JWSS - Journal of Water and Soil Science

Potassium fixation is one of the most important factors influencing the availability of this ion for plants. This research was carried out to evaluate the relationship between potassium (K) fixation with some physical and chemical characteristics of soils and clay minerals and to investigate the effect of the dry and wet cycle on potassium fixation in Kakan Plain, in Kohgilouye & Boyerahmad Province. To measure the amount of Potassium fixation, four levels of K were added to the samples and the samples were shaken for 24 h and then dried in the oven at 50°C for 24 h. The drying and wetting cycle was repeated three times. Another set of soil samples was similarly incubated for a period similar to the previous treatment, but drying was performed at room temperature in an equilibrium state. The results showed that potassium fixation was increased with the potassium concentration increment, whereas K fixation percentage was reduced. Also, potassium fixation showed a positive significant relationship with cation exchange capacity (CEC) as well as clay content, in both normal and dry and wet treatments, and a negative significant relationship with organic carbon. Moreover, potassium fixation was enhanced with the increase of smectite content in both normal and dry and wet treatments. Besides, due to more organic carbon and less smectite, surface horizons fixed K less than the subsurface horizons.

Among the heavy metals, arsenic is known as a carcinogen material and its high concentrations in the ecosystem can be a major concern for public health and environment. The aim of this study was to evaluate the risk map of arsenic contamination and the possibility of its entering into the food chain using the fuzzy method in the central part of the Hamedan-Bahar plain. For this purpose, arsenic concentration in 94 points of groundwater and 49 points of surface soil was analyzed and evaluated in the study area. Soil physico-chemical parameters (clay, organic matter and pH), soil and groundwater contamination probability map, and land use map were selected as the input of this method. In the fuzzy method, two operators (and & or) were used. In order to standardize the parameters, the fuzzy linear function was used. Comparing the classified risk assessment using these operators showed that the results of the operator had the maximum trust. So in areas where concentrations of arsenic in soil and groundwater were high, the physico-chemical parameters such as pH, organic matter and clay content of the soil were low and agriculture products had a high ability to absorb heavy metals and ensure its better to use for the operator.

The effect of broad-leaved forest trees (Alnus glotinusa, Ulmus glabra, Popolus caspica and Parrotia persica) and their canopy position on soil C and N storage and mineraization in the plain forest areas of Noor was investigated. Soil samples were taken from two positions (near and away from the main stem) with the microplots of 30×30×15 cm. Litter (C and N), soil physical (bulk density, texture and water content), chemical (pH, EC, organic C, total N and available Ca), biochemical and biological (N mineralization and microbial respiration) characteristics were measured at the laboratory. Carbon mineralization rate (CMR) was calculated using the equation [incubation time period (hour) ×soil volume (gr) / CO₂ amount (mol C)]. Soil C and N storage (ton/ha) was calculated by C and N contents, bulk density, and the soil sampling depth. The results showed that there was no significant difference between the C storage under the studied tree spcies, whereas N storage presented significantly greater amounts, under Alnus glotinusa (0.79 ton/ha) rather than Ulmus glabra, Popolus caspica and Parrotia persica (0.69, 0.45 and 0.21 ton/ha, respectively). The higher values of soil C (0.001 mol C/kg) and N (0.3 ml N/kg) mineralization were significantly recorded under Alnus glotinusa instead of tree species. Soil C and N storage and mineralization process were not affected by the sampling positions. According to the results, soil C and N storage and mineralization were influenced by litter quality and soil chemistry.

In recent years, with the excessive use of underground water resources in the Malayer Plain, the water level has dropped sharply and underground water resources, which serve as the main source of water supply for the agricultural sector and drinking, the city is facing a serious risk. Because of the relevance of each of the fields with other agricultural fields around, this study was done to show the potential effect of this problem on the welfare. So, in this study, the special econometric method was employed. The purpose of this study was to analyze the welfare of farmers and how it is affected by the exploitation of underground water resources. For this purpose, by using social welfare function, the effect of change in the value of groundwater level of social welfare producers was addressed. The necessary information was collected from 119 questionnaires carried out in 2015 .Moran's I statistics showed that the results of special regression method were better than those of Ols. The results of this study indicates a decline in the welfare loss of groundwater level and the continuation of the harvest of underground water resources would lead to a reduction in access to water and reduced production. The rate of change in return for the welfare of the reduction of every meter of underground water level to cultivate wheat and potatoes was 6983 and 7634 million Rials, respectively.

