Journal of Water and Soil
Year:2012 | Volume:25 | Issue:5|Papers Count:32

Due to limited water resources and occurrence of recent droughts, the use of new management and planning methods for optimal irrigation scheduling of agricultural crops is inevitable. Present of appropriate mathematical and dynamic relationship between yield, evapotranspiration and water use efficiency parameters is the first and most important step in the optimal management of irrigation and application of deficit irrigation strategy in the field level. Accordingly, In order to determine the water Production function of Basil plant, a pot experiment was conducted in completely randomized block design with four irrigation treatments include: 100, 80, 60 and 40 percent of water requirements and three replications in the glass greenhouse of Kurdistan University. The results showed, in linear water production function, marginal water use efficiency for evapotranspiration values is fixed. So, it is not suitable for explanation details of relations. However in the quadratic water production function of marginal water use efficiency decreased whiles the increasing of evapotranspiration. And in The evapotranspiration of 348 mm was cut water use efficiency curv. At in this point elasticity of water production is 1, and it has maximum water use efficiency. The results showed the Maximum yield occurs at 376 mm evapotranspiration. At in this point elasticity of water production is 0. Observed maximum water use efficiency and maximum yield don’t happen at a same point ET would need 8 percent greater than the ET for maximum water use efficiency, while the value of yeild increased by 4/2 percent. In addition to that, Yeild Response factor in the quadratic water production function is greater than this factor in the linear production function.

Petroleum pollution is one of the most common and dangerous pollutions that is due to petroleum industries such as refineries, and consequently of oil pipes and tanks leak causing environmental pollutions. One of the newest born technologies in this area is phytoremediation, in which plants are used for decreasing of petroleum pollution. This technology is used for remediation of soil, underground and waste water pollution, because of low expenses and simple application. In this research bioremediation system by three plants barley, vetch and bean at three levels of density, with three replications in factorial experiments, randomized complete block design (RCBD) was used. In three steps of plant growth, concentration of total petroleum hydrocarbons (TPHs) of soil was measured. Statistical analysis showed that the amount of soil remediation had a direct relation with increasing plant density levels. The maximum remediation belonged to barley which in its maximum density level, it reduced the amount of pollution up to 45.78%. Generally, because of high resistance of barley to petroleum pollution and its ability for remediation of pollution, barley was recognized as the best plant among the evaluated treatments for remediation of petroleum polluted soils.

Phosphorus (P) sorption in soils is a key process governing the availability of P to crops. P sorption characteristics and their relationship to soil properties were determined in twenty-one paired surface soil samples (21 cultivated and 21 adjacent virgin soils) belonging to five soil types: Typic Calcixerepts, Typic Haploxerepts, Typic Endoaquepts, Vertic Endoaquepts, and Vertic Calcixerepts from sugar beet growing areas located in the north-west of Iran. After determining P adsorption isotherms, adsorption data was fitted to Langmuir and Freundlich equations to derive adsorption parameters. In comparison with Langmuir equation (R2=0.82), Freundlich model provided a better description of P adsorption isothems (R2=0.97) in both cultivated and adjacent virgin soils. Total P ranged from 1000 to 1398 and 1011 to 1394 mg kg-1, respectively. Continuous cultivation resulted in a considerable increase in available P (Olsen P) in cultivated soils. The amount sorbed P differed among soil types. The results showed that in all soils types except Typic Haploxerepts, equilibrium solution P concentration (EPC) was almost lower than the requirement for most crops (<0.4 mg L-1). The amount of sorbed P at 0.4 mg L-1 EPC ranged from 36 to 75 and 21 to 52 mg kg-1 for cultivated and adjacent virgin soils, repectively. The maximum P adsorption (b) ranged from 152 to and 171 to 220 mg/kg for cultivated and adjacent virgin soils, respectively. Maximum P adsorption (b) ranged from 152 to 230 and 171 to 220 mg kg-1 for cultivated and adjacent virgin soils, respectively. The amount of sorbed P increased in most studied soil subgroups as a result of cultivation indicating improper management of P fertilizer application which resulted in the depletion of P from soils and an increase in P soption.

