JWSS - Journal of Water and Soil Science

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The aim of the study was to examine the effect of CaCl₂ on the firmness and post harvest retention of Berry Grape (Vitis vinifera L.) cv. Askari. The experiment was carried out in 2006 in vineyard in the Sisakht region in a completely randomized design with 7 treatments. Experiment includes two parts: 1- spray with 3 levels 0.1, 0.25 and 0.5 %. (Two weeks before harvest and repeated one day before harvest) and 2- Dipping clusters in CaCl2 solution with 3 levels 1, 2.5 and 5 % post harvest. Grapes were stored at 0ºc for 1 month in cold store room. Results showed that the effect of CaCl₂ was significant on post harvest abscission berries percentage at 1% level. Minimum post harvest abscission of berries percentage was observed using 5% dipping and 0.25% spray after 30 days storage in cold storage room. Highest abscission of berries was observed in control. Effect of CaCl₂ on decay berry was significant at 1% level after 30 days of storage. Minimum decay percentage was observed in 0.25 % spray and the highest decay percentage was obtained in control. Effect of CaCl₂ on palatability (TSS/TA) was significant at 1%level.

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Because of its tenderness, long distance between field and consumer locations and unsuitable condition of transportation, 30 – 40 percent of strawberry fruits is wasted during the transportation between field to markets. One of the recommended ways for cutting down the wastes of strawberry is application of calcium salts after harvest stage to increase the content of Ca2+ in fruit flesh. For this reason, the selected fruits were treated by immersing them in 0, 25, 50 and or 75 mmol/lit concentrations of CaSO4, CaCl2 or Ca(NO3)2 for 4 min. After drying in atmospheric tempetature, fruits were stored at 5°C for 5 and for 10 days. To evaluate the effect of calcium solutions on fruit quality, some quantitative and qualitative tests were carried out on them. The results showed that by increasing the concentration of calcium salts, the amount of acidity and calcium of fruits is significantly increased, but the percentage of mouldy fruits is decreased. In most cases, the 50 and 75 mmol /lit concentrations of CaSO4 showed similar effects. Among the different calcium solutions, Ca(NO3)2 had the best effect on improvement of fruit quality, such as increasing the calcium and firmness of fruit , but CaSo4 prohibited the moulding of fruits better than other solutions. By increasing the period of storage from 5 to 10 days, the amount of acidity and firmness decreased significantly, while mouldness percentage increased. The organoleptic test showed that when the concentration of CaCl2 and Ca(NO3)2 solutions is increased, the acceptability of treated samples is decreased by consumers. Because of the bitter taste, the least score was given to the samples treated by 75 mmol/lit concentration of Ca (NO3)2 solution. The panelists didn’t recognize any difference in taste between control and samples treated by 25 mmol/lit concentration of CaSO4 and CaCl2 solutions. None of the treatments showed initial attributes (tenderness and shape) of fruits after storage period. This method isn't recommended to increase the strawberrys' shelf life for home use, but it can be used for the ones which are to be consumed in food processing industries.

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To optimize the use of sulfur in drying of apricot, four following treatments including: sulfiting and drying, sulfiting- blanching and drying, blanching- sulfiting and drying, and finally sulfiting- drying to % 50 of initial moisture- blanching and finish drying were studied. The levels of sulfur addition were from 0 to 1500 ppm, SO2 and drying was carried out at 50 to 74 °C. The quality of dried apricots was judged by extent of browning development and hardness determination. A response surface statistical design was applied to evaluate the quality of slabs and to determine optimum drying conditions. The results showed that sulfite was the major factor in controlling dried apricot quality. At present of sulfur, the role of temperature can be neglected. The amount of used sulfite has no significant effect on drying time of apricots. Blanching reduced drying time of product significantly. By increasing the drying temperature, loss percentage of SO2 was reduced for all treatments. Blanching and then sulfiting, increased loss in residual sulfur of products significantly. Application of sulfiting– drying method, using 900 ppm of SO2 at 50 to 68 °C was found to be the best treatment because of production of slabs whit average hardness and color texture equal to 1.44 N/m2 and 0.07 Od respectively.