Many studies have been done on various properties of dust and one of the most important characteristics of dust is the ability to carry different microorganisms from the source points. The aim of this study was to investigate the bacterial and fungal community of dust and to identify its dominance species in a single event of intense dust storm, in the northern regions of Sistan and Blauchestan Province (Sistan plain). Dust samples were accordingly collected by Siphon dust samplers after one of the most intense dust storms in 28-31 August, 2015, from 5 cities in the northern regions of Sistan and Blauchestan Province; after that, the microbial community of dust was determined by culturing in petri dish and its dominant bacterial and fungal species were identified. The results showed maximum aerobic and anaerobic bacteria population was observed in the Hirmand city dust (1875000 CFU/g and 156667 CFU/gr, respectively). The maximum aerobic fungi population was observed in the Zabol city (833 CFU/g) and the maximum anaerobic fungus population was observed in Zahak city (2167 CFU/g). The most frequent type of bacteria was Bacillus sp, which was followed by Streptomyces pactum. The most frequent type of fungi in this research was Penicillium sp and the second one was Aspergillus. The results showed the high and variated microbial community, especially pathogenic fungi associated with dust in this region.

Assessment of soil quality helps to make a balance between soil function and soil resources, improving soil quality and achieving the sustainable agriculture. For the quantitative evaluation of soil quality in the Shahrekord plain, Chaharmahal va Bakhtiari province, 106 compound surficial soil samples (0-25 cm) were collected. After the pre-treatments of soil samples, 11 physico-chemical soil characteristics/indicators as the total data set (TDS) were measured using the standard methods. Statistical analysis showed the usefulness of Principle Component Analysis (PCA) transformation. The minimum data set (MDS) was selected using PCA. Analytical Hierarchy Process (AHP) was carried out for the quantitative determination of indicator priorities and weights. Soil quality of the samples was calculated by introducing TDS and MDS into Integrate Quality Index (IQI) and Nemero Quality Index (NQI). The results showed the soil quality of the land uses was as Rangelands> Drylands<Irrigated croplands. The correlation coefficient between IQI-TDS and IQI-MDS was 0.97, while this value for NQI-TDS and NQI-MDS was 0.98. The correlation coefficient between IQI-TDS and NQI-TDS was 0.87 and that between IQI-MDS and NQI-MDS was 0.91. Classification of the resulted soil quality map IQI-TDS revealed that 12.5 % and 15.5 % of the plain were in very high and low quality conditions, respectively.

Studying the trends of water table in any region especially in arid and semi-arid regions is an important issue. This study focuses on assessing groundwater table changes in Tabriz plain. For this purpose, non-parametric Mann-Kendall test is used. In studing groundwater level the information of 14 pizometric wells in the period of 1991-2013 was used. Significant levels of 1, 5 and 10% were used for the trend test. Slope of trend lines is estimated using the sen's estimator method. The homogeneity of trends were tested using the Van Belle and Hughes method. The results showed that groundwater level in the most of pizometric wells have decreasing trend, That was significante in 1% sifnificance level. According to the research, trend of groundwater level was negative in all of the stations in April and maximum negative trend was belong to Dizaj Leily Khany station (Z= -6/47) that was significante in 1% sifnificance level. Also the minimum negative trend was belong to Ana Khaton station (Z= -0/322). The minimum groundwater level was -1.45 in Said-Abad station.

The present study was conducted to evaluate the ecological risk indices of Zn, Cu, Cd, Pb and Ni in the soils from Urmia region (Ghahramanloo village), as irrigated with treated wastewater. Accordingly, six different soil sites (five soil sites under wastewater irrigation and one soil site under well water irrigation as the control) were selected and sampled (AP horizon, 0-30 cm depth). Soil samples were air dried, passed through a 2-mm sieve, and analysed to determine the chemical properties and the studied heavy metals. The results showed that irrigation with the treated wastewater significantly increased the total elements in the order of Cd (228%)> Zn (118.5%)> Ni (81.5%)> Pb (54.2%)> Cu (23.5%). Nevertheless, with the exception of cadmium, other elements were within the admissible range based on the national and international standards. Ecological risk index (min = 125, max = 152, mean = 140) showed a considerable risk in all studied soils and Cd could be regarded as the major metal affecting the index yield.

