Showing 388 results for Water
M Navabian , A Liaghat ,
Volume 14, Issue 51 (4-2010)
Abstract
Environment pollution is an important problem in the world. In agriculture irrigation, drainage and fertilization activities cause water resource and environmental pollution by effecting on solute, nutrient and sediment transport. Combined methods of water and nutrient management could consider in pollution transport controlling that reducing runoff and deep percolation, providing opportunity for solute infiltration, reducing sediment transport even economic and easy usage. In this research, affect of two different management in irrigation (cutback and continues) and fertilization (solid and fertigation) on nutrient loss was evaluated. Comparing nitrate, phosphor and potassium loss in different management explicate cutback flow with no uniform solid distribution of fertilizer is more useful to prevent nutrient loss. Because of similar results, increasing in fertilizer distribution in furrow length and easy usage between nitrate losses in six managements, show cutback flow with three proceeding solid, fertigation and fertigation (with 1/4, 1/2 and 1/4 ratio) fertilization was recommended replacement of cutback flow with three proceeding solid fertilization.
M Sarai Tabrizi, H Babazadeh, M Parsinejad, S.a.m Modares Sanavi,
Volume 14, Issue 52 (7-2010)
Abstract
Deficit irrigation is one of the irrigation management methods that is used to increase Water Use Efficiency. Considering the internal plant adaptability characteristic to water shortage, Partial Root Drying method has been introduced in recent years. In this field research improvement of Water Use Efficiency for Soybean was determined. This experiment which was conducted at four furrow irrigation treatments at the Research Field of Tehran University in Karaj in 2008, consists of full irrigation (100% soil moisture deficit compensation), conventional deficit irrigation at 50 and 75 percent soil moisture deficit compensation and Partial Root Drying at 50 percent soil moisture deficit compensation with three replications. The amounts of irrigation used were exactly compensation level (negligible loss). Results indicated that Water Use Efficiency according to Duncan's Multiple Range Test at the five percent level of probability there was a significant difference between partial root drying treatment (PRD50%) and conventional deficit irrigation treatment at fifty percent soil moisture deficit compensation (DI50%),. Water Use Efficiency in PRD50% compared with DI50%, DI75% and full irrigation increased by 48.3%, 61.9% and 70.1% respectively.
A Jalali, M Galavi, A Ghanbari, M Ramroudi, M Yousef Elahi,
Volume 14, Issue 52 (7-2010)
Abstract
Using treated wastewater led to increasing crop yield, but it may causes heavy metals accumulations and also their toxicity in soil and plant. In order to investigate the effects of wastewater on yield, forage yield components, and heavy metals concentrations in stem and leaf of sorghum, an experiment was conducted in the agricultural Research Institute of Zabol University in 2006-2007, using a randomized complete block design with four replication. The irrigation treatments were: 1) well water for whole growing season as control (T1), 2) well water for all growing season along with NPK application (T2), 3) wastewater during the first half of growing season (T3), 4) wastewater during the second half of growing season (T4), 5) wastewater and tapwater alternately (T5) and 6) wastewater for whole growing season (T6). The results showed that irrigations with wastewater and well water alternately and wastewater for whole growing season produced the maximum forage yield and the maximum heavy metal accumulation in plant organs observed by irrigation with wastewater for hole growing season, and wastewater and well water alternately. There was significant increase between T5 and T6 relative to control and other treatments. The elements concentration such as Cu, Pb and Fe in leaf was more than stem, but Zn and Ni concentration in stem were more than leaves. There were no significant differences for Mo and Cr concentration between stem and leaf. Forage yield in T6 and T5 relative to T2 were increased 38.96 and 51.95 percent respectively. In all irrigation treatments the amount of elements and heavy metals in sorghum were lower than standard limits. Based on the results, alternative irrigation method (T5) is recommended for forage sorghum production.
