WATER AND SOIL SCIENCE (AGRICULTURAL SCIENCE)
Year:2019 | Volume:28 | Issue:4 |Papers Count:17

The aim of this research is to evaluate some methods of developing analytical-probabilistic models in runoff volume estimation and it is shown that analytical models can be obtained with varying degrees of complexity based on different rainfall-runoff conversions. In this research, calibration and validation of analytical models were evaluated following a hybrid method. The efficiency of different types of rainfall-runoff transformations was measured in the western part of Kerman. The results of the analytical model were compared with the observed and simulated runoff with the storm management model (SWMM). According to outputs if for a runoff coefficient a value is considered in the range of 0. 6-0. 7, The first-order analytic-probabilistic model yields close results to the simulation ones that obtained from the storm management model with less relative difference. In order to evaluate the reliability of the analytical model performance, with the constant considering the permeability zone runoff coefficient, was gradually increased the Impervious component of the basin. The results indicate that with the gradual increase of the permeability of the basin, is less sensitivity the effect of the permeable area runoff coefficient on the annual runoff volume. Using this model, was obtained a good accommodation between observational and computational data. Analytical-probabilistic models due to less computations than continuous simulation models can be used as a continuous simulation model for analyzing urban runoff systems.

The water scarcity is one of the crucial problems in arid and semi-arid regions such as Iran. Therefore, application of unconventional water, where suitable quality water supplies are not available, is increasing. One of these sources is treated urban wastewater (TUW), which can supply water and nutrient requirements of plants. Therefore, in this research, growth and yield of corn (zea mays-single cross 260) and tomato plants (solanum lycopersicum tiger) were evaluated using TUW under greenhouse conditions. The experiment was done as a randomized complete design with three replications. In this research, three treatment of irrigation water were applied including TUW, alternative TUW-water and water. The results showed that the application of TUW had a significant effect on increase of the corn and tomato yields when compared to the treatment of water application. The highest and lowest impacts of TUW on tomato growth indices were related to leaf dry weight (28. 6%) and stem diameter (6%), respectively. Similarly, these extreme amounts in the corn were related to the grain weight (28%) and corn diameter (10 %), respectively. So, considering the water scarcity, this method can play significant role in the sustainable development and decreasing the irrigation and fertilization costs. Thus, application of TUW as a new water resource can reduce commercial fertilizer usage due to containing rich nutrient elements (nitrogen, phosphorus and other macro and micro nutrients).

The grain size distribution of the riverbed materials plays an important role in the erosion, sedimentation, change of river morphology and riverbank stability. The complex hydraulic flow on the one hand and the changes in the composition of the sediment of the riverbed as the eroded or deposited particles on the other hand causes changes in the sedimentation and erosion patterns at the river confluences. The literature review shows that few experimental studies have been conducted on this topic. Although applying numerical models are entwined with some limitations, they could be used as the suitable and economical tools. In the present study, firstly the SSIIM1 model was calibrated by the measured data at the confluence of the two rectangular open channels with the crossing angle of 60o and then, the impact of riverbed materials’ grain size distribution on sedimentation and erosion patterns was studied. In this regard, four types of grain size distribution with the same D50 and different standard deviation (σ g) values were applied and their results were compared with each other and with uniform distribution, as well. The results illustrated that the maximum depth of erosion was decreased by increasing σ g and its spatial location was closer to the downstream corner of channel confluences. Moreover, the maximum height of the sedimentation increased with increasing σ g. In the following, the spanwise changes in sediment concentrations and paths of maximum sediment transport have been detected.

