نشریه تحقیقات سامانه ها و مکانیزاسیون کشاورزی
پیاپی 74 (بهار و تابستان 1399)

In this study, a single tire tester was used to study the effects of vertical load, inflation pressure and moisture content on tire rolling resistance in a soil bin. A Goodyear 12.4-28, 6 ply tractor drive tire was employed and the soil texture was a clay loam. The experimental design was a completely randomized with factorial layout at three replications. A multivariate regression model was obtained with the correlation coefficient of R2=0.85 to predict the tire rolling resistance based on vertical load, inflation pressure, and moisture content. A multilayer feed-forward ANN (artificial neural network) with standard BP (back propagation) algorithm and LM (Levenberg-Marquardt) training function by using of two hidden layer in the network architecture was employed. RMSE (root mean squared error) and R2 was used as modeling performance criteria. Tire inflation pressure was identified as the controller parameter of tire rolling resistance at low moisture content and also moisture content was the most effective parameter on changing of rolling resistance in regression model. Also the obtained R2=0.977 from ANN model showed that ANN data were more close to actual data than the regression model.

Long time processing, high energy consumption and non-uniformity in layers moisture are common problems in paddy drying using conventional batch type dryer, leading to increase the chance of kernel breaking during milling process. In this research, drying time, grains moisture content change and energy consumption of a newly rotary dryer were compared with that of a conventional batch type dryer for paddy (Hashemi variety) drying. Besides, quality parameters as hulling milling ratio, head rice yield and white rice breaking percent were studied in paddy dried using both dryers. All Experiments were done triplicate and data analyzed using T- student method in 5% probability. Results showed that newly rotary dryer caused uniformity in drying processes and cleaning of dried paddy; but, in conventional batch type dryer, because of environmental warm air around it, drying time and energy consumption were about 9 and 8.9 percent, respectively, less than what were calculated in newly rotary dryer. Specific energy consumption for paddy moisture evaporation was 13.5 MJ/kgH2O and it was about 11 percent less than that in rotary dryer. The difference of paddy moisture contents and temperatures in top and lower part of layers of batch type dryer were 2 percent and 6 °C respectively.  Milling ratio increased 3.8 percent when rotary dryer was used. Rotary dryer did not have significant effect on paddy hulling. The main effect of using rotary dryer occurred on head rice yield and it was increased about 7.5 percent, comparing with batch dryer. Using rotary dryer caused 7.8 percent decrease in broken kernels, comparing with conventional batch type dryer.

Today, farmers are looking for solutions to increase production and income. One of these solutions is the supplyink off-season crops and horticultural products. Considering the high level of okra production and consumption in Khuzestan province, this study was conducted with the aim of evaluating the economic systems of this product. In this area, okra is cultivated in three ways: okra planted under plastic, mulch and open field. Required data was collected using face-to-face questionnaire from 120 okra growers. The highest amount of net income (287.44 million Rials per hectare) was obtained in okra planted under plastic, plastic mulch (87.06) and open field (61.98) were in the next priorities respectively. The highest amount of benefit-cost ratio (3.7) was obtained in okra planted under plastic, open field (2.3) and plastic mulch (2.1) were in the next priorities respectively. The highest amount of production cost (103 million Rials per hectare) was obtained in in okra planted under plastic, plastic mulch (78.5) and open field (48.7) were in the next priorities respectively. The highest amount of mechanization cost index (10.6%) was obtained in open field, plastic mulch (6.8%) and okra planted under plastic (4.6%) were in the next priorities respectively.

In this research, the adaptive neuro-fuzzy inference system was used for predicting the imposed forces on the tines and tractor fuel consumption during subsoiling operation. The draft and vertical forces imposed on subsoiling tines and tractor fuel consumption were measured under the effect of tine type (subsoiler and paraplow), tillage depth (30, 40 and 50 cm) and forward speed (1.8, 2.3, 2.9 and 3.5 km/h). The field data were used to create the regression and ANFIS models for predicting the studied parameters; the results obtained from applying two models were compared with each other. The field results showed that all independent variables were effective on the studied parameters. Increase in forward speed and tillage depth resulted increase in draft force, vertical forces, and also fuel consumption. Moreover, from the point of consumption of fuel, the paraplow tine was more profitable than subsoiler tine. The results of ANFIS part showed that draft force, vertical force, and fuel consumption, the membership functions of Gaussmf, Trimf and dsigmf, with the mean square error of 0.0156, 0.0231 and 0.0212 also correlation coefficient of 0.999, 0.989 and 0.991, respectively, were the best models for prediction. ANFIS models were found more accurate than regression models, and it could be possible to calculate the model outlet for a special inlet using ANFIS outlet surfaces.

