نشریه پژوهش های حفاظت آب و خاک
سال بیست و چهارم شماره 5 (آذر و دی 1396)

In regional and local climate studies usually coarse-resolution outputs of global climate models are downscaled to produce necessary fine scale data. Regional climate modeling is a dynamical downscaling method. In this study HadGEM2 general circulation model outputs have been downscaled by RegCM4 Regional Climate Model coupled CLM4.5 land surface scheme. The model was run over Toyserkan plain for a reference period (1999-2005) for model evaluation and a projection period (2015-2025). In the projection period, regarding to the importance of water resources in the study area, water budget components and surface water balance equation have been evaluated.
For the reference period, daily modeled precipitation, temperature and runoff were compared with observed values at available meteorological stations in the region. Modeling efficiency, correlation coefficient, bias, mean absolute error and root mean squared error statistical indices were used to evaluate model’s simulations. Modeled precipitation was compared with observations of 6 available stations in the region, Observed temperatures of the station of Hamedan- Airport were also used for modeled temperature verification; For runoff verification, the only river station at the outlet of the catchment was used. Projections are based on RCP4.5 scenario of the Fifth Assessment Report of Intergovernmental panel on climate change. For the projection period spatiotemporal variations of surface water budget components including precipitation, evapotranspiration and runoff have been studied and water balance equation in the catchment has been evaluated.
Model evaluation results showed that the model has its worst performance for runoff, because of low modeling efficiency and relatively large errors while has its best performance in simulating precipitation (especially for the first five stations) and temperature. Finally, the model shows its best performance for temperature and precipitation respectively, regarding to more positive efficiency, higher correlation and smaller errors. For the first year of projection period (2015) the highest values of precipitation occur in eastern and central parts while the lowest values occur in southwestern part of the catchment. Through the next 10 years (2016-2025), precipitation decreases in most parts except small parts in east and south of the catchment. The highest values of precipitation decrease (about %12) also occur in northeastern and central parts. Since the amount of precipitation determines available moisture, spatial distribution and variation of evapotranspiration are same as those for precipitation. The highest values of runoff occur in eastern and northeastern (high elevation) parts and during 2016-2025 a %30-50 increase in eastern part and a %10-20 decrease in central part will occur. Annual water budget evaluation shows that for 7 years there is a water balance, but for the remaining 3 years (2017, 2023 and 2024) differences between two sides of the water balance equation are large.
Considering small area of the catchment and short time of projection period that does not allow to detect impacts of climate change, small amount of mean 10-year difference between two sides of the equation (1.3 mm) shows that the model performance in estimating water balance for the catchment is acceptable. Generally, although the water balance estimation has been improved, the land surface scheme has shortcomings in water budget parametrization especially for runoff. But regarding to improvement of mean temperature simulation, model has an appropriate performance in simulating the energy budget.

Making an appropriate decision and providing solutions to improve the performance of irrigation networks require being aware of abilities and weakness of its components. This study initially identifies the upcoming treats, including natural, human-caused and operational hazards against the main water conveyance system in irrigation networks then presents a systematic framework assess the risk of irrigation network. Risk assessment method is widely used in the similar system such as urban water-supply system or wastewater collection, but so far it is not used in irrigation networks. This study at the first part has developed an integrated hierarchical such a way that it’s applicable for all of the irrigation districts considering different levels of operation and diversity of conveyance, regulation and delivery structures. At the second part assesses the risk of identified hazards.
by doing library research, field study and interview with experts, treating hazards of each component are identified. Likelihood, consequences of treating hazards and vulnerability of component against the hazards are determined by using questionnaires, and the risk of the component is calculated. To deal with the uncertainty of expert’s opinion, the calculation is based on triangular fuzzy numbers, and finally, in order to make the results of the model tangible, fuzzy numbers transform to crisp numbers. To obtain the weight of the component, treating hazards, consequence criteria, and vulnerability criteria method of the fuzzy analytic hierarchical process was employed and to aggregate, the result of risk assessment the method of simple order weighted was conducted.
the result of risk assessment revealed that at hazards level, the five riskiest hazard are: poor maintenance in the main canal with risk of 1.758, vandalism in Nyrpic module with risk of 1.6, poor maintenance in intersection structures with risk of 1.618, untrained operators’ error and inaccurate calibration in operation able gates with the risk of 1.54 and1.4. The result of risk aggregation according to hierarchical structure showed that in conveyance system among conveyance, regulation and delivery structures, the third one is the most critical structure with the risk of 1.966. Between two source of water supply, reservoir and well, the risk was obtained 1.274 and 0.99 respectively and indicated the criticality on the reservoir in compare with well. In the systems level conveyance system with the risk of 1.937 has the most risk. The result of model sensitivity analyses indicated that the change of overlap area in fuzzy membership, used in scoring stage, changed caused 1.2% and 2.12% change in decrease and increase mode respectively and the prioritization of the component and the riskiest hazards have no changes.
According to the founding of this research and determined risk value, hazards prioritization revealed that pain part of risky hazards generally categorized in hazards group which is related to the operation so concentration to an operation method and risk reduction of this threatening can bost the Reliability of system performance. Considering capability of the proposed model in determining the probability of hazard occurrence, multidimensional consequence and assessing the vulnerability of component against the hazards and also rectifying shortcomings of other conventional assessment methods applying the proposed model as a decision support method during management process and making decision recommended.

