جستجوی مقالات مرتبط با کلیدواژه « energy » در نشریات گروه « منابع طبیعی »

The objective of this study was to measure the energy efficiency and its effective factors in canola production in Tabriz county. In this regard, the data collected from canola farmers in the crop year of 2021-2022. Then were used to estimate stochastic frontier production function (based on energy input and crop) along with the function of inefficiency and the technical efficiency of farms determined. In the following, energy ratios including energy efficiency, and net energy productivity were calculated. The estimated translog production function (in terms of energy and crop energy) showed that the mean energy efficiency was 71.17 percent and the factors of age, product insurance, education level and the number of plots affect the efficiency. Energy indexes, including energy efficiency and energy productivity were calculated as 2.32 and 0.09 kg / mj, respectively. Considering the positive effect of education and age of farmers on efficiency, it is recommended to pay attention to educated and experienced producers of canola. In addition, reducing the number of planting plots of canola yield will caused to increase energy efficiency. Finally, considering the direct relation between the estimated energy efficiency and the SFA approach and the efficiency and productivity index in future studies, both approaches will be used to make decisions with more certainty about the conditions governing the production and efficiency of the product.

The objective of this study was to evaluate the energy efficiency and environmental ramifications of alfalfa and silage barley production in Qazvin province, Iran, under different irrigation systems. The outcomes showed that subsurface irrigation utilized a total input energy of 95667.71 MJ ha-1, whereas surface irrigation had a positive impact on alfalfa production with a total input energy of 902683.07 MJ ha-1. Flood irrigation had the highest input energy of 110973.39 MJ ha-1 and the lowest output energy of 523644.31 MJ ha-1 compared to other irrigation methods for barley. The primary contributors to On-Farm emissions were diesel fuel and chemical fertilizers, but subsurface irrigation systems had lower levels of diesel fuel related pollutants due to reduced usage, while flooding irrigation systems had higher levels of such contaminants. Based on the finding, silage barley cultivation was a better option than alfalfa cultivation in terms of energy consumption and environment. Based on the finding, silage barley cultivation was a better option than alfalfa cultivation in terms of energy consumption and environment.

Energy consumption has increased directly and indirectly in the agriculture sector to meet the needs of growing population. Regarding the scarcity of production resources including energy, the present study aimed to measure the technical efficiency of rainfed wheat farms and its effective factors. For this purpose, the required data collected from 217 farmers in Ahar county and input and output (wheat) quantities converted to energy equivalents. The results of estimating the translog stochastic frontier production function along with the inefficiency function showed that the energy factors of labor, pesticides and machinery have a significant effect on output energy of wheat. Meanwhile, factors such as distance from fields to village, land slope, number of rainfed wheat farms and the cultivated land of wheat are affective on inefficiency use of energy. The mean of energy efficiency of wheat producers was 51%. Therefore, the output energy can increase by 49 % if efficient use of input energy and principal component of field operation followed. Considering the existence of suitable methods for improving energy efficiency is recommended with increasing information of farmers, holding extension courses and applying modern technologies

Sesame harvesting is mainly done manually due to the use of dehiscence cultivars and high seed loss in mechanized harvesting. In recent years, with the introduction of non-dehiscence cultivars, the mechanized harvesting of sesame has become possible. In this study, the traditional and mechanized methods of sesame harvesting were investigated in terms of seed loss, cost, energy consumption and time required for harvesting. Data of traditional system were collected from farmers in Dezful, Shush and Andimeshk counties and data of mechanized system were obtained from Shahid Rajaei Agricultural production Company in Dezful. In the mechanized harvesting, the seed loss were measured in three amounts of seed planting rates (5, 10, and 12 kg/ha) and three ground speeds of the combine harvester (1.5, 2 and 2.5 km/h). The average seed loss in the combine was 4.83%, of which more than 94% was related to the combine header. The findings showed that with the increase in plant density, seed loss in combine is greatly reduced. The average labor in traditional harvesting was 315 labor-hours, which was 98 times more than in the mechanized method. The average cost of harvesting in traditional and mechanized methods was calculated as 49.4 and 2.7 million rials/hectare in 2019, respectively. The input energy in traditional and mechanized harvesting was 2088 and 1510 MJ/ha, respectively, that in the traditional method, human energy was the major part of the input energy. The results showed that the use of non-dehiscence cultivars and mechanized harvesting allows the development of sesame cultivation.

Tillage is one of the most important field operations in agriculture. For this operation, it is essential to determine suitable working conditions. According to the results of researches on tillage, this operation is always associated with high energy consumption. For this reason, it is necessary to choose the appropriate forward speed and plowing depth of tillage tools in terms of optimal energy consumption. In this research, by using the management method TOPSIS, the appropriate speed-advancement and plowing depth have been investigated according to the parameters of energy consumption. In this research, three types of primary tillage machines (Moldboard plow, disc plow and chisel plow) at 3 different forward speeds (3, 4.5, 6 km/h) and different depths (15, 20 and 25 cm) was selected and performed in loamy clay soil with a moisture content of 7%. The parameters of energy consumption include drawbar power (kW), fuel consumption (l.ha-1), traction efficiency (%) and energy efficiency (OEE) (%), mechanization capacity (kW.h.ha-1) and specific traction (kN.m-1) was measured. The results showed that for the moldboard plow and disc plow 4.5 km/h forward speed and 25 cm depth and for the chisel plow, 6 km/h forward speed and 15 cm depth were the best conditions in terms of energy consumption. In most of different working speeds and depths, chisel plow was advantageous in terms of energy consumption, compared to disc plow and Moldboard plow, according to TOPSIS analyses.