In recent years, expanding of technics in transplanting of sugar beet bare-root seedlings has become one of the priorities of the Ministry of Agriculture of Iran. Bare-root seedlings grown in traditional nursery plots, have no uniformity in root size, therefore automatic transplanters are not so efficient to put seedlings properly into the furrows or to cover them properly with soil. To introduce a semi-automatic transplanter, common methods of conveying seedlings to the soil, including rotary grippers and gravitational delivery tube, were evaluated in a completely random design experiment. In gravitational method, dropping seedlings with different lengths into the bottom of the furrow resulted a non- uniform placement of their crowns, leading to establishment of less than one third of total planted seedlings. Implication of rotary grippers also caused some seedlings to be partly uncovered resulting in establishment of less than two third of total seedlings. Therefore, manual placement of seedlings directly into the soil opener was considered as an intelligent method for proper lodging of seedlings. By omitting the conveying mechanisms of the machines and modifying them for direct transfering of seedlings into the furrows, the quality of transplantation was considerably improved. Among the modified machines, the one with disk ridgers and floating units had an acceptable result with 86% stand establishment. However, low field capacity of the machine still does not guarantee the feasibility of the method in large scale sugar beet farms.

Currently, the area of agricultural land under  conservation practices in the world exceeds 180 million hectares, one of the main advantages of which is improvement in crop water productivity (CWP). An investigation in soybean cultivation  in a farm with different level of management of residues was carried out in a randomized complete block design with split plot design in 2010 and 2011 at Gorgan Agriculture Research Station. Main treatment was residue management at three levels: R1: burning of residue , R2: retaining 50% of residues, and R3: maintaining 100% of residues; the secondry treatment was tillage practises at three levels: T1: conventional tillage (plowing + disk + row crop planter), T2: minimum tillage (stubble cultivator + row crop planter) and T3: no tillage (sowing with no till planter). The best results obtained from R2 and T3: 42.7% and 17.4% increase in yield respectively, comparing R1 and T1. The highest and lowest of water consumption level were found  3950 m3 ha-1 and 2690 m3 ha-1 in  R1 and R3 respectively. The maximum and minimum CWP were found in R2 and R1 treatments with 1.13 kg m-3and 0.55 kg m-3 respectively. Sowing with no tillage system in irrigated conditions improved CWP by 15.3% compared to the conventional method.

In recent years, the drying blossom of date palm caused extensive damage to a considerable part of date palm orchards of Bam and Baravat, south of Iran. Drying blossom is responsible for a large amount of product loss and has been expanding in recent years. In this study, the technology of GIS was used as a quick and easy solution for monitoring of the drying blossom of date palm. It was carried out in three stages: collecting field information from damaged orchards,  feeding GIS with all collected data, and extracting  required information and the maps from the system which showed the severity and distribution of drying blossom in Bam and the suburb by three methods nearest neighbor, inverse distance weighted (IDW), and kriging. Results, upon data normalization, and the trend analysis showed that the severity of the damage in the southern coastal orchards was much higher than that in central and northern regions; the finding led us to focus on certain geographical coordinates (58 degrees and 20 minutes east longitude and 29 degrees and 4 minutes northern latitude to 58 degrees and and 26 minutes east longitude and 29 degrees and 2 minutes north latitude). It has been found  that the rate of drying blossom of date palm in 57.2% of the total damaged orchards were between 20-30%, and in 5.9% of the damaged gardens higher than 40%. Interpreting the results of the distribution of drying blossom on maps showed a relation between the severity of the disorder and the elevation of the area. It could be seen that the palm trees grown at altitudes above 1000 m suffered less damage; in other words, the higher the altitude, the less severity of drying blossom. The pictures received from Sentinel satellite showed that 56.2% or 2049 ha out of 3647 ha total area of palm orchards of Bam and Baravat was affected by drying blossom.

