جستجوی مقالات مرتبط با کلیدواژه "یونجه" در نشریات گروه "مکانیزاسیون کشاورزی"

Today, the development of the livestock industry and feed supply is a vital issue due to the growing world population, the importance of animal protein supply, and the growing requirement for livestock products.A porous medium refers to a solid-void (pore) space that is occupied by a fluid (gas or liquid). Generally, many of these pores are interconnected which makes the transportation of mass and heat possible through the pores and this contributes to a faster transportation process through the solid matrix. Porosity is the fraction of void space to total volume.While the pores are large enough, water vapor and air in the porous media can be transported by molecular diffusion. Molecular diffusion of a gas species (e.g., vapor) in a gas mixture (e.g., vapor and air) is described by Fick’s law.

In this study, the samples were classified into four categories, including control, 3-impacts (low conditioning), 8-impacts (average conditioning), and 13-impacts (high conditioning). Each category included six samples (50-grams) that were used to measure different characteristics at different stages. All samples were weighed every two hours using a digital scale (0.001 gr precision). The leaf-stem separation force then was extracted using a texture analyzer. All experiments were repeated three times, and finally, the mean of these three repetitions was reported as the final value for the intended parameter.The geometry of the alfalfa stem was drawn in Gambit software and after meshing and applying boundary conditions; it was transferred to ANSYS Fluent software. Then, while the solver was selected, adjusted under relaxation factors were applied. In the following, mesh independency was checked and the results were reported.

To ensure numerical accuracy, the experimental data should be validated with the simulation results. For this purpose, experimental moisture losses were compared to the software results and showed a good agreement. Then, the moisture ratio curves (kinetics of drying) and force-time chart were presented.The impact of the moisture content of the tissue was evaluated on the value of force per time. Therefore, three samples of alfalfa with different relative humidity in terms of leaf-stem separation force were reported.The results of the numerical simulations were presented as two main contours: the velocity magnitude and moisture (water vapor) mass fraction. The simulation results were provided for all different modes and compared to the experimental data. Finally, errors between both results were presented in a table.

Regarding the quality and losses of the final product and comparisons between four different modes (control, 3 impacts, 8 impacts, and 13 impacts), the mode with 8 impacts was selected as the best mode. The Force-time chart illustrated two peaks due to the special multi-layer texture of the alfalfa. Regarding reducing the moisture ratio of the alfalfa as compared to the optimal, the force required to separate the leaves from the alfalfa stem was significantly decreased. Also, a significant increase in the losses was observed for impacts modes higher than 8.

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.

  Potassium is a macroelement essential for plant growth and its importance in agriculture is well understood. Potassium in clay minerals is an important source of potassium for plants in many soils. No precise information is available on the impact of lime on potassium uptake by plants. Therefore, this study was conducted to investigate the effect of lime on K availability form phlogopite mineral in alfalfa rhizosphere. This study was conducted using a completely randomized design with factorial arrangement. Alfalfa was grown in media containing a mixture of quartz sand and phlogopite, different levels of lime (0, 2, 5, 12, 25%) and under two types of nutrient solutions (complete and potassium free) with three replications for a period of six months. Alfalfa shoots and roots were harvested and their potassium concentration was measured. The Data obtained from this experiment was statistically analyzed using SAS software and comparison of means was performed with the LSD test. The results showed that both shoot and root biomass was significantly affected by lime. Potassium concentration in shoot and root significantly reduced as the level of lime increased. The amount of soluble calcium increases as the level of lime in medium increases. This is mainly due to the hydrolysis of lime which also reduces the ratio of potassium to calcium and magnesium. This causes a great decline in potassium uptake by plant. Reduced uptake from the root surfaces of the plants in medium containing lime can also be caused by calcium oxalate precipitation on the root surfaces due to the abundance of calcium ions in the the root zone. Despite the fact that the amount of potassium supplied by different media has been the same, plants were not able to absorb equal quantity of potassium. Plants grown in lime-containing pots were indirectly deficient in potassium. Indirect exposure of plant to potassium deficiency means that, despite the high soil available K level, due to physiological reasons, potassium uptake by roots and its transfer to shoots is restricted. This is attributed to the negative effects of high concentration of magnesium and calcium compared to that of potassium in soil. Potassium concentration of plant roots was less than that of the shoots. This is mainly due to higher demand for K in shoots as compared to that in roots. Besides, the ability of plants to transfer potassium from root to shoot is very high. Shoot dry weight in plants with a complete nutrient solution major than the plants with a potassium free nutrient solution. Maximum dry weight was found in plants supplied with the complete nutrient solution with no lime added. In contrast, plants supplied with potassium free nutrient solution grown in pots containing 25% lime had the least dry weight. Lower root biomass could be caused by differences in physical characteristics of the root environment due to the presence of lime. Under potassium free nutrient solution, the amount of potassium uptake was significantly influenced by the amount of lime as such that the least potassium uptake of shoot and root occurred in treatments with %25 lime. The maximum K uptake (145.84 mg/pot) was obtained in plants treated with the complete nutrient solution. There was a highly significant correlation between the shoot dry weight and potassium uptake and also between the shoot dry weight and potassium concentration indicating that the plant shoot yield increases as the K concentration and uptake increase. The results obtained in this study clearly indicate that the presence of lime in the root zone could be a limiting factor for potassium uptake by plants. Although the concentration of potassium in plants was in the sufficient range defined by standards, but potassium uptake significantly reduced as the level of lime in medium increased. The decreasing trend was more obvious in the plants treated with potassium free nutrition solution. Plants treated with potassium free nutrient solution with no lime added to the medium have been able to take up a high amount of potassium. It appears that plant roots can influence on clay minerals to release potassium by the secretion of H+. But the presence of lime in the medium could release high level of Ca2+ ions into the solution, which, in turn, could reduce the release of potassium from phlogopite and its uptake by plants. In general, in media containing micaceous minerals as the only source of potassium, the presence of lime can have a negative impact on potassium release from minerals and its uptake by plants. Therefore, in calcareous soils with high potassium storage, the level of lime should be considered when potassium fertilizer is recommended. Besides, the amendment of highly calcareous soils by organic matters is suggested to improve the soil physical properties in order to have a better K uptake.