Zinc (Zn) is an essential micronutrient that the higher plants require it for normal growth and quality and quantity development. High soil pH, low amount of soil organic matter and high calcium carbonate content are the most important factors that led to a decrease of Zn bioavailability in soil. The aim of this research was to investigate the effects of arbuscular mycorrhizae fungi inoculation and application of two types of organic manures and their derived biochars on distribution of Zn chemical forms in a calcareous soil after corn cultivation using a sequential extraction procedure.
To do this research, appropriate amount of soil from the surface layer (0-30 cm) of a calcareous soil was collected, air dried and passed through 2mm sieve. A factorial experiment as a completely randomized design was performed with three replications under greenhouse conditions. The first factor including organic manure at five levels (without organic manure (C), sheep manure (SM), poultry manure (PM), sheep manure biochar (SMB) and poultry manure biochar (PMB) each at 2 % w/w) and the second factor was fungal inoculation at three levels (non-inoculation (NG), inoculation with Funneliformis mosseae (FM) and Glomus versiform (GV)). Biochars were produced using the pyrolysis of organic manures (500 0C during 4 h) in the limited oxygen conditions. After applying treatments to the soil, corn seeds (Zea mays L.) were planted in plastic pots and held for 10 weeks. Sequential extraction procedure of sing et al. was used to determine the zinc chemical forms in the soil after corn cultivation. This procedure separate the soil Zn into 7 different fractions including: soluble笗Ⅺ砞榹 (WsEx-Zn), carbonatic (Car-Zn), Organic (OM-Zn), Manganese oxide (MnOx-Zn), Amorphous iron oxides (AFeOx-Zn), Crystalline iron oxides (CFeOx-Zn) and Residual (Res-Zn).
The concentration of WsEx and OM fractions of Zn were significantly increased and Zn concentration in AFeOx and CFeOx forms were significantly decreased compared to control by application of fungi treatments. The greatest increase of Zn concentration in WsEx (31.9 %) and OM (12.9 %) forms were observed in the GV treatment. The sequence of effect of various organic treatments application on enhancement of Zn concentration in each chemical forms were different however, the effect of PMB treatment on increasing the concentration of most Zn chemical forms (Car-Zn (81.1 %), OM-Zn (42 %), MnOx-Zn (15 %) and AFeOx-Zn (14.1 %)) was more than the other organic treatments. Distribution of native Zn chemical fractions were as follows: Res >> CFeOx > AFeOx > Car > MnOx > OM > WsEx whereas the distribution of Zn chemical fractions as influenced by application of GV, PM and SMB treatments were changes in this way: Res >> CFeOx > AFeOx > Car > MnOx > WsEx > OM. There were positive and significant correlations between WsEx-Zn, Car-Zn, AFeOx-Zn and CFeOx-Zn fractions with DTPA extractable Zn, which is indicating the effective role of these fractions in the supply of required Zn plant. The results of interaction effects of treatments showed that the effect of simultaneous application of fungi and organic manure on the concentration of each Zn chemical fractions was different and depended on type of organic manure and mycorrhizae fungi applied.
Application of both species of arbuscular mycorrhizae fungi caused the conversion of Zn from less available forms to fractions with more bioavailability in the soil and the effect of the GV species was considerably more than the FM species. Also, Zn added to the soil as affected by application of organic manures, concentrated in fractions with more bioavailability and the effect of the PMB treatment was more obvious than the other treatments.

Effect of organic and inorganic acids in calcareous soils of Iran has not been properly investigated. The aim of this study was to evaluate the effect of organic acids of acetic, citric and oxalic acid and mineral acids of sulfuric and phosphoric acid on the soil pH and EC and release of essential nutrients in soil solution.
To investigate for releasing nutrient by organic and inorganic acids, the two calcareous loamy soil samples were used. Extraction of soil with solutions of citric, acetic, oxalic, sulfuric and phosphoric acid in concentrations of 1, 5 and 10 mM (25 ml of solution and 10 grams of soil) and deionized water as control for 1 hours was done. The pH value and electrical conductivity of solutions were measured immediately after extraction. Concentrations of potassium, phosphorus, calcium, magnesium, ammonium, nitrate, iron, zinc, copper and manganese was measured in the obtained extract.
In general, the pH value of the soil extractions decreased after one hour between 0.03 to 1.66 unit. The pH reduction was almost the same in both soils. The pH value was reduced with increasing acid concentration. Phosphoric acid treatment with 10 mM concentration in both soil samples showed the greatest decrease in pH. Various concentrations of organic and inorganic acids had a significant positive effect on released phosphorus, potassium, calcium, magnesium, nitrate, ammonium and micronutrients. The highest released P, Ca, Mg and ammonium with amount of 4.23, 1078, 2797 and 67.2 mg per kg of soil respectively and also the highest amount of Zn and Cu with amount of 61 and 74 µg per kg of soil was seen in 10 mM concentration of acetic acid in soil 2. The highest released K and nitrate with amount of 673 and 247 mg per kg of soil respectively was seen in 10 mM concentration of phosphoric acid in soil 2. The highest released Fe and Mn with amount of 5420 and 10320 µg per kg of soil respectively was seen in 10 mM concentration of citric acid in soil 2.
The results of this study showed that the use of organic and inorganic acids in the soil, depend on acid type caused the release of essential nutrients in short time (1 hour) in the soil solution. Also phosphoric acid has the greatest effect on soil pH reduction.
The results of this study showed that the use of organic and inorganic acids in the soil, depend on acid type caused the release of essential nutrients in short time (1 hour) in the soil solution. Also phosphoric acid has the greatest effect on soil pH reduction.

