نشریه دانش آب و خاک
سال بیست و دوم شماره 4 (زمستان 1391)

The application of chaos theory and genetic programming has been gained a special attention in hydrology by abilities of these two models. In this study, a daily streamflow series with 30 years records of Lighvan River has been studied using these models. First in chaos theory, possibility of the existence of deterministic chaos in the daily streamflow series has been investigated by employing the correlation dimension method and after determination of the necessary parameters for reconstruction of phase space; daily streamflow is predicted by the use of local prediction method. To reconstruct the data pertaining to phase space, the time delay and embedding dimension are needed. For this purpose, autocorrelation function and algorithm of false nearest neighbors have been used and the amount of the obtained correlation dimension expresses chaotic behavior in the time series under investigation. Finally, local prediction method was used for prediction of the daily discharge and the results illustrate acceptable accuracy of this theory. The genetic programming has been used for daily discharge modeling and the best input pattern consists of antecedent discharge with four time lags has also been selected. The obtained correlation coefficient being equal to 0.926 from local prediction method and 0.931 from genetic programming indicate good accuracy and similar results obtained from both methods for streamflow prediction. Thus, according to the obtained results, both methods can be used for streamflow prediction and modeling.

Plant growth promoting microorganisms enhance plant growth and yield by virtue of direct and indirect mechanisms. In this study the effects of plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on plant height, yield, chlorophyll a, b, relative water content (RWC), carbohydrate and proline content of Hyoscyamus plant were evaluated. The soil was polluted with different concentrations of cadmium (0, 10, 30 and 100 mg kg-1 soil), and experiment was done in a factorial with randomized complete block design with three levels of microbial inoculation including fluorescent Pseudomonads as PGPR (P. putida, P. fluorescence and P. aeruginosa), fungal inoculation with Glomus species as AMF (G. mosseae, G. intraradices and G. fasciculatum) and control condition (no inoculation). The results indicated that the experiment treatments increased significantly (P≤ 0.05) plant height, shoot dry weight compared to control condition. Furthermore, as cadmium concentration raised in soil the contents of chlorophyll a, chlorophyll b, and relative water significantly decreased. However, plants inoculated with PGPR and AMF showed considerable amount of chlorophyll a, b as well as RWC. Under Cd contamination, the contents of soluble sugar and proline increased in inoculated plants in comparison to control plants. Cd addition also significantly decreased (73% compared to Cd0) mycorrhizal root colonization. It is concluded that at the presence of Cd, inoculation with PGPR and AMF could sustain and promote plant growth.

The oxidation of Cr(III) to Cr(VI) in soils causes an increase in chromium mobility and subsequent environmental risks. In this research the influence of pH, Cr(III) concentration and the nature of background solution on chromium oxidation in some soils of north and north-west of Iran were investigated. The results showed that oxidation of Cr(III) to Cr(VI) in nitrate medium increased with increasing pH from 3 to 5, whereas such oxidation in chloride medium became greatest at pH=4. With increasing chromium concentration, percentage of Cr(VI) production decreased in chloride medium and was nearly constant in nitrate media. Oxidation of Cr(III) to Cr(VI) in chloride medium showed a rising increase during the experiment, whereas such oxidation reached a maximum during 30 minutes or earlier in nitrate medium. According to the results, the amount of Cr(VI) production in nitrate medium showed no relation with any general properties of the soils. However, the amount of Cr(VI) production in chloride medium was positively related to easily reducible manganese in the soils. Also, kinetics studies showed that parabolic diffusion equation was best fitted to the data of the oxidation of Cr(III) to Cr(VI).

