOx. With increasing the compression ratio, the amount of NOX increases, which is due to the high temperature in the cylinder at a higher compression ratio. The viscosity and density of fuels have an effect on NOX emission, and because of the larger droplets of the fuel, it released NOX. The highest NOx emissions from biodiesel fuel are due to the high oxygen content of this fuel and the lowest NOx emissions from decane fuel, due to the low density of the fuel compared to other fuels.  Conclusions The results of this study showed that the decane fuel with a compression ratio of 19 in total had the best functional and pollutant characteristics among the six fuel used in this study. Therefore, this fuel can be the best alternative for diesel fuel

Prediction of lateral surface, volume and sphericity of pomegranate using MLP artificial neural network

Introduction: Fast and accurate determination of geometrical properties of agricultural products has many applications in agricultural operations like planting, cultivating, harvesting and post-harvesting. Calculations related to storing, shipping and storage-coating materials as well as peeling time and surface-microbial concentrations are some applications of estimating product volume and surface area. Sphericity is also a parameter by which the shape differences between fruits, vegetables, grains and seeds can be quantified. This parameter is important in grading systems and inspecting rolling capability of agricultural products. Bayram presented a new dimensional method and equation to calculate the sphericity of certain shapesand some granular food materials (Bayram, 2005). Kumar and Mathew proposed atheoretically soundmethod for estimating the surface area of ellipsoidal food materials (Kumar and Mathew, 2003). Clayton et al. used non-linear regression models for calculation of apple surface area using the fruit mass or volume (Clayton et al., 1995). Humeida and Hobani predicted surface area and volume of pomegranates based on the weight and geometrical diametermean (Humeida and Hobani, 1993). Wang and Nguang designeda low cost sensor system to automatically compute the volume and surface area of axi-symmetricagricultural products such as eggs, lemons, limes and tamarillos (Wang and Nguang, 2007). The main objective of this study was to investigate the potential of Artificial Neural Network (ANN) technique as an alternative method to predict the volume, surface area and sphericity of pomegranates. Materials and methods: The water displacement method (WDM) was used for measuring the actual volume of pomegranates. Also, the sphericity and surface area are computed by using analytical methods. In this study, the neural MLP models were designed based upon the three nominal diameters of pomegranatesas variable inputs, while the output model consisted of each of the three parameters including the volume, sphericity and surface area. Priorto any ANN training process, the data normalized over the range of [0, 1]. Fig. 1 shows a MLP with one hidden layer. In this study, back-propagation with declininglearning-rate factor (BDLRF) training algorithm was employed. The mean absolute percentage error (MAPE) and the coefficient of determinationof the linear regression line between the predicted values fromthe MLP model and the actual output were used to evaluate the performance of the model. Results and Discussion: The number of neurons in the hidden layerand also theoptimal values for the learning parameters η and αwere selected bytrial and error method. The bestresult was achieved with five neurons in the hidden layer. The results showed thatthe optimum modelof performance was obtained at constant momentum termequal to 0.8 and learning rate equal to 0.9. In this study, 300 epochs were selected as the starting points of the BDLRF. Some statistical characteristics of the actual values of volume were estimated by WDM, surface area was computed by equation (3) and sphericity of pomegranates was computed by equation (1) and the predicted values of them using the neural network method were shown in Table 1. The obtained results verified that the differences between theactual values and the estimated ones can be ignored. But, the predicted values of the volume using the MLP model in comparison with equation (2) are much closer to the actual values. Statistical comparisons of desired and predicted data and the corresponding p values are given in Table 2. The results showed that P-value was greater than 0.08 in all cases. Therefore, there was no significant difference between the statistical parameters. However, the P-value for equation 2 is much less than that of the MLP model. The results shown in Figures 2, 3 and 4 show that the coefficients of determination between actual and predicted data were greater than 0.9. Considering all the results in our study, the MLP model is more accurate than the WDM and analytical methods. Conclusions: In this paper, we first measure the actual volume of the pomegranate using WDM and equation (2). Also, assuming an elliptical fruit, the sphericity and surface area are computed analytically based on the three nominal diameters of a pomegranate. Finally, the results of achievements of the MLP designed revealed that the MLP model could be successfully applied to the prediction of thesphericity and surface area. Therefore, the MLP model can be a viable alternative to the analytical methods. However, this is possible only if there is a precise way to compute the three nominal diameters of pomegranates. In addition, according to the MAPE, the accuracy of the MLP model in prediction of volume of pomegranates was twicethe analytical method

