Showing 7 results for Irrigation Water
B. Mostafazadeh, M. Kahnouji,
Volume 6, Issue 1 (4-2002)
Abstract
The emitter discharge is affected by parameters such as pressure, irrigation water temperature, manufacturer’s coefficient of variation, and emitter clogging. In order to study the effects of irrigation water temperature on emitter discharge and to determine the discharge-pressure variations and manufacturer’s coefficient of variations, an experimental trickle irrigation system was designed and studied in the greenhouse, College of Agriculture, Isfahan University of Technology. Since the sensitivity of different emitters to water temperature variations is variable, four different, widely used, types of Iranian emitters including in-line long-path emitter, gun emitter, pressure compensating emitter, and double-chamber tube were used. Each emitter was evaluated under 14 different irrigation water temperature treatments ranging from 11 to 43.5°C.
The results showed that in general as water temperature increases, the emitter discharge increases linearly in all types, except for the pressure compensating emitter in which the discharge decreases linearly. The emitter uniformity, absolute emission uniformity and Christiansen uniformity coefficient parameters were affected by emitter discharge variations. For each type of emitter under study, the changes in manufacturer’s coefficient of variations due to irrigation water temperature were different. The manufacturer’s coefficients of variations at a water temperature of about 20°C for double-chamber tube, in-line long-path emitter, gun emitter and pressure compensating emitter were equal to 5, 7, 13 and 22 percent, respectively. Moving from gun emitter to the double-chamber tube and finally to the in-line long-path emitter, the sensitivity to irrigation water temperature decreased. Sensitivity to pressure variations decreased in the order of gun emitter, double-chamber tube, in-line long-path emitter, and finally pressure compensating emitter.
Z. Banihashemi,
Volume 9, Issue 2 (7-2005)
Abstract
The dissemination of Phytophthora spp. in the surface irrigation water was studied during 1993-94 in Marvdasht area and certain other parts of Fars province. Monthly the water samples were taken along 100Km of the Kor river 22Km up stream from the Doroudzan Dam to about 80Km down stream to Mardvdasht where Sivand and Kor rivers joined. The other sampling locations includede the Maeen river adjecent to the Dam, and the Sivand river from Dashte-Morghab to Mardasht. Few samples were also obtained from Shapour and Dalaky rivers and also from Yasouj and the Sisakht regions in Khkilueh and Boir Ahmad. The water temperature, pH and EC were measured and samples were assayed on the same day of the collection. The water sample was filtered through the two layers of the cheese cloth and about 1L was placed in a plastic container (30 × 20 Cm) 2-3C deep and 100 fresh citrus leaf disks (6mm dia) were also added and incubated at the room temprature. After 48hr, disks were collected, washed, blotted dry and plated on Phytophthora were collected, washed, blotted dry and plated on Phytophthora selective medium (PARPH). At least 50 disks were used in the 5 plates for each sample. The five to 8 boiled hemp seeds were placed on each growing colony and transferred to the distilled water, after 12hr for sporangium production. The Phytophthora species were idenified by their morphological characteristic and temperature requirement. Phytophthora spp. were present in the most rivers except the Shapour and Dalaky. The predominant species were non-popilate high temperature (above 35C) species mainly P. cryptogea and P. drechsleri. In some cases P. capcisi and the other unidentified species were also detected. Phytophthora spp. were present throughout the year but the lowest population was detected during winter months. The fluctuation of the phytophthora population and the other water microorganisms in the Kor river after shiraz petrochemical complex during the growing season was very high, but sometimes reduced to zero (perhaps due to the water pollution). No Phytophthora colonies were detected in the dam lake or in the most cases in the cement canals.
J. Niazi Ardekani, S. H. Ahmadi,
Volume 10, Issue 4 (1-2007)
Abstract
In this paper, the effect of irrigation water salinity levels on seed germination, dry matter weight of seedlings at eight-leave stage, and the salt tolerance of 8 rapeseed cultivars was investigated. Relative yield reduction in saline and non saline conditions, salt sensitivity index and Van Genuchten-Hoffman methods were used to determine the salt tolerance of the cultivars. Results showed that the effect of different salt levels, cultivars and their interactions on germination and dry matter weight of seedlings was significant at 0.01(the higher the salt level, the lower the germination and dry matter). Also, using the Van Genuchten-Hoffman method, the irrigation water salinity corresponding to 10%, 25%, 50% and 90% reducts in germination and dry matter of seedlings were determined. Statistical analysis showed that a single cultivar gives different responses to salinity during growth stages and it may be tolerant in one stage, but sensitive to salinity in another growth stage. In this research, ACSN1, Falcon, and Shirali in germination stage and ACSN1, Falcon, and Cobra in seedling growth stage were salt tolerant. The three cultivars Oyerka, Global, and Ceres and the next three Shirali, Global, and Oyerka were sensitive to salinity in germination and seedling growth stages, respectively. Finally, the ACSN1 and Falcon cultivars were introduced as salt tolerant, and Oyerka and Global were considered as salt sensitive.
