نشریه مهندسی زراعی
سال سی و چهارم شماره 1 (پاییز 1390)

One of the problems of canola production is the lack of interest in farmers towards planting this crop. This could stem from lack of suitable planting method and the high amount of grain loss at harvest. In order to evaluate the effect of seeding methods، type of combine platforms and their interaction on canola grain yield and harvesting losses، a field experiment was conducted in Safi Abad، Khuzestan during 2007. The experiment was a split plot، arranged in a randomized complete block design with 3 replications. The seeding methods were the main plots، including two flat seeding methods with 12 and 24 cm row spacing and two row planting methods with 2 and 3 seeding lines on the row. Combine harvester platforms were the subplots، including conventional cereal platform and canola harvesting header extension. The results indicated that the seeding method significantly (P≤0. 05) affected the yield، plant density at harvest time and stem diameter of canola. The highest yield (3224. 92 kg/ha) was obtained with the flat seeding method with 24 cm row spacing and the lowest yield (2513. 66 kg/ha) was obtained with the row planting method with 2 seeding lines on the row. Type of platform significantly (P≤0. 01) affected the amount of grain loss. The grain loss of 20. 99% of the total yield (593. 03 kg/ha) was obtained by using the conventional cereal platform and grain loss of 13. 08% of the total yield (370. 48 kg/ha) was attained using the header extension.

Transmission of water through a magnetic field will cause some changes in water characteristics, affecting the overall behavior of water molecules including increasing solubility of some of compositions and decreasing water surface tension. This study was conducted with the aim of examining the effects of magnetic water on the level of remaining cations and anions of saline soil, in laboratory conditions, in a compeletly randomaized design. Soil with loam silt texture was poured in pipes with the height of 50 cm and diameter of 10 cm while the end of each pipe was closed with a filter paper and a plastic net. By passing water through the magnetic field with different intensities (6500 Gaousses in first magnetic treatment, 8000 Gaousses in second magnetic treatment), leaching was performed alternatively. At the end of the leaching experiment, the experimental soil was divided into three equal depths and amount of cations ana anions was measured. The result of chemical analysis showed that the avrage amount of the remaining sodium of the soil in the first magnetic treatment, 11.7 %, and in second magnetic treatment, 22.8 %, was lower than the controlled treatment. The avrage amount of the remaining potassium of the soil in the first magnetic treatment, 2.8 %, and in second magnetic treatment, 8.5 %, was lower than the controlled treatment. The avrage amount of the remaining calcium of the soil in the first magnetic treatment, 2 %, and in second magnetic treatment, 16 %, was lower than the controlled treatment. The avrage amount of the remaining magnesium of the soil in the first magnetic treatment, 6 %, and in second magnetic treatment, 13 %, was lower than the controlled treatment. The avrage amount of the remaining chlorine of the soil in first magnetic treatment, 14 %, and in second magnetic treatment, 14.7 %, was lower than the treatment. The avrage amount of the remaining sulfate of the soil in the first magnetic treatment, 2 %, and in second magnetic treatment, 5.8 %, was lower than the controlled treatment.

In recent years, many studies have been carried out on the biological changes of micaeous minerals and their potassium release by plant types and microorganisms. However, there is little information on the effect of organic matter (OM) on the biological transformation of biotite and its potassium release. The objective of this study was to investigate the biological transformation of biotite and its potassium release influenced by organic matter treatments.A pot experiment was carried out in a completely randomized design with factorial combination and three replicates. Growth medium was a mixture of quartz sand, biotite and OM (0, 5 and 10 gr/kg cocopeat). During 120 days of alfalfa cultivation, plants were irrigated with either a complete or a K-free nutrient solution and distilled water as needed. At the end of the experiment, the dry matter of plants was determined and K uptake was measured by flame photometer, following dry ash extraction. Mica and its weathering products were separated from the quartz sand to analyze their clay fractions using X-ray diffraction (XRD). Under the K-free nutrient solution, an increase in plant dry matter and potassium concentration in shoot occurred in pots containing biotite and organic matter as compared to those with no organic matter amendment. Significant increase of plant K uptake occurred in pots containing biotite and organic matter, as compared to those without it, under both nutrient solutions treatments. XRD data showed the transformation of biotite under both nutrient solution treatments. Under complete nutrient solution, the addition of organic matter had a negligible effect on mineralogical transformation of biotite. However, under K-free nutrient solution, the addition of organic matter significantly increased the mineralogical changes.

