JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2002 | Volume:2 | Issue:9|Papers Count:9

One of the surface irrigation methods is furrow irrigation which is used in different ways. One of the methods in furrow irrigation is alternate (every-other) furrow irrigation in which the furrows are irrigated alternatively. In this irrigation method water infiltrates more horizontally than vertically. Appropriate infiltration equation should be used in designing a surface irrigation method. Thus, the differences in infiltration equations for ordinary and alternate furrow irrigations should be investigated. Some of the infiltration equations are empirical and are obtained from field measurements. Some others are physically based equations and their performances should be tested in field. In this research four different methods were used to solve the Green-Ampt equation for alternate and ordinary furrow irrigations to simulate the advance phase, recession phase and outflow hydrograph. The results of simulation were compared with field data and the best method for solving the Green-Ampt equation was proposed. Among the four methods (slug, modified slug, exponential and dimensionless), for solving the Green-Ampt infiltration equation to simulate the advance, recession and outflow hydrograph in furrow irrigation, the exponential model were preferred for both ordinary and alternate furrow irrigation. The furrow spacing in ordinary and alternate furrow irrigations were different (60 and 120 cm, respectively) and was one of the input data to the model. Finally, appropriate results were obtained by the exponential model for both ordinary and alternate furrow irrigations with different furrow spacings.

Bread plays a significant role in the diet of a large portion of the Worlds population. Increasing of bread consumption, low capacity of silos and limitation of harvest time are factors that cause wheat flour consume in bakeries and factories immediately after harvesting. In maturing process of flour, its quality will improve, gluten content of dough increases and dough quality becomes better. Flour may treat with different additives for:1) Flour bleaching, 2) Improve of baking quality, 3) Improve of gluten properties, 4 )Improve of amylaze activity of flour. In addition of chemical agents, physical methods can also improve flour quality. In this study, maturing of flour by chemical and physical methods and common methods for flour storage (bag) were compared. In order to physical maturing of flour a container with mixer was designed and constructed and flour samples were stored in it for different times. Final quality of Lavash breads that prepared from these treatments were evaluated. Results showed that flour storage improve its properties. The best period for providing bread quality for flour storage in bag was 20 days were as in container with mixer was 2 days. Storage of flour in cantainer with mixer for 10 days and addition of benzoyel peroxide (45 ppm) was selected as the best physical and chemical treatment, respectively.

Hydraulic jump stilling basins are among energy dissipators which commonly designed at the downstream of spillways, chutes and sluice gates. The slab of the structure is effected by the hydrostatic pressure and uplift pressure in which during operation fluctuate. Therefore the effect of pressure fluctuation is an important aspect of slab design in which have not been considered in the past. In this study an extensive experimental program have been conducted to clearly define new design criteria. The experimental set-up consisted of a flume 20.0m long, 0.9m width. Tests were performed at the downstream of ogee spillway l.2m height. Six different discharges ranged from 30 to 170 lit/sec applied to produce different discharges numbers ranged from 5 to 12. For each test, the pressure fluctuation was recorded every 30 second resulted 108000 data. To determine the criteria for slab stability, three slabs in different sizes made of concrete were installed in the test section and each slab was tested under different hydraulic conditions. Applying the dimensional analysis, a general relation was developed. Using this relation and experimental data a formula was developed to be applicable for the design of slab at the base of hydraulic Jump stilling basins. The experimental program and results are presented. A comparison of the new method with previous method is presented also.

In arid and semi-arid regions, the most restrictive factor in producing agricultural products as well as food self - sufficiency, is water scarcity. Therefore, any attempt to improve the irrigation efficiency and decrease water loss at farm level is basic in optimizing water use and agricultural development. Investigation and recognition of different irrigation managements and their performance is essential for evaluating, improving undesirable conditions and increasing irrigation efficiency. In this research, on-farm water application efficiency of different surface irrigation systems under farmers management and different crops such as wheat, barley, corn, carrot and potatoes were measured in some parts of Isfahan province. After selection of the irrigation plots and measurement of water discharge and runoff rates, soil moisture before and after the irrigation and rooting depth, application efficiency was determined. The results showed that application efficiencies are higher than what is said to be the mean efficiency for Iran (37%) and they vary extremely with respect to soil texture, crop, irrigation method and farmers management. The average application efficiency for wheat in Kabutar-abad and Golpayegan regions was about 17.6% and 59.1 %.

The effect of sprinkler irrigation on the population of sucking pests on cotton, was studied in the Golestan province during 1996-1997. Investigations indicated that effect of irrigation systems including: sprinkler (Classic and overhead) and furrow on Sucking pests were significantly different. Population density of aphids (Aphis gossypii Glove) was much higher in sprinkler systems (classic and overhead) than in furrow treatments. Population density of Bemisia tabaci was increased 3-5 days after irrigation due to high humidity in sprinkler system (classic and overhead) treatments. The density of sucking pests including leaf hopper and Thrips, alfalfa bug, cotton mite was not significantly different. The activity of natural enemies such as: Conccinellids, chrysopids, etc. was increased due to high humidity and aphids high population Because of the scareity of water for irrigating cotton and other strategic crops, in this region and the need for efficient use of water, are recommended.

Field tractive performances of the four most commonly used tractors in Iran were evaluated. During mouldboard plowing effective parameters on tractive performance, including drive axle load and power, inflation pressure, operating speed, wheel slip and soil cone indexes of the fields were measured. By using the empirical relations suggested by Gee clough et al. (1978), tractive power loss, ratio of actual to optimum tractive efficiencies and or change of forward speed that is required for tractors to operate at optimum tractive conditions were estimated. All of the tractors tested were under-ballasted and over- inflated. The average forward speed and drive wheel slip of the tractors during plowing operations was observed to be 1.14m/sec and 14.02%, respectively. The tested tractors were wasting about 59% of their available power and average ratio of actual to optimum tractive efficienies was estimated to be. 0.56. Comparison between the four most commonly used kind of tractors in Iran showed that John Deere 3140 (0.67) had the highest tractive performance followed by Universal 650, Massey ferguson 285 and John Deere 2040, respectively (0.56,0.53. 0.49).