JWSS - Journal of Water and Soil Science

---

This research was conducted to study the nutritive value of Jerusalem artichoke (JA) as animal feed. The aerial part of the JA plant was harvested, at full bloom stage, and then chopped and dried. The chopped JA hay included 0.0, 10, 20, 30 and 40 % of alfalfa hay, used as experimental diets, and tested for in vitro digestibility. In a changeover experiment with Latin square based design the in vivo digestibility was studied by sheep. The samples of dried JA forage as well as the experimental diets were collected and analyzed chemically. The nutrient contents of JA were relatively similar to alfalfa hay except for the crude protein that was lower in JA. The in vitro dry mater and organic mater digestibility were not affected by the levels of JA in the diets, but the digestible value reduced (p<0.05) when the JA ratio was increased to the 40% of the diet. The in vivo digestibility of dry mater, organic mater and fiber fractions was decreased in the diet containing 40 percent JA however, total digestible nutrients and metabolisable energy were not significantly different among the treatments. It may be concluded that nutritive value of JA is similar to alfalfa hay, when it is used up to 30% instead of the alfalfa hay based diet

---

Soil water characteristic curve shows the relationship between soil water content and matric suction, which has an important role in water movement in the soil. The measurement of this curve is expensive and time-consuming in laboratory therefore, many methods have been proposed for its estimation including pedotransfer functions. By using the pedotransfer functions, soil water characteristic curve can be estimated based on other easily measured soil physicochemical properties. Parametric pedotransfer functions have been offered for parameters of the existing soil water characteristic curve models. In this study, 12 internal and external parametric pedotransfer functions of Brooks and Corey, Campbell and van Genuchten models were used and evaluated for 30 top soil samples in Fars province. To this end, the soil water characteristic curve and other necessary soil properties were measured, and then all soils according to the texture were divided into three groups of fine, medium and course textures. The results showed that the parametric pedotransfer functions of van Genuchten model were better than the other models, beacause of the better fit of this model to the measured data. Also, the results demonstrated that the parametric pedotransfer functions of Wosten et al. were the most appropriate method for estimating the soil water characteristic curve for the selected soils in Fars province, and that internal pedotransfer functions were not appropriate

---

This study performs trend analysis of hydroclimatic varibles and their possible effects on the water resources variability. Nonparametric Mann-Kendall and spearman tests were used to investigate trend analysis of mean annual and 24-hr maximum rainfall, flood and low flow parameters of 23 hydrometery and 18 synoptic stations in Sefid-Roud basin. The results showed that mean annual and 24-hr rainfall parameters are decreasing in few stations while most of stations representing negative trend for low flow and flood time series. Applying Sequential Mann-Kendall test revelad that this negative trend is started from 1965 to 1970 for rainfall parameters and from 1970 to1980 for flow (low flow and flood) parameters. Results show that climate change has probability affected variability of climatic variables, while changing of land use may have aslo affeteced extreme flow trends during recent decads. Therefor it can be noted that combination of climate chanege effects and human activities on water recources have affected the negative trend of hydroclimatics variables.

---

Non-exchangeable potassium (NEK) release is necessary to supply potassium for plant in different soils. A few studies on the NEK release have been done in soils and particularly on its components. This study was intended to investigate the NEK release from soil and the components of clay and silt through successive extractions with oxalic acid (0.01 M) over a period of 1844 (h) in 4 soil series of Golestan province. The amount of NEK release from whole soil, silt and clay fractions after 1844 (h) were 242 to 450, 380 to 550 and 105 to 199 mg kg-1, respectively. The cumulative rates of NEK release after 1844 (h) were well described by simplified Ellovich, parabolic diffusion and power function equations. The rate of K release was high initially, and then decreased gradually in all soils and in their silt and clay fractions. The amount of released NEK (with high rate) consisted of lower percentage of total NEK, but in spite of less amount, this K form plays a vital role in K dynamic and soil fertility.

