JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2006 | Volume:7 | Issue:28|Papers Count:17

Dried fruits in Iran are mostly contaminated with mold, yeast and coliform which sometimes pass over the standard level. In order to enhance the export of dried fruits, the products should be free of any contamination. In this study, microwave and 802 fumigation methods in decontamination of dried fruit were applied. Total count, coliform, mold and yeast counts and ascorbic acid content of dried fruit samples (plum, raisin and apricot) were measured before and after the treatments. Ascorbic acid content of plum samples was found to be significantly higher than fumigation method. There were no significant differences in ascorbic acid content in the case of raisin and dried apricot samples. SO2 residue was found to be 1200 p.p.m in raisins, which was more than standard level. Results indicated that, microwave treatment could be recommended for decontamination of dried fruit products.

In order to evaluate the effects of nutrition, irrigation regimes and harvest time on the quality and shelf life of Red Delicious apple (Malus domestic), this research was carried out in Uromieh region during two years (2000-2001). Treatments were including irrigation (full irrigation, regulated deficit and removal irrigation two weeks before harvest), harvest time (138, 145 and 152 days after full bloom) and nutrition control (foliar spraying of CaCl2 (1%) and spray and dipping of fruits in CaCl2 solution (4%) at harvest time). All treatments were stored for 6 months at 0o C and 85- 90% humidity. Samples were analyzed for firmness, TSS, pH, TA, density, juiciness, medium weight and macro elements in harvest time and also every 30 days firmness, TSS, pH, TA and macro element were measured. The result showed that the effect of harvest time (in 1% level), interaction between nutrition and irrigation and harvest-irrigation (in 5% level) on firmness were significant. Effect of harvest time and interaction between 3 treatments (in 1% level) on TSS was significant. However, harvest time showd a significant effect on pH (in 5% level) and TA (in 1% level). Effect of harvest time and irrigation on the medium weight and the juiciness of fruits (in 1% level) and interaction between irrigation and harvest (in 5% level) were significant. However, their effect on density was not significant. Harvest time and interaction between nutrition and harvest time, interaction between nutrition and irrigation and interaction between three treatments on calcium content of fruits in 1% level was found the treatments to be significant. In general, overall quality of fruits at the end of storage time was the same for all. In panel test scores, top number was related to the 4thnutrition treatment, second harvest time and second method of irrigation. Therefore, it is recommended to harvest Red Delicious apple 145 days after full bloom, to apply CaCl2 solution (1%) in spray method four times, to dip fruits in 4% solution for 10 minutes and to cut of irrigation two weeks before harvest.

Wheat-forage corn is the most common rotation in irrigated land of Iran. The wheat conventionally is sown on the flat bed where the forage corn is planted on the raised beds typically 30-35cm wide with 75cm spacing between furrows. Using two different seed bed shapes for the consecutive crops is a limiting factor for implication of no-tillage or minimum tillage systems. To evaluate the possibility of applying a minimum tillage system in this rotation, hence the performance of wheat planted on raised beds need to be investigated. In a field experiment conducted at Kabootar Abad Research Center on a clay loam soil in 2002, the wheat broadcasted on flat bed was compared with grain drilling in two and three rows on the raised beds. This followed by the evaluation of the minimum tillage (reshaping the ridges used for wheat) and the conventional tillage (plowing + forming new ridges) for subsequent forage corn planted in one and two rows on raised bed. The parameters measured for comparing of wheat treatments were grain yield and yield components, biomass and the plant height. These were number of established plants, plant spacing, biomass and dry yield for the treatments applied in corn planting. The results showed that there was no significant difference in yields between the bed shapes (flat and raised-bed) used in wheat cultivation. For treatments with the equal number of seed row on ridges, the minimum tillage had no significant difference in biomass yield and stand establishment compared with the conventional tillage. It seems that the raised-bed planting for wheat and maintaining ridges for the subsequent corn can be recommended as an alternative method in wheatcorn rotation.

Man has long attemped to control the environment according to his needs. One of the phenamena with which he has always encoutered for this control is the frost damage of crops. A usefull method to protect the plant from frost is sprinkler irrigation which is based on the heat released from the formation of ice on the sprinkled plant limbs. To evaluate this method, an automated overtree sprinkler irrigation system was designed and tested on a 1700 m2 peach orchard block in Badjgah area (Fars province) to protect peach buds from low temperature damages. An adjucent 1000 m2 block was left unprotected as the control block. Achieving a good management is of the most importance in applying irrigation systems to protect plant from frost. FROTPRO, a mathematical model developed to predict proper application rates to adequately protect plants, was used in this research. The irrigation system was designed in order to supply the application rate predicted by the model using the proper climate data from the region. The system was evaluated during three frost events in spring 1382 and could successfully keep the bud temperatures above the adjusted critical level (-1.5oC) during all spring frost events. On the other hand, the flowers were lost 12 and 41.5% for protected and control orchards, respectively. Furthermore, 36% more fruit yield per tree was obtained for protected trees. The results indicated that the designed and managed sprinkler system by using FROSTPRO model was effective to protect the peach orchard in the study area.