In order to study the effect of biological and chemical phosphate fertilizers on growth trend, physiologic indices and biological and grain yield of maize under deficit irrigation conditions in Karaj region, an experiment was conducted as split-split plot arrangement based on randomized complete blocks design with three replications. The experiment treatments were included: irrigation (full and deficit irrigation), phosphate biological fertilizer (co-application of mycorrhizal fungi and Pseudomonas fluorescens bacteria, application of Pseudomonas fluorescens bacteria, application of mycorrhizal fungi and control) and chemical phosphate fertilizer (optimized consumption of triple superphosphate, consumption of rock phosphate and control). The results showed that the maximum leaf area index was equal to 3.9 with 1350 GDD and maximum crop growth rate was equal to 3.4 g m-2 with 1150 GDD obtained with co-application of mycorrhizal fungi and Pseudomonas fluorescens bacteria treatment under full irrigation condition. Application of mycorrhizal fungi and Pseudomonas fluorescens bacteria compared to the control treatment increased leaf area index, crop growth rate, relative growth rate and biological and grain yield of maize under both full and deficit irrigation conditions. The co- inoculation of seeds with fungi and bacteria increased 5.13 and 11.76 percent leaf area index and crop growth rate in terms of the optimized consumption of triple superphosphate than rock phosphate, respectively. Grain yield and biological yield at co-application of AM fungi and Pseudomonas fluorescens along with optimum consumption of triple superphosphate were also higher by 15% and 13.6%, respectively, than application of microbial inoculants along with consumption of rock phosphate. Overally, results of this experiment showed that application of mycorrhizal fungi and Pseudomonas fluorescens bacteria reduced negative effects of stress on investigated traits. Application of microorganisms along with balanced consumption of phosphorus chemical fertilizers also increased growth indices and grain yield and reduced consumption of phosphorus chemical fertilizers.

In the present study, the width and height of steps, also the slope and height of spillways are considered as varied parameters, and has been tried to represent a comprehensive method for optimal designing of stepped spillways. For this reason, a complete program has been written in Matlab programming environment. In this program, Genetic Algorithm has been used for optimization. A stepped spillway with optimized dimensions was designed instead of a smooth spillway of Saroogh Reservoir Dam, which is located in West Azarbaijan province. The results showed that the replaced stepped spillway led to increase the energy dissipation and declined the dimensions of energy dissipator at toe of the stepped spillway. Also, for a constant discharge and varying slope, the variation of optimum height of steps was negligible. The sensitivity analysis of objective function showed that the relative energy dissipation on the stepped spillway for a constant discharge was independent of optimum height of steps and it was decreasing by increasing the slope of spillway. Also, increasing the discharge led to decrease the energy dissipation and increased the optimum height of steps for a constant slope. Results show with the slope 11.3 (%) and discharge 422 m3/s, the proper step height is 1.6 m and energy dissipation is 60.42 (%). With the same slope but discharge 776.9 m3/s (design discharge), proper step height is 2.25 m and energy dissipation is 43.7 (%).

Side weirs are flow diversion devices which are widely used in irrigation and drainage systems as a head regulator of distributaries, land drainage and urban sewage systems. In this research, flow pattern and free surface of water in a channel with a sharp crested side -weir is simulated by using FLUENT software. The volume of fluid (VOF) scheme and RSM turbulence model are used for numerical simulation of the turbulent free surface flow. Comparison between numerical results and laboratory measurements of water surface profile and channel discharge show that the model can predict the flow pattern over side weir with reasonable accuracy. By comparing flow patterns over a side-weir within the maximum and minimum discharge ratio it was revealed that, distance of the dividing stream surface from left wall varies in depth. Also size and location of 3D vortex flow is dependent on discharge ratio of side-weir.

Runoff estimation is almost one of the main concerns of hydrologists, water resources managers and planners. Unit hydrograph models are the most popular and widely used tools to model the rainfall-runoff process. Ralating Synthetic Unit Hydrograph models to watershed geomorphologic properties can provide a reasonable representation of runoff estimation by considering both rainfall and watershed characteristics and extend the usage of SUH models in ungauged catchments. This study evaluates three conceptual reservoir based rainfall-runoff models including Geomorphologic unit hydrograph reservoir (GUHR), NASH and HYBRID models for four rainfall-runoff events in Kamanaj Olia watershed located in eastern Azerbayjan province. Comparison of resulted and observed unit hydrographs using five error criteria;(coefficient of determination, Nash- Sutcliffe, error in volume of hydrograph, error in peak flow and time to peak) indicated desirable accuracy estimation through all three models. All three models computed peak flows smaller than those of observed, but generally GUHR model simulated peak flows and time to peaks better than others.

