Editorial
Volume 19, Issue 71 , January 2019
Original Article
Zahra Saedi; Mojtaba Maderi-Boldaji; Bahram Hosseinzadeh
Abstract
To manage the traffic-induced soil compaction in a field, the applied stress on soil with machinery traffic needs to be controlled below the soil bearing capacity (i.e. precompression stress, σpc) to prevent increase in soil compaction. Precompresson stress is primarily a function of soil moisture ...
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To manage the traffic-induced soil compaction in a field, the applied stress on soil with machinery traffic needs to be controlled below the soil bearing capacity (i.e. precompression stress, σpc) to prevent increase in soil compaction. Precompresson stress is primarily a function of soil moisture and secondarily soil texture. This study aimed at developing an empirical -analytical algorithm for daily prediction of soil precompression stress in a selected field at Shahrekord University. Statistical analyses showed that using the meteorology variables of each year including the precipitation of the target day and its previous day, temperature, radiation and wind velocity, daily changes in soil moisture could be well predicted (R2 = 0.85, RMSE= 3.3%). To determine the relationship between the soil moisture and precompression stress, remolded soil samples were prepared at three bulk densities of 1.15, 1.22 and 1.3 Mg m-3 and four moisture levels of 10, 15, 20 and 25% and subjected to stepwise confined compressive stress. Precompression stress was estimated at the point of maximum curvature on the void ratio- log stress curves with fitting Gompertz function. In addition, the analytical model of Elbanna & Witney (1987) was tested for extending the results to different soil textures using an empirical relation between cone index and precompression stress. The results showed that the model predicts well the variations in precompression stress as affected by soil moisture. The algorithm developed in this study can be implemented in managing the machinery traffic and predicting the trafficable days of each year.
Original Article
A. Hedayatipour; M. Younesi alamouti
Abstract
Application of minimum and no- tillage operation not only increase soil organic mater and soil fertility, but also decreases the production cost and energy consumption in wheat production. In order to evaluate the effect of tillage methods on amount of input and output energy as well energy indices and ...
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Application of minimum and no- tillage operation not only increase soil organic mater and soil fertility, but also decreases the production cost and energy consumption in wheat production. In order to evaluate the effect of tillage methods on amount of input and output energy as well energy indices and grain yield in wheat-corn rotation, a randomize complete block designe experiment (RCBD) with three replications comprising of four tratments was conducted during 2012-2013 and 2013-2014 at Research Farm of Agricultural and Natural Resources Research and Training Center of Markazi Province. Treatments were: Moldboard plow and disk as prevailing tillage method, Minimum tillage by chisel plow, Minimum tillage by combined plow and No-tillage. During course of investigation fuel consumption, consumed energy for all inputs, output energy as well as energy indices were measured. Results showed that the effect of tillage methods was not significant on yield (p<0.05). Fuel consumption in first, second, thirs and fourth treatments were 80.46, 31.46, 33 and 14/5 L/ha respectively. The highest and the lowest energy pruductivity was that of no-tillage and conventional metod with 0.075 and 0.062 Mega joule per kilogram of crop harvested. Energy consumption in conventional, chisel plow, Combined Plow and No-tillage treatments were 57670, 50849, 50949 and 47609 Mj respectively. Considering the energy indices, best treatment, was related to no-tillage method.
Original Article
saeeyed babak salvatian; kourosh majd salimi; Arzhang Javadi
Abstract
This study was carried out to determine energy consumption in various stages of processing of black tea in tea factories at Guilan province in Iran. Direct energy (thermal energy and electric energy) and indirect energy (man power, depreciation, and lubricants) were measured and evaluated in 9 tea factories; ...
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This study was carried out to determine energy consumption in various stages of processing of black tea in tea factories at Guilan province in Iran. Direct energy (thermal energy and electric energy) and indirect energy (man power, depreciation, and lubricants) were measured and evaluated in 9 tea factories; four factories using diesel fuel and the remaining five used natural gas. The results showed that approximately 70 percent of the energy consumed in tea processing is thermal energy of which 31 percent used in withering and remaining 69 percent used in drying stage. The amount of thermal energy consumed in tea factories with natural gas fuel is about 5 percent less than that in factories used diesel fuel. Electric energy has contributed 28 percent of total energy consumed in production of black tea. Withering, rolling and air heaters used 58.16, 16.58 and 11.39 percent of energy consumption in tea factories, respectively. Man power has contributed the lowest percentage of energy consumption in tea processing. Inappropriate designing, burnout ovens, lack of proper insulation, and improper structures of mechanical parts are responsible for significant energy losses at tea factories. The following steps could help reducing energy consumption in tea processing: installation of new designed furnaces, insulation the present furnaces and drying machines, and improving power supplying systems.