From the environmental point of view, application of bioengineering techniques in civil projects such as landslide stabilization is given priority in recent years. In this paper, the influence of the diameter of tree roots on the increase of shear resistance of soil was investigated by means of series of in-situ direct shear tests. Thirty tests were carried out on a natural deposit CL soil containing midow roots by means of a set up designed in soil laboratory of SCWMRI. Since the existing roots in natural deposits have different diameters, a no dimensional index referred to as Root Diameter Ratio (RDR) was defined as the ratio of the mean root diameter to the maximum root diameter. The results showed, in general, the increased shear resistance of the soil due to the presence of roots was inversely proportional to the root diameters. In fact the apparent cohesion of soil increases considerably as the root diameter increases, while at the same time the internal friction angle decreases smoothly. However, the shear resistance growth stops at a given diameter, then stabilizes after a slight declination. A similar behavior was observed for the soil cohesion, while the internal friction angle showed a completely opposite behavior.

The Research was carried out in order to study the effects of different levels of water application in drip irrigation on yield and water use efficiency of Grape in Golmakan Agricultural Research Station of Khorasan in 1999. Experimental design was factorial complete randomized block with 4 replicates. The factors were levels of water application (50, 75 and 100% of plant requirements) and drip irrigation method (drip and T- Tape). Planting distances were 2 meters and rows distances were 2.5 m. Four rows including 6 trees in each one were selected for treatment. The Grape variety namely Soltani that enrooted previously was planted in March of 1999. The irrigation method was surface irrigation in 1999. But Drip and Tape were used in 2000. Water requirements of Grape were obtained from national document on water, considering shadow percent in each irrigation. Yild was not considerable during 1999, 2000 and 2001. The combined analysis results of yield in years 2002, 2003 and 2004 showed that there was no significant difference between Drip and Tape irrigation methods. But there was significant difference between different water application levels. The levels of 100, 75 and 50 % of water consumption were located in A, Band C of statistical group by yield of 8.597, 7.707 and 4.827 tons per hectare, respectively. It shows that the yield in 2 levels of 75 and 50 % water consumption decreased by 13 and 43% in comparison with the 100% water consumption level. There was no significant difference between irrigation methods where water use efficiency was considered but water use percentage showed differences at 1% level. The highest record 75% found by water use with 1.844kg Grape/1m3 water efficiency followed by 50 and 100 present with 1.720 and 1.574kg/m3 respectively. It can be reported that water use efficiency at 75 and 50% water consumption level was about 17 and 9% higher than 100%. According to the results, where shortage of water is not a problem, complete (full) irrigation and where we are facing to the shortage, 75% water use level is recommended with consideration to the yield, water consumption and water use efficiency. Two irrigation methods are both applicable.

To illustrate the impact of variouse levels of irrigation water on grain yield and yield components of rice, a study was conducted based on randomized complete blocks as a split plot design with 3 replicates and 3 treatments for 2 years. Three depths of irrigation water including: Irrigation under 3.5cm water during growth period (I1), Irrigation under 2.2 cm water during growth period (h) and 0-1.5 cm above the soil surface (I3) were considered as main plots and 8 rice varieties (Geredeh mahali, Zayandeh-rud, Sazandegi, Hasani, 67-97, 67-113, 67-47 and 67-72) as subplots in a experimental site located in Shahid Fozveh Research Station. The treatments were compared based on yield grain, yield components and water Use Efficiency (WUE). Results showed that irrigation treatments had significant effects on sterility percent, plant height, panicle length, root length, dry root weight, and WUE (p£0.01). Significant differences (p£0.01) were observed in number of days until 50% of grain ripening, root lenght, dry root weight, plant height, panicle length, 1000 kernels, sterility percent, grain yield, seedlength, seed width, number of tiller, number of grain in panicle and WUE among the cultivars. Also cultivars had significant effect (p£0.05) on number of days until complete ripening. The highest WUE was measured 0.91 kg/m3 in h for Zayandeh-rud and for 67-113 and for Sazandegi the measured WUE were 0.86 and 0.85, respectively. Considering the importance of water consumption optimization as the main scope in arid and semi - arid lands of Iran, the treatment of I3 was recommended.

Nowadays, using the technology and computer for making decision in specialized fields is one of the subjects which in the levels of industrial management and decisions has been very much noticed. In particular, the decisions which on the base of current specific conditions are required, such as making decision in the selection of primary tillage suitable equipment for a given condition of farm. Tillage consumes more energy than other agricultural operation, in this case, one mistake in optimum selection of tillage equipment, not only will waste the huge amount of energy, but also leads to serious impacts to soil, crop and other farm operation. The optimum selection of tillage quipment is affected by environmental and geographical condition factors and available facilities. In this study an attempt has been made to combine all of the important factors in making decision and to suggest a classified list of equipment that farmer can use, by using the data fusion theory (Ordered Weighted Averaging). Based on, the results obtained from software and experts's suggestions, it can be concluded that the software is compatible with scientific references by 99% confidence whereas experts's suggestions are compatible with scientific references only by 94% confidence.