M Motamednia , S.h.r Sadeghi, H Moradi, H Asadi ,
Volume 14, Issue 52 (7-2010)
Abstract
An extensive data collection on precipitation and runoff is required for development and implementation of soil and water projects. The unit hydrograph (UH) is an appropriate base for deriving flood hydrographs and therefore provides comprehensive information for planners and managers. However, UH derivation is not easy job for whole watersheds. The development of UH by using easily accessible rainfall data is then necessary. Besides that, the validity evaluation of different statistical modeling methods in hydrology and UH development has been rarely taken into account. Towards the attempt, the present study was planned to compare the efficiency of different modeling procedures in hydrograph and 2-h representative UH relationship in Kasilian watershed with concentration time of some 10h. The study took place by using 23 storm events occurred during four seasons within 33 years and applying two and multivariable regression models and 36 variables. According to the results, the median of estimated errors in estimation of 2-h UH dependent variables for verification stage varied from 37 to 88%. The results verified the better performance of cubic and linear bivariate models and logarithm-transformed data in multivariable model as well. The efficiency of multivariable models decreased when they were subjected to principle component analysis. The performance of backward method was frequently proved for estimation of dependent variables based on evaluation criteria, whereas the forward was found to be more efficient for time-dependent factors estimation.
M Bashiri Seghale, S.h.r Sadeghi, A.s Rangavar ,
Volume 14, Issue 52 (7-2010)
Abstract
Erosion plots are basically used for studying erosion processes and many related problems. However, the possibility to extend the results of experimental plots to surrounding watersheds is rarely taken into account. In the present study, an attempt was made to study on the accuracy of soil erosion plots in estimation of runoff and sediment yield from small watersheds. Towards this attempt, 12 experimental plots with length of 2, 5, 10, 15, 20 and 25 meter were installed on two north and south facing slopes in Sanganeh watershed, northeastern Razavi Khorasan Province with an area of ca. 1 ha. The performance of the plots in estimation of runoff and sediment was controlled by data collected at the main outlet associated with 12 storm events occurred during November 2006 to June 2007. The results showed that the accuracy of plot estimates on sediment and runoff improved while the plot length increased. The optimal length for estimation of sediment and runoff parameters was found to be equal to average slope length and more than 20m.
S Akhavan, J Abedi Koupaee, S.f Mousavi, K Abbaspour, M Afyuni, S.s Eslamian,
Volume 14, Issue 53 (10-2010)
Abstract
Temporal and spatial distribution of water components in watersheds, estimation of water quality, and uncertainties
associated with these estimations are important issues in freshwater studies. In this study, Soil and Water Assessment
Tool (SWAT) model was used to estimate components of freshwater availability: blue water (surface runoff plus deep
aquifer recharge), green water flow (actual evapotranspiration) and green water storage (soil water), in Hamadan-Bahar
watershed. Also, the Sequential Uncertainty Fitting program (SUFI2) was used to calibrate and validate the SWAT
model and do the uncertainty analysis. Degree of uncertainty is calculated by R-factor and P-factor parameters. In this
paper, results of calibration and validation are given for the river monthly discharge. In most stations, especially in
outlet of the watershed (Koshkabad station), simulation of river discharge was satisfactory. Values of R-factor in
calibration of monthly runoff were 0.4-0.8. These small values show good calibration of runoff in this watershed.
Values of P-factor were 20-60%. These small values show high uncertainty in estimations. For most stations of the
watershed, lack of data on river-water withdrawal caused poor simulation of base-flow and therefore the P-factor values
were low. Nash-Sutcliff (NS) coefficient was 0.3-0.8 after calibration, which shows good model calibration of outlet.
This study provided good information on the components of freshwater availability at spatial (sub-basin) and temporal
(monthly) scales with 95% prediction uncertainty ranges. The results of uncertainty analysis of components of
freshwater availability show that uncertainty ranges of average monthly blue water are larger than the other
components, because of its sensitivity to more parameters.