Recent drought phenomenon in Iran has limited feed supplying for livestock enterprises. In this situation, forage fodder production in hydroponic condition could be a reasonable solution to overcome the water resources limitations in forage production process; however, all aspects of this system should be investigated prior to using it. In this research, these four treatments of forage production: hydroponic barley forage, conventional corn forage, conventional irrigated barley, and conventional alfalfa forage,  were compared from the point of view of water productivity and energy indices, in the form of a completely randomized experimental design with 12 replications in Niriz, Fars Province, south of Iran. Results showed that hydroponic barley forage and conventional method of producing barley had the maximum yield (1605052 kg/ha per year) and the minimum yield (6235 kg/ha per year) respectively. The highest water productivity (65.3 kg/m3) and the lowest water productivity (0.64 kg/m3) were obtained from hydroponic barley forage and the conventional method of producing alfalfa , respectively. Results also indicated that the conventional corn forage had the highest energy ratio, net energy gain, and energy productivity (1.88, 125844 MJ/ha, and 0.281 kg/MJ); the lowest amounts of energy indices (0.65, -15252661 MJ/ha, and 0.037 kg/MJ) belonged to the hydroponic barley forage. Conclusions showed that producing barley fodder in hydroponic condition could be a proper solution for supplying adequate forage for livestock in semi-arid climate condition of Niriz twonship,  provided that some amendments could be made in this  method of fodder producing system to reduce energy consumption and to enhance energy productivity.

Potato storage is essential to ensure the continued supplying of potatoes to consumers and the potato processing industry. During storage, physiological changes and water loss lead to changes in color, shape, size, and texture of potatoes. Therefore, there is a need for a quick and accurate method to measure the quality of the product. In this study, machine vision and neural network methods were used in classification and modeling of two stored potato samples (Agria and Clone 8-397009)  under constant and variable conditions. Among 29 measured parameters relating to color, texture and morphological features of potato, some features were selected as the main parameters to monitor the chnges in product during storage period: Major Axis Length, Compactness, and area (morphological features), L* and b* (color features) and Average contrast (Ac) and Average gray level (Agl) (texture features). Among the training algorithms, Levenberg–Marquardt (LM)  training algorithm with the lowest root mean square error (RMSE=0.012) and the highest coefficient of determination (R2=95.01) were considered as an optimal model for classification of two samples stored in non-technical and technical storage. The accuracy of identification of the Agria genotype was 89.2% and 87.6%, and the accuracy of the genotype Clone 8-397009 was 92.4% and 90.3%, in non-technical and technical storage respectively.

Maintaining the quality of fruits and increasing their shelf-life are the main concerns during post-harvest processes. One of the important methods for increasing the shelf-life of fruits is the use of modified atmosphere packaging (MAP). In this study, changes in some qualitative characteristics (color, pH, TSS, texture stiffness) of apricot fruits were reviewed using MAP method at three levels of storage temperatures (ambient 22, 4 and 8 °C), three different gas mixes (first combination: 8% CO2, 4% O2 and 88% N2; second combination: 10% CO2, 15% O2 and 75% N2; third combination15% CO2, 10% O2 and 75% N2) and two thicknesses of polyethylene packages (30 and 50 µm). The data were extracted and analyzed within one week intervals by relevant tests. The results showed that the slop of color, TSS and pH changes were ascending and the slope of the texture stiffness was declining in all treatments. The highest total changes in color, TSS, pH and texture stiffness were 26.27, 7.6 (%), 3.17 and 18.04 (N), respectively, attributed to ambient storage temperature (22 °C), third gas composition (10% CO2, 15 % O2 and 75% N2) and 30 µm thickness of the package . Also, the lowest total changes of the parameters were 14.16, 2.0 (%), 1.11 and 13.49 (N) attributed to 4 °C temperature, first gas composition (8% CO2, 4 % O2, and 88% N2) and 50 µm package thickness of package.  The later considered as the best treatment.

Frostbite is one of the most important reasons for crop loss in Iran. Radiation frost due to inversion condition causes temperature drop below critical damage point which leads to extracellular ice formation inside the plant tissues. The purpose of this study was to identify the most important factors affecting radiation freezing. A region near the city of Shiraz with a chance of happening frostbite, according to previous weather reports, was selected. The temperature and wind speed were measured at the field level in the first and second half of the year, in nights expecting frostbite could be occurred. Then, the CFD simulation of heat transfer and thermal distribution was carried out using the FLUENT software, based on the time and the height of the ground surface under unstable conditions during frostbite. The numerical model was studied based on the data which obtained from the field stand. The results showed a good correlation between empirical and analytical data, so that the estimation by the root means square error method, 0.99, was obtained for experimental and simulation temperature values. Also, the results illustrated the wind blowing had a significant effect on preventing a sudden drop in temperature and frosting of products take place.