The purpose of this study was to determine the energy consumption, production costs and greenhouse gas emissions in white radish production in Ilam province, Iran. Data were collected through face-to-face questionnaires from 63 farmers in the studied region in 2018. The results showed that the input energy was 12105 MJ ha-1, of which the highest share was related to gasoline, nitrogen fertilizer and diesel fuel with 34.5, 29.7 and 13.75 percentages, respectively. The lowest input was belong to seed with 0.01%. The total greenhouse gas emissions in white radish production was 520.88 kg carbon dioxide per hectare, of which gasoline, manure, nitrogen fertilizer and diesel fuel constitute the highest input with 39.78, 33.11, 13.12 and 10.23 percent, respectively. The result of analysis using Cobb–Douglas production function showed that the effect of labor work, irrigation water, machineries, chemical fertilizers, manure and seed on yield was positive and the effect of pesticides, diesel fuel and gasoline was negative. The economic analysis revealed that the profit-to-cost ratio was 2.93.

In this study, the amount of energy consumption and its efficiency for pomegranate fruit production in areas of Mahwalat city of Khorasan-Razavi, was investigated by data envelopment analysis approach. The information required for the study was completed by completing 80 questionnaires among pomegranate orchard farmers in 2017. According to the data collected from the field study on how to perform agricultural operations on this crop, the amounts of input and output energies were calculated and their efficiency was evaluated. The results showed that the energy of two inputs of fuel and nitrogen fertilizer with 44.15 and 29.64%, respectively, were the most consumed energy inputs in production. The average production of pomegranate in Dughabad village was 7043.75 kg / ha and the total energy consumption in pomegranate orchards was 13383 MJ / ha. The results also showed that with decreasing the use of chemical fertilizers and increasing the use of machinery in pomegranate orchards, the average efficiency increases. Therefore, it is recommended to use less chemical fertilizers in pomegranate orchards. It is also suggested to increase the use of agricultural machinery to save time and increase efficiency.Keywords: Energy, Performance, Pomegranate, Mahvelat city, Consumption Pattern

One of the applications of solar systems in agriculture is in product dryers. Drying of agricultural products after harvesting stage is one of the major units operations in order to increase the length of storage and maintain its quality. The purpose of this research is to model and design a solar flat plate air collector in order to supply the energy need of a grain drying warehouse with an area of 36 square meters and assumed capacity of 1.5 tons of corn for each loading. The amount of the required energy to reduce the moisture content of corn (from 23% to 13%)  was calculated as 961.1 MJ/1.5 tons. To provide this amount of energy, two types of collectors, type A (without obstacle) and type B (with obstacle installation in the air channel) were analyzed by Matlab code. The use of obstacles in the air channel increased the thermal efficiency of the collector from 37 to 55 percent in the single cover type and from 48 to 62 percent in the double cover type. The average of the best tilt angle of the collector installation was recorded at 27.5 degrees in south direction. The required energy supply time (961/1 MJ/1.5 tons) for a solar system with an area of 30 square meters, for A and B type collectors was calculated as 41.25 and 27.69 hours in single cover and, 31.14 and 24.1 hours in two cover, respectively.

In this study, the energy consumption of button mushroom production in Khorasan Razavi province (Iran) was calculated. Data were collected from 13 production units with face to face questionnaire method. The production units were divided into three levels (categories) based on their area as: smaller than 7,000 m2 , 7,000-20,000 m2 and larger than 20,000 m2 . The results showed that the energy input per areafor the production of button mushroom was 2,480.86 MJ.m-2 . In between the the different energy sources, the highest share of energy consumption belonged to fuel (79.76%) followed by wheat straw (12.40%) and machinery (5.59%). The Cobb-Douglass model results revealed that the wheat corn and poultry manure had the highest regression coefficient (1.30 and 0.77) among the other inputs (for button mushroom and by-product compost production). Furthermore, the effect of poultry manure input on button mushroom yield was significant at the level of 5%. The production units with cultivated area of 7,000-20,000 m2 consumed the least amount of energy and had the highest energy ratio.

Limitation of fossil fuels and the growing awareness of the detrimental environmental consequences resulting from greenhouse gas emissions have reinforced the importance of biomass as an energy resource. The conversion of rice straw and rice bran into briquettes as solid fuel is an important issue. The aim of this study was to determine the physical and chemical properties of rice straw and rice bran, and also the energy required for milling rice straw by hammer mill. Particle size distribution and particle density were determined for the milled straws, produced by four sizes of hammer mill screens at six particle size levels. FTIR test was carried out for determination of rice straw factor groups and distinction relation test. The required energy for grinding decreased with increasing of moisture content of the materials and the size of hammer mill screen. Normal distribution was observed for particle sizes of rice straw, grinded at 2 and 4 mm hammer mill screen sizes. The friction angle and bulk density of rice straw decreased with increasing the rice straw particle size. For the friction surfaces, the highest and lowest friction angles belonged to iron and aluminum surfaces, respectively. Based on the results of FTIR, during the burning process, lignin was fully destroyed in the oxidation reaction.