M. Ozhan , M. Mahdavi , Sh. Khalighi Sigaroudi , A. H. Haghiabi ,
Volume 14, Issue 54 (1-2011)
Abstract
Direct measurement of discharge in rivers is time-consuming and costly, and sometimes, impossible under flood conditions because of the high speed of water, its transitory nature, and the existence of different floaters along the water. Therefore, the discharge-stage relation, known as Discharge Rating Curve is used. Moreover, to design hydraulic constructions, the maximum flood discharge and its maximum height are required. Therefore, to calculate the flood discharges, one should extend the discharge rating curve by using appropriate methods. In this study, in order to determine the best method for the extension of discharge-stage curve, and to estimate the corresponding discharge with high stages, the logarithmic method, the Manning method, the Chezy method, and the Area-Velocity method in 13 hydrometric stations at the Karkheh watershed in Lorestan province were compared. Data measured at each station were gathered for a ten-year statistical period. Results of calculating the Root Mean Square Error (RMSE) and the Mean Bias Error (MBE) for each method showed that the logarithmic method was more accurate than other methods, and it was more appropriate for the extension of the curve at the low average discharge stations. The Area-Velocity method, after the logarithmic method, especially at the stations with higher average discharge showed good results. The Manning and Chezy methods showed the least accuracy.
H.r. Memari, E. Tafazoli, A. Kamgar-Haghighi, A. Hassanpour, N. Yarami,
Volume 15, Issue 55 (4-2011)
Abstract
Many experiments have been carried out to decrease the negative effect of drought stress and obtain suitable growth under water deficit conditions. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. This study was conducted to investigate the effect of Cycocel application on growth of two olive cultivars (Shengeh and Roghani) under water stress condition. The design of experiment was completely randomized with six replications (Factorial arrangement). Treatments included irrigation intervals (2, 4, 6, 8 weeks) and Cycocel concentrations (0, 500,1000,2000,4000 mg per litter). Some indices such as height, chlorophyll, leaf area, root, and shoot weight (fresh and dry) were measured. Results indicated that interaction of C.C.C treatment and irrigation intervals on height of olive cultivars was not significant, probably due to the response of these cultivars to concentrations of C.C.C. Although drought stress decreased the number of leaves in both cultivars, the application of CCC (500 mg per litter) thwarted the adverse effects of drought stress. Cycocel increased chlorophyll content significantly (500 mg per litter in Roghani and Shengeh and 6 weeks irrigation interval). Cycocel application decreased leaf area, but in Shengeh cultivar increased leaf area in 6 week irrigation interval. Overall, the results indicated that the application of Cycocel with concentration of 500 mg per litter in 6 week irrigation intervals in both cultivars (Roghani and Shengeh) was the best treatment for controlling the adverse effects of drought. Also, results indicated that such changes were dependent on Cycocel concentration and drought level.
M. Farzamnia, F. Abbasi,
Volume 15, Issue 55 (4-2011)
Abstract
Qanat is a traditional structure that provides water without spending much energy and expense. Therefore, in eastern regions where there are no big rivers available qanat can play an important role in public economy and should be taken into consideration. The regions around Kerman such as Joupar, Mahan, Bam, Narmashir and Fahraj have many qanats with high discharges. Therefore, protection of this water resource is essential in view of either our cultural heritage or water resources. For this reason, in the present research exploitation problems, water distribution, planting pattern, and variation of water quality and quantity in 15 qanats of Kerman province were studied. Results showed that qanats’ discharges have changed in long run and had a noticeable decrease in the recent decade, and as a result planting pattern and areas in downstream fields have been changed. In the above mentioned fields, average water conveyance efficiency and roughness coefficient in water canals and mean application efficiency were 83.6 percent, 0.024 and 59.3 percent, respectively. Mean water productivity for cultivated crops such as wheat, alfalfa, sugar beet, grain corn, forage corn, watermelon was 0.43, 0.51, 0.31, 0.65, 4.75, 8, and for horticultural crops such as pistachio, almond, date palm, citrus, and stone and pome fruit was 0.52, 0.3, 0.66, 1.1, and 0.54 kg/m3, respectively. Based on the results, the main problems of qanats are the lack of necessary budget allocation by agricultural organizations, digging deep wells on qanats border, technical issues, exploitation, and maintenance management problems.