---

Biological indicators are considered soil quality elements, due to their dependence on soil organisms. In order to investigate The effect of compost and vermicompost enriched by chemical fertilizers and manure on soil organic carbon, microbial respiration, and enzymes activity in basil plant's rhizosphere, a field experiment was conducted as a split-plot design with randomized complete blocks and three replications in 2006. The main plot involved six levels of fertilizer including: 20 and 40 tons of compost enriched, 20 and 40 tons of vermicompost enriched per hectare, chemical fertilizer and control without fertilizer and sub-plot, and period of application (two, three and four years). The results showed that application of compost and vermicompost at all levels increased soil organic carbon (OC) and soil microbial respiration, microbial biomass and urease activity compared to the controls (p<0.05), but increasing trend among the treatments was not similar. The maximum amounts of OC, soil microbial respiration and enzyme activity were observed in 40 tons of vermicompost enriched with chemical fertilizer ha-1 with four years of application. In high levels of compost application, the urease activity was decreased.

---

In order to describe soils polluted with hydrocarbons, the amount and distribution pattern of soil heavy metals (Ni, Cd) in soils were studied. Soil samples were taken from one of the western oil field of Iran. The field was naturally exposed to crude oil spillage into soil and consequently was environmentally polluted during the development, production, transportation and storage of crude oil. Sampling was started near the oil wells with maximum relative contamination and continued to the remote places based on grid sampling pattern. Samples were characterized by physicochemical analysis. The results revealed different levels of total hydrocarbons (from 0.12 to 2.99 mg/kg of dry soil), Ni (from 32 to 136 mg/kg. of dry soil) and Cd (from 0 to 4mg/kg of dry soil). In addition, the role of soil agents such as pH and EC and sedimentary indexes was considerable in controlling the pollution trend in the studied area. Finally, by interpolation module and prediction of unknown values via Kriging techniques, the expansion plans were created. The extracted plans obviously illustrated the decrease in the levels of pollution indexes with the increase in distance from the given centers of pollution

---

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

---

Heavy metals contamination of soil and plants has very important and vital role in relation to health and life of human and other organisms. The aim of this study was to assess the efficiency of sorghum (Sorghum bicolor) and sommon lambsquarter (Chenopodium album) in phytoremediation of Zn from soil. Efficiency of 0.01M CaCl2, 0.1M NaNO3, and 1M NH4NO3 for extraction of “bioavailable fraction of soil Zn was also compared. Correlation between the Zn concentrations extracted by these methods and plants response (relative yield and shoot Zn concentration) to soil Zn contamination was then evaluated. For this purpose, a calcareous soil sample was contaminated with different concentrations of Zn. Sorghum and common lambsquarter, were grown in pots containing the contaminated soil and were analysed for their Zn concentrations after harvest. Results of this study showed that, common lambsquarter was more tolerant to low and medium concentrations (≤900 mg/kg), but sorghum tolerated high concentration of Zn. Also sorghum was more capable in removal of Zn from soil in comparison to common lambsquarter, so that soils contaminated with low Zn levels (≤900 mg/kg) can be remediated by sorghum. In addition, there was a significant correlation between 1 M NH4NO3-extractable soil Zn and the plants response (relative yield and shoot Zn concentration) to soil Zn contamination.

---

While the mass density current penetrates the stagnant fluid, a plunge point occurs. In this regard, the boundary of the dense fluid with ambient fluid is determined at the plunge point height. In this research, the hydraulic parameters of the dense flow and the bed slope of the stagnant fluid which have a significant effect on the plunge point have been investigated under the two turbulence models: the k- and the RNG at the Flow-3D model. To achieve the purpose of this research, a physical model was set up at the hydraulics laboratory of Shahid Chamran University (SCU), Ahwaz, Iran. Then, using the Flow-3D model with both the k- and the RNG turbulence model, the height of the plunge point was simulated according to the same experimental condition. Findings showed that the predicted depth under the RNG model is closer to the results of the physical model. For example, the k- and RNG model for the 12% slope can estimate the plunge point depth by 30% and 12.28% respectively more than the experimental data. However, for all the slopes, the k-e model can on average overestimate by 27% and RNG model 10.5% more than the results of experimental data. The statistical analysis showed that the RNG model predicts the plunge point depths with a satisfactory precision.

