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Showing 20 results for Greenhouse
Volume 4, Issue 4 (12-2015)
Abstract
The strawberry spider mite (SSM), Tetranychus turkestani Ugarov & Nikolski, is an important pest of greenhouse cucumber in tropical and temperate regions of the world. The use of the host plant resistance is a basic method to reduce pesticide application in greenhouses. In this study, the biological responses of SSM to six greenhouse cucumber cultivars (Puia, Hedieh, Milad Ghadim, Milad Jadid, Khasib and Negin) were investigated. Non-choice tests were performed to evaluate the interaction between the host plant-mite. All tests of this study were carried out under laboratory conditions at 28 ± 1 °C, 60 ± 5% RH and 16:8 h (L: D) in a walk-in growth chamber. The results indicated that immature development time and adult longevity of SSM was significantly influenced by cucumber cultivars. The highest r, λ, and R0 were 0.275 (day-1), 1.316 (day-1) and 36.180 (offspring/generation) all of which were recorded for the mites reared on the Hedieh cultivar. No significant difference was observed for these parameters among the other cultivars. Mean generation times of T. turkestani reared on Negin (14.020 day) and Milad Ghadim (13.57 day) cultivars were significantly longer than for the other cultivars. This mite had the shortest generation time on Puia cultivar (11.43 day). In conclusion, it seems that Hedieh and Milad Jadid cultivars are the more susceptible and resistant cultivars to the SSM than the other tested cultivars, respectively.
Volume 5, Issue 4 (12-2016)
Abstract
The effects of some micronutrients (iron, zinc and silicon) and macronutrients (nitrogen, phosphorus and potassium) were evaluated on the root-knot nematode, Meloidogyne incognita and plant growth parameters of cucumber (Cucumis sativus cv. Negin) in two independent trials. Each of iron, zinc and silicon micronutrients was used at 5 mg/kg of soil, as iron sequestrene (Fe-EDDHA), zinc sulfate (ZnSO4) and sodium siliconate (Na2O3Si), respectively. Furthermore, nitrogen at 60, 120 and 180 mg/kg, phosphorus at 25, 50 and 75 mg/kg and potassium at 12.5, 25 and 37.5 mg/kg of soil were used as urea, triple superphosphate and potassium sulfate, respectively. At four-leaf stage seedlings, 8000 nematode eggs and juveniles (2 egg and juveniles/gr soil) were added around the roots. After 60-days, data analysis indicated silicon + iron, significantly reduced the number of galls/g of root by 55 and 42% compared to control, in the two experiments, respectively, but none of these treatments resulted in significant positive effects on the growth or yield of the studied cucumber cultivar. When macronutrients were evaluated, results showed that N120P25K25 (120 mg/kg of Nitrogen, 25 mg/kg of phosphorus and 25 mg/kg of potassium) and N120P50K25 (120 mg/kg of nitrogen, 50 mg/kg of phosphorus and 25 mg/kg of potassium) significantly reduced the number of galls by 96 and 81% (experiment 3) and 79 and 70% (experiment 4) when compared with control, respectively. These both treatments also improved cucumber growth parameters such as shoot dry and fresh weights, root fresh weight and fruit yield.
Volume 6, Issue 2 (7-2018)
Abstract
Aims: Greenhouse gas (GHG) emission estimates were made from agriculture sector in Jammu and Kashmir to assess the 2015 situation and future trends in emission which would help in formulating a policy for mitigation.
Materials and Methods: The Intergovernmental Panel on Climate Change (IPCC) tier-II methodology (IPCC, 1997) has been adopted for estimating methane (CH4) emissions from enteric fermentation in livestock and Tier-I methodology for other sectors of agriculture for GHG emission.
Findings: Agriculture in J and K accounted for a total GHG emission of 5.411 Tg of carbon dioxide (CO2)e in the year 2015. Source-wise, enteric fermentation was responsible for emittance of 160.233 Gg of CH4 and 1.399 Gg of nitrous oxide (N2O), manure management for 8.25 Gg of CH4 and 0.276 Gg of N2O, rice cultivation for 28.75 Gg of CH4, cultivated soils for 1.988 Gg of N2O, and residue burning for 0.405 Gg of CH4, 0.029 Gg of N2O, and 118.01 Gg of CO2.
Conclusion: Higher GHG emission from enteric fermentation was mainly due to higher population of livestock in the state. The most effective methods for reducing GHG emissions in the state would be to adjust the part of animal feed to decrease digestion time, using feed additives to reduce metabolic activity of rumen bacteria that produce CH4, and increase nitrogen-use efficiency by applying nitrogenous fertilizer or manure to crops as per crop needs and time of need.