Phosphorus (P) has been one of the major nutrients limiting agricultural production in many rice growing regions of the world, and certainly this is the case in north of Iran, where soils deficient in proper and balanced P management in the cultivated paddy fields. Phosphorus (P) chemistry in paddy soils is complicated due to various chemical and biological processes involve in its availability through various P fraction pools. Therefore, P fractions play a crucial role on soil available P supplying capacity especially in paddy fields. Proper and effective managerial practices of P and assessment of their effects on rice production requires an understanding of their variability in concentration across the fields. The spatial variability of soil properties and P content is the outcome of the interaction of several soil characters and processes and in agricultural fields involves also effects of management practices. Thus, the objective of this study was to conduct a large-scale analysis of the spatial variability of available and organic P, and also inorganic P fractions, and the important physical and chemical soil characters on P factions’ distribution for better fertilizers managerial practices.
This experiment was conducted at Some-e-Sara city in Guilan province. Soil samples were collected from 103 paddy fields with uniform geographical distribution in grids of 2x2 km. Soil samples were analyzed to determine available P, organic P, their effective physical and chemical properties (Texture, pH, CEC, T.N.V, Clay and O.C), and also sequentially extracted to determine inorganic P fractions(soluble P, Al-P, Fe-P and Ca-P). Descriptive and spatial variability analysis, and mapping was done by using SPSS (ver. 16), GS (ver. 5.1) and Arc GIS (Ver. 9.1), respectively.
The highest coefficients of variation belonged to available P and its controlling P fractions, Al and Fe bounded P, about 132 and 194, respectively, whereas, pH showed the lowest CV, 10.6. The nugget to sill ratio ranged from 12 to 60% for almost all the studied data sets, showing moderate to strong pattern of spatial dependence. The small to moderate nugget effects also indicate that the sampling grid used was proper to reflect the spatial dependence of the studied soil properties and P fractions. Analysis of semivariogram corresponding to experimental data sets showed that the values for the range of spatial dependence of the semivariogram models varied from 2700 to 6000 m. Based on the results obtained from linear correlation analyses and spatial distribution maps, available P strongly correlated with both Al and Fe-P fractions and OC, about 0.84, 0.94 and 0.40, respectively.
Based on the results obtained from linear correlation analyses and spatial distribution maps, available P strongly correlated with both Al and Fe-P fractions and OC. Therefore, we concluded that determination of spatial correlation’s area of these soil chemical properties can effectively improve P fertilizers management in paddy fields. In this case, incorporation of remained rice straw with soil through shallow ploughing two weeks after grain harvesting enhance the oxidative condition of soil and consequent better straw decomposition increase the soil available P balance. These two mechanisms considerably decrease application of P fertilizers. Moreover, due to lack of, and/ or, insufficient P application in studied area, continuous flooding influence on available P condition by altering soil oxidative status to reduced, naturalizing the pH, and increasing P minerals stability.

Drought is a normal and continuous feature of climate. Although, Most of people consider as a rare and random event, But this phenomenon are main features and iterative in the different climate. From the perspective of meteorologists, there is no difference between Regions and temporal distribution rainfall in one or several seasons, only the amount of precipitation during the water year is especially important. Droughts often started from meteorological drought and hydrological drought, and goes to socio-economic drought. One of the problems that humanity is facing, especially in recent years, is the water crisis and drought. Almost every five years, a period of two or three-year drought in the country have been seen. This droughts reduced the groundwater and surface water resources and leading to reduce the amount usable water. This shows important of water resources management, the aim of this study is drought monitoring in the meteorological and hydrological aspect using the SPI and SDI indices in the West of Lake Urmia.
In this study, inspections and completing of the statistical gaps considered, and the number ten meteorological stations and five hydrometric stations with a length of 32 years selected. The Kolmogorov–Smirnov (K–S) used to check the goodness of fit for the precipitation and stream flow data using means of an adjusted normal distribution. After determine the correlation, Determined compliance classes between Standardized Drought Index and Stream-flow Drought Index with giving codes between one to eight climatic different classes introduced and calculate the sum of The Square for absolute value the difference between classes. The spatial distribution of drought severity obtained from the SDI and SPI indices in October–December (3-month), Oct–March (6-month) and 12-month (Year) of the 1999-2000 was shown. The Spearman correlation test was further applied to explore the relationships between meteorological droughts and hydrological droughts based on the SPI and SDI series respectively. Different combinations of periods including no-lag, 1 month-lag, 2 month-lag, and 3 month-lag between the meteorological and hydrological droughts considered.
Kolmogorov-Smirnov test results, showed that all of the series follow a normal distribution. The results of the goodness-of-fit K-S test showed that the log-normal distribution was the best fit probability distribution for the stream flow series and normal distribution for the period October-December and in other period's gamma distribution, was the best fit probability distribution for the precipitation series. The results of Spearman correlation and non-compliance between indices SPI and SDI For the entire study area shows, the highest correlation is related to the period of October-June. The Spearman correlation analysis was applied to explore the relationships between meteorological and hydrological droughts which indicated a strong correlation between Apr–Jun -SPI series and the May–Jul -SDI series with a value of 0.67.
This study aimed at Monitoring droughts meteorological and hydrological using the SPI and SDI indices by considering the different delays in the West of Lake Urmia the K–S test was applied to all time series to test which distribution fitted the time series best. The exponential, gamma, uniform, log-normal and normal distributions were tested, and ultimately, the latter was used log-normal and gamma distributions, respectively to calculate the SDI and SPI. Considering to fluctuations intense in rainfall in recent years, its impact is evident in the volume flow of passing, so the effective development and implementation of programs and utilization of water resources and of the effects of drought when the flow volume fluctuations can greatly Reduction transmission losses incurred.