---

In this research, the hydraulic behavior of two kinds of envelopes including synthetic envelope, PP450 and gravel envelope with USBR standard in two soil tank models with silty loam texture was investigated. Three water heads including 55, 75 and 105 cm (water logging) from drain level were used. The discharge of pipe drain in the steady state condition for gravel envelope and at 55, 75 and 105 cm water heads was 188.9, 172.0 and 897.0% more than those in PP450, respectively. Envelope hydraulic conductivity rates at gravel envelope for 55, 75 and 105 cm water heads were 24.6, 14.0 and 21.2 times higher than those in PP450, respectively, and gradient ratios in these water heads for gravel envelope were 14.5%, 2.8% and 14.2% lower than those for synthetic envelope. There were also different behaviors in the two kinds of envelopes for hydraulic conductivity and entrance resistance of pipe and envelope in 55 and 75 cm water heads relative to 105 cm. In general, according to the measured parameters in this research, gravel envelope showed a better performance.

---

Determination of relationships between different forms of potassium in soils and their constituents can help us to resolve some nutritional problems such as potassium fixation and release and its fertilization management in soil. This investigation was carried out to determine the contribution of soil and their constituents (clay and silt) Kex and Knex to available potassium for plants in 12 loess-like and loess-derived soil series of Golestan province in a pot experiment of corn. Total K uptake of corn in the greenhouse experiment was used as an index of soil-available K. Results showed that the contribution of Kex to plant K uptake was more than that of Knex in clay fraction of all soils. Whereas the contribution of Knex to plant K uptake was more than that of Kex in silt fraction of all soils excluding Oghchi soil series with the highest initial Kex. Therefore, the silt fraction is an important K source for supplying the plant need for K in loess-like and loess-derived soils.

---

Evaluation of pollutant transportation in soil is important from different environmental aspects such as soil and groundwater contamination. The purpose of this study is to measure 2, 4-D concentrations in a silty loam soil under two different treatments (normal and deficit irrigation) in a corn field and simulate the results using the PRZM-3 and LEACHP models. Total concentrations of 2, 4-D in the soil profile in 8, 13, 23, 30, 37, and 57 days after application for normal irrigation were 18.5, 16.36, 11.67, 10.47, 8.47 and 3.2 mg kg^-1, respectively. For these dates, PRZM-3 model simulated 18.5, 16.36, 11.67, 10.47, 8.47 and 3.2 mg kg^-1 of 2,4-D, respectively and LEACHP model simulated 23.34, 20.93, 16.7, 16.3, 12.9 and 11.41 mg kg^-1 of 2, 4-D, respectively. Total concentrations of 2, 4-D in the mentioned dates for deficit irrigation were 20.2, 16.7, 11.22, 10.05, 8.8 and 7.3 mgkg^-1, respectively. For these dates, PRZM-3 model simulation results were 21.9, 19.89, 14.2, 10.62, 9.6 and 8.22 mg kg^-1, respectively and LEACHP model simulation results were 25.22, 21.3, 19.43, 18.58, 18 and 16.27 mg kg^-1, respectively. The simulation results showed that performance of PRZM-3 model was better than LECHM model in both treatments. In this research, the half-lives of 2, 4-D for 0-10 cm and 10-20 cm of soil depth were 7 and 33 days in a normal irrigation, and 9 and 34.65 days in a deficit irrigation, respectively.