Materials and Methods: The Intergovernmental Panel on Climate Change (IPCC) tier-II methodology (IPCC, 1997) has been adopted for estimating methane (CH4) emissions from enteric fermentation in livestock and Tier-I methodology for other sectors of agriculture for GHG emission.
Findings: Agriculture in J and K accounted for a total GHG emission of 5.411 Tg of carbon dioxide (CO2)e in the year 2015. Source-wise, enteric fermentation was responsible for emittance of 160.233 Gg of CH4 and 1.399 Gg of nitrous oxide (N2O), manure management for 8.25 Gg of CH4 and 0.276 Gg of N2O, rice cultivation for 28.75 Gg of CH4, cultivated soils for 1.988 Gg of N2O, and residue burning for 0.405 Gg of CH4, 0.029 Gg of N2O, and 118.01 Gg of CO2.
Conclusion: Higher GHG emission from enteric fermentation was mainly due to higher population of livestock in the state. The most effective methods for reducing GHG emissions in the state would be to adjust the part of animal feed to decrease digestion time, using feed additives to reduce metabolic activity of rumen bacteria that produce CH4, and increase nitrogen-use efficiency by applying nitrogenous fertilizer or manure to crops as per crop needs and time of need.
Volume 7, Issue 1 (6-2016)
Abstract
CO2 biosequestration by using algae is one of the promising and environmentally friend methods. The present study aimed at investigating the ability of Spirulina platensis in terms of growth and carbon dioxide fixation under different salinity levels and also variety of CO2 concentration. To this purpose, analysis of growth parameters including biomass productivity, specific growth rate and carbon fixation rate during the 8-day periods by maintaining the same conditions, under 3 salinity levels (3, 1500 and 34000 µs/cm) and four CO2 concentration (0.03%, 2%, 5% and 10%) were performed. this test have been performed in flat plate reactors by using pure stock of Spirulina platensis culturing in Zarrouk's medium . in all cultures, microalgae showed the highest specific growth rate during the first four days, as 0.35, 0.23, 0.24 and 0.24 d-1 in natural water, respectively. The highest carbon fixation rate and biomass production of Spirulina platensis were related to natural water (the city of birjand) under 10% CO2 concentration( 0.49 and 0.98 gL-1 d-1) that is followd by pure water of 0.45, 0.09 gL-1 d-1 and artificial sea water of 0.42 and 0.84 gL-1 d-1 respectively.the growth rate was lower in artificial sea water because of high salinity.
Volume 8, Issue 3 (6-2019)
Abstract
Abstract: Western flower thrips, Frankliniella occidentalis (Pergande), an important pest in rose greenhouses, has several generations per year, and in addition to direct feeding damage to rose flowers it also transmits tospoviruses. Because of resistance to insecticides, alternative strategies are needed to manage this pest, including trapping. In this study, trapping by sticky traps of two different colours (blue and yellow) was experimented at three different heights (at canopy level, and 20 cm above and below canopy level) on two rose cultivars (Red one and Avalanche). The numbers of trapped thrips were counted after five days. The number on the blue sticky traps, regardless of their height of placement and type of cultivar, was significantly higher than that on the yellow traps. Number of thrips on blue traps at 20 cm above the canopy was significantly higher than on blue traps at the other levels in both cultivars. In contrast, the number of thrips that were trapped in yellow sticky tarps in various heights as well as cultivars was not significantly different.
Volume 10, Issue 4 (11-2021)
Abstract
Tomato leafminer moth Tuta absoluta (Meyrick) is an important pest of the tomato plant. Light traps can play an influential role in reducing the pest population. Different light colors, three trap sizes, and three installation heights were evaluated under laboratory conditions. The light colors were white, yellow, green, red, blue, and blacklight blue (BLB). The traps, transparent containers of three sizes were 8.5, 10.5, and 14.5 cm in diameter and 15, 19, and 26 cm in height, respectively. The trap installation heights were 50, 75, and 100 cm above the plants’ canopy. The BLB color proved significantly more attractive to T. absoluta, followed by yellow and white colors. The light traps captured more males than females and more mated females than virgin ones. Both of the larger traps (10.5 cm d × 19 cm h and 14.5 cm d × 26 cm h), and higher installed ones (100 cm and 75 cm above the plants), captured a significantly higher number of moths compared to the smaller trap size and lower installation height. Accordingly, for mass trapping of moths, light traps with BLB source of light, with 10.5 cm in diameters and 19 cm in height, and installation at 75 cm above the canopy is recommended in greenhouses.
