Search

Purpose: Identification of pomegranate cultivars with higher tolerance to salinity stress was the purpose of the current study. Research Method: One-year-old rooted cuttings of the pomegranate cultivars including 'Malase Saveh' ('M-Saveh'), 'Malase Isfahan' ('M-Isfahan'), 'Robabe Ghermeze Shiraz' ('Robab'), 'Gabrie Yazd' ('G-Yazd'), Gabrie Torshe Yazd' ('GT-Yazd'), 'Zaghe Sefide Yazd' ('ZS-Yazd'), 'Zaghe Torshe Yazd' ('ZT-Yazd') and 'Malase Torshe Pishva' ('M-Pishva') were cultured in plastic pots and treated with different concentrations of sodium chloride in irrigation water including 0 (control), 3, 6, 9 and 12 dS m-1. Findings: At 12 dS m-1salinity level, the lowest decrease in plant height was observed in 'Robab', and 'M-Pishva' and the lowest decrease in the plant diameter was recorded in 'ZT-Yazd' and 'G-Yazd'. At the same salinity level, 'GT-Yazd' showed the lowest percentage of increase in electrolyte leakage (EL) compared to the control (23%). The highest increase in proline content was observed at 9 dS m-1 salinity for 'ZS-Yazd' and at 12 dS m-1 salinity for 'GT-Yazd'. At high salinity levels, leaf chlorophyll content decreased in pomegranate cultivars compared to the control. The activity of peroxidase enzyme in 'M- Pishva', ZT-Yazd' and 'GT-Yazd' followed an increasing and then decreasing with increasing salinity levels. The activity of the superoxide dismutase enzyme was highest in 'G-Yazd', 'M-Isfahan' and 'Robab'. Limitations: Investigation of salinity tolerance in pots is one of the limitations of this study. Originality/Value: Yazd cultivars including 'G-Yazd', 'GT-Yazd', 'ZS-Yazd' and 'ZT-Yazd' were more tolerant to salinity stress.

In this study, the effect of irrigation water salinity on rooted cuttings of eight pomegranate cultivars namely ‘Malase Saveh’ (‘M­Saveh’), ‘Malase Isfahan’ (‘M­Isfahan’), ‘Robabe Ghermeze Shiraz’ (‘Robab’), ‘Gabrie Yazd’ (‘GYazd’), Gabrie Torshe Yazd’ (‘GT­Yazd’), ‘Zaghe Sefide Yazd’ (‘ZS­Yazd’), ‘Zaghe Torshe Yazd’ (‘ZT­Yazd’) and ‘Malase Torshe Pishva’ (‘M­Pishva’) was studied. Sodium chloride was added to irrigation water to get final concentrations of 3, 6, 9 and 12 dS/m. Leaf and root mineral content, leaf abscission and root characteristics were determined at the end of the experiment. The results showed that the salinity reduced significantly fresh and dry weight of root in all pomegranate cultivars. Water salinity up to 3 dS/m increased slightly roots fresh and dry weight of all cultivars and thereafter decreased. With increasing water salinity to 12 dS/m, accumulation of sodium and chloride both in roots and leaves increased, but nitrogen, phosphorus, magnesium and calcium contents decreased. The change of leaf potassium content was dependent to pomegranate cultivar. The lowest sodium and chloride accumulation in root was observed in ‘ZT­Yazd’, but ‘M­Pishva’ translocated the lowest sodium and chloride to leaf. The low ability of nitrogen absorption was found in ‘M­Saveh’, whereas ‘M­Pishva’ maintained the highest leaf nitrogen under salt stress conditions. The most potassium content of root was observed in GT­Yazd’, while ‘ZS­Yazd’ and ‘G­Yazd’ translocated the highest potassium to leaves. Generally, the responses of pomegranate to absorption and translocation of elements to leaves under salinity conditions were completely dependent to cultivar. ‘MPishva’ and Yazd cultivars showed higher tolerance to salinity stress.