In this research, using a split-block design and implementing two single-line source sprinkler systems, effects of 0, 90, 180 and 270 kg N/ha as urea source and 9600, 8550, 7500 and 6400 m3/ha of irrigation water on silage corn (Zea Mays L. ), S. C. 704 variety in two conventional and minimum-tillage systems were studied. The results showed that there was not a significant difference between water use efficiency, phosphorous uptake and foliages yield of two tillage systems. The main effects of water and nitrogen on the stems height and diameter, fresh foliage yield, nitrogen, phosphorus and zinc uptake and the amounts of soil organic carbon were significant at 1% level and on the dry foliage yield and water use efficiency were significant at 0. 05% level. At all levels of nitrogen, agronomic and physiological efficiencies in conventional tillage were higher than those in minimum-tillage system. The optimum amount of foliage yield in conventional tillage system was obtained from combined application of 8550 m3/ha water and 90 kg N/ha and in minimum tillage was obtained from combined application of 7500 m3/ha irrigation water and 270 kg N/ha. In terms of water use efficiency, in conventional tillage, combined application of 180 kg N/ha and 7500 m3/ha of water and in minimum tillage combined application of 180 kg N/ha and 6400 m3/ha of irrigation water were superior treatments. Based on obtained results, minimum-tillage system can be used instead of the conventional system in the similar corn fields but more nitrogen and less water is required.

The study of population and survival of enteric bacteria in vegetables is very important in order to keep health and to inhibit epidemic diseases. The aims of this study were assessment of coliforms in soil and in tissues of the vegetables irrigated with untreated municipal wastewater in Hamadan, Iran. Samples of aerial parts of the vegetables and the soil around the roots were taken monthly from May to September, 2011. The abundance of E. coli, the lactose positive and negative coliforms in soil were 5. 32, 5. 81 and 5. 39 log CFU g-1 respectively. The difference between the numbers of the lactose positive and negative coliforms in the soils irrigated with the untreated wastewater and their numbers in the control (Hydare) soil was not significant (p>0. 05) in June and July. But their numbers were significantly (p<0. 05) lower in the control soil in September. The means of E. coli, and the lactose positive and negative coliforms in the tissues of vegetables were 0. 3, 3. 97, 3. 72 log CFU g-1 respectively. The E. coli was not detected in the vegetables in most cases. Irrigation with the untreated municipal wastewater had a significant effect (p<0. 001) on the abundance of the lactose negative coliforms in the tissues of vegetables. The highest abundance of lactose negative coliforms was found in the Farhangian vegetables (4. 58 log CFU g-1) and the lowest abundance of the lactose negative coliforms was found in the Hydare vegetables (1. 08 log CFU g-1). The numbers of the lactose positive and negative coliforms in the vegetables did not have significant correlations with their numbers in the soils but they had high significant correlations with their abundances in the irrigation waters (p<0. 001).

Generally, side weirs are used for regulating and controlling the flow in the main channels. U-shaped channels are used as transition structure from rectangular to circular cross-section in sewage systems. This study presented a flow field simulation in the U-shaped channels along a side weir using FLOW-3D software, the RNG k-ε turbulence model, and volume of fluid (VOF) scheme under the subcritical and supercritical flow conditions. The good agreement was obtained between the results of the numerical simulation and the experimental measurements for both flow regimes. For example, the root mean square error for subcritical and supercritical flow regimes was computed as 2. 86% and 2. 21%, respectively. In subcritical flow regime, a secondary flow was created in the main channel which developed toward the downstream. The lateral flow increased from the beginning of the side weir toward the downstream end of the weir under supercritical flow regime. The effects of the side weirs submergence were investigated on the flow pattern in the main channel too. The maximum transverse velocity almost happened at the middle of the submerged weir length.

One of the problems associated with the sub-surface water intake systems is the sediment inflow control, which is usually solved by a filtration system. Geotextile filter is one of the filter types for controlling sediment in the subsurface water intakes. In this research in order to investigate the capability of geotextile filter for filtration of water through the sub-surface vertical pipe intake, various experiments with different arrangement of the geotextile were carried out in a flume with the height of 1. 2 m, width of 0. 5 m and a length of 5 m, located in Soil Mechanics Laboratory of Shahrekord University. Based on the dimensional analysis, the effective parameters on the discharge capacity and the filtration efficiency were identified. The results showed that the different arrangements of the geotextile filters (laminated and rolled geotextile sheets) did not show a significant impact on flow capacity of the system. The results also showed that the sediment trap efficiency for rolled geotextile sheets was obtained 60 to 70 percent but it was about 80 to 90 percent for the laminated geotextile sheets. It indicates that the laminated geotextile sheets controlle the sediment by 36. 6% more than the rolled geotextile sheets.