Sara Gilani, Behrouz Mohammad Kari,
Volume 11, Issue 2 (9-2011)
Volume 11, Issue 2 (9-2011)
Abstract
Solar energy can be utilized through different types of passive and active solar systems. One of the passive systems is the Greenhouse that provides different functions. In this research, heating performance of Greenhouse in cold climate is simulated, investigated, and analyzed by means of computer software. The results of this research showed that Greenhouse, in comparison with Direct Gain glazing system, decreases building heating load, despite the diminution of the direct radiation gains. In Ardebil, the optimal building orientation, in order to get the maximum solar gain and the minimum load in the heating period, is obtained in south west and west direction of the facade. The maximum heat loss and minimum solar gain occur through the north side of the building, which is considered as the most inappropriate facade direction for the Greenhouse system.
Volume 13, Issue 2 (3-2011)
Abstract
This research was conducted under greenhouse conditions to evaluate the optimum combination of irrigation and fertilizer levels to attain the best yield and quality of tomato crop. The experiment was conducted by using a split-plot design with three replicates. Irrigation levels were applied to the main plots and fertilizer levels to the sub-plots. For each experimental unit, the irrigation levels were W1=8mm/day, W2=7mm/day, W3=6mm/day , and W4=5mm/day. Fertilizers treatments varied during the growing season. For the period after transplanting till flowering, the treatments consisted of weekly applications of F1= (N1, P1, K1, respectively, 9.8, 6.13, 7.35 g /plot), F2= (N2, P1, K1, respectively,14.7, 6.13 , 7.35g/plot), F3= (N2, P2, K1, respectively,14.7, 9.19, 7.35 g/plot), and F4=(N2, P2, K2, respectively, 14.7, 9.19, 11.0 g/plot). Fertilizer levels were increased as the plants developed during the growing season. Plant height and the number of flowers per tomato plant were measured during the growing season and at harvesting time. Random samples of tomato leaves and fruits were taken from each experimental plot to determine the percentage of dry matter, total nitrogen, phosphorus, and potassium contents of fruits and leaves. Total yield during harvesting period and average fruit weight were also measured. Results indicated that irrigation and fertilizer levels had significant effects on the number of flowers per plant and W1F2 combination was significantly the most effective treatment compared to the other treatments. Plant height was not affected significantly by any treatment. The total yield significantly increased in W3F1 treatment. Average fruit weight was significantly higher in W2F3 as compared to the other treatments .The percentage of dry matter was significantly affected by the treatment W3F3 in both leaves and fruits. Total leaf contests of nitrogen, phosphorus, and potassium significantly increased in W2F4 treatment. Total nitrogen content in tomato fruits did not show any significant difference among different treatments, whereas fruit phosphorus and potassium contents significantly increased in W2F3 and W4F4 treatments.
Volume 13, Issue 4 (12-2024)
Abstract
Suitable conditions bring about a high population of pests or diseases in greenhouses. Therefore, frequent pesticide application occurs in this production system, which causes public health concerns about pesticide residue in greenhouse-grown crops such as tomatoes. Residue levels of 55 pesticides were investigated in 43 greenhouse-grown tomatoes collected from four cities in Hamadan province using modified Quick, Easy, Cheap, Effective, Rugged, Safe (QuEChERS) extraction followed by GC-MS. The residue of 8 pesticides was detected in some samples. Overall, 7% of samples had residue levels above MRLs, 33% of samples had residue at or below MRLs, and 60% of the samples had no pesticide residues. The residues of methidathion (2 samples) and fenpropathrin (3 samples) were above the MRLs (0.05 mg/kg). Non-carcinogenic probabilistic risk assessment was evaluated by Hazard Quotient (HQ) and Hazard Index (HI) based on the Monte Carlo Simulation (MCS) method. The arrangement of pesticides based on HQ ranking was methidathion > cypermethrin > chlorpyrifos > fenpropathrin > diazinon > pirimicarb > metalaxyl > malathion. HI for adults was calculated to be 0.06, and for children, 0.30 in tomato. However, as HI was less than 1, consumers were not at considerable non-carcinogenic risk.