The heavy reliance on pesticides to control Colorado beetle (Leptinotarsa desemlineata) has resulted in insecticide resistance and the use of higher dosages of insecticides increased environmental pollution and production costs. In the recent years, the use of pneumatic control systems to dislodge and collect insects from plants have been emerged which were successful comparatively. The major drawback in application of these machines is potato plant damage caused by tractor wheels, thus they don't have appropriate efficiency in small farms. In addition, cost of purchase and application of them is relatively high. This study was conducted to develop and evaluate a pneumatic Colorado beetle control machine with simple structure and low cost which could be used in small farms. The machine has two blowing units that place opposite and offset to each other and settled in two sides of potato plants row. By blowing airstreams from each nozzle, insects dislodged from plants and down into the opposite collecting containers. Air stream was produced by centrifugal pump of an atomizer sprayer. To evaluate the machine, experiments were conducted in the laboratory. Colorado beetle adults and larvae settled on the potato plants were exposed to horizontal airstreams of different velocities ranging from 20 to 40 m/s. Results indicated that in the laboratory conditions, airflow velocity of 40 m/s had the most effect on dislodging of insects from plants and the most collecting rate of adult insects and larvae were 67.5% and 41.25% respectively, obtained at airflow velocity of 35 m/s.

The refinement of starch hydrolysate is an important stage in glucose syrup production. This paper aimed to study the effect of operational parameters on the permeate flux and the properties of clarified syrup. Glucose syrup (DE = 41) obtained from corn starch using acid conversion method. A polysulphonic Membrane with 30kDa molecule weight cut-off (MWCO), spiral module and 0.75m2 surface area was used. The optimum transmembrane pressure for syrup with the concentration about 40 Brix and 10 or 12LPM velocity was respectively 724 and 793kPa. Decreasing the concentration of syrup led to an increase in optimum transmembrane pressure. The tangential velocity had a linear effect on the increase of permeate flux. Clarified syrup has the good quality aspects such as turbidity (less than 0.2 NTU). Ultrafiltration can reduce the color of hydrolysates. Results show that decolorization effect of membrane increases with the increase of transmembrane pressure. Also ultrafiltration can reduce the protein content of syrup about 79.4% but it has no effect on the sulphated ash content.

According to needs, many models have been developed for simulation of crop yields. MEDIWY (Model for Estimation of Dryland and Irrigated Wheat Yield) is one of these models which presented for simulation of yield for Adle winter wheat under irrigated and rainfed conditions in Badjgah area. This model has been developed in Irrigation Department of Shiraz University. However, its extensive application requires model evaluation for different wheat varieties under different climatic conditions. In present study, the MEDIWY model was evaluated and modified for simulation of Sabalan winter wheat under irrigated and rainfed conditions in Maragheh area (Eastern Azarbayejan province) for three consecutive crop years (1378-79 to 1380-81 , H.S.). The simulated and measured grain yields were compared. It was indicated that the simulated grain yield under irrigated condition was satisfactory, but it was not able to simulate the grain yield under rainfed condition. Therefore, the coefficient of soil readily available water was changed from 0.65 to 0.90 for rainfed grain yield simulation. The modified MEDIWY model properly simulated the grain yield under rainfed condition. Furthermore, it was found that this model was not able to simulate the grain yield for crop years with high rainfall during the growing season in spring and summer due to plant disease infection. The amount of this rainfall was more than 140 mm and the model was modified for this parameter. Therefore, the modified model for excess rain was able to simulate the grain yield of Sabalan winter wheat under irrigated and rainfed conditions in Maragheh area even for years with high rainfall during the growing season in spring and summer. Further, modified model was validated by data obtained for Alamoot cultivar and the results were satisfactory.

Watermelon is the largest fruit in volume and mass; these characters cause many problems in its transportation and handling. This research performed to determine and compare physical and mechanical properties in different sizes and varieties of watermelon in order to obtain parameters usable in transportation, handling, harvest and storage. A statistical factorial experiments in the form of completely randomize design (2x3) was used to determine the physical properties of watermelon such as mass, volume, dimensions, density, spherical coefficient and geometric mean diameter. Another statistical factorial experiments in the form completely randomize design (2x3x4) was used to determine mechanical properties of watermelon such as stress, strain, elasticity modules and toughness. The results were analyzed by SPSS V.9 software. It is found that increasing watermelon size tends to decrease spherical coefficient and density. The smallest size of Charleston gray had maximum density (0.96gr/cm3) while the largest size of Crimson sweet had minimum density (0.93gr/cm3)between treatments. Comparing mechanical properties in two varieties of watermelons showed that the mechanical properties of watermelons are significantly affected by size and variety.