JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2005 | Volume:6 | Issue:22|Papers Count:12

Providing the sugar beet water requirement using new irrigation methods such as sprinkler, drip and subsurface irrigation methods is very important because of high water requirement and long growth period of sugar beet. The aims of this study were to study the effects of irrigation methods on quantity and quality parameters of sugar beet and comparison of water consumption and water ues efficiency. The experiments (C.R.B.D.) were conducted in 2001 at Kamal-abad research station in Karaj with 3 replications. The treatments were: 1) sprinkler irrigation at 30×72 plots, 2) furrow irrigation at 4×82 m plots and 3) furrow irrigation with cut-back at 4×82 m plots. Under sprinkler irrigation method, the sugar beet water requirement was stimated using Penman-Monthith method. Furrow irrigation was irrigated based on traditional farming. In furrow irrigation with cut-back, the entrance discharge was decreased to 0.7-0.8 furrow irrigation after completing advance phase. The results showed that sugar content, root impurities (K, Na, αN), white sugar content, exractability, mollasses sugar, shoot weight, root weight, sugar yield and white sugar yield parameters haven't significant difference (p<0.05) between the irrigation systems. Sprinkler irrigation had better preference over furrow irrigation because of 31% saving in water and 55% increase in water use efficiency on the basis of root weight. Use of cut-back in furrow irrigation caused no significant difference in root weight and its water use efficiency compared to sprinkler irrigation (p<0.05).

A study was conducted to investigate the effect of planting layout on sugar beet water use efficiency in a silty loam soil in Kabootar Abad research station in Esfahan, during 1999 to 2000. The treatments were as following:1-Single rows 50 cm apart; all furrows irrigated.2-Single rows 50 cm apart; alternate furrows irrigated.3-Single rows 60 cm apart; all furrows irrigated.4-Single rows 60 cm apart; alternate furrows irrigated.5-Variable spacing rows; 40 cm apart on each broad planting bed and 50 cm apart on each side of the furrow.6-Variable spacing rows; 40 cm apart on each broad planting bed and 60 cm apart on each side of the furrow.The results indicated that the most and the least amount of water consumption were noticed in treatments 2 (22693 m3 ha-1) and 6 (15300 m3 ha-1), respectively. Narrower width of ridges in the single row treatments compared to the double row ones, along with considerable clay and silt contents of soil resulted in the collaps of ridges by the shear force of water flow during each irrigation practice.These effects were augmented by lack of sufficient soil organic matter content. Collaps of ridges not only impeded the rate of water advance, but also increased runoff and deep percolation and caused poor water distribution uniformity along the furrows. During those years, the highest root yield was obtained in treatment 5 for 45.85 t/ha. Also, the highest sugar yield was noticed in treatment 5 for 6.88 t ha-1 which was related to the high root yield in this treatment. Finally, variable row spacing treatments are recommended for their higher water use efficiencies in both root and sugar yield along with ease of irrigation management in these treatments.

In order to investigate the effect of water stress at different growth stages on the yield and quality of tomato, a field experiment was conducted at Agricultural Research Center of Semnan (Shahrood), during 1999-2001 years. The split-plot design with subplots in strips and three factors were used. Tomato varieties (Mobile, Cal- j) were trans planted in two strips in each block. Main plots were different amounts of water (50, 75 and 100 percent of full irrigation), and subplots were growth stages of plant (transplanting- flowering, flowering-fruit formation, fruit formation-first harvesting and after first harvesting-end of season). Irrigation requirement was determined by class-A evaporation pan. Irrigation method was furrow irrigation. The results showed that, there was no difference between the yield of the two varieties. Irrigation levels of 75 and 50. (25 and 50 percent water stress) decreased the yield of tomato in the S2 stage (flowering-fructify). This decrease was about 13 ton per hectare (50 percent stress), but water stress had no significant effect on the yield, at other growth stages. Water levels of 50, 75,100 percent with two season average yields of 58.3, 57 and 62 ton per hectare, respectively, were not significantly different. Water stresses affected the pH and BRIX index of the samples. The pH and BRIX increased with increase of water stress, so that the maximum pH and BRIX were obtained from 50% water stress treatment. The pulp to juice ratio decreased with increase of stress. The maximum water use efficiencies were 9.6 and 9.5 (kg/m3ha) for 75% in the 4th growth stage and 50% irrigation in the first growth stage, respectively.