Volume 14, Issue 1 (1-2012)
Abstract
The relationship between initial population density of rice white tip nematode (Aphelenchoides besseyi) and yield was examined on Oryzae sativa cv. Alikazemi. Experiments were conducted in greenhouse, micro-plot and field conditions. Seinhorst’s model was used to describe the relationship between nematode population density and crop yield. The parameters of the model, minimum yield (m), constant coefficient (z) and tolerance limit (T) were obtained from the experimental data. On this basis, the predicted yield was calculated within the initial population (Pi) range. To evaluate the difference between the observed yield (Yo) and the predicted yield (Yp), a discrepancy ratio (DR) was calculated. The results revealed that there was a significant correlation between mean yield reduction and nematode populations (P<0.01). At the highest initial population density, grain yield was reduced by 69%. In greenhouse experiments, the discrepancy ratio was larger than 0.03 and the predicted yield was overestimated compared to that predicted in microplot or field experiments. The model had the minimum mean of error when data were incorporated from the field experiments (ME= 0.0149). The indices from microplot and greenhouse experiments were 0.0823 and 0.2036, respectively. The relationship between nematode population density and relative grain yield fitted to the model was under field conditions.
Volume 14, Issue 6 (11-2012)
Abstract
This study was conducted to determine a relationship between energy input and yield in greenhouse basil production in Esfahan Province, Iran. Data were collected from 26 greenhouse basil producers through a face-to-face questionnaire. The data collected belonged to the production period of 2009–2010 with the following results obtained. A total energy input of 236,057 MJ ha-1 was estimated to be required for basil production. The share of electricity (75.68% of the total energy input) was the highest form of energy required. The expense was followed by plastic cover (9.69%) and chemical fertilizer spending (7.28%), respectively. The energy ratio, productivity, specific, and net energies were found out as 0.25, 0.11 kg MJ-1, 9 MJ kg-1 and -177377 MJ ha-1, respectively. A determination of the efficient allocation of energy resources was modeled through Cobb–Douglas production function. The results of econometric model estimation revealed that the impact of energies spent in the form of human labour and plastic coverings on yield was significantly positive at 1% level. Sensitivity analysis of the energy inputs revealed that the marginal physical productivity (MPP) value related to human labour was estimated as the highest.
Volume 18, Issue 4 (12-2018)
Abstract
The aim of this study is to explain the idea of forming emissions cap-and-trade market as a new market- based instrument to reduce emissions of greenhouse gases (GHGs) in the Iron and Steel industry in Iran. Thus, as the first step of formation of such market in line with joining Iran to the Kyoto Protocol and Paris conference in 2020, this study deals with the feasibility of establishment such market in the Iron and Steel industry. In this regard, 10 factories are selected as representatives of all iron and steel production firms. Currently, these producers account for more than half of nominal capacity of steel products. In addition to examine the feasibility of emissions cap-and-trade market in Iron and steel industry, a hypothetical market is constructed for selected firms, and emissions cap and trade program was evaluated in economic terms. Findings show that forming such market as economic and environmental tool is impossible, or there is no incentive for establishing this market, and the economic savings will be negligible.
Volume 19, Issue 1 (1-2017)
Abstract
Net-screen covered greenhouses operating on natural ventilation are used as a sustainable approach for closed-field cultivation of fruits and vegetables and to eliminate insect passage and the subsequent production damage. The objective of this work was to develop a real-time assessment framework for evaluating air-temperature inside an insect-proof net-screen greenhouse in tropical lowlands of Malaysia prior to cultivation of tomato. Mathematical description of a growth response model was implemented and used in a computer application. A custom-designed data acquisition system was built for collecting 6 months of air-temperature data, during July to December 2014. For each measured air-Temperature (T), an optimality degree, denoted by , was calculated with respect to different light conditions (sun, cloud, night) and different growth stages. Interactive three-dimensional plots were generated to demonstrate variations in values due to different hours and days in a growth season. Results showed that air temperature was never less than 25% optimal for early growth, and 51% for vegetative to mature fruiting stages. The average in the entire 6 months was between 65 and 75%. The presented framework allows tomato growers to automatically collect and process raw air temperature data and to simulate growth responses at different growth stages and light conditions. The software database can be used to track and record values from any greenhouse with different structure design, covering materials, cooling system, and growing seasons and to contribute to knowledge-based decision support systems and energy balance models.