This research was conducted to evaluate the effects of single and co-inoculation of maize plant (Zea mays L.) with Bacillus mycoides and Glomus mosseae, both indigenous to the contaminated areas, on the growth, and nutrients (P, Fe, Zn and Mn) and cadmium uptake in the soil polluted with Cd (0, 100 and 200 mg/kg). At the levels of 0 and 100 Cd(mg/kg) there were observed the improvement of plant growth and symbiosis potential (root colonization and soil spore numbers), the increase of shoot nutrients (P, Fe, Zn and Mn) uptake and the decrease of Cd concentration and uptake in root and shoot of plants co-inoculated with B. mycoides and G. mosseae in comparsion with single inoculation of plant with B. mycoides. At the level of 200 Cd (mg/kg), plants inoculation with G. mosseae was the most effective treatment in plant growth improvement and nutrients uptake. Co-inoculation of plants with B. mycoides and G. mosseae increased and decreased root and shoot Cd uptake respectively compared to the plants colonized with G. mosseae. As the levels of Cd increased, plants colonized with Glomus mosseae had higher amount of biomass, root colonization, shoot P, Fe, Zn and Mn concentration and uptake, and Cd uptake of shoot and root than those of the control plants. At levels of 100 and 200 Cd (mg/kg), the most effective treatments in Cd uptake of the plant were control and inoculated treatments wtith G. mosseae respectively.

Micromorphological observations on aggregates size, pores and their distribution can provide precise expression of soil structure and simplify the interpretation of soil behavior. This research aim was to study the effect of two natural organic conditioners (vermicompost and manure) on soil micromorphological characteristics such as pore and aggregates size distributions, total porosity and microstructure in a sandy loam soil. In this study it was assumed that the aggregation and porosity increase due to reduction in macro and micropores portion with respect to mesopores in soil, and the structure of the soil improves comparing with the control treatment. Soil sampling has been done by Kubina boxes (3×4×6 cm) in 0-30 centimeters of topsoil of soil columns treated by two conditioners and incubated during 30 or 180 days at 0.75Fc. All samples were impregnated with resin and hardener after drying and then thin sections were prepared and finally studied with polarizing microscope. Based on the obtained results, structure development by both conditioners especially at the second application rate (5 & 25 g/kg dry soil for vermicompost and manure, respectively) and 180 days of incubation was observed that had remarkable effect on aggregation and caused large and highly developed aggregates. Both organic conditioners increased meso and macropores conspicuously at the second application rate and 180 days of incubation.

In recent years technical tools have shown great progress for modeling many problems of water resources. Multiple criteria decision-making process is a helpful tool to resolve water management issues. Fuzzy analytic hierarchy process is a developed form of conventional analytic hierarchy process that confirms all the comparisons in the form of fuzzy logic. In this study a hierarchical structure was designed to determine water allocation priorities of Mahabad Dam's for water users of the dam water with different purposes. In this structure three criteria and six subcriteria were considered for six alternatives of water use of the dam. Results showed that the economic criterion with local weight of 0.45 was the most important one. In addition the allocation of water to the agricultural sector with a global weight of 0.356 was the first priority and other priorities were urban drinking, recreation - environmental, power generation and flood control respectively.