Gh. Omidi Ardali , M. J. Bahrani,
Volume 15, Issue 55 (4-2011)
Abstract
The optimum levels of soil moisture and nitrogen are important to obtain higher yields. To investigate the effects of water stress, nitrogen levels and application times on yield and yield components of sunflower (Helianthus annuus L.), the cultivar Euroflor at different growth stages, a two year study (2006-007) was conducted at Research Fields of College of Agriculture, Shiraz University (Badjgah) using a split factorial design with four replications. Treatments were water stress at three levels, (non-stress and stress at flowering and seed formation) as main plot and three N levels (0, 70, 140 kg ha-1) and N application times (split application at planting and stem elongation, planting and heading, and stem elongation and heading) as subplot. Number of seed per head, 1000-seed weight, seed yield, Oil yield and HI were measured. Results showed that the effects of water stress and N rates on yield and yield components were significant, but the effects of N application times and interaction between water stress, nitrogen rates and application times were insignificant. Overall, the crop showed more sensitivity to drought stress at flowering time, and 70 kg N ha-1 is recommended for the region.
J. Abedi-Koupai, Z. Nasri, Kh. Talebi, A. Mamanpoush, S.f. Mousavi,
Volume 15, Issue 56 (7-2011)
Abstract
In this study, chemical quality of Zayandehrud river between Zayandehrud Regulating Dam and Nekouabad Diversion Dam, three discharging drains and one Fehlman well were measured using HPLC with determine the pollution concentration of diazinon insecticide from July 2006 to March 2007. Also, Zayandehrud’s assimilative capacity was determined. The results showed that river water and drains were not polluted to diazinon. Physical, chemical and biological factors effective in the diazinon detection were assessed. Diazinon was detected in the groundwater sample in October with concentration of 32.1 ng/L. This level was lower than the maximum permissible level for drinking water. Also, the NO-3 concentration in this month was 24 mg/L that is 2.4 times the standard level (10 mg/L). Due to the increased discharge of different wastewaters to Zayandehrud, its assimilative capacity decreased from upstream to downstream. So, prevention of use of pesticides and pre-treatment of wastewaters that are discharged to this river need more attention.
M. H.nazarifar, R. Momeni,
Volume 15, Issue 56 (7-2011)
Abstract
Deficit irrigation is one of the strategies used to obtain products with maximum profits in recent years. In this context, research on determining appropriate levels of deficit irrigation is essential. Since determining the different levels of performance through field experiments is difficult, the use of simulation models is a strategy through which we can examine the water balance data, simulate the growth process, and to study different managerial scenarios. The purpose of this study was validation and evaluation of CropSyst, a plant growth model, to determine suitable cropping patterns in deficit irrigation conditions. Applying three deficit irrigation scenarios in model, with values of 10%, 20% and 30% on six crops, fava bean, bean, wheat, potato, sunflower and rice, we concluded that the applied deficit irrigation of 10% to bean, potato and beans, 20% to sunflower and 30% to wheat had been suitable, and it is better not to apply deficit irrigation in rice. Also, since in final selection, the rate of water productivity is one of the basic criteria in each crop mentioned above, determining net benefit based on drop index (NBPD) per cubic meter showed that the most NBPD is related to bean with 6853 Rials per cubic meters and the lowest amount is related to sunflower with a value equal to 2809 Rials per cubic meters.
A. Mahdavi , M. R. Nouri Emamzadei, R. Mahdavi Najafabadi, S. H. Tabatabaei,
Volume 15, Issue 56 (7-2011)
Abstract
In recent years, surface water resources in Chaharmahal and Bakhtiari province have decreased and groundwater level has fallen down. Thus, groundwater must be strengthened by surface water resources. The objective of this search was identification of artificial recharge sites thorough Fuzzy Logic in Shahrekord Basin. Effective factors in ground water recharge such as slope, infiltration rate, thickness of unsaturated zone, surface water EC, land use and stream network were determined. They were classified, weighted in software packages Arc View 3.2a and Arc GIS 9.3 and they were integrated using multiplying operator in fuzzy model. The obtained results showed 4.79 % of all areas are suitable and 17.94 % are somewhat suitable in this method. To include the effect of land use parameter, it was overlaid on the final maps, showing a decrease in suitable areas up to 1/3. Generally about 30 points were introduced with priorities A, B, AB as having potential for artificial recharge.