Volume 21, Issue 2 (3-2019)
Abstract
The tomato (Solanum lycopersicum L.) is one of the most popular and widely consumed vegetables in the world, being also the most common vegetable within the Mediterranean diet. The last few years have seen the appearance on the market of several types of agricultural plastic developed to alter the spectrum of radiation that enters the greenhouse, sometimes filtering it and, in other cases, intensifying certain wavelength bands. The objective of this study was to evaluate the production of tomato cultivated under different covers and to analyze the profitability of the yield, under each of them. A study was carried out in six tunnel greenhouses, with an area of 100 m2 each, to evaluate the effect of different types of plastic roof, with different radiation properties. The yield of tomatoes was recorded and valued economically as a function of the mean prices of the Consejería de Agricultura de la Región de Murcia (CARM) (Department of Agriculture of the Region of Murcia) of the last years and one survey of the wholesale markets network (Mercas) and farmers, in order to know the weekly prices according to the caliber. The production costs of each of the alternatives were determined and the net present value of the yield and the annualized value were obtained. The highest annualized value was obtained with the UVA100%e cover (€24,856.04 per year), followed by UV90%e and PeTc (€18,931.49 and €16,205.53 per year, respectively). The LDe and Anti NIR covers provided the poorest results (€3,954.93 and €10,480.40 per year, respectively).
Farid Haghighat Shoar, Bahman Najafi,
Volume 21, Issue 3 (2-2021)
Volume 21, Issue 3 (2-2021)
Abstract
One of the major problems in the world is the supply of energy. Biodiesel is one of the alternative fuels and renewable energy sources. The use of B5 biodiesel in diesel fuel mixtures is common and most countries have planned to use B20 biodiesel. The use of natural gas in diesel engines and the study of the possibility of using it in high quantities is another new solution, which can reduce dependence on diesel fuel. In this study, biodiesel was produced from waste oil by transesterification process and used in two levels of 5 and 20% in diesel composition. Then natural gas was used in three levels of 60, 70, and 80% (% G / T) in the diesel engine. Engine tests were performed at full-load at 1500 rpm. In general, the test results showed that in conditions where biodiesel B20 was used in the composition of diesel fuel and gaseous fuel was used in the amount of 80% in a diesel engine, suitable conditions in terms of reducing emissions, increasing energy efficiency, and reducing economic costs were obtained; Under these conditions, compared to a conventional diesel engine, brake power, and energy efficiency increased by 8.86 and 29.06%, respectively. Also, brake specific fuel consumption, CO and CO2 were reduced by 26.5, 57.58, and 4.54%, respectively. Although the amount of NOx increased slightly, but, decreased the economic cost compared to diesel 26.47% $/kwh, so the results were valuable.
Volume 22, Issue 1 (3-2018)
Abstract
The purpose of this study is to answer the question of the factors affecting the failure of greenhouse business among failed local entrepreneurs in Jiroft villages, which is based on the theory of fundamental theory and Futuristic Approach. The view of these entrepreneurs who have experienced critical situations, general characteristics and their common personality characteristics is obtained. This research is a new study aimed at helping theoretical literature and preventing from business failures by categorizing relevant issues and registering characteristics and statements of failed entrepreneurs. Lack of studies about business failure in Iran and significant differences in this area justify the originality and need for this study. Considering these reasons, the study of unsuccessful entrepreneurs and presentation of a framework and model based on it seems necessary. Accordingly, the present study seeks to answer this key question, which are the most important factors affecting on entrepreneurs failure in the rural greenhouse sector in Jiroft.
Research method
This research is combination of (quantitative and qualitative) that seeks to identify and investigate the factors affecting on bankrupt entrepreneurs, which first identify the most important factors by using the qualitative method. Then, using the futures research method and using MICMAC software, the effect of identified factors on the greenhouse business failure factor is obtained.
The statistical population of this study is failed people including greenhouses owner in five rural areas of Jiroft in Kerman province (as the pole of greenhouse products in Iran). For this purpose, 35 samples were interviewed. Twenty-two of the interviewees were Turkish greenhouse owner, and 13 were experts of agricultural Jihad and professors.
Findings
According to the results, 90.2% of respondents were male, 73% were between the ages of 55-55 years old and 60.3% of them had literacy equivalent to a diploma. Also, about 38% of them had an area of land between 1 and 2 hectares, with an average of 10 to 50 million tooman per year. All respondents had experience in the greenhouse industry and failed in this regard. Regarding the funds provided, about 70% of them were using personal loans and borrowing from friends and relatives and the rest by using a loan from Government agencies and charities, including the Committee on Relief and Welfare Project..