---

Chemical fertilizers have important role in modern agriculture, and in the other hand led to rigid environmental pollution. Urea fertilizer is one of the most widely used and least expensive nitrogen fertilizers in Iran. Since it is high solubility in water a significant of it, if irrigation or precipitation is heavy, easily washed and led to change to change the quality of groundwater, rivers or seas. Hence, in this study the effects of deficit irrigation and fertilization on pollution using SWAT for Tashk-Bakhtegan basin (land area between Dorudzan dam and Khan Bridge) were simulated. This model by comparing model outputs with actual observations of hydrological, crop yield (wheat, barely, corn and rice) and nitrate by using SUFI2 algorithm in SWAT_CUP software were calibrated and validated. Then the calibrated model used to evaluate different management strategies (e.g. irrigation and fertilizer amount). When the impacts of different levels of urea (0 to 70 percent reduction in urea application) were modeled, yield of these crops reduced between 1 to 27, 0.8 to 24, 0.42 to 21 and 0.47 to 9 percent for wheat, barely, corn and rice, respectively. However, these tends to decline nitrate leaching 16-81, 18-80, 15-85 and 12.5 to 83.6 percent, respectively for these crops.  Therefore, by comparing yield and nitrogen loss changes, this result can conclude that a significant reduction in nitrogen loss by minimum cost on yield can achieved by optimize fertilizer application. 

---

In this research dense fluid discharge was experimentally investigated under the surface jet in the shallow acceptor. The investigated parameters were depth of the acceptor ambient, flow rate and the concentration of surface jet. In order to investigate the relationship between these parameters, a physical model experiments were performed in the hydraulic laboratory of Shahid Chamran University. The results showed that progressive length of the surface jet core is directly proportional to Froude number of fluid density, and is inversly proportional to fluid density concentration. Besides, the progressive length of the jet core increases with increasing the depth of the acceptor ambient. This length increase is due to the decrease of water surface tension. In average, increasing the depth of acceptor ambient twice, the progressive length will increase 38%, and its increasing three times, will increase progressive length of jet core 62%. Besides, in the relationship obtained for the progressive length of jet core R ² is 0.94.

---

The last two decades have seen increasing applications of digital terrain modeling in hydrological, geomorphological, pedagogical, and biological research, aided by rapid advancement of geographic information system (GIS). Hydrologic models are sensitive to change in the input values to the model, so the change of pixel size input data affects the output values of the model and produces different significant results. In this study, using topographic maps 1:25000 and 1:50000 and choosing ten pixel sizes (10, 15, 20, 25, 30, 50, 75, 80, 100, and 200) and software Arc GIS and HEC-HMS, output values of HEC-HMS model have been studied. Results of this study indicate that accuracy of peak discharge calculated by HEC-HMS model in the spatial scale map 1:50000 is more than the peak discharge calculated by HEC-HMS model in the spatial scale map 1:25000. Also accuracy of the calculated peak flows in a smaller pixel sizes (20 to 50) is more than the larger pixel sizes.

---

The uniformity parameters in drip irrigation system are influenced by the slope of manifold and therefore, the evaluation of drip irrigation systems is important in slopping lands. In this research, different slopes of 0.2, 6, 11, 16, 20 and 25% were applied on the ground surface and manifold of drip irrigation system with diameters of 50, 63 and 75 mm and length of 70 m were installed on these uniform slopes. The lateral pipes with 16 mm diameter and 40 m length were placed on the contour lines and connected to manifold bilaterally. The results showed that in the normal emitters in above slopes, the qv(avg) values were 289, 6740, 46, 135, 38 and 27 percent, respectively, qv(max) values were 222, 48, 53, 90, 27 and 9 percent, respectively, and the CV values were 300, 114, 33, 140, 63 and 25 percent, respectively, higher than compensating emitters. However, in the normal emitters in above slopes, the EU values were 33, 34, 12, 25, 17 and 9 percent, respectively, EUa values were 26, 23, 6, 21, 15 and 13%, respectively, UC values were 17, 16, 4, 13, 14 and 9%, respectively, and US values were 10, 8, 2, 8, 5 and 4 percent, respectively, less than compensating emitters. Therefore, even in high slopes (20 and 25%), the irrigation efficiency in compensating emitters were better than normal emitters. The relationship between slope and discharge of emitters represented small changes in discharge of compensating emitters in sloping lands.
 

---

---

---

---