F. Aghababaei, F. Raiesi,
Volume 15, Issue 56 (7-2011)
Abstract
The positive and beneficial effects of mycorrhizal symbiosis on the growth of various plants have already been documented. Most arable crops can mutually establish symbiosis with endo-mycorrhizal fungi, however, mycorrhizal associations with almond (prunus amygdalus), particularly in calcareous soils of arid and semi-arid regions, have not been studied. Thus, to realize the symbiotic association between mycorrhiza fungi and economically important native almond genotypes in Chaharmahal va Bakhtiary province, an experiment consisting of a randomized complete factorial design with three factors: almond genotypes (Mamaei, Rabee, Talkh, Sefid), soil phosphorus levels (0 and 150 kg P ha-1) and mycorrhizal treatments (almond inoculated with Glomus intraradices, Glomus mosseae and without inoculation) with three replications was conducted under greenhouse conditions by 4 months. Results showed that physiological traits including chlorophyll concentration, net photosynthetic rate and water use efficiency, were significantly increased for 20%, 300% and 300%, respectively in mycorrhizal almond plants, while transpiration rate was decreased
(8-10%). Although the genotype of almond and soil P were dependent on these factors, mycorrhiza species had the same effects. Increased available P in the soil enhanced the growth in all treatments and photosynthesis of nonmycorrhizal almonds.
N. Khorsandi, M. H. Mahdian, E. Pazira, D. Nikkami,
Volume 15, Issue 56 (7-2011)
Abstract
Rainfall erosivity force as on important factor in soil erosion and sediment yield has been introduced in different indexes. The objective of this study was to determine suitable rainfall erosivity indices for two climates of semi-arid in Maravetape and very humid in Sangdeh, both in Khazar watershed, by correlation between rainfall erosivity indices and sediment outflow from erosion plots. For this purpose, the rainfall intensities in different time steps and the amount of rainfalls of 12 events in Maravetape and 11 events in Sangdeh have been used. Twonty five rainfall erosivity indexes were calculated based on rainfall intensity. The amount of soil loss measured after each rainfall event in 1.8×22.1 m2 erosion plots. The results of the study revealed that in very humid climate of Sangdeh and in semi-arid climate of Maravetape had high correlation of 0.803 and 0.727 (at the level of 99 percent) with sediment yield and they were applied indices in these climates of Khazar watershed. In general, the groups of 10 and 30 minutes are better than other erosivity indices in the study areas.
A. R. Masjedi, H. Kazemi, A. Moradi ,
Volume 15, Issue 57 (10-2011)
Abstract
In this research, the effect of installing position of bridge pier on scouring depth was studied in a bend laboratory flume, which is made of Plexiglas with 180 bend and a relative radius of Rc/B=4.7. Tests were conducted using one pier 6 cm in diameter under four discharge conditions with constant depth of 12 cm and clear-water conditions. Flume bed was fully paved by uniform sand. It was found that maximum scouring depth occurred in bend when bridge pier was installed in the position of 60 degrees. Also, in all situations increased scouring depth occurred by increasing discharge.