Conclusion
As it has been mentioned, loss and failure is a major part of human life. The failure provides a comprehensive database for individuals to learn to create flexible capacity in difficult times. Today, the rate of businesses failure in the agricultural sector in the Iran villages has grown substantially. With regard to issues such as climate change and water and land constraints, it is essential to adopt appropriate policies for setting up agricultural businesses. The purpose of this study is to identify factors affecting the failure of local entrepreneurs' businesses in rural areas of Jiroft using basic theory and futuristic approach to determine the most important factors affecting the failure of local and small entrepreneurs. Firstly, the key factors were identified in qualitative way around six key questions and using the basic theory method. Then, in order to realize the futuristic approach, using the Delphi method and in the form of the Mick-Mac software, the identified factors from the impact or impact dimension it was tested. The results of the futuristic approach showed that most of the key strategic and key factors are influential external factors such as the lack of information and communication, the existence of economic sanctions (high customs duties, high exchange rates, and economic sanctions), lack of :union: Trade leads to natural hazards.
Research method
This research is combination of (quantitative and qualitative) that seeks to identify and investigate the factors affecting on bankrupt entrepreneurs, which first identify the most important factors by using the qualitative method. Then, using the futures research method and using MICMAC software, the effect of identified factors on the greenhouse business failure factor is obtained.
The statistical population of this study is failed people including greenhouses owner in five rural areas of Jiroft in Kerman province (as the pole of greenhouse products in Iran). For this purpose, 35 samples were interviewed. Twenty-two of the interviewees were Turkish greenhouse owner, and 13 were experts of agricultural Jihad and professors.
Findings
According to the results, 90.2% of respondents were male, 73% were between the ages of 55-55 years old and 60.3% of them had literacy equivalent to a diploma. Also, about 38% of them had an area of land between 1 and 2 hectares, with an average of 10 to 50 million tooman per year. All respondents had experience in the greenhouse industry and failed in this regard. Regarding the funds provided, about 70% of them were using personal loans and borrowing from friends and relatives and the rest by using a loan from Government agencies and charities, including the Committee on Relief and Welfare Project..
Conclusion
As it has been mentioned, loss and failure is a major part of human life. The failure provides a comprehensive database for individuals to learn to create flexible capacity in difficult times. Today, the rate of businesses failure in the agricultural sector in the Iran villages has grown substantially. With regard to issues such as climate change and water and land constraints, it is essential to adopt appropriate policies for setting up agricultural businesses. The purpose of this study is to identify factors affecting the failure of local entrepreneurs' businesses in rural areas of Jiroft using basic theory and futuristic approach to determine the most important factors affecting the failure of local and small entrepreneurs. Firstly, the key factors were identified in qualitative way around six key questions and using the basic theory method. Then, in order to realize the futuristic approach, using the Delphi method and in the form of the Mick-Mac software, the identified factors from the impact or impact dimension it was tested. The results of the futuristic approach showed that most of the key strategic and key factors are influential external factors such as the lack of information and communication, the existence of economic sanctions (high customs duties, high exchange rates, and economic sanctions), lack of :union: Trade leads to natural hazards.
Volume 22, Issue 1 (1-2020)
Abstract
Climate change has arisen due to "enhanced greenhouse effect", as a result of human activities and lifestyle. Mitigation of greenhouse gases is dependent on climate change risk perception. Therefore, the present study aimed to provide a conceptual model to determine risk perception and explore whether knowledge about causes and consequences of climate change influence individuals’ environmental attitudes, beliefs in the happening of climate change, and risk perception. The study was designed as a cross-sectional survey. The study sample consisted of 320 undergraduate students who were selected through random sampling. Structural Equation modeling showed that the relationship between knowledge of causes and consequences and risk perception was mediated by environmental attitude and beliefs. Respondents with higher knowledge about the causes and consequences of climate change are significantly more likely to consider climate change as a risk. Knowledge of causes and consequences has a direct effect on the belief that climate change is happening and on environmental attitude, and indirect effect on risk perception. Environmental attitude and belief have a significantly positive effect on risk perception. The suggested model could account for about half of the variance (49%) in risk perception. The results showed that the suggested framework is an effective tool for the prediction of risk perception.