In this research, conjunctive and integrated operation of surface and ground water resources of Behbahan plain (Maroon dam's reservoir and existing wells, respectively) was investigated. Simulation of allocation of water demands in this basin was performed by four scenarios, using WEAP software: 1) current conditions (M1), 2) reference scenario for the next 16 years (M2), 3) land development scenario (M3), and 4) optimal scenario (M4). The optimal scenario was performed with multi-purpose linear programming. Based on the results, drinking water demands was satisfied completely in all scenarios. Under the scenario of current conditions, all agricultural demands, except the traditional rights, supplied more than 50% in the low-flow months. In the reference scenario, water supply for agricultural demands in some months was less than 100% and even in June and July, the water supply for North and South Irrigation networks of Behbehan plain was less than 10%. In the land development scenario, agricultural demands of all irrigation networks, except Ramhormoz network, satisfied more than 90% in all months. The optimal scenario performed better than other scenarios for minimum Maroon River flow and volume of storage in the reservoir. Comparison of the four scenarios in satisfying the environmental needs also revealed that the optimal scenario performed better than the other three scenarios in the spring months. However, it provided less than 100% of water needs in the whole year. Comparison of the four scenarios also showed that the first two scenarios had the highest reliability percent in the Jayzan-Fajr, South Behbahan and North Behbahan Irrigation Networks and traditional water rights. Frequency of storage-time-probability from the storage volume in the optimal scenario also showed that maximum storage lifetime of the lasting storage volume was 558 million m3 (which was equal to half of the volume of Maroon dam’s reservoir) with the highest probability (60%).

Lack of the proper conjunctive use of surface and groundwater resources causes large water stresses in one of these resources. Conjunctive use of surface and groundwater, especially in arid and semi-arid regions, is a scientific and practical solution for sustainable water resources management. The aim of this research was to prepare some mathematical modeling to apply the conjunctive use of surface and groundwater in the Dehloran plain aquifer. In this study, the mathematical model of the Dehloran plain aquifer was developed using GMS 9.1 and the river data were entered. For the steady state condition, the time series data in the average year 2010-2011 were utilized. In the next step, the time series data from October, 2010, to September, 2011, were used for the unsteady state analysis. In the unsteady state, four stress periods were taken; then the model calibration was carried out in three steps for each stress period; after the optimization of the hydrogeological parameters of the model, its verification was done for the period of 2011-2012 period. After the calibration of the model in the unsteady state, the values of the mean error (ME), the mean absolute error (MAE) and the root mean squared (RMS) errors measured in piezometers were obtained to be -0.24, 0.46 and 0.65, respectively. The results of verification confirmed the ability of the model in simulating the natural conditions of the aquifer. Finally, applying different scenarios to the model showed that the proper conjunctive use of surface and groundwater could increase the volume of water at a rate of 2.23 million cubic meters per year.

Due to the impact of climate change on the plant water demand and the availability of water, especially in drylands, it is vital to estimate the evapotranspiration rates accurately. In this study, the vegetation status in the marginal desert areas of Varamin Plain was studied, and the actual evapotranspiration and water demand of intercropped farms were assessed. This study also evaluated the potential relationship between the evapotranspiration of different agricultural lands and their vegetation index using remote sensing techniques. A collection of satellite images from Landsat 7 in consecutive seasons was used to determine the greenness rate of marginal desert areas during 2013 and 2014. ENVI software was used for the image processing, which included geometric corrections and atmospheric corrections, to develop NDVI maps. Also, weather data and crop properties of Varamin Plain were collected, and the actual evapotranspiration rate of plant cover was estimated using CropWat. The correlation between NDVI extracted from satellite images and the evaluated evapotranspiration rate was assessed. The results showed a strong relationship between evapotranspiration of heterogeneous agricultural lands and NDVI. This confirmed that the NDVI derived by remote sensing approach could be a useful index to evaluate vegetation status and water demand of farmlands in the desert borders.

The study of floods has always been important for researchers due to the great loss of life and property. Investigation of flood bed can provide appropriate solutions to reduce this phenomenon to managers and researchers. In this research, the compound channel (with flood plain on one side of the main channel) Been paid, Therefore, two experimental models of compound channel in laboratory flume were examined by considering dimensional analysis. With the goal Investigation of lateral slope of flood wall in laboratory model In the first model, transverse slope 0 And in the second model, a value equal to 50% Was considered. Also in order to investigate the effect of longitudinal slope of river bed sediments Longitudinal slope in three steps 0.00 2, 0.004 and 0.006 Was changed. Examining the ADV speedometer data, the results showed that with increasing the longitudinal and transverse slope (slope of the flood wall) of the channel, the maximum longitudinal velocity changes to the floor of the channel. In order to investigate the effect of average sediment diameter on the scouring process during experiments Mm was used. The results showed that increasing the longitudinal and transverse slope had a great effect on increasing the volume of washed sediments 3 and 0.9 of sandy sediments with a diameter Along the canal and with the increase of these longitudinal and transverse slopes in the channel, more sediment transport volume occurs. In the following, using Investigation of dimensionless numbers obtained from dimensional analysis, dimensionless weight landing number was introduced to evaluate this value value of other hydraulic parameters and Was introduced. A relationship based on nonlinear regression with correlation coefficient Acceptable was introduced at around 0.88.