A.a. Shahroudi , M. Chizari,
Volume 11, Issue 42 (1-2008)
Abstract
The purpose of this study was to investigate and analyze the factors affecting farmers’ attitudinal dimensions toward participation in Water Users’ Association (WUA) by comparing two groups of farmers in irrigation networks with WUA and without it. The methodological approach was a descriptive-correlational and causal-comparative study of the survey type. The target population in the study consisted of 2551 farmers of irrigation networks in Khorasan-e-Razavi Province, Iran. Using stratified random sampling technique, 335 participants were chosen. Data were collected through a questionnaire, and analyzed using SPSS, V.13. Content and face validity of the instrument were obtained by the faculty members of Agricultural Extension and Education, Agronomy and Irrigation Departments at Tarbiat Modarres University and also specialists board of Agricultural Jihad Organization and Regional Water Joint-stock Company in Khorasan-e-Razavi Province. The reliability analysis was conducted and cronbach’s alpha values for the various sections of instrument were estimated between 0.73 and 0.86. The descriptive findings of the study showed that the majority of farmers’ overall attitude with respect to participation in WUA was at a good level. The results obtained from Pearson correlation analysis indicated that there are significant and positive relationships between such variables as education level, size of irrigated cultivated landholding, annual income, extension contacts, social capital components, water users’ perceptions regarding irrigation networks status and farmers’ participation status concerning irrigation networks management with the farmers’ overall attitude toward participation in WUA. The result of stepwise multivariate regression analysis indicated that 61.1% (R2 = 0.611) of the variance in farmers’ attitudes with respect to participation in WUA could be explained by farmers’ behaviour regarding optimum farm water management, social participation, social confidence, water users’ perceptions regarding irrigation networks status, farmers’ participation status concerning irrigation networks management. Also, significant differences were found between the two respondent groups in irrigation networks with WUA and without it in relation to farmers’ attitudinal dimensions.
S. M. Mousavi, A. Hoshmand, S. Bromandnasab, M. Yazdani,
Volume 16, Issue 60 (7-2012)
Abstract
The common method of irrigating rice in paddy fields of Iran, like most countries, is flooded irrigation. The water required in this method is too much. However, because of water shortage in recent years, and malfunctioning of irrigation systems, it is needed to use water in a reasonable way and increase water use efficiency. Therefore, it is necessary to know water loss amounts at the paddy fields. The deep percolation (DP) was measured by closed- and open-bottom rings in 4 locations, and 7 sites at each location, of paddy fields in Somae-Sara city, Guilan province. These locations were selected on the base of different physiographic units. The average DP of these locations was also monitored during plant growth season. The measurements were performed twice a week. Results showed that the rate of DP varied during the season, and could take a positive or negative value. The most important factors of these variations were the lateral seepage (from surrounding rice fields) and the high perched groundwater table in paddy fields.
S. Heydari Soreshjani, M. Shayannejad, M. Naderi, B. Haghighati,
Volume 19, Issue 73 (11-2015)
Abstract
In order to investigate the effect of different levels of irrigation on qualitative and quantitative yield and determine the corn's optimum depth of Irrigation in sShahrekord, a randomized complete block design experiment was done with 7 treatments including 40, 55, 70, 85, 100, 115 and 130 percent of soil moisture deficit and three replications in furrow irrigation. Effects of irrigation levels on yield, water use efficiency, weight of dry matter, plant height, stem diameter, median diameter, length and weight of corn were significant. Different levels of irrigation had no significant effect on seed oil and protein content, but their impact on plant fiber content was significant. With increasing depth of irrigation, stem length, grain weight and plant fiber content increased. The minimum and maximum corn yield were related to 40 and 130% of full irrigation with the yield of 43.1 and 88.1 tons per hectare, respectively. The maximum and minimum use efficiencies were 55 and 130% of full irrigation treatments with values of 16.17 and 10.1 Kg per cubic meter, respectively. The result of economic analysis showed that the water consumption is 5/582 mm, equivalent to 86% full irrigation depth.
M.m. Matinzadeh, J. Abedi Koupai, M. Shayannejad, A. Sadeghi-Lari , H. Nozari,
Volume 25, Issue 4 (3-2022)
Abstract
Using water and fertilizer management at the farm level can be increased water use efficiency and reduce the volume of drainage water, fertilizer losses, and other pollutants in farmland with deep underground drains such as Khuzestan agro-industrial Companies. In the present study, a comprehensive simulation model for the water cycle and the nitrogen dynamics modeling was used for water and fertilizer management modeling on farmland of sugarcane in Imam Agro-Industrial Company using a system dynamics approach. To reduce irrigation water consumption and nitrogen fertilizer losses, five different scenarios were considered including four scenarios of water management consist of 5, 10, 15, and 20 percent reduction in the amount of irrigation water (I1, I2, I3, and I4) compared to the current situation of irrigation in Imam agro-industrial Company (I0), and one scenario of integrated water and fertilizer management (20% reduction in the amount of irrigation water and urea fertilizer 210 Kg/ha, I4F). The results of modeling showed that the scenario of I4F caused to reduce 31, 70, 71, 70, and 85 percent of the cumulative volume of drainage water, cumulative nitrate and ammonium losses, total losses of cumulative nitrate, and ammonium by tile-drain and cumulative losses of denitrification process, respectively. Thus, the implementation of this scenario, not only saves water and fertilizer consumption but also reduces environmental pollution effectively. So the scenario of I4F (amount of irrigation water for six months 2656 mm and urea fertilizer 210 Kg/ha) is recommended for sugarcane in the Imam agro-industrial Company.