In this research, different strategies were developed to establish an agricultural service center in terms of the number and capacity of services provided. A separate location model was developed to locate agricultural service centers for each solution. For this purpose, the location-allocation model was used to develop the location models and the branch and bound algorithm to solve the models. The main purpose of these models was to minimize the cost of deploying agricultural service centers (including start-up and shipping costs to the point of service). In the model solved in this study, measures such as cost of establishment, cost of service start-up, distance between service center to customers, transportation costs and number of trips required to meet each customer's demand were considered. In this study, in order to show the practical capabilities of developed methods and models, a case study was conducted in Razan city, in Hamadan Province. After implementation of the location-allocation model, the optimal locations to establish agricultural service centers in all  villages of the area were determined separately. The results of this study can be used by national and regional managers and planners in locating agricultural service and planning centers to provide services to agricultural users.

Greenhouse structure is one of the most important factors in the greenhouse industry; enhancing its strength and decreasing the cost of its manufacturing have always been among manufacturers consideration. The aims of this study were to design an octagonal greenhouse with square cross-sectional components with enough resistance to standard loads applied by structure stress analysis methods. Design and optimization of this greenhouse involved selecting the minimum thickness of the profiles and columns. In addition, the layout of the trusses is led to minimum weight of structures per square meter. This greenhouse was designed to have nessecary structure standards and could be used in different climate conditions of Iran. In design process, initially the effects of wind load with 120 km/h were determined by using fluid dynamics calculations. Afterward, the main frame of the structure including columns, horizontal beams and trusses, were designed according to wind, snow and pendant loads. The results showed that the wieght of metal to be  used to build the structure of greenhouse was less than 8.5 Kg/m2 ,  very lower than that in similar stuctures (20 kg/m2).

In this study, three harvesting methods of sugar beet, including semi-mechanized, multi-stage mechanized and single-stage mechanized (by combine) in Khorasan Razavi province (Jovein town) were compared from the view of some technical factors. The total losses of sugar beet, including the weight of cut crown beets, damaged beets and unharvested healthy beets were 1944 kg ha-1 (i.e. 3% of yield), for for multi-stage method; for  single-stage and semi-mechanized methods this figure reduced to 542 and 454 kg ha-1 respectively. The highest increase in soil compaction in terms of cone index was measured for the single-stage method followed by the multi-stage method. The fuel consumption in the single-stage and semi-mechanized methods were 25% and 33% of the fuel consumption in multi-stage mechanized method. Energy consumption in single-stage and semi-mechanized methods was  less than what had been consumed in  multi-stage method,  24% and 34% respectively. Results also showed that single-stage mechanized (combine) harvesting method, compareing with two other methods, had relative advantages, except in soil compaction, for which some technical optimizations would be needed.

Safflower, a plant compatible with dry and semi-arid regions, is cultivated for its seeds and petals. In this study, a harvesting machine was designed and constructed for harvesting safflower (Goldasht cultivar) petals. The harvesting machine had cutting blade, vacuum motor, flexible tube, motor holder box and bag, an electric motor and a chassis for moving in the field. In order to evaluate the machine, from the point of  harvesting time and the rate of losses, a field experiment was conducted using completely randomized block design with three replications.  Experimental levels included air vacuum rate at low, medium, and high levels: 19 m/s (air velocity) and 3500 rpm (engine rotational speed); 25 m/s (air velocity) and 4000 rpm (engine rotational speed); and 36 m/s (air velocity) and 4800 rpm (engine rotational speed) respectivly;  and manual harvesting by the labors (control). The results showed that harvesting time had a significant difference at 1% level at three levels of vacuum rate. The lowest time for harvesting was recorded in third level,  the maximum time for harvesting safflower was recorded in manual harvesting method. The loss of safflower, comparing with  manual harvesting, was reduced up to 79.1%,  93.09%, and 94.9% when level 1, 2, and 3 were used, respectivly. This machine could harvest 3 to 4 kilograms of safflower petals in 8 hours