Several quantitative stability indices including wet aggregate stability (WAS), mean weight diameter under fast wetting (MWDf) and dispersible clay (DC) have been employed to evaluate soil structure stability. Polyacrylamide (PAM) and organic matter as soil conditioners are vastly used to improve soil structure. This project was carried out to study the effects of PAM and organic matter on aggregate stability of two sandy loam and clay loam soils. It was conducted in pot under greenhouse conditions with applying anionic PAM at three rates (0, 10, 30 mg kg-1), organic matter to form decomposed animal manure < 0.5 mm at two rates (0 and 5 % by weight) and cycles of wetting and drying at five rates (1, 3, 5, 10, 15) with moisture contents ranged from FC to about 1/2 FC. The pots were kept at 22 – 250C under laboratory condition. The experiment was conducted as a factorial based on randomized complete block design with three replications. Indices of WAS, MWDf and DC were measured after 1, 3, 5, 10 and 15 wetting and drying cycles in three replicates. Results showed that with 5 % OM and 30 mg kg-1 PAM, WAS increased about 3.28 times in sandy loam and nearly to 2.4 times in clay loam soil. The climax effect of PAM on WAS in sandy loam occurred after 3 cycles of wetting and drying and thereafter it gradually declined to about half. In the clay loam soil both WAS and MWDf steadily increased up to 15 cycles and never decreased. The effect of PAM on DC at both rates of PAM application was the reverse of WAS and MWDf. As an organic amendment, PAM appeared to have great ability in improving structure stability in both soils.

Surface drip irrigation system tends to improve irrigation efficiency, and this system is appropriate for solving the problems of water deficit. However, using this method needs economical analysis. In this study, in summer of the year 2009 at a selected field in Marvdasht region in Fars province, the surface drip irrigation system was used for cropping corn. The experiment was arranged in a split plot based on randomized complete block design with three replications. The main plot consisted of three drip tape spacing (60, 70 and 75 cm), and the subplot had two levels of irrigation (full and alternate). The crop yield of each treatment was measured at the end of the season, and the partial budgeting method was used for economical evaluation of the treatments. The results demonstrated that the treatment of 60 cm drip tape spacing with alternate irrigation was the most economical state for corn cropping with surface drip irrigation system in the study area.

Recently, sewage sludge as a cheap organic fertilizer and rich in nutrients has received considerable attention in many countries. The aim of this study was to determine the effects of Tabriz petrochemical factory’s biological sludge on some soil biochemical and chemical indices such as the number of microorganisms, substrate-induced respiration, electrical conductivity, hot water-soluble carbohydrates and total nitrogen as well as their temporal variations in a calcareous soil selected from Mohaghegh Ardabili University’s Research Station. The greenhouse experiment was done as a factorial randomized complete block design with three replicates. The first factor was the rates of applied sludge as 0 (control), 25, 50, 75 and 100 ton/ha of air dry soil and the second factor was the incubation times as 30, 90 and 180 days. Incubation of the treatments was done at 22±4 ◦C and 0.75 field capacity moisture for 6 months. The results indicated that the all rates of applied sludge significantly increased the average of number of microorganisms, substrate-induced respiration, electrical conductivity, hot water-soluble carbohydrates and the percentage of soil total nitrogen 23, 53, 105, 58 and 138% as respectively compared to the control. Also, the effect of incubation time on all parameters except for the number of microorganisms was significant. The rates of carbohydrate and nitrogen in sludge treatments significantly increased at 180 days rather than the 30 days.

Morphometric analysis provides a quantitative description of geometric characteristics in a watershed to understand its morphologic conditions. These characteristics play an important role to estimate hydrologic variables in ungauged watersheds. In such watersheds, determination of morphometric similarities among sub-watersheds helps to prioritize soil and water conservation measures. In this study multi-averaging clustering technique or K-means Cluster Analysis (KCA) and Hierarchical Cluster Analysis (HCA) have been used to classify 24 sub-watersheds in Pol-Doab Shazand watershed using 10 morphometric parameters. After extracting morphometric parameters data were standardized. To determine proper numbers of clusters, Davis-Bouldin Index was used. Considering this index, 5 clusters have been chosen to do final classification of the sub-watersheds. The Results show that number of sub-watersheds based on KCA technique is 3, 7, 3, 7 and 4 for clusters 1, 2, 3, 4 and 5, respectively. The results indicate that number of sub-watersheds based on HCA technique is 3, 7, 2, 8 and 4 for clusters 1, 2, 3, 4 and 5, respectively. Comparison of the results reveals that 23 sub-watersheds (95%) out of 24 can be classified based on both techniques of KCA and HCA.