Temperature is one of the most basic meteorological parameters of frequency applications in agricultural science and technology. The aim of this study was to compare the data recorded in a standard synoptic weather station (Rasht agro meteorology station) and temperature recorded in rice fields and in the average canopy height of rice.
Material and For this purpose, the temperature of paddy field installed in standard screen box is measured in 65 cm in height using thermograph and thermometer, and it was compared with the data of the Agricultural Meteorological Station in the vicinity of the farm.
Results show that temperature changes during the season at the station and farm and in all measurements are incremental, but the increase in the maximum is higher than the minimum. The mean comparisons of the canopy have a significant difference in measurements of farm and the station. Differences in maximum temperature are greater than the minimum temperatures, indicating that the effect of farm microclimate on reducing the maximum temperature is more effective. The differences of field (daily) thermometer and stations in the whole season were between 1.1 and 6.1 degrees Celsius respectively in average temperature and maximum, but no significant difference in minimum is seen. In this study, growing degree days (GDD) calculated from three sources has significant differences and reflects the importance of accuracy in the calculation of these parameters in agricultural meteorology. Before the end of the growth phase (Phase II) there is no significant difference between the thermometer in field and station, so station data can be used directly instead of field data. Most differences are seen in the middle stage and end-stage growth (0.9 and 2.3 degrees Celsius on average and 1.4 and 2.9 degrees Celsius of the maximum). Maximum and mean temperatures of the whole period at stations with coefficients of determination values, 0.79 and 0.74, can be converted to farm temperature. By stopping irrigation and entering to complete maturity, the similarity between the field and the station records become greater. Because minimum temperatures last longer than the maximum and there is sufficient time for thermometer to be adjusted to the environment, the registered minimum in the thermograph has less difference than the maximum data in comparison of the same elements in stations.
Development of canopy causes significant differences between data recorded in paddy field and station and difference in maximum temperature is more than minimum temperature. The accuracy of data which is measured by thermograph and to extract maximum and minimum temperatures, it is important to consider the persistence of the temperature, If the temperature continues longer hours it has probably more accurate results. However both maximum and minimum temperatures have increasing trend, the difference between maximum and minimum increase during the season in all methods. Rain reduces the difference between the maximum and minimum temperature. With the interruption of irrigation and reaching maturity stage, the difference between the station and the farm is not meaningful.

An important form of gully erosion which usually develops in farmlands is ephemeral gully erosion. Researches have shown that soil loess due to ephemeral gullies is around 2 to 90 m3.h1.yr1. Given the high soil loess of loess deposits and intensive cultivated lands in Golestan province, assessment of factors affecting the development of ephemeral gullies is of great importance. The main objective of this study is the efficiency assessment of the Ephemeral gully erosion model (EGEM) to estimate gully erosion in the Iky-Aghzly watershed.
The area of Iky-Aghzly watershed is around 703 hectares, located in the basin of the Gorganroud (Golestan province). Its mean annual precipitation and temperature is 424 mm and 15.7 ºC, respectively. Through field reconnaissance in three stages (seasonally), 12 ephemeral gullies were identified and their locations recorded by GPS. Morphometric characteristics recordings and soil sampling were conducted in the head of gullies as well. Apart from measuring of morphometric characteristics and soil physicochemical properties, physical specifications of watershed adjacent to each gully was calculated. EGEM efficacy was validated by Chi-square test in R software, by comparing the observed variables (mean annual soil erosion and width of ephemeral gullies) with the same variables estimated by the model.
The average soil loss caused by ephemeral gully erosion was around156.7 t yr-1 for all ephemeral gullies. The depth and width of gullies was between 10 to 45 cm and 15 to 60 cm in the last measurements. The average soil loss per each ephemeral gully was around 3.76 to 12 t h-1.
The results showed that there is a significant difference at the 5% level between the measured annual average gully erosion rate and estimated erosion by the model. But the annual average width of ephemeral gullies corresponding to the model output variable, was not significantly different. The rate of ephemeral gullies erosion estimated by The EGEM is not acceptable in the Iky Aghzly watershed, while the width of ephemeral gullies (EGEM) was near the observed width.
Generally, according to the results of this research, it can be concluded that the ephemeral gullies were formed coinciding with the autumn rains and tillage (4 ephemeral gullies) and in the late winter (8 ephemeral gullies (.The reasons for ephemeral gullies emerging are rainfall intensity, antecedent soil moisture content, tillage along the slopes in the study area. According to these results, for accurate assessment of EGEM as event-based model in Iky-Aghzly watershed, individual participations is recommended.