Introduction: Water crisis as a majorlimitation factor for agriculture, like other arid and semiarid regions exists in Isfahan province which is located in the central part of the Zayandehrud River Basin (ZRB). Rice appears to be the far-most profitable crop but at the same time it has a major impact on basin scale water resources, especially affecting downstream farmers. In the study area (ShahidFozveh Research Station), the water resources for agricultural production face heightened competition from other sectors like industry and domestic use. This necessitates considering different crops, altered agricultural systems and innovative methods that can reduce the water requirements for the irrigation of rice. The Alternative Wetting and Drying (AWD) seems to be an effective method reducing water use for rice crops and possibly save the water for downstream users. There have been no qualitative evaluations of rice production under deficit irrigation practices in Isfahan area. This study sought to determine, under study area conditions, the quantities of water irrigation used with AWD practices, the resulting water productivity (WP) and the effects of alternative irrigation management on yield, quality indices and rice production performance. Materials and Methods: The ZRB (41,500 km2) is a closed basin with no outlet to the sea. The research was conducted in the Qahderijan region of Isfahan province, which is located in the central part of the ZRB. The ShahidFozveh Agricultural Research Station (32°, 36’ N, 51°, 36’ E) is located at the altitude of 1612 m above the sea level. In order to improve WP and illustration of the impact of various levels of flooding depth on grain yield and quality indices at rice production, a field experiment (3000 m2) was conducted at ShahidFozveh Research Station for 2 years arranged in a split plot design with three replications. It will be necessary to use different scenario of water flooding depth management to achieve the highest irrigation application efficiency and WP. The treatments included: three levels of irrigation managements I1: permanentflooding under 3.5 cm water during growth period, I2: permanent flooding under2.2cm water during growth period and I3: 0-1.5cm. (AWD) were considered as main plots and eight advanced rice cultivars (Geredehmahali, Zayandeh-rud, Sazandegi , Hasani, 67-97, 67-113, 67-47 and 67-72) as sub plots. The treatments were compared based on grain yield and quality indices for irrigation management and rice varieties including: amylose content (AC), Gelatinization temperature (GT) and gel consistency (GC). Production (grain yield), quality indices, the consumption water, WP and cultivars reactions to different irrigation management were evaluated in different treatments. The soil of the experimental area, according to USDA Soil Taxonomy 1994 is of FINE CLAYEY. At the soil depth of 1m, soil salinity (6.2 dS.m-1), water salinity (3.9 dS.m-1), and soil moisture at saturated capacity (48 Vol. %) at the field site were measured or experimentally obtained in the Isfahan Soil and Water Laboratory. The results were subjected to an ANOVA to analyze the effects of the treatments and their interactions using PROC GLM (SAS 9.1, SAS institute Ltd., USA). Duncan’s multiple range tests at 0.05 probability level was used for paired mean comparison. Results and Discussion: Results showed that water flooding depth treatments had significant effect on gel consistency, geletination degree and WP (P0.01). Significant differences (P0.01) were noticed in Gelenation degree, gel consistency, grain yield, WP among the cultivars. Also cultivars have significant effect (P0.05) on amylose contents. The highest magnitude of WP was calculated 0.91kg.m-3for (I3) followed by Zayandehrud, 67-113 and Sazandegi with 0.86 and 0.85, respectively. Maximum WP obtained from AWD irrigation management and Zayandehrud rice variety, its amount was 9.1kg.mm-1. At this treatment with 33.4 percent reduction of irrigation water, have resulted only 11.1 percent decreased of paddy grain yield. Results showed that it is not necessary to maintain the rice field submerged in whole growth period. Considering the importance of water flooding depth optimization as the main scope in arid and semi-arid lands of Iran, (I3) is recommended. Conclusion: During the two years of conduction of an experiment in ZRB with clay texture and mild saline water with the three (3) irrigation treatments imposed on the rice crop. The highest WP was achieved for (I3) followed by Zayandehrud, 67-113 and Sazandegi, respectively. It was found that the AWD irrigation management, despite its lower yield than other irrigation treatments, increased water productivity. Thus, this treatment is desirable therefore highly recommended for agricultural rice production in arid region.