Volume 23, Issue 3 (5-2021)
Abstract
Strawberry Anthracnose Fruit Rot (AFR) is one of the main limiting factors for strawberry production industry worldwide including Iran. Due to the restrictions associated with fungicides application across strawberry fields, their adverse effects on environment and the possible fungicides resistance development among fungal strains of the pathogen, the use of resistant cultivars is considered the most effective method for the management of this disease. In this study, reactions of 25 commercial strawberry cultivars were evaluated against the fungus Colletotrichum nymphaeae, causing strawberry AFR using fruit, leaf, and crown-based assays. According to the results of this study, the strawberry cultivars showed different reactions to the disease depending on the inoculation of their leaf, fruit, and crown with C. nymphaeae PET1 under in vivo and greenhouse conditions. However, fruit-based assay was a better indicator of AFR disease susceptibility due to nature of AFR disease caused by C. nymphaeae. Overall, ‘Blakemore’ and ‘Kurdistan’ cultivars were significantly more resistant compared with others, except ‘Aliso’, ‘Mrak’, ‘Diamant’, ‘Yallova’, ‘New Kurdistan’, ‘Mac Donance’ and ‘Ten Beauty’, respectively. On the contrary, ‘Gaviota’ cultivar was significantly the most susceptible than the rest, except ‘Camarosa’. The common commercial cultivars grown in Iran including ‘Camarosa’, ‘Paros’, ‘Pajaro’, and ‘Queen Eliza’ were categorized on the list of susceptible and highly susceptible cultivars in this study. To the best of our knowledge, this is the first study evaluating the reaction of some commercial strawberry cultivars against C. nymphaeae causing strawberry AFR.
Volume 24, Issue 2 (3-2022)
Abstract
The purposes of the study were: (i) To comparatively estimate the economic performance and productive efficiency of owner and sharecroppers in Kaş District of Antalya Province in Turkey, (ii) To find out the factors affecting the profitability of owner operators and sharecroppers, and (iii) To formulate the policy options in the light of findings. Research data were collected from randomly selected 58 owner operators and 45 sharecroppers by using questionnaire. Cluster analysis was performed to select similar sharecropper and owner operator in terms of farmers’ profile, farm income, and land size. Data envelopment analysis (DEA) was used to estimate the efficiency measures. Research result showed that labor cost of sample farm had largest share in total farm expenses. The tomato and pepper yield of sharecroppers were higher than that of owners. Net farm income of owner operator and sharecroppers per hectare were $44518.3 and $51248.8, respectively. The mean technical, allocative and economic efficiency of owner operators were 0.724, 0.729 and 0.528, respectively, while that of sharecroppers was 0.851, 0.598 and 0.509, respectively. Sharecroppers had higher technical efficiency score compared to owners, but reverse was the case for allocative and cost efficiency scores. According to the research findings, farmers can increase their technical competence, if both owner operator and sharecropper improved their skills by participating in training and extension programs. Implementing performance-based earning systems may accelerate improving farmers’ technical capability. Reorganizing of farm and controlling marketing cost may also be beneficial for increasing economic efficiency in the research area.
Volume 25, Issue 1 (3-2025)
Abstract
Aim and Introduction
The purpose of this study is to investigate the multiple effects of energy substitution from technology development on the growth rate of economic-environmental indicators in Iran's agricultural sector using the translog cost function. While one of the main goals of improving energy efficiency with the implementation of the Energy Subsidy Targeting Law in Iran was to deal with the rapid growth of fossil fuels, but looking at the energy consumption situation in the agricultural sector, it is clear that not only with the implementation of this plan, the consumption of fossil fuels has not decreased, but also increased in coparison to the time span before the plan. The increase in the annual growth rate of energy consumption has created many environmental challenges. In this way, the amount of carbon dioxide emissions, which is the most important greenhouse gas in Iran's agricultural sector, has reached from 13,682 tons to 17,639 tons in 2019. In other words, the average increase in the annual growth of carbon dioxide emissions in agricultural sector during this period was equal to 28.92%. The implementation of some energy saving policies may have the opposite effect on energy consumption and the environment as well.
Methodology
Translog cost function has been used to investigate the multiple effects of energy substitution from technology development on the growth rate of economic-environmental indicators in Iran's agricultural sector. The data used for the period 1988 to 2020 were collected from Central Bank, Iran Statistics Center, Ministry of Energy and World Food Organization.
Results and Discussion
The results has revealed that if the level of technology development increases, the substitution between capital and energy decreases and on the contrary, the substitution between labor and energy increases. The results have also shown that by reducing the amount of substitution between capital and energy, its negative effects on the economy and the quality of the environment are significant, and in contrast to the increase in the amount of substitution between labor and energy, it has a positive effect on the economy and the quality of environment. The higher level of technology development has increased the level of energy substitution.