Concentration Index (CI) is actually an index to examine the statistical characteristics of daily precipitation. This concept could be also used in irrigation planning and designing new systems. Unbalanced distribution of precipitation could reduce the agricultural crops yield through reduction of moisture in soil and increment of irrigation periods. Besides, unbalanced distribution of precipitation means drought. The precipitation less than regional average may cause dangerous floods since soil moisture will reduce and vegetation will be destroyed. The aim goal of this study is evaluation the distribution and concentration of daily rainfall in the basin of Lake Urmia.
In this study used the 42 rain gaging station in Urmia Lake basin to evaluation the daily precipitation concentration. Concentration Index (CI) and related concentration curve are in fact used to define inequality quantity of a parameter from a specified variable. For example, it could be used in statistics to determine improved level of health subside for poor people in different countries as well as precipitation dispersion in an area or country. Concentration Index is defined by a concentration curve (Lorenz Curve). The Lorenz curve is actually a concept used in economic theories to examine the temporal-spatial changes in time series of daily precipitation and concentration
The results of CI index in Lake Urmia basin during the statistical period in spring showed that CI>0.6 is not observed in none of the areas under study. Majority of Lake Urmia areas in spring had the CI values between 0.4 and 0.5. In this season (spring), aggressive and terrifying precipitations were observed in none of the basin areas. As spring in the study under area in autumn, CI> 0.6 was not observed in any of the stations studied. In winter as well as spring and autumn, a part of the South and the Northeast of Lake Urmia and also an area of the Northeast of basin had average CI between 0.5 and 0.6 in statistical period and show the high concentration of daily precipitation and irregularity in distribution of daily precipitation in these areas. It can be concluded that the amounts of daily rainfall in listed areas were not divide into rainfall days. The CI in most of the areas under study were between 0.4 and 0.5. The southern areas of Lake Urmia basin had severe irregular precipitation in summer and it could be concluded that 70% of rainfalls in this season occurred only in 25% of rainfall days. In this season the Northeast and South regions of Lake Urmia, an area in Northeast of Lake as well as a station in the Southwest of lake had irregular distribution of precipitation in summer. In annual scale, most of the Lake areas had average concentration. In annual scale, similar to seasonal scale, Northeast and South of lake had more irregular concentration compared to other areas.
In this study to evaluation the concentration and pattern of daily precipitation in Urmia Lake basin in period of 1984-2013 used the concentration index (CI). The results of concentration index in basin area showed that daily precipitation in Lake Urmia basin was not in regular and severe irregular situation in none of the stations under study. The entire stations surveyed were in relatively regular, average concentration and relatively irregular situation in terms of daily precipitation distribution. Most of the studied stations were in average concentration category in terms of daily precipitation concentration. In autumn, winter, spring and summer in annual scale, almost 74, 90, 81, 74 and 84% of stream-gaging stations showed average precipitation concentration.

Potassium (K) is an essential element for plant growth and its forms and availability may be affected by soil properties, clay mineralogy and crop cultivation. Potassium exists as four forms in soil including soluble, exchangeable, non- exchangeable and structural. The non-exchangeable and structural K are related to the content of some minerlas like feldspars and micas; while exchangeable K is defined as K ions adsorbed on clay minerals and organic matter. Soluble K constituted In the current investigation, three different areas incluging Gyan, Droud and Kangavar were selected. Then 15 soil series with different properties and crop cultivation history were selected and soil profiles were dugged and described. The selected soils were under cultivation of orchard, wheat, rice, maize, canola, sugar beet and grape. Soil samples were collected from different horizons and physicochemical and mineralogical characteristics were measured in the laboratory. Different forms of K including soluble, exchangeable, non-exchangeable and total were determined.
All soils were calcareous and classified as Inceptisols. The contents of clay, silt, calcium carbonate equivalent and organic matter ranged 27.5-53.2, 21-49.8, 15.3-50.3 and 0.7-1.8 percentage, respectively. The contents of soluble, exchangeable, non-exchangeable and total K in the studied soils ranged 3-62, 105-676, 32-2083 and 3600-9333 mg/kg, respectively. Results indicated that the mean contents of soluble (44.2 mg/kg), non-exchangeable (1585 mg/Kg) and total K (7251 mg/Kg) were the highest in paddy soil may be due to the higher clay content and lower content of calcium carbonate content; while the exchangeable K content was the highest in the soils under maize cultivation (676.4 mg/Kg). Mineralogical analysis indicated that smectite (20-30%), vermiculite (30-50%) and illite (10-20%) are the predominant clay minerals in the surface and subsurface horizons, respectively. Significant relationships were observed between exchangeable K and organic matter and clay contents. Different forms of K in the studied soils was also correlated with illite content of the clay fraction.
It is concluded that most studied soils had considerable contents of different K forms. The paddy soils had higher contents of soluble, non-exchangeable and total K than non paddy soils. It seems that illite and vermiculite are the predominant K-bearing minerlas in paddy soils. Crop cultivation had significant effects on K status of the studied soils due to different K demand and agricultural practices. Generally, it is recommended that crop rotation and clay mineralogy should be considered for better management of K fertility.

