JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2001 | Volume:2 | Issue:8|Papers Count:8

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. Appropriate infiltration equation should be used in designing a surface irrigation method. Thus, the differences in infiltration equations for ordinary and alternate furrow irrigation should be investigated. Some of the infiltration equations are empirical and are obtained from field measurements. Therefore their parameters should be determined for ordinary and alternate furrow irrigation. In this research empirical Lewis-Kostiakov infiltration equation for ordinary and alternate furrow irrigation was calibrated in a Daneshkadeh soil series at Bajgah area with different inflow rates of 0.4,0.8 and 1.1 Lis. This research was conducted in the field laboratory of the Irrigation Department, Shiraz University in furrows with length of 100 m.Two methods used for Calibration of infiltration equation: first method used from advance data only and second method used from advance and storage phase data.By using two methods the parameters of Lewis-Kostiakov infiltration equation for ordinary and alternate furrow irrigation were determined for various inflow rates.Comparison of the results from different methods for determining the parameters of infiltration equations, showed that the second method was more appropriate.

An important rice variety of Gilan province (Binam), with 20.6% initial moisture content was chosen to be used. Factorial experiment based on completely randomized block design was adopted to analyze drying process with three factors: drying temperature (at five levels of 30, 40, 50, 60 and 70°C), drying air velocity (at two levels of 0.5 and 2 m/s) and moisture content of paddy at the end of drying process (at two levels of 10.5% and 14% on wet basis). The germinative ability of the samples was measured by two experimental methods: germination and active embryo tests. The results showed that germinative ability decreased with and increase in air velocity, decreasing final moisture content and increasing drying temperature, especially at temperatures above 50°C. It was also found that the negative effect of high temperatures on germanation could be compensated with low air velocity or with prevention of too much reduction of final moisture content.The results indicate that among three factors of the experiments, air temperature has the most distinctive effect on germinative ability. Good correlation was found between germination and active embryo tests (r=0.97), Therefore both experimental tests can be used to determine germinative ability with low error rate.

Iran is one of the Experienced countries in growing orchards. Traditionally, these orchards are irrigated by surface methods. Due to water scarcity in most parts of Iran, for obtaining higher water use efficiency, application of modern irrigation systemes would be unavoidable. In this study, five irrigation methods including: surface irrigation, bubler, double drip system, spagetti and microjet were tested in aged apple garden located in Semirom region in Esfahan.The systems were compared based on production index, fruit quality, canopy cover and volume of applied water. The study was conducted in a randomized block design with 3 replicates for 3 years. The results indicated siginificant differences among the treatments, in which the double drip system had the maximum yield, while the surface method showed the minimum one. The maximum and minimum trunk diameters , were observed in treatments irrigated with spaghetti and surface methods, respectively. Trees irrigated with double drip system and bubler method had the maximum and minimum height, respectivly.For the main shoot diameter, shading area, and shoots vegetative growth, no significant differences were detected among the treatments. Regarding other vegetative Parameters such as crop yield, qualitative characteristics of fruit, color uniformity, marketing, storage period, sugar content, acidity percentage, and volume of water consumed, double drip and microjet treatments showed the best results.

There are many factors determining qulitative and quantitative characteristics of raisin. Total soluble solid (TSS) of fruit juice, function of fruit growth and development, plays a significant role in determining quality, yield and production efficiency of raisin. This investigation was carried out to study the effects of TSS content on changes of raisin characteristics and production efficiency, and also determining acceptable minimum percentage of TSS for producing favorable raisin with high efficiency, in one of Takestan vineyards on Sultana grape, during 1399- 2001. In order to obtaining the same fruits with different TSS, fruits harvested from the first of Shahrivar with 10-day intervals in RCBD with four replications. Each experimental unit contained four plants. In each date, samples (10-12 kg) were harvested from two central bushes of plot and %TSS, berry weight and volume, raisin color, marketing value, 50-seed weight and amount of recoverable raisin were measured. Samples were classified to ten groups according to TSS content, which. each group contained four samples with nearly the same %TSS (as the four replications).Results showed that higher %TSS was together with significant increase of quality, color, and 50-seed weight and raisin production efficiency. %21 is recommend able as minimum percentage of TSS, for producing favorable raisin with high efficiency.

The Performance of a center-pivot irrigation system was evaluated. The system was located at station # 37, section 4 of Pars Agro- industry company in Moghan. The system irrigated 47.26 hectares of a loamy soil land, planted weed corn in 2000. The object of this study was to investigate application design problems of the system, in order to improve irrigation water use efficiency. Evaluation factors: Potential Application Efficiency of Low Quarter (PELQ), Application Efficiencey of Low Quarter (AELQ) and Distribution Uniformity (DU), following FAO and ASCE standards, were calculated using field data analysis. Field data including soil moisture content before irrigation and after 24-48 hrs., root depth rotating speed of the system and water distribution pattern were measured and recorded during the irrigation season. To observe water distribution pattern, containers were set up on four radial rows under the system in a six-meter spacing.The averages of PELQ, AELQ and DU were found 38.00,37.07 and 49.01 percent, respectively. These values, according to the above mentioned standards, are considered- to be low, indicating that the performance of the system was far from ideal.Based. on the analysis of the results, recommendations were made as to adjustment of rotating speed, application frequencies, water supply in proportion to crop requirements etc. for improving application design of the system.

One of the basic requirements in research on agriculture and natural resources is climatic data. Most of basins in Iran have not any weather station and because of insufficient data and short observed records, the estimation of data for larger area is difficult. Moreover, most times one or more methods are selected regardless of considering other methods. The application of interpolation methods for estimation meteorological data has not been widely used in Iran. In this research, the three following methods have been used: Kriging, Weighted moving average (WMA), and Thin plate smoothing splines (TPSS). The results showed that TPSS was showed the most appropriate for estimation of monthly and annual evaporation. Also, The TPSS method showed the most precise results for estimation of both monthly and annual air temperature. In addition, the effect of climate scheme on the accuracy of temperature and evaporation was investigated. Based on the results, the climate scheme had a positive effect on temperature, but no effect on evaporation was observed.