The upcoming climate change has become a serious concern for the human society. These changes, caused and aggravated by the industrial activities of the international community and the increase in the concentration of greenhouse gases in the atmosphere, are seen as a threat to the food security and environment. Temperature change and precipitation are studied in the form of different probabilistic scenarios in order to have an outlook for the future. The present study was conducted to address the effects of climate changes on temperature and precipitation in Qazvin plain in the form of five AOGCMs including Hadcm3, CSIRO-MK3, GFDL, CGCM3 and MICROC3.2, and 3 greenhouse gas emission scenarios of A1B, A2 and B1, based on different possible scenario combinations in the next 30 years, 2021-2050 and 2051-2080 (near and far future). On basis of the study results, all 4 target stations, on average, will have experienced a change between two ratios of 0.5 and 1.4 of  the observed precipitation period  by the end of 2050, and the mean temperature will have had a change  between -0.1 to 1.6 °C, relative to the observed period.  By the end of 2080,  the  precipitation will also have fluctuated between the two proportions of 0.5 and 1.7 times of the observed precipitation period and the mean temperature will touch an increase between 0.6 and 2.6 °C. Both SPI and SPEI indices suggest the increment in the number of dry periods in the near and far future. However, the total number of negative sequences differed considering the 3, 12 and 24-month intervals at the stations level. Given the SPEI index, as compared to the base period, the total negative sequences of drought and number of dry periods will increase at 3 stations of Avaj, Bagh-Kowsar and Shahid-rajaei-powerhouse and decrease at Qazvin station in the future; however, SPI gives different results, such that  for Bagh-Kowsar, there will be an increase in both total negative sequences of drought and number of dry periods, as  compared to the baseline period; three other stations will have more dry periods, specifically, but less total negative sequences. The results reported that the drought events would become severe, and the wet events would become extreme in the future.

Soil salinization is a phenomenon that threatens agricultural lands and natural areas, leading to reduced productivity, declinations of soil resources and vegetation covers, and finally, the abandonment of these areas. This study has quantified the groundwater Capillary Rise (CR) and actual Evapotranspiration (ETa) and their relationship with the soil salinity of Azadegan plain, west of Khuzestan Province. The study area has an arid climate, characterized by shallow and saline water table and a high potential evaporation rate. For this purpose, field samplings were carried out in four consecutive seasons of the year to measure salinity, soil moisture, and texture, groundwater table, and salinity at 27 scattered representative points of the study area. The CR values were estimated in different seasons of the year using UPFLOW model. Moreover, four representative Landsat satellite images were acquired to map seasonal changes of ETa through the SEBAL algorithm. Then, the effects of ETa on CR and consequent soil salinity build up were quantified in a seasonal time scale. The results showed that the average daily ETa of Azadegan plain varied from 1.55 to 7.96 mm day^-1 in different seasons which caused a capillary rise of around 1.2 to 1.5 mm.day^-1. This has led to the upward movement of 12 to 18.8 ton ha^-1  month^-1 of salts from shallow groundwater to the soil surface, which has caused surface soil salinization. Also, there was a close relationship between ETa, CR, and soil salinity parameters, which can provide insight into modeling of spatial and temporal changes of soil salinity and provision of solutions to reduce the accumulation of solutes in the soils of the study area.

In the past years, by increasing population and water consumption, as well as the high cost of developing surface water resources, the exploitation of groundwater resources has increased significantly. In the current situation, a significant part of the country's water consumption in all sectors of consumption is provided by groundwater sources. On the other hand, the development of industry and the entry of pollutants, including heavy metals, into the groundwater endanger the health of humans. The present research has investigated the non-cancerous risk caused by heavy metals in the groundwater of Urmia plain for both children and adults. This research is based on a descriptive-analytical method based on the available data, in which the concentration of polluting metals obtained from the studies conducted in the fall and winter of 2016 from the number of 12 wells supplying rural drinking water in the Urmia plain has been analyzed. Also, human health risk assessment was measured using the United States Environmental Protection Agency index. The results showed that there are six heavy metals including cadmium, copper, iron, manganese, nickel, and lead in the region's groundwater, among which two of the wells have cadmium and lead values higher than national and international standards. Also, the total non-cancer risk index through ingestion and skin absorption for both children and adults groups was found to be 0.23 and 0.096, respectively, which is less than one, and this indicates that the water quality of the region is suitable for drinking.