Original Article
M. Asghari Chenar; M. H. Rahmati; Sh. Nowrouzieh
Abstract
Gourd is one of summer crops cultivated in some provinces in Iran. Gourd Seeds contain high amounts of oil and proteins. Farmers in Iran usually use small pieces of lands to cultivate gourd. Therefore, it is not possible to apply big mechanical equipment for gourd harvesting and so for seed harvesting. ...
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Gourd is one of summer crops cultivated in some provinces in Iran. Gourd Seeds contain high amounts of oil and proteins. Farmers in Iran usually use small pieces of lands to cultivate gourd. Therefore, it is not possible to apply big mechanical equipment for gourd harvesting and so for seed harvesting. In other words, gourd seed harvesting should be done by small size ground seed harvesters. A device was designed, fabricated, and finally evaluated for mechanically harvesting gourd seeds in the workshop of Department of Agricultural Machinery at Gorgan University of Agricultural Science and Natural Resources. The effects of rotational speeds of separator cylinder (70, 65, 55 rpm), pitch angle of the cylinder (zero angle and three degrees with negative slope), and the size of meshes (1x3, 2x2 and 3x3 cm) on harvester performance were studied. In this research we used factorial experiments with 3 factors in three replications in completely randomized design. Results indicated that the effects of rotational speed and pitch angle of separator shaft on harvesting gourd seeds were significant at 5% level, and the effects of rotational speed of thresher cylinder on seed breaking were not significant. The results suggest that the best rotational speed for separator cylinder was 55 rpm and the best mesh size and pitch angle were 2x2 cm and zero degree.
Original Article
hormoz asadi; Mohammad Reza Mostofi Sarkari
Abstract
The purposes of this study were to estimate cost and benefit for owners of harvesters and to determine profitability indexes. This study was carried out in agricultural farms in Tehran province, Iran. Using split plot in a completely randomized block design with three replications, assuming that current ...
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The purposes of this study were to estimate cost and benefit for owners of harvesters and to determine profitability indexes. This study was carried out in agricultural farms in Tehran province, Iran. Using split plot in a completely randomized block design with three replications, assuming that current combines were economically acceptable. To find out if the assumption proved, we used partial budgeting technique including net present value (NPV), economic and non-economic test for substitution of harvesters under mean and maximum harvesting condition and marginal rate of return (MRR). In order to determine if differences of costs and incomes were significant; analysis of variance of variables and L.S.D. were used. Four types of combines were tested: New Holland (TC-56), John-Deer (JD-1165), John-Deer (JD-955) & Class-S 68. Economic analysis revealed that JD-955 combine, compared with other combines, had showed lowest cost and highest profits. Marginal rate of return (MRR) for substitution of JD-955 combine, instead of other combines was estimated more than 73.9%. In maximum harvesting condition, New-Holland (TC-56) combine proved more profitable. Marginal Rate of Return (MRR) for substitution of New-Holland (TC-56) combine instead of other combines was as high as 79.2%. A significant difference detected between costs of treatments, but no-significant difference between income of treatments in 5% level.
Original Article
Meisam Lesani; Saeid Minaei; Jafar Massah; Reza Salehi
Abstract
Today, development of vegetable farming is involved with the development of knowledge and equipment for production of grafted plants. This area is classified in the field of biosystems engineering and mechanics of cutting should be investigated as the first steps in this field. In this research, effects ...
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Today, development of vegetable farming is involved with the development of knowledge and equipment for production of grafted plants. This area is classified in the field of biosystems engineering and mechanics of cutting should be investigated as the first steps in this field. In this research, effects of the type of cutting blade, loading rate, oblique angle, and tilt angle were studied on two important parameters in cutting including cutting energy and maximum cutting force of tomato and eggplant seedlings. The results showed that the maximum specific cutting force and the specific cutting energy were in the range of 0.2-5.5 N per millimeter of stem diameter and 0.2-5 mJ per square millimeter of stem cross section, respectively. Statistical analysis of the data revealed that only blade type and oblique angle significantly affected the cutting parameters. Among prevalent blade types in vegetable grafting operations, razor blade requires the minimum cutting force and increasing the blade oblique angle is useful in making a smooth cut.
Original Article
Mahboobeh Roozbahani; Mohammadjavad Sheikhdavoodi; Abbas Asakereh
Abstract
Assessment of land suitability is one of the basic approaches to maximizing profits and protecting environmental resources. The purpose of this study was to determine the land suitability of Ahwaz county for cultivation of irrigated wheat using AHP Method and GIS. Ecological factors, agricultural factors ...
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Assessment of land suitability is one of the basic approaches to maximizing profits and protecting environmental resources. The purpose of this study was to determine the land suitability of Ahwaz county for cultivation of irrigated wheat using AHP Method and GIS. Ecological factors, agricultural factors and other parameters affecting wheat cultivation in Ahwaz county were determined. Soil permeability, soil texture, EC, pH, slope, accessibility to main roads and markets, and net income were selected. Data were collected by questionnaires distributed among farmers, experts, and government organizations. The results showed that economic criteria and soil characteristics had the highest weight, so that net income with the weight of 0.316 was ranked first. It has been found that average net income and benefit/cost ratio were 10.2 million rials per hectare and 0.44, respectively. The highest cost in wheat production was observed in machinery and equipment. Based on integration of GIS layers and assessment of land suitability, it was found that of total land area, 11.1% was very suitable, 32.5% was suitable, 30.4% was moderate, and 26% was unsuitable for wheat cultivation.