One of the important parameters of soil properties for application in the Plaxis, to analyse the behavior of earth structures and their failure mechanisms, is shear modulus of elasticity. An intensive geotechnical survey, field and laboratory tests were executed to estimate the values of this parameter and other soil properties in the body of dike and polder. To determine this parameter, 9 different methods were used. Because of large differences among the given values, characteristic values for each layers of soil, were calculated by using a statistical procedure. Then, calibration of stresses and strains were used to verify the characteristic values and appropriate soil test. Both of the calibrations resulted in values more than characteristic values of shear modulus which were close together. The comparison of results of calibrations with foregoing methods showed that the characteristic values were not reliable because of the shortage of data and utilization of triaxial test to determine the shear modulus was better than others.

Nowadays losses in rough rice milling process is a big problem in Iran. Wrongly operating the processing machines, including whitening apparatus, is one of the most important factors that has a remarkable effect on the grain breakage level and grain quality losses. In order to evaluate the effect of whitening machine parameters on breakage of rice grains, long-grain Khazar variety was selected. The effects of two operating variables, hub speed (in six levels: 650, 700, 750, 800, 850 and 900 rpm) and machine outlet cross-sectional area (in five levels: 615, 660, 705, 750 and 795 mm2) were investigated. Results showed that by increasing hub speed from 650 to 900 rpm, rice grain breakage increased. It was also concluded that the cross-sectional area of the machine outlet was the most important factor in grain breakage level; and increase of this variable, grain breakage level will decreased. It was shown that the highest breakage percentage corresponded to the combination of hub speed of 900 rpm and outlet area of 615 mm2; and the lowest breakage percentage corresponded to the combination of hub speed of 800 rpm and outlet area of 705 mm2.

The role of energy is the most important factor in agricultural development. In recent years, energy consumption, particularly fossil fuels, and chemical fertilizers has been increased and energy consumption per area for crop production is much more than before. The main factors of the increasing of energy consumption in agriuclutral sector are increasing of population, limitation of arable lands, the cheapness of fuel and fertilizer, and high standard of living and people expectations. In this paper, energy required in agricultural sector, particularly rice production and paddy processing to white rice, was assessed. As well as the determination of the calculation method of consumed and produced energy in rice production and effective factors on it, energy efficiency index (the rate of output energy to input energy) in two methods, traditional and semi- mechanized for rice production in Gilan province was also calculated.The required data were collected by field studies and interview and energy consumption in rice (Khazar variety) production and energy efficiency index has been also calculated and determined. The results indicated that semi-mechanized method was more efficient than traditional method. The total energy requirements for rough rice production and its processing to white rice per hectare for a common variety of rice in Gilan province, in traditional and semi-mechanized methods by considering water consumption were 72488.7 and 68633.8 MJ and efficiency index were 2.09 and 2.21, respectively. The semi- mechanized method was an efficient and low cost method, thus it was necessary to provide credit and facilities for farmers and mills. In other hands, design and development of machinery in rice production must be considered from point of view of size, farms and energy consumption.