In order to precise design, the determination of flow behavior in open channels have always been subjected by the hydraulic researchers. The traditional Manning-Strickler, Keulegan, and Colebrook-White equations provide inaccurate estimations for resistance coefficients in roughened rectangular channels. In this research, flow resistance coefficients both in smooth and rough rectangular channel sections were investigated by using experimental models and three types of river materials. The results show that the revised Strickler formula estimates Manning's n with an average error about 2. 56%; and the revised Keulegan equation for smooth and Colebrook-White equation for roughened channels give some good agreements with the experimental measurements by an error of less than 4. 91% and a correlation coefficient of 0. 983. Some empirical derived equations are also presented which gives the value of Nikuradse sand equivalent roughness, ks, as a function of roughness diameter size. A new explicit formula presented for friction factor, f, using gene expression programming (GEP) for uniformly roughened rectangular channels with an average relative error 5. 1% and the corresponding correlation coefficient, 0. 981.

In order to investigate the effect of acid humic application method including soil application, spraying and fertigation on iron (Fe) supplying in rapeseed, an expriment was caried out consisting of 10 treatments and 4 replications. Treatments included humic acid soil application in three levels (1, 2 and 4 g kg-1 soil), spraying at three levels (0. 1, 0. 2 and 0. 4%) and with fertigation at three levels (1000, 2000 and 4000 mg L-1) and control treatment (without humic acid). The results showed that the highest total iron and active iron concentration in stalk was 85 and 44. 9 mg kg-1, respectively, in the treatment of 2000 mg L-1 of humic acid with fertigation, and the lowest value, respectively, with an average of 54. 62 and 20. 40 mg kg-1 for control treatment. Also, the ordre of significance for extractable-Fe from the pot soil by various extractants was as follows: rapid ammonium oxalate > hydroxylamine hydrochloride >AC-EDTA> DTPA> AB-DTPA >EDTA. The results obtained in present study showed that extracted iron was significantly correlated with chlorophyll content by most of the extractants. Among extractants, only extracted Fe with DTPA correlated positively and significantly with total Fe (r=0. 69*) and active Fe (r=0. 79*) while, total iron of leaf had weak and non-signifcant correlation (r= 0. 35) with DTPA. Based on the results of this study, active iron measurements can be a suitable method for predicting iron deficiency in canola plants.

Water quality assessment of rivers, in order to insure human health and environmental sustainability, is one of the most important purposes of the physical and numerical models of solute transport in rivers. In this research, some tracer experiments were done and also the numerical model of OTIS was used to simulate solute transport. This model predicts the solute BT curve for a given hydraulic and geometrical parameters at downstream sections of river with respect to concentration of pollutant resource at upstream boundary condition. The experiments were conducted in a flume with length, width and depth of 12, 1. 2 and 0. 8m. Two longitudinal slopes of 0. 004 and 0. 007 and three discharges of 7. 5, 11. 5 and 15. 5 (l/s) were selected for the experiments. A given mass of NACL solution was instantaneously injected into upstream of the flume and then the breakthrough curves were plotted based on the measured electric conductivity values along the centerline of the flume for the different sections at downstream of the injection point. To assessment the goodness of the simulated and observed BT curves, the statistical indices including the root mean square error (RMSE), Nash and Sutcliffe (NS) and mean absolute error (MAE) were extracted. With comparison of the observed BT curves with the numerical results (obtained with OTIS), the longitudinal dispersion coefficient values in different reach of flume were calculated. Analysis of the results showed that for a constant longitudinal slope and discharge, by increasing the distance from the injection location, the coefficient of dispersion was increased. Also, for constant slope, with enhancing the discharge rate, the dispersion coefficient was increased but for a given discharges, the dispersion coefficient was decreased with increasing the longitudinal-slope.