Using soil moisture storage techniques, simultaneously with irrigation management practices play an important role in coping with the problem of water shortage and water crisis. Therefore, the aim of this study was to evaluate the simultaneous effect of partial root zone drying and vermicompost on the water use, yield, biological yield, harvest index and leaf relative water content (RWC) of maize in sari.
The experiment was arranged in split plots based on complete randomized block with 3 replications were carried out during years 2015 to 2016. The experiment treatments were full irrigation and chemical fertilizer (FIT1) as control treatments, full irrigation and 50% chemical fertilizer 5.5 tons per ha of vermicompost (FIT2), Full irrigation and 11 tons per ha of vermicompost (FIT3), deficit Irrigation and chemical fertilizer (DIT1), deficit irrigation and 50% chemical fertilizer 5.5 tons per ha of vermicompost (DIT2), deficit irrigation and 11 tons per ha of vermicompost (DIT3), partial root zone drying irrigation and chemical fertilizer (PRD1), partial root zone drying irrigation and 50% chemical fertilizer 5.5 tons per ha of vermicompost (PRD2), partial root zone drying irrigation and 11 tons per ha of vermicompost (PRD3); while in DI and PRD 65% water of FI was irrigated. TDR access tubes were installed in the soil profile to measure soil water content.
The results showed that the effect of irrigation treatments was significant on all physiological parameters considered in this study. The effect of fertilizer treatments was significant on all parameters except RWC. The highest yield was attained in FIT2 treatment, equal with 8 and 8.2 tons per ha in 2015 and 2016, respectively. The PRD treatments was caused to significant increase in yield, biological yield and RWC compared with the DI treatment. The use of vermicompost in combination with chemical fertilizer increased yield, biological yield and harvest index. Vermicompost increased RWC was compared to chemical fertilizer.
simultaneous use of PRD and vermicompost was saved more water (26.3 %) than using them separately. Compared with FIT2 treatment was no significant difference in the values of yield and other physiological parameters of maize. Therefore, PRD2 is recommended to compatibility with the problem of water shortage. simultaneous use of PRD and vermicompost was saved more water (26.3 %) than using them separately. Compared with FIT2 treatment was no significant difference in the values of yield and other physiological parameters of maize. Therefore, PRD2 is recommended to compatibility with the problem of water shortage.

Water retention in the soil and increasing soil water content in the rhizosphere is the first way to enhance crop yield particularly in the dry-farming lands. Agricultural practices along with intrinsic land characteristics (topography, soil, etc.) can affect the water retention in the soil and in consequence crop production. Most of these lands in Iran are located in semi-arid regions and are usually ploughed along the slope which accelerates the water runoff, hence increasing soil erosion. The change of plough direction from slope direction to contour line is the first strategy for water retention in the soil. However, there is no possible for the changing plough direction due some limitations in the farm and restriction on the movement of cultivation machines. The choice of proper row spacing is important in the dry-farming lands ploughed in the slope direction for water conservation as well as crop production. Therefore this study was carried out to investigate the effect of two common row spacing in two plough directions on the water retention and wheat grain yield in a dry-farming land in semi-arid region.
The study was conducted in a dry-farming land with 10% slope steepness in Zanjan during winter wheat growth period from October 2015 to June 2016. A total of 12 plots (1.5 m × 5 m) were installed to study the effect of two row spacing (20 cm and 25cm) in two plough directions (up to down slope and on the contour line) on the soil water content (SWC) and wheat grain yield (WGY). Soil properties were determined using the common methods in the lab. SWC was determined by a Time- Domain Reflectometry (TDR) interval during the growth period. Seasonal variation of SWC for different treatments were determined during the growth period. WGY for different row spacing and plough directions was related to SWC. Wheat plants were harvested from all plot surfaces to determine WGY early June.
Results indicated that both SWC and WGY were significantly affected by plough direction (P The study revealed the plough direction in the first order and the row spacing in the second order are the major factor controlling SWC as well as WGY in the dry-farming lands. Application 25 cm row spacing with contour line plough is the best cultivation method for increasing water retention and achieving higher WGY. The importance of these two cultivation methods is obvious in spring when rainfalls are intensive and frequent.

Temperature and rainfall are two important meteorological variables, especially in arid and semi-arid areas. As a result, determining the value of these variables, their changes and prediction of these phenomena are necessary for more precise planning in the management of agricultural, economic and social sectors. Nowadays, incompatibility of temporal and spatial scales required in investigated models on the effect of climate change with GCM outputs and the need to assess the change trend in meteorological threshold variables at the regional scale has led to develop various downscaling methods. So, the aim of this study is the comparative comparison of data mining models in downscaling of rainfall and temperature based on data of NCEP general circulation model.
Material and The study area in this research is bazoft- e- Samsami watershed. This basin is one of the northern Karun sub-basins located in the northwest of Chaharmahal and Bakhtiari province. Marghak rain gauge and hydrometric stations are located at its outlet.
In this study, the performance and efficiency of four methods including decision tree (M5), Nearest Neighbor (KNN), Multilayer Perceptron (MLP) and Simple linear regression (SLR) were evaluated for modeling monthly rainfall and temperature of Marghak station during the training period of 1971-1990 and The 1991-2000 test period using NCEP output parameters.
Monthly rainfall modeling results using mentioned models showed that the output of all models except the KNN model provides negative values for rainfall. The rainfall prediction by M5 model in January, March, April and December is lower than the observed values (P). This situation is also somewhat seen in other models. Also, given that the minimum rainfall is zero, it can be concluded from the low predicted values rather than observed values that the maximum limit of rainfall with these models is not well predicted. The prediction of rainfall by all models in all months except May has a lower standard deviation than the observed values (P).
The predicted results of monthly temperature also showed that only MLP output provides negative values for the temperature, which can be due to the extrapolation and generalizationin in MLP method. Also, The standard deviation obtained from all models in January, February, March, April, July, August, October, November and December is more than standard deviation of observed temperature. The results of statistical analyzes also showed that M5 than the other models in the test stage according to RMSE, MBE and R2 have better estimates for rainfall and monthly temperature. Although the results of determination coefficient (R2) in the test stage for monthly temperature estimation are weaker than monthly rainfall.
The results of the efficiency of four models of KNN, M5, SLR and MLP in monthly rainfall and temperature modeling in Marghak meteorological station with NCEP output data showed that these models were weak in downscaling the monthly rainfall and temperature. Therefore, despite the relative superiority of M5 model compared to other models, the use of these data mining models is not recommended to predict rainfall and temperature variables in Margak station.