One of the most important factors in the accuracy of a DE model is the shape of elements in the model. Currently circular shape (spherical in 3-D) is the common approach for the simulation of particulate bio-material. As the real shapes of these particles are mostly non-spherical, these models can not accurately represent the behaviour of a system comprising some real particles. In this paper a new model is introduced which can generate and simulate arbitrary non-spherical particles suitable for the simulation of fruits and vegetables which are not spherical. The results obtained from the analytical validation of the model showed 0.07% error which indicates that, formulas and the algorithms were well implemented in the model. The experimental validation of the model also showed that the model could predict the behavior of a physical system with 82% accuracy. Consideration of both the analytical and experimental validations of the model showed that on the whole the match between experiments and simulations were very good given the noise introduced by physical replication of the particle assembly and the variation in physical particle geometry and the hopper structure. To demonstrate the capability of the model some simulation examples have been presented. In these examples different particle shapes have been used in some systems typical of most agricultural system operations. The snapshots obtained from the simulations indicate that the Multi-sphere model can be a promising technique for the simulation of particulate bio-materials problems.

Paddy, is one of the principal grains, and before storage, and at the beginning of the milling process needs to be dried. A major part of grain losses occurs during drying. In order to examine the different factors affecting rice losses due to the drying process, the following research was conducted. The experimental design that used in this research was A split-split plot design having four factors of rice variety (Beenam and Kazemi), drying air temperature (40, 50 and 60ºC), final paddy moisture content (10, 12 and 14% w.b.) and depth of grain in the drying bin (0-10, 10-20 and 20-30 cm) at three replication. Effects of these factors on percentage of cracked (after drying) and broken rice kernels (after milling) were investigated. Results of the experiments showed that Kazemi variety is more sensitive to cracking than Beenam variety is. Paddy moisture content of 14% was found to be appropriate for milling of both varieties. Beside, statistical analysis of the data indicated that suitable temperature for drying of padd is 40ºC. In this way, the cracked and broken grains are reduced after milling. Amount of cracking as well as rice breakage (after milling) going up with increasing depth of paddy in the dryer bin.

In this study, the Khazar variety has been used. The statical analysis was carried out using factorial experiment by Completely Randomized Design (CRD) with three replications. The factors were initial moisture content of paddy in two level (%16.3± 0.7 and %20.5± 1.5 in wet basis) and drying method in three level (one, two and three pass drying). The percentage of brown rice, head rice, broken rice and drying time were analyzed. In the first year, paddy with moisture content %19.6, the single pass drying had %39.3 head rice (minimum amount) and three pass with %42.9 had maximum head rice. The maximum head rice was obtained with the two and three pass methods, and the minimum percent of head rice was associated with the single pass method in paddy with moisture content %15.70. The result of second year showed that multi pass (three) drying with %56.6 maximum and single pass with %52.7 minimum amout of head rice were obtained when moisture content paddy was %21.80. The minimum and maximum head rice were obtained in single and three pass drying method with %52.5 and %55.8 respectively for initial moisture content of paddy %16.20. The result of this study showed that drying procedure was not significant on milling yield. The multi pass procedure is more efficient and economic because the dryer is used only when the kernel surfaces are relatively moist, as a result of tempering. In conclusion for Khazar variety with moisture content of %19.0-%22, three pass is a appropriate method and with moisture content of %15.5-%17.0, the method of two pass drying is recommended.

Fruits and vegetables are highly perishable and require proper post harvest management, using appropriate techniques for handling, packaging and storage to minimize loss. This study was ran to minimize loss and export development of fresh fruit (apricot), and carried out in three steps. 1. post harvest process for all treatments were precooling, disinfection and removing water drop 2. packaging treatments were also: different thicknesses of films, size and heights of packages 3.storage after packaging. Condition of storage after packaging for all treatments was: cold storage with 90-95% relative humidity and -0.5ºC, curing room with 70% relative humidity and 40ºC and cold storage with 90-95% relative humidity and -0.5 to +0.5ºC. Treatments were evaluated by chemical, physical and organoleptic tests. Data compared with statical analyze. Results showed that the best treatment for apricot packaging was: Pack size 500gr, fruit high in pack 2 layer, film thickness 25µm and 100 holes on area unit.