Fabrication and evaluation of variable rate fertilizer system

Introduction: In conventional farming, the soil and crop are considered uniform in different locations of the farm and the fertilizers are applied according to the average of soil needs with an additional percentage for safety (Loghavi, 2003). Non-essential chemical fertilizers in the field have harmful effects and social, economic and environmental concerns will increase. Many fertilizers go into the surface waters and ground waters and cause poisoning and environmental pollution without being absorbed by the plants. In variable rate technology, the soil fertilizer needs a map of all parts of the farm which is prepared with the GIS system. This map is uploaded on the computer before variable rate fertilizer machine starts. The computer continually controls the fertilizing rate for each part of the farm using a fertilizing map and global positioning system. The purpose of this study is to construct and evaluate a map-based variable rate fertilizer system that can be installed on a common fertilizer in Iran to be used as a variable rate system. Materials and methods: In common variable rate fertilizers, the rotational speed change of the distributor shaft is used to apply fertilizers. In this way, a DC motor is assembled on the main shaft of all distributors, which reduces the fertilizing accuracy. The reason for this is that there is no separation for units along the width of the fertilizer. Therefore, we used one DC motor for each distributor and another motor to rotate the agitator in the tank. System Set up: To design and select a suitable engine, the required torque for the rotation distributor shaft was measured by a torque meter and the amount of 2.1 Nm was acquired for that. With regard to the maximum rate of nitrogen fertilizer for land and tractor speed at the time of fertilizing, the order of 350 kg per hectare and 8 km per hour, the maximum distributor shaft speed and power required to rotate distributor shaft were calculated to be 55 rpm and 6.9 watts, respectively. The selected motor was rated 27.5 watts, 24 volts and 7.5 amperes (Since there were no 6.9 watts motors in the market, a more powerful motor was selected). According to the gear ratio and motor speed, the speed of the distributor shaft was adjustable in the range of 0 to 65 rpm. To determine the speed and position with respect to the direction, a central encoder (E50S8-600-6-L-5 model manufactured by Autonix Korea) was used on the ground wheel. The encoder had 600 pulses per revolution of the axis. Performance evaluation of the system: Performance evaluation of the system consists of two parts; static and moving tests. In static tests, the purpose was the determination of the fertilizer loss (in grams), due to changes in distributor speed as well as the accuracy of the electromechanical control system according to the command values sent to the device. Results of this part were used for the calibration of the device. In motion tests: In motion tests, the assessment of fertilizer loss was due to values set in a given situation and the accuracy of planted fertilizer in place (delay and acceleration) is reviewed. The delay is found by the determination of the distance that the fertilizer was placed after the desired location on the ground and the acceleration is found by the determination of the distance that the fertilizer is placed before the desired location on the ground. Results and discussion: The distributor flow rate on F0 valve position was measured for different rotation speeds. The correlation (linear regression) between the planted fertilizer and rotation speed of distributor shaft (rpm) were 0.99 for y=71.636x+75.182. So, it can be deduced that these two parameters have a good linear correlation. The results achieved from diagrams and regression model were used in the programming of the system control unit. Thus, by reading the distributors motor speed, the amount of fertilizer can be calculated and the amount of used fertilizer according to the need of the farm in each part is controlled. The effect of plot length on the amount of fertilizing on 25% need level was not significant, but it was significant on 50% need level. This is due to stopping and starting fertilizer flow during the test, changes in motors speed and error of these on fertilizer output at a certain amount of fertilizing so that at the 25% need level, the error resulting from these factors had less share on the amount of plant fertilizer and the effect of plot length was not significant according to the system default. On the other hand, the effect of forward speed was significant on the 50% need level and insignificant on the 25% need level. Conclusions: In order to calculate the accuracy of the system, the error from the application amount of fertilizer was measured at different fertilizing rates. The correlation between the adjusted fertilizing rate and the measured fertilizing rate was 0.98 with regression model of y=1.0475x which shows the good accuracy of the system