In recent years, water crisis has caused wastewater using in agriculture section. According to the welcome and the need to use wastewater and recycled water in agriculture, more wastewater treatment plants in the country with the aim of reuse of wastewater in agriculture, are designed and implemented. Treatment action cause to the amount of organic material to be refined. So, Investigation of wastewater pollution reduce is necessary .In this Investigation, the use of filters and natural absorbent such as zeolite, perlite and anionic resin to improve wastewater characteristics will be examined.
Material and This study was conducted in 18 PVC columns to evaluate the combination filters, including modified zeolite, perlite and anion resins to reduce pollution in wastewater. Test units are made of PVC pipe internal diameter 10.5 cm and a height of 60 cm. Five centimeters bottom of each column were filled out using a sand filter to prevent soil particles. On the sand filter, to a height of 40 cm of soil or soil combined with modified zeolite, perlite and anion resin as mixed or layers was filled. The experiment consisted of nine treatments and two replications. The statistical plan was conducted in a completely randomized plan with two factors. The first factor, the use of modified zeolite, perlite and resin include of two mixed and layer by layer types and the second factor is the percentage of modified zeolite, perlite and resin in two levels 2 and 4 weight percent. To measure BOD5 and COD, wastewater was injected in columns 10 times the frequency of weekly. Drainage wastewater collect from columns 24 hours after were irrigated. After the ninth round took a leaching. Then the samples were transferred to the laboratory for the measurement of BOD5 and COD.
Result and The results show that layer treatment including zeolite, perlite and resin with 4 weight percent, has the highest effect among all treatments. As amount of BOD5 and COD declined more than 47 and 16 percent, respectively. Control treatment has the lowest effect with 36.2 percent for BOD5 and 12.26percent for COD, too. Also, results show the use of zeolite, perlite and resin to form of mixed, cause to reduce the BOD5 and COD than the control column, but the layer column are more able to reduce them. Moreover, effect of perlite is more than to zeolite to decline BOD5 and COD and more weight percent of used particles cause more effect of them.
The results show, used filters decline more in BOD5 and COD than to control treatment. But weight percent change of filters from 2 to 4 percent doesn’t have a lot of effect on BOD5 and COD.
Application of combination filter as layer by layer including zeolite, perlite and resin with 4 weight percent has most effect on reduce of output BOD5 and COD and the lowest of effect is for zeolite filter with 2 weight percent. One of the reasons for higher ability to remove BOD5 and COD wastewater in layer column is slower passing of water from this column. Zeolite, perlite and resin layers in the soil column prevent the cross of organic material and due to the low concentration of organic matter in the drainage water, chemical and biochemical oxygen demand was reduced. Also, compare of the BOD5 and COD amount of output from test columns to the amount authorized for use in agriculture shows that its value is less than the allowed limit.

One of the ways to carry out surface irrigation is furrow irrigation, which is special for row crops. In this way the water by coming in parallel furrow, placed at the disposal of the plant and the intended plant are grown in ridges. In this method the irrigation efficiency is low and in some areas reach under thirty percent. Many methods have been proposed to increase the efficiency of this type of irrigation that has not been implemented yet due to various reasons. No experimental and practical work has been performed yet on the method of furrow irrigation with perforated half-pipe which is proposed in this research.
Material and This research has been done in two steps. The first step was performed on a perforated half-pipe in the laboratory. The second step was performed in a greenhouse experiment in which performance indicators of water requirement efficiency, application efficiency, deep percolation ratio, distribution uniformity, and tail water ratio in the proposed method were compared with those of ordinary furrow irrigation in a created furrow of soil on a flume. In this study the choice of a half-pipe polyethylene 4 m long, which has a diameter of 250 mm holes in the laboratory with whole distance of 20 cm and a diameter of 5 mm on bed has been created. After discharge from the tube at three different times, 3 different discharges and 3 different slopes, water outlet holes were measured. In this study, the relationship between the discharge pipe, tube and floor slope time system performance was evaluated in comparison with the value of water delivered. Since the percentage of the floor slope is a dimensionless parameter, therefore, in the analyses and comparison of the experiment results, the ratio of discharge (runoff discharge divided by inflow rate) instead of discharge and the ratio of time (advance time divided by the time of system operation) instead of time is used.
Result and desiccation: The results of the first step of the research on the perforated half-tube in the laboratory showed that there is the best uniformity of distribution compared to other modes when the discharge ratio, time ratio, and gradient are respectively (0.3020), (272/0) and (2.6%). In this case, the depth of infiltration was almost uniform from beginning to end. In the second stage, the perforated half-pipe was tested in the sandy soil furrow in a flume in the greenhouse, as well as the sandy furrow was tested alone and the results were compared. In these tests the slope of 2.6%, flow ratio of 0.302 and times ratio of 0.272 were adjusted. The five key performance indicators were calculated for both rigorous testing revealed that even experiments with perforated pipe that has higher runoff than in the usual method, but others including distribution uniformity is much better than a usual irrigation.
The best results obtained from the data analysis are when the slope is 2.62%, the discharge rate is 3.31 times the tail water runoff and the operating time of the system is 3.67 times the advance time. This method is used in small farms where pressure irrigation systems cannot be applied, also in low flows that water movement is slow and deep percolation losses are high, and the duration of irrigation and labor costs increases, in farms where the number of agricultural land is high and they are managed in a small way, the method is very usable. Therefore, from an economic and social perspective, and simple to implement, it is very practical and suitable for farmers.