Conclusion
The results of this research have shown that with an increase in the level of technology development on changes in energy consumption, the substitution between production factors in agricultural sector changes, which means that a 25% increase in technology development leads to an increase in energy consumption by 0.567%. In comparison, the changes in energy consumption are aligned with the development level of technology, which means that a small increase in the level of technology development leads to the rebound effects of energy. These energy feedback effects lead to an increase in substitution between capital and energy by 0.068% and a decrease in substitution between labor and energy by 0.412% compared to the initial level of technology development, but with a further increase in the level of technology development, the effect of energy feedback effects on energy substitution decreases. The results have also shown that with an increase in the level of technology development in the targeting period of energy subsidy, the amount of energy return effects increases, but at a higher level of technology development, these energy return effects decrease in the agricultural sector. Therefore, it is concluded that in the early stages of technology development, which is at a lower level, its effects on energy return are significant, but with the development of technology at a higher level, its value has gradually decreased and does not remain stable. The results have also revealed that with an increase in the level of technology development, the degree of substitution between capital and energy decreases and on the other hand, the degree of substitution between labor and energy increases, and these effects are greater at a higher level of technology development. Therefore, increasing the level of technology leads to a decrease in investment and an increase in employment in the agricultural sector at the same time. In addition, it was found that by reducing the substitution between capital and energy, the negative effects on economic indicators and environmental quality are significant. The reason that the development of the level of technology in Iran's agricultural sector has had significant negative economic effects can be seen in the exhaustion of the technology used in the production of this sector. The application of these technologies, will lead to a higher cost of production which in turn result into a lower rates of profitability in the sector. Therefore, the incentive for production, investment and job creation in this sector decreases in the long term.
The purpose of this study is to investigate the multiple effects of energy substitution from technology development on the growth rate of economic-environmental indicators in Iran's agricultural sector using the translog cost function. While one of the main goals of improving energy efficiency with the implementation of the Energy Subsidy Targeting Law in Iran was to deal with the rapid growth of fossil fuels, but looking at the energy consumption situation in the agricultural sector, it is clear that not only with the implementation of this plan, the consumption of fossil fuels has not decreased, but also increased in coparison to the time span before the plan. The increase in the annual growth rate of energy consumption has created many environmental challenges. In this way, the amount of carbon dioxide emissions, which is the most important greenhouse gas in Iran's agricultural sector, has reached from 13,682 tons to 17,639 tons in 2019. In other words, the average increase in the annual growth of carbon dioxide emissions in agricultural sector during this period was equal to 28.92%. The implementation of some energy saving policies may have the opposite effect on energy consumption and the environment as well.
Methodology
Translog cost function has been used to investigate the multiple effects of energy substitution from technology development on the growth rate of economic-environmental indicators in Iran's agricultural sector. The data used for the period 1988 to 2020 were collected from Central Bank, Iran Statistics Center, Ministry of Energy and World Food Organization.
Results and Discussion
The results has revealed that if the level of technology development increases, the substitution between capital and energy decreases and on the contrary, the substitution between labor and energy increases. The results have also shown that by reducing the amount of substitution between capital and energy, its negative effects on the economy and the quality of the environment are significant, and in contrast to the increase in the amount of substitution between labor and energy, it has a positive effect on the economy and the quality of environment. The higher level of technology development has increased the level of energy substitution.
Conclusion
The results of this research have shown that with an increase in the level of technology development on changes in energy consumption, the substitution between production factors in agricultural sector changes, which means that a 25% increase in technology development leads to an increase in energy consumption by 0.567%. In comparison, the changes in energy consumption are aligned with the development level of technology, which means that a small increase in the level of technology development leads to the rebound effects of energy. These energy feedback effects lead to an increase in substitution between capital and energy by 0.068% and a decrease in substitution between labor and energy by 0.412% compared to the initial level of technology development, but with a further increase in the level of technology development, the effect of energy feedback effects on energy substitution decreases. The results have also shown that with an increase in the level of technology development in the targeting period of energy subsidy, the amount of energy return effects increases, but at a higher level of technology development, these energy return effects decrease in the agricultural sector. Therefore, it is concluded that in the early stages of technology development, which is at a lower level, its effects on energy return are significant, but with the development of technology at a higher level, its value has gradually decreased and does not remain stable. The results have also revealed that with an increase in the level of technology development, the degree of substitution between capital and energy decreases and on the other hand, the degree of substitution between labor and energy increases, and these effects are greater at a higher level of technology development. Therefore, increasing the level of technology leads to a decrease in investment and an increase in employment in the agricultural sector at the same time. In addition, it was found that by reducing the substitution between capital and energy, the negative effects on economic indicators and environmental quality are significant. The reason that the development of the level of technology in Iran's agricultural sector has had significant negative economic effects can be seen in the exhaustion of the technology used in the production of this sector. The application of these technologies, will lead to a higher cost of production which in turn result into a lower rates of profitability in the sector. Therefore, the incentive for production, investment and job creation in this sector decreases in the long term.
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