Because of environmental crises duo to drying of Lake Urmia, the need for applying high efficiency irrigation systems is important in this watershed. Drip irrigation systems are suitable solutions for optimal use of water resources. Drip irrigation implementation requires analysis of water quality to avoid emitters clogging. In this study, qualitative parameters of springs in part of West-Azerbaijan province including the electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR) and Langelier saturation index (LSI), were determined and investigated for application in drip irrigation systems in the study area. So, quality information of 1705 springs in the study area were taken from West-Azerbaijan regional water company and analyzed. Results indicated that the LSI has positive values in 87. 3% of springs, so there is the Carbonate sedimentation potential. In 11. 0% of springs TDS has amounts between 1000-1500 mgL-1 that is hazardous. TDS values in 33. 4% have amounts between 500-1000 mgL-1 and in 55. 6 % have amounts between 0-500 mgL-1 which are not hazardous. SAR values in 97. 7% of springs are in the suitable class. To select a suitable interpolation method to provide the zoning map, various interpolation methods were evaluated using normalized root mean square error (NRMSE) and relative error (RE) statistics and the kriging method with the least errors than other methods, was used to interpolation of quality parameters. Application of spring's water in West-Azerbaijan province for drip irrigation is recommended; however, the risk of emitter clogging especially in the northern parts of the province is high.

Soil quality appraisal is essential for sustainable agricultural production and should provide some information for decision. In this means soil quality indicators are introduced as criteria for assessment. This research was conducted to determine a suitable crop rotation system in parsabad region of Ardabil province, based on diffrent soil quality indicators. Three adjacent sites under rice cultivation that their second cultivation were fallow, clover and wheat with at least 4 consecutive years under this crop rotation, were selected. Soil sampling was performed on a random pattern from depth of 0-50 cm (30 samples in each plot) after secend cultivation harvest. Statistical results revealed that the frequency distributions of all variables were normal. pH and microbial biomass (C) had the lowest and highest CV among the three selected rotations respectively. Analysis of Variance (ANOVA) and comparison test revealed that there were significant differences between the soil quality indicators. Organic matter content, total nitrogen, microbial respiration, cation exchange capacity, aggregates’ mean weight diameter and microbial biomass C were significantly greater in Rice-clover rotation systems than those in the other systems. However, bulk density and textural fractions components were not significantly different in the crop rotation systems. Overall results of this research showed that the rice rotation with legumes such as clover over a long time improved the soil quality.

The current study is conducted to identify and compare soil quality index in different land covers including three afforestation masses (Alnus subcordata, Populus deltoids a Taxodium distichum) and a natural mixed stand (Quercus, Carpinus betulus, Parrotia persica) located in Caspian forest seed center (Amol Province). In each of the masses, along four 200-meter transects, four soil samples (with a 20×20 m2 quadratic sampler with 10 cm depth) at 60-m intervals were taken. A total of 16 samples were collected from each forest. The soil properties including bulk density, organic carbon, total nitrogen, nitrate, ammonium, papulation of earthworms, and soil microbial respiration were measured in vitro. Finally, using the obtained values, rate of mineralization of the soil carbon, as well as the soil quality index were measured for each of the studied masses. ANOVA analysis of the physical, chemical and biological properties of the soil samples, taken from different forest stands, indicated significant statistical difference between them at level of 99%. Alnus Subcordata significantly showed the highest soil quality index (5. 84 at 95%). Other masses, i. e. Populus deltoids, natural mixed, and Taxodium with quality indices values of 5. 26, 4. 66, and 4. 40, respectively, were the next ones in the categories. The results indicated the very effective role of Alnus Subcordata forest cover in improving the quality of soil ecosystem.

Investigating groundwater level variations is very important for sustainable management and planning of water resources. In the present study, groundwater system response to the consumptions and surface water discharge were utilized as input variations of nonlinear regression and gene expression programming models to estimate groundwater table. The used data consisted of monthly consumption amounts, surface discharge rates and groundwater levels of Bam Normashir plain (Kerman province) during the period of 2002 to 2011. The cross-correlation analysis indicated that 12 lagged monthly surface discharge as well as the current monthly consumption values had the highest impact on groundwater level fluctuations. The global relationship between these three variables was obtained using the two equations produced by ordinary nonlinear regression and gene expression programming (GEP) model. For estimating the groundwater level fluctuations, the consumption magnitudes and surface discharge values were predicted using artificial neural network (ANN) and Thomas-Firing methods, respectively. Then, the values were putted in the regression-based equations to predict the groundwater level. The obtained result revealed that in the case of using observational data, the performance of GEP was slightly better than regression models (RMSE and MAE values were 0. 793, 0. 636 meter respectively), while by use of the data produced by employing Thomas-Firing and ANN, the regression models gave a promising result with RMSE and MAE values of 1. 437 and 1. 118 meter, respectively.