High concentrations of fluorine ion in the Dashtestan area of the Bushehr province, has given rise to the prevalence of dental fluorosis among the local population. The high concentration of this ion in plants provides one possible mechanism for it to enter the body. This, along with the absorption of fluoride from water, can lead to a higher probability of acute fluorosis for the local population. The main objective of this research is to study the fluoride concentration in soil, and its probable bioaccumulation in plants.
Material and Dasthestan's Posht-e-kooh is part of the Dashtestan's district, situated to the east and souteast of the Burazjan district in the Bushehr province. In order to measure the concentration of fluorine in the soil, thirty-four in-situ soil samples were collected from the date orchards and wheat farms. To find the correlation between soil pH and fluoride concentration, soil pH was also measured. In addition, 14 wheat samples and 10 date samples were collected and analyzed for fluoride. Separate samples were taken from the root, stem, and leaf. The F- concentrations in plant and soil samples were determined using the alkaline fusion method with a fluoride ion-selective electrode (Metrohm Swiss model 781 ion meter).
The average fluoride concentration found in dates is 10.0 mg/kg; whereas wheat roots and shoots contain on average 30.0 and 19.0 mg of fluoride per kg, respectively. In the present study, we have found relatively high F- concentrations in dates and wheat, which are staple foods for the population of Bushehr. The average F- content in dates of 10 mg/kg is much higher than the mean value of 2.9 mg/kg reported for Southern Algeria. The uptake of the fluorine ion by plants is controlled by many factors, such as soil type, pH and the clay content of the soil due to direct contact between soil and water. There is no available report regarding the soil of the Algerian region mentioned above. The F- content of wheat is also high, and approximately 10 mg/kg higher in the roots compared to the shoots. The soil in the study area has a pH of 8.03, which means that F- can be absorbed by the plants. F- can be absorbed (transported) from the soil into the stem through fine hair rootlets, and some can reach the leaves. Acidity is the most important factor in the geochemistry of fluoride-bearing soil. An average soil pH of 8.03, shows high alkalinity. High pH value promotes the exchange of OH- anion in the groundwater and F- in some of the minerals present in the soil, which facilitates the leaching of fluoride from the soil into the plant. X-ray diffraction analysis has confirmed the presence of fluoride-bearing minerals in the study area.
Considering the importance of fluoride for the health of teeth and bones, the high concentration of fluoride in dates resulting in a high intake of fluoride by the people living in posht-e-kooh of Dashtestan is cause for great concern. The high concentration of fluoride in the soil and local plants, implies a high probability of fluorine entering the food cycle. Identifying sources of water with high concentrations of fluoride, is an important step in tackling the health problems facing the local population.

Limitation of water resources in the country and devoted the large amount of it to agricultural and natural resources, would be a crucial and vital issue in increasing the efficiency pattern and water use. In this regard, applying modern technology such as super absorbent polymer may play the significant role in decreasing the dry stress in the arid and semi-arid regions Super Absorbent Polymers lead to increase soil water capacity and thus improve the water application efficiency. Surface irrigation, due to its simplicity, is regarded as the most common method of irrigation. Determination of the parameters of water infiltration in soil, is one of the essential steps in the designing and the management of surface irrigation systems. The purpose of this study is precision the impact of super absorbent polymer analysis in estimating infiltration parameters methods in furrow irrigation and choosing the best method based on combination of superabsorbent polymers in the field of the study.
The experiment were performed in the educational farm of the Gorgan university of Natural Resources and Agriculture in a no cultivation conditions. In this research four combinations of superabsorbent polymer A200 with soil which were composed of 0, 7, 11, 16 gram of polymers in square at a depth of 25 cm and the electric current of 0.75 liter per second were considered. The experiment were arranged as randomized complete design with four replications. In this research accuracy of four infiltration methods consist of Elliott and Walker two-point method, Benami and Ofen advance method, Shepard et al., and Valiantzas et al., one-point methods. Then, it simulated by SIRMOD software and full hydrodynamic model in different steps of irrigation such as advance phase, Recession phase and infiltrated volume in furrow irrigation.
Ithe results showed that the minimum average relative error (RE) in prediction of infiltrated water is devoted to Elliott and Walker and Shepard et al. methods with 1.88 and 20.8 percent minimum and maximum respectively for estimating total infiltrated volume.in the other hand, results indicated that the average standard error in prediction of advance phase time is devoted toElliott and Walker method is 1.02 percent which is the minimum percentage of error and maximum of percentage of error is 22.13 percent in the method of Sheppard et al; and in prediction the the time of recession phase Elliott and Walker method (1.62 percent) had the minimum standard error.
The results of this research showed that Elliott and Walker method has the best evaluation in prediction of the volume of infiltrated water, advance phase and recession phase and so increasing the amount of polymers and irrigation stages showed that Elliott and Walker two-point method and and Shepard et al., one- point method has the decreasing trend in error percent. .