IntroductionAgricultural productions has been identified as a major contributor to atmospheric greenhouse gases (GHG) on a global scale with about 14% of global net CO2 emissions coming from agriculture. Identification and assessment of environmental impact in the production system will be leading to achieve the goals of sustainable development, which would be achieved by life cycle assessment. To find the relationship between inputs and outputs of a production process, artificial intelligence (AI) has drawn more attention rather than mathematical models to find the relationships between input and output variables by training, and produce results without any prior assumptions. The aims of this study were to life cycle assessment (LCA) of Alfalfa production flow and prediction of GWP (global warming potential) per ha produced alfalfa (kg CO2 eq.(ha alfalfa)-1) with respect to inputs using ANFIS.
Materials and MethodsThe sample size was calculated by using the Cochran method, to be equals 75, then the data were collected from 75 alfalfa farms in Bukan Township in Western Azerbaijan province using face to face questionnaire method. Functional unit and system boundary were determined one hectare of alfalfa and the farm gate, respectively. Inventory data in this study was three parts, included: consumed inputs in the alfalfa production, farm direct emissions from crop production and indirect emissions related to inputs processing stage. Direct Emissions from alfalfa cultivation include emissions to air, water and soil from the field. Data for the production of used inputs and calculation of direct emission were taken from the EcoInvent®3.0 database available in simapro8.2.3.0 software and World Food LCA Database (WFLD). Primary data along with calculated direct emissions were imported into and analyzed with the SimaPro8.2.3.0 software. The impact-evaluation method used was the CML-IA baseline V3.02 / World 2000. Damage assessment is a relatively new step in impact assessment. The purpose of damage assessment is to combine a number of impact category indicators into a damage category (also called area of protection). To assess the damage in this study, IMPACT 2002 V2.12 / IMPACT 2002 method was used. ANFIS is a multilayer feed-forward network which is applying to map an input space to an output space using a combination of neural network learning algorithms and fuzzy reasoning. In order to enable a system to deal with cognitive uncertainties in a manner more like humans, neural networks have been engaged with fuzzy logic, creating a new terminology called ‘‘neuro-fuzzy method. An ANFIS is used to map input characteristics to input membership functions (MFs), input MF to a set of if-then rules, rules to a set of output characteristics, output characteristics to output MFs, and the output MFs to a single valued output or a decision associated with the output. The main restriction of the ANFIS model is related to the number of input variables. If ANFIS inputs exceed five, the computational time and rule numbers will increase, so ANFIS will not be able to model output with respect to inputs. In this study, the number of inputs were ten, including machinery, diesel fuel, nitrogen, phosphate, electricity, water for irrigation, labor, pesticides, Manure and seed and GWP was as the model output signal. To solve this problem and employ all input variables, we proposed clustering input parameters to four groups. Correspondingly, the proposed model was developed using seven ANFIS sub-networks. To obtain the best results several modifications were made in the structure of ANFIS networks, and some parameters were calculated to compare the results of different models. Making a comparison between different topologies the employment of some indicators was a pivotal to get a good vision of various the structures, such as the correlation coefficient (R), Mean Square Error (MSE) and Root Mean Square Error (RMSE). In addition, for checking comparison between experimental and modeled data, the t-test was performed. The null hypothesis was equality of data average. To develop ANFIS models, MATLAB software (R2015a) was used.
Results and DiscussionImpact categories including Global warming potential (GWP), eutrophication potential (EP), human toxicity potential (HTP), terrestrial ecotoxicity potential (TEP), oxidant formation potential (OFP), acidification potential (AP), Abiotic depletion (AD) and Abiotic depletion (fossil fuels) were calculated as 13373 kg CO2 eq, 19.78 kg PO4-2 eq, 2054 kg 1,4-DCB eq, 38.7 kg 1,4-DCB eq, 3.84 kg Ethylene eq, 90.64 kg SO2 eq, 0.015 kg Sb eq and 205169 MJ, respectively. The results of damage assessment of alfalfa production revealed that electricity in three categories, human health damage, climate change and ecosystem quality had maximum role, but in the resources damage category was the largest share of damage related direct emissions. The value of the climate change was calculated as 13373 kg CO2 eq. The best structure was including five ANFIS network in the first layer, two network in the second layer and a network in output layer. Values of R, MSE and RMSE for the final ANFIS in k-fold model were 0.983, 0.107 and 0.327 and in C-means model were 0.999, 0.007 and 0.082, respectively. The p-value in t-test was 0.9987 that indicates non-significant difference between the mean of modeling and experimental data. Coefficient of determination (R2) between actual and predicted GWP based on the best k-fold and C-means models were 0.994 and 0.99, respectively. The coefficient of determination for these index demonstrated the suitability of the developed network for prediction of GWP of alfalfa production in the studied area.
ConclusionsBased on the results of this study, to reduce the emissions, electricity consumption should be reduced. Adapting of electro pumps power with the well depth and the amount of required water taken for field will be a possible solution to reduce the use of electricity in order to trigger of electro pumps and thus reducing of emissions related to it. In some situations, the type of mineral fertilizer is the main determinant of emissions at the whole farm level and changing the type of fertilizer could significantly reduce the environmental impact. Comparison of GWP modeling results using two methods of k-fold and C-means revealed that C-means method has higher accuracy in prediction of GWP. Also the high quantities for the determination coefficient related to both modeling methods demonstrates high correlation between actual and predicted data.