In this study, the applicability of 16 series of the developed pedotransfer functions for estimating soil water characteristic curve (SWCC) of 57 soil samples from Mazandaran and East Azarbaijan provinces were examined. Clay, sand and silt percentages, bulk density, soil particle density, organic carbon percentage and depth of sampling were used as readily available soil parameters to estimate the water contents at different matric suctions, while parameters of Brooks and Corey and van Genuchten models were considered as difficult to measure soil parameters. The measured and estimated water contents at the different matric suctions were compared with each other and the pedotransfer functions were evaluated by statistical criteria. The results showed that clay and organic carbon percentages and bulk density had significant correlations with the most of the coefficients of the Brooks and Corey and van Genuchten models. The Campbell and Shiosawa parametric pedotransfer functions with the inputs of clay and sand percentages and bulk density had the amounts of IRMSE=0. 0676 cm3cm-3 and AIC=-3600 (the best model) and Mayr and Jarvis parametric pedotransfer functions with the inputs of clay, silt, sand and organic matter percentages and bulk density had the amounts of IRMSE= 0. 2452 cm3cm-3 and AIC=-1900 (worst model), for the 0 to 15000 cm matric suctions. The results showed that some of international pedotransfer functions could be used to estimate the water content of Iranian soils.

Nowadays, due to increased water consumption and demands, optimum water allocation should be taken as a serious need. In this research, WEAP and Vensim softwares are used to plan and manage the water resources and demands in Nazloo River basin, located in West-Azarbaijan province. By use of these softwares, two models were prepared: One for supplying water demands of the region using river flows (without Nazloo dam) and the other one with the same condition but by considering the Nazloo dam operation effect. Water demands of the region were assessed up to 2016, river flow of the past 40 years was analyzed, and river discharge of 2013-2016 was estimated by ARIMA method. Results showed that average differences between the results of WEAP and Vensim softwares were 3. 74% and 8. 91% for the with-dam and no-dam options, respectively. The highest water deficiency was in water supply to agricultural demand in September, which with construction of the dam, the average supply in this month increases from 15. 8% to 94% of the demand amount. To verify the obtained results of the unmet water demand in various years, the SPI index was used, which in 72. 5% of the cases it was consistent with the results of the softwares. In general, without constructing the dam, water needs of industry and environment will be mainly supplied, but there would be some deficiencies in water supply for agriculture. For water supply, instead of constructing a dam with a storage capacity of 154 MCM, a dam with a capacity of 100 MCM will be enough.

Loess– paleosol sequence is a valuable information source related to previous climate of the environment. Studying clay minerals is a suitable index for evaluation of climate change in previous conditions. The aim of this study was to study the evolutionary and mineralogical indices according to Infrared Spectrum Transformation and analyzing X-ray Diffraction in a loess– paleosol sequence in Neka region, Mazandaran Province. For this purpose, a transect was selected and were conducted. Disturbed and undisturbed soil samples from 13 identified horizons and layers were selected for physical, chemical and mineralogical analysis. Results showed that studied soil experienced four soil formation stages. Mineralogy results showed that in paleosol, presence of weathered minerals like smectite, vermiculite and mixed minerals including smectite-ilite represent moister and weathering-favorable conditions during interglacial period. Presence of primary clays and without evolution as loess covers represents glacial arid and cold conditions. Results of investigations indicated that at initial stages of soil weathering and development, it is possible to releasing non-crystalline (active) iron from soil minerals being more than crystalline (pedogenic) iron and cause increasing Feo/Fed ratio, while by increasing soil age and degree of evolution, pedogenic iron increases and reduces the ratio. Mineralogy using infrared spectroscopy confirmed presence of kaolinite in old horizons.