The current study was conducted to compare the effect of different tillage methods on wheat yield of canola-wheat rotation in dryland areas during three years (2005-2008) north of Khouzestan (Baghmalek city). Randomized block design with five treatments was applied by using four replications. Canola tillage was done with conventional method and the experimental wheat treatments were: (1) moldboard plow + grain-drill, (2) chisel plow + grain-drill, (3) moldboard plow with removed moldboard + grain-drill, (4) sweep plow + grain-drill and (5) no-till-drill. The investigated indices were percent age of organic materials, soil moisture content (W.B), wheat yield and other agronomical factors. Complex variance analyses of the three years data showed no significant difference between tillage methods and interaction of tillage methods with year in case of soil moisture content in different plant growth stages. However, the effect of years was different for this factor. Analyses of variance for different tillage methods showed that there was no significant difference between percent age of organic materials in soil depths. The complex variance analyses of data also showed that tillage methods had a significant effect on harvesting index and biological yield but the difference in grain yield and other agronomical factors was not significant. In general, the tillage methods did not affect wheat yield. Hence, the conservation methods are recommended for this condition. Regarding the harvest index, the sweep plow with 43 percent had the highest and no-till-drill with 36 percent had the lowest amount. Moreover, in biological yield, the moldboard plow with 5263 and sweep plow with 3718 kg/ha had the most and the least values respectively.

Persian lilac fruit is an inedible fruit that contains oil seeds which can be used for industrial purposes. Dehulling is a primary step which must be done on the fruit before extracting oil from them. In this research, the process of dehulling Persian lilac fruits by sodium hydroxide was investigated in two, stages, using completely randomized design method. In the first stage, the effect of 6, 9, 12 and 15% (w/w) concentration at 90°C on the duration of dehulling was studied. In the second stage, the effect of solution temperature at 25, 40, 70 and 80°C with 6% (w/w) concentration on the peeling duration was investigated. The results indicated that increasing the concentration of the solution from 6 to 15% left no major impact on drying duration, but the duration significantly decreased by increasing the temperature of the solution. The dehulling durations were 33 h and 20 min, 18 h, 2 h and 30 min and 1 h and 25 min for 25, 40, 70 and 80°C, respectively. The experiment indicated that increase of the dehulling time was positively related to the light diffraction of the solution. A model for predicting the level of light diffraction as a function of the dehulling time and another model for stating the remaining time of dehulling process as a function of light diffraction of the solution were proposed. Both models were highly fitted to the experimental data (R2>0.96).

Maintenance plays an important role in sustaining the reliability, availability, product quality, reducing risk, increasing efficiency and security. Hence being aware of maintenance costs and also replacement age of machines seems necessary. In this research the costs of repair and maintenance related to 24 AUSTOFT 7000 sugarcane harvester, being used in Imam Khomeini agro-industry co., has been studied. The research was carried out by collecting the costs of spare parts, wages paid for repairs, lubricant, grease and filters and also rate of annual functions of harvesters. Comparing the shares of components maintenance costs showed that spare parts play the most important role in repair costs six various mathematical models were tested by using computer software, in order to choose a suitable mathematical model, and finally a quadratic model was selected. The replacement age diagram, drawn by using amortization cost digits, capital interest, insurance and accumulated repair and maintenance costs showed that none of the machines had reached the replacement age until the year of research study. Therefore, replacement age of harvester was estimated to be between 9 and 11 years, by using the selected mathematical model and estimating the repair costs up to fifteenth life year of the machine.

Chemical spraying is one of the important field operations in wheat production. Farmers usually use lance sprayers, micronair sprayer and atomizer sprayer (motorized knapsack mist blower) in order to control the sunn pest when wheat plant is reach to a desire high. Sunn pest damaged on wheat plant lead to a serious problem in which when targeted plants spray with chemical, the sunn population keep protecting themselves by moving down ward to the lower parts of plant stem. The above mentioned sprayers can not be used to spray with in wheat canopies, while it has been shown that a modified atomizer sprayer is capable of targeting the lower portion of wheat canopies. In this study a conventional atomizer sprayer was manipulated with an boom type to provide a modified atomizer sprayer. Then the modified atomizer sprayer was used to compare with lance atomizer and micronair sprayers in relation to chemical spraying efficiency for controlling the sunn pest damaged in wheat production. The experimental design was setup randomized completed block design (RCBD) with three replications. Results showed that modified atomizer and lance were the first and last sprayers which had lethal effects of 92.6% and 46.5% respectively on the sunn pest at the 5% confidence level. Amount of drifting were 43.1% and 8.3% mioconair and modified atomizer sprayers respectively, at the 1% confidence level. The least amount of solution consumption (11.4 lit/ha.) and the best spraying uniformity were occurred under micronair sprayer operation.VMD and NMD were 388 µm and 286 µm for micronair sprayer respectively. When plant stand was evaluated, there was not any significant difference among sprayer systems in regard to crop lost, except for the lance sprayer which has showed 5.6% crop damaging at the 1% confidence level. Findings in the present study indicated that modified atomizer sprayer is capable of covering more spaces at the middle and bottom of plant canopies with high density (droplets / square cm) than other sprayers. Boom modified atomizer sprayer is strongly recommended as the sunn pest controller in wheat crop, when the plants reached to desirable height.