This study examines the pattern of energy consumption in the production of alfalfa, economic analysis and modeling of energy and the production cost of alfalfa in the Bukan township. Data were collected through interviews and filling specialized questionnaires. The results showed that the consumption and production total energy were 212428 and 232567 respectively. Electricity with a share of 68 percent of the input total energy was the most consumed inputs. Indicators of energy efficiency, energy efficiency, energy intensity, net energy, net income, the ratio of benefit to cost and economic efficiency were 1.09, 14.43 Mj/kg, 0.07 kg/Mj, 20139.6 Mj, 1527.14 $/ha, 2.06 and 10.17 kg/$ respectively. Values of R, RMSE and RMSE for the final ANFIS in modeling of energy efficiency were 0.97, 0.033 and 0.2, respectively and for the final ANFIS in modeling of production cost, 0.98, 0.011 and 0.1, respectively. R2 value between actual and predicted values of Production costs and energy productivity was 0.94 and 0.97 respectively

The most advanced part of precision agriculture technology is yield monitoring of grain and non-grain crops. In this study, the horizontal pressing force of baling plunger and the angular position of the plunger connecting rod were simultaneously measured by installing a load cell and a shaft encoder on the connecting rod and plunger flywheel of a small rectangular baler, respectively. The signals of these sensors were processed in an electronic board and the output data were recorded on a portable computer for monitoring and further analysis. Before baling the harvested alfalfa from the test field, random samples were collected and weighted to obtain a referenced measure of the yield variation along the entire field. Comparing the yield data with the pressing energy and angular position data indicated a good correlation between the throughput rate of the baler and the horizontal force imparted on the baler plunger. The estimated crop yield variations were geo-referenced by using a GPS receiver. By combining the output data of the installed sensors and the positioning data, the yield map of the test field was prepared.

Precision Agriculture is continuously trying to address the sources and factors affecting the in-field variability and taking appropriate managerial decisions. One of the popular research focuses in the recent three decades has been on the development of new approaches to making yield variability maps. Advancement in development of sensors and the importance of quality factor in high value crops has motivated scientists to investigate real-time and nondestructive testing methods. This study tried to introduce and evaluate a new approach to concurrent yield mapping and to estimate some nutritional qualitative factors of alfalfa production. In this study، yield quantity was determined by measurement of added hay slice in every hay compression cycle by employing a new star wheel and integrating its output with positioning data from Global Positioning System. To predict some nutritional quality properties، measurement of specific shear energy applied on the cutting blade and compressive energy on plunger head of a hay baler in field conditions were also evaluated. The results of statistical analysis of yield quantity measurement data showed a very good correlation between the suggested approach and yield mass (r=0. 96 and R2=0. 92). The results of using specific shear energy for estimation of crude fiber and cumulative index RFV with regard to field conditions were rated as acceptable. Using specific compression energy was suitable only for estimating the dry matter. None of the suggested methods was able to estimate the hay crude protein. Further investigations at more extensive variations of quality indices and alfalfa varieties are suggested.

Moisture is one of the most important factors during and after the harvest in hay crops. Hay moisture content has a considerable impact on different stages of harvest and post-harvest such as baling, transportation, storage, etc, and therefore its role is very evident in production performance. The conventional method of moisture measurement of forage is by weighting method that is time-consuming and destructive. In this study, a capacitive sensor for real-time and continuous measurement of hay moisture content was designed, fabricated and evaluated. Alfalfa samples used in laboratory evaluation was obtained from alfalfa fields at research farm of College of Agriculture at Shiraz University, at three levels of moisture content, three levels of density and five levels of capacitor plates spacing. The results showed a significant relationship between moisture content and capacitance sensor’s output. Also temperature showed a significant effect on the sensor’s outputs.