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The transport process of chemical-fertilizers, radioactive materials and other solutes in soils and porous media is important to understand the environmental and economic effects of industrial, agricultural and urban waste disposal methods. In unsaturated porous media, large gradient in aqueous osmotic potential derives significant water vapor fluxes towards regions of high solute concentrations. In this research, the effects of osmotic potential (resulting from salinities of 0.5, 1 and 1.5%) on water vapor transport in three soil textures (silty clay loam, loam and sandy loam) were examined by using a physical laboratory model. Then, the experimental results were compared with Kelly and Selker (2001) model for validation of the predicted water vapor transport. The results showed that the rate of water vapor transport reduces significantly as soil texture gets heavier. For example, in salinity of 0.5% and 5th day of experiment, the amount of transported vapor in sandy loam, loam and silty clay loam soils was 0.362, 0.196 and 0.12 kg/m2, respectively. Large osmotic potential near the high solute concentration in soils caused significant vapor movement toward dense solutions. In salinity of 1.5%, transported vapor in these soils was 1.47, 0.723 and 0.38 kg/m2, respectively. Total water vapor movement until the 15th day was more than the 5th day. Comparison of experimental results with Kelly and Selker model results, using Mathcad PLUS 6.0 software, showed a good agreement between the observed and predicted data. Since water vapor delivered from uncontaminated soils to the contaminated soils can result in increased contaminant plume volume, these physical and chemical processes must be included in the predictive models of contaminant transport in the vicinity of concentrated sources

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Due to the time and space changes of hydrological events in the arid and semi-arid regions, recharge measurement in these areas is very difficult. Hence, groundwater recharge is a complicated phenomenon for which there is not a fixed method to determine. The aim of this research was to develop a method for estimation of groundwater recharge based on a hybrid method. In this study, a hybrid method for calculating recharge was presented by combining empirical methods with a mathematical model, MODFLOW, and AHP analysis. The results showed that the most important parameters affecting groundwater recharge are soil properties, unsaturated thickness, land cover, land slope, irrigation and precipitation, from which the soil properties and precipitation are most important. The results showed that the overall impact of small changes in precipitation and temperature significantly affect the groundwater recharge, and heavy soils are much more sensitive to these changes than light soils. By changing 10% precipitation, the recharge rate is changed between 16% and 77% and by changing 1ºC temperature, the recharge rate is changed between 6% and 42%. Also, results showed that precipitation and evapotranspiration changes in four months including December, January, February and March had significant effects on annual recharge rate. Using the results of this research, the vulnerable areas of the plain, appropriate places and time for artificial recharge could be identified. Overall, the results of this study can be useful in various aspects of groundwater management.

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With regard to the confirmation of climate change in most regions of the world and its effects on different parts of the water cycle, knowledge of the status of water resources is necessary for proper management of resources and planning for the future. Hence many studies have been done in different areas with the aim of analyzing the impact of climate change on hydrological processes in the upcoming periods. In present research, the effect of climate change on surface runoff in Bazoft watershed has been studied. Bazoft watershed, located in North-West of Chahar Mahal & Bakhtiari province, has significant contribution in the production of water resources of the region due to its special topographical and geographical status. In this study, climatic model – HadCM3- and A2 and B2 emission scenarios have been used to assess uncertainty in forecasting climate change. For this purpose, a statistical model –SDSM- has been applied to downscale large- scale precipitation and temperature data and hydrological model –WetSpa- has been used to simulate runoff. After calibration of the hydrological model, downscaled precipitation and temperature data in near future (2020-2050) and far future (2070-2100) periods were introduced to WetSpa model and runoff was simulated for mentioned periods. Results of this study represent suitable performance of SDSM model in downscaling climatic data, especially minimum and maximum temperature. Also, performance evaluation of Wetspa model shows proper performance of this model for runoff simulation in Bazoft watershed, so that Nash- Sutcliffe efficiency during calibration and validation was 0.63 and 0.65, respectively. Moreover, assessing the amount of predicted runoff for future periods indicates an increase in annual runoff in the Bazoft watershed under both A2 and B2 scenarios.

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