Original Article
Mohammad Hossein Saeidirad; Saeed zarifneshat
Abstract
A considerable part of investment on producing potato are spent in harvesting stage. This research was carried out in the form of factorial experiment with the base of randomized complete block design to compare the technical performance of potato harvesters in different planting methods. This ...
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A considerable part of investment on producing potato are spent in harvesting stage. This research was carried out in the form of factorial experiment with the base of randomized complete block design to compare the technical performance of potato harvesters in different planting methods. This research was conducted to find out the effects of planting methods (in two levels: using two-row and six-row planter machines), harvesting methods (in three levels: using combine harvester, two-row harvester, and combination of harvester and combine machines), and two levels of soil moisture content (11 and 15%) on efficiency, effective field capacity, fuel consumption, fuel and laborer energy consumption in harvesting process, and tuber losses. Results showed that the highest effective field capacity and efficiency (0.59 ha/h and 81.1%) was related to combination harvesting method. The lowest effective field capacity happened when two-row harvesting machine was used, while the lowest efficiency (65.49%) were observed when combine harvester was employed. The highest (3.38%) and lowest (0%) of products left on the field, were observed in combination method and two-row harvesting method respectively. Results showed that in all three methods, energy consumption increased when the moisture content increased from 11 to 15% ; results also indicated that the highest amount of energy consumption happened in harvesting of potato by two-row harvesting machine and when soil moisture content was 15%.
Original Article
dadgar mohammadi; Sadegh Afzalinia
Abstract
This study was conducted at Darab Agricultural Research Station in wheat-cotton rotation for four years. A complete block experimental design with three treatments (no-till, reduced tillage, and conventional tillage methods) and four replications were used. Tillage methods were compared economically. ...
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This study was conducted at Darab Agricultural Research Station in wheat-cotton rotation for four years. A complete block experimental design with three treatments (no-till, reduced tillage, and conventional tillage methods) and four replications were used. Tillage methods were compared economically. The most beneficial treatment was selected based on estimating the costs and incomes of different treatments and using the net present value method of gross margin changes. Analytical hierarchy analysis (AHP) method was also used to select the most appropriate tillage method. Results showed that there was no significant difference between tillage methods for wheat and cotton yield during most of the years that this investigation was in processing. Reduced tillage and no-till methods decreased wheat and cotton production costs, compared to conventional tillage, for 5 and 10% respectively. These conservation tillage methods, compared to the conventional tillage, also reduced fuel consumption for 60 and 77%, respectively. Conservation tillage methods increased effective field capacity of seed bed preparation and planting operations, so that time required for seed bed preparation and planting operations decreased in reduced tillage and no-till, compared to the conventional tillage, for 62 and 74%, respectively. Conventional tillage had maximum present value of gross margin (53662 thousands Rials) compared to reduced tillage (46379 thousands Rials) and no-till (38149 thousands Rials). Considering different factors in decision making, parameters such as crop yield (0.312), production costs (0.221), and water consumption (0.219) had the highest weight in farmers’ decision for selecting tillage method, and the conservation tillage methods received the highest priority for selection.
Original Article
athena keshvari; afshin marzban
Abstract
Planning for development of mechanization is one of the most important components in development of agriculture sector. Awareness about mechanization status in a region can help planners to apply the most principled planning methods to minimize regional inequalities. Cluster analysis as a planning tool ...
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Planning for development of mechanization is one of the most important components in development of agriculture sector. Awareness about mechanization status in a region can help planners to apply the most principled planning methods to minimize regional inequalities. Cluster analysis as a planning tool enables planners to classify and interpret regions in an appropriate manner based on the existing homogeneity between them. Therefore, present study aimed to zoning of agricultural needed tractor power distribution in Khuzestan province using FCM cluster analysis. For assessment of clustering function, some assessment tools including four validation functions, coefficient of division and fuzzy division entropy and also two functions based on the concept of density within clusters and clusters separation, were used. Based on the validation results, the optimal number of clusters was obtained as 2. Degree of membership higher than 40% was considered as lower limit of counties accountability in each cluster. According to this, the number of members in cluster 1 and 2 was 16 and 18, respectively. Spatial analysis of clusters showed that northern and eastern regions of Khuzestan province are located in cluster 1 and have not good status in terms of power and are in the priority from the point of view of need to tractor power distribution. Central regions to south and some parts of eastern regions are belonged to cluster 2 and their status is relatively better for access to power.