S.h. Tabatabaei, M. Ghazali ,
Volume 15, Issue 57 (10-2011)
Abstract
The accuracy and precision of the input data in decision making is important. Error originates from data collection, data entry, storage, retrieval and analysis of the data which consequently result in model error. One of the errors in spatial analysis is interpolation error. The main objective of this research was the suitability assessment of some interpolation methods for estimation of groundwater level in Farsan-Joneghan and Sefiddasht aquifers, located in Beheshtabad catchment, Chaharmahl-Va-Bakhtiyari province, Iran. Cross-validation technique was employed for the determination of each method's error. The RMSE and MAE indices were used for the error comparison. The results show that the modified Shapard's method with an MAE=6 and RMSE=7 was the most accurate for interpolation of groundwtaer level in the Sefiddasht aquifer. The inverse distance power method with MAE=6 and RMSE=9 was the best interpolation method for Farsan-Jonaghan aquifer. The Kriging with MAE=7 and RMSE=12 is the second best method in these aquifers. The moving average, minimum curvature and polynomial regression procedures produce the maximum error in the aquifers (17
H. Zare Abyaneh, H.noori, A.m.liaghat, V.karimi, H.noori,
Volume 15, Issue 57 (10-2011)
Abstract
Fertilizers in agriculture are potential sources of environmental pollution, especially in ground water quality and soil resources. Studying factors effective in water and nutrient transport through soil profile is helpful for nutrient management to minimize adverse impacts on environment and nitrate leaching below the root zone. In this study, the ground water level and nitrate leaching transportation below the root zone were measured in a paddy rice field and the data were simulated with the DRAINMOD-N model. For evaluating DRAINMOD-N software in a paddy rice field under surface drainage in Mazandaran, the ground water level and nitrate transportation were measured during four months (June, July, August and September) in 2008. The DRAINMOD-N model was calibrated by adjusting nitrification and denitrification rate constants to reach the best fit between measured and predicted data. Results indicate that predicted ground water level and nitrate concentration by model were significant at one percent level. The statistical comparison was done by model efficiency (EF) 0.84 for estimation of ground water level and 0.97 for estimation of nitrate concentration, respectively. The DRAINMOD-N model can be used as a tool to manage environmental pollution of nitrate in paddy rice fields.
K. Kamali, M. Mahdian2, M. Arabkhedri1, A. Charkhabi1, N. Ghiasi1 and A. M. Mahdian, M. Arabkhedri, A. Charkhabi, N. Ghiasi, A. Sarreshtehdari,
Volume 15, Issue 57 (10-2011)
Abstract
Floodwater Spreading (FS) plays an effective role in improving soil fertility, ground water recharge, vegetation cover, and desertification control. The soil fertility might increase as a result of a suitable suspended sediment material transferred to the downstream by flood events. To define a relevant FS method which increases the efficiency of the FS projects, it is necessary to study the quality and quantity of transported sediment material, spatially and temporarily. In this research, this subject was investigated by taking soil samples throughout 13 FS stations for physical and chemical analysis over 5 years. Within each of the 13 selected stations in the three first flooded dikes, soil sampling was carried out using random-systematic method. The total Nitrogen, absorbed Phosphorous and Potassium, and Organic Carbon of each sample were analyzed. Because of the abnormality of data, nonparametric test was adopted to compare means. All stations were classified into three groups using cluster analysis method. Based on the results, the variations of fertility factors are irregular between the dikes and amongst years. This could have been affected by several factors such as the quality and quantity of diverted flood, the characteristic of FS sites, and irregularity of sediment material deposited on the sites. Despite the low quality of soil fertility prior to the construction of these stations, in general, FS has a considerable role in improving the soil fertility. However, desirable objectives may be achieved in long term through occurrence of diverse flood events and suitable maintenance of the stations.
A. Shirzadi, K. Chapi, P. Fathi,
Volume 15, Issue 58 (3-2012)
Abstract
Estimation of flood hydrograph is of necessities in hydrological studies such as flood mitigation projects. This estimation in un-gauged watersheds is usually taken place using geomorphological characteristics of watersheds. The objective of this research is to estimate synthetic unit hydrograph using regional flood frequency analysis and geomorphological parameters of watersheds. 1-hour and 2-hour hydrographs of two watersheds, Kanisavaran and Maranj Watersheds, were generated using maximum discharge data based on regional flood frequency analysis. Estimated hydrographs were compared with observed data and the efficiency of the model was evaluated using Nash-Sutcliffe coefficient, absolute and bias errors. The results showed that multiple regression models give more acceptable results among others for the computation of synthetic unit hydrograph (higher coefficient of determination). The Nash-Sutcliffe coefficient was 0.98 for 1-hour hydrograph while it was 0.93 for the 2-hour hydrograph. The absolute error in 1-hour hydrograph and 2-hour hydrograph was 0.13 and 1.2, respectively. The bias error was close to zero for both hydrographs, indicating that the proposed model is efficient. The model may be used for estimation of synthetic unit hydrograph in similar un-gauged watersheds.