The Zayanderoud River stretches over 350 Km along a roughly west-east direction, originates in the Zagros Mountains on the west of Isfahan, and discharges into the Gavkhoni Swamp on the east of Isfahan. The Zayanderoud River supplies for the irrigation, domestic, and industrial water demands in Isfahan Province. In this paper, some water quality parameters of this river including EC, TDS, pH, HCO3, and Cl were simulated at different stations using artificial neural networks. The results showed an ascending trend for EC and TDS along the river. The trend in simulated HCO3 was found to be similar to that over the past few years and was equal to the long-term average. The trend for Cl was ascending at upstream stations and also similar to the long-term average at downstream stations. In general, the simulations of water quality parameters EC, TDS, pH, and HCO3 were evaluated to be highly satisfactory and the one for Cl satisfactory.

Water scarcity and salinization are major threats to sustainable irrigation in Iran as well as other parts of the world. Irrigation schemes are part of a basin and as such, irrigation research must be conducted in a basin context. For the Zayanderood basin in central Iran, a simplified Water and Salinity Basin Model (WSBM) was developed for a quick analysis of river basin processes. The model was calibrated and used for current and past water resources analyses. Despite the simplicity of the model, observed and simulated stream flows were similar, proving that the model could be used for scenario analyses. The first scenario was defined where the effect of an increase of water extraction for Isfahan was evaluated. In terms of basin scale water quantity aspects this increased extraction is negligible as extractions are relatively low and return flows are high. A second scenario was developed to study the additional releases required from the reservoir to provide sufficient water for expansion of the Rudashtain irrigation scheme. If no restriction is imposed on water quality, additional releases from the reservoir are limited. However, if salinity levels are not to exceed 2ds m-1, mean annual water release requirements from the reservoir will increase from 52 to 64 m3 s-1, and peak requirements during the irrigation season will increase from 85 to 112 m3 s-1. Finally, it was concluded that the methodology and the model developed were useful for a swift and transparent analysis of past, current and future water and salt resources, and performing scenario analyses.

History reveals that waterworks began thousands of years ago in ancient Iran. The main objective in operation and maintenance of an irrigation network is to increase the efficiency of the system. In this study , the performance of regulating structures of Doroodzan Irrigation Network (mainly slide and radial gates)were compared with those of Neyrpic module orifices, in Zayandeh-rood Irrigation Network. The comparison was based on perfomance and operation of each system. Based on the results obtained, the following recommendations are made: Performance of the structures becomes poorer with time due to the operation and maintenance of both systems. Department of Agriculture should be more involved in the management of the irrigation networks. Land consolidation is a key parameter in better performance of the systems. Government should stop subsidizing the water tariff for the farmers. Instead, the budget should be allocated for operation and maintenance purposes. This will help minimizing the water losses of the systems. Establishment of the independent irrigation and drainage cooperations run by the farmers. With an overall project efficiency of around 46%, about 20% of the total delivered water was distributed unreliably. Water distribution equity along tertiaries was also found to be poor. A contributing factor could be the poor operation and maintenance of gates.

This paper provides an overview of the hydrology and water use in the Zayandeh Rud basin based on the data available over the 11- years period 1988-1998. The inflows into Chadegan reservoir, the releases from the reservoir, and the extractions along the river for irrigation and other purposes are considered, and a rapid water balance of the basin is performed. Inflows to the Chadegan reservoir, which serves to collect and regulate the runoff from the upper catchment of the basin to better meet the downstream water requirements for irrigation, urban and industrial uses, follow a regular pattern with moderate variability. But the limited year-to-year storage in the reservoir makes the basin vulnerable to prolonged periods of drought. Water releases from the Chadegan reservoir also show a predictable pattern, with the only deviations occurring during flood events. There is a high reliability of meeting the water requirements during periods of peak demand. But releases during the winter months, at the end of the irrigation season, are lower and more variable. This results in low discharges in the Zayandeh Rud and reduced water quality, especially in the lower reaches of the river. A simple water-balance approach was used to estimate the proportion of return flows in the basin. An average annual value of 30% was obtained, with the magnitude of return flows being particularly important in the lower reaches of the basin. But more investigation, especially including groundwater and water quality aspects, needs to be carried out before a definitive value can be advanced. Given the limited supply of fresh water in the Zayandeh Rud basin, further water resources development and water management improvements can only be envisaged in there is scope for real water savings in the basin. This can be assessed if a basin-wide approach, leading to a good understanding of water use (and reuse) at the farm, system and basin levels, is adopted.