This study was conducted to investigate, under incubation conditions (FC moisture and temperature of 30o c), the effect of the potassium concentration and the cultivation background on the K- fixation in Khuzestan’s sugarcane under-cultivation soils. For this reason, 70 complex soil samples in 35 pairs each coupled out of two different depths (0-30 and 30-60 cm), chosen from the under-cultivation soils of 3 different farmland: Haft Tappeh Agro- industry (with a maximum cultivation background of 41 years), Karun (with a maximum cultivation background of 30 years), and sugarcane Development Plan (with a maximum cultivation background of 8 years) were supplied. In order to study of the effect of the Potassium concentration and the sugarcane cultivation background on the K- fixation, a factorial experiment with 4 levels of the K concentration (0, 150, 300, 600, mg kg-1), and 4 levels of the cultivation background (less than 10 years, 10-20, 20-30, and more than 30) in based on completely randomized design was conducted. The results showed that the amount of Potassium fixation ranged from 17.74 mg kg-1 to 129.15 mg kg-1. With an increase in the potassium concentration, the amount and percentage of the K- fixation were both increased (p<0.01).the results showed that even after 6 month of incubation, about 70 percent of the K added still remained in the form of available for the plant. Until before 30 years of cultivation background, there was not observed any significant difference between various backgrounds and amount of K- fixation as well as increase in potassium availability, but at longer times, Kfixation was increased with increase of cultivation background. (P<0.01).The results showed that the amount of available Potassium, in 82.8 percent of the surface soils (0-30 cm), and 85.8 percent of subsurface soils (30-60 cm), is less than 120 mg/kg of soil. A negative and significant correlation between the amount of Potassium fixation and clay, PH, CEC, OM, exchangeable and available Potassium was obtained.

In order to investigate the effect of irrigation and nitrogen fertilizer, on yield peanut plant, with furrow method of irrigation and water use efficiency (WUE) in management to create a proper and better production, split plot experiment was over taken as in complete randomize blocks with three replications and main plot with 6, 12 and 18 day interval irrigation and no irrigation and subplot of nitrogen Fertilizer with amount 0, 30, 60 and 90 (kgN/ha) in the year 2009 in Astaneh Ashrafiyeh in Guilan province. The results of this investigation showed that in irrigation management, the maximum yield for the seed are in 6 day interval irrigation with total water use 328 mm has the highest pod yield 4093 and seed yield 2345 (kg/ha) Among the amounts of nitrogen also, the fertilizer amount of 60 (kgN/ha) with pot yield of 3376 (kg/ha) and the seed yield of 1796 (kg/ha) were the highest. The WUE for peanut as for pod and seed yield under irrigation, with 6 day interval irrigation for seed, pod and biomass have 0.71, 1.24 and 2.88 (kg/m3) of other irrigation management more, the amount of nitrogen 60 (kgN/ha), for seed, pod and biomass have 0.62, 1.21 and 2.58 (kg/m3) of other management higher than. Also the 6 day irrigation and without irrigation, the amount of 96 and 76 percent, have the highest and the least amount of RWC. Also the management irrigation and nitrogen fertilizer was effect on total biomass, weight of 100 seeds and harvest Index.

At present study constant rate of strain (CRS) consolidation under Non-Darcy condition was investigated. In this study a governing conditions of drainage pore water were investigated using proposed equation. The CRS experiments under different rates of strain were conducted on different soil samples. Results these experiments and there comparison with proposed equation showed that flow of pore water drainage in the most part or each test was Non-Darcy and changed to Darcy condition in the final one forth of test. According to the results the threshold that Non-Darcy flow changes to Darcy is dependent on variations of relative pore water pressure versus total strain and it can be determined based on variations in inclination of relative pore water pressure-total stress curve.

Saturated water content is one of the important parameters which its measurement is necessary in estimation of soil water retention and unsaturated hydraulic conductivity curves. In several researches, saturated water content is assumed to be equal to soil total porosity. In some others, its value is estimated by pedotransfer functions using readily available parameters, such as bulk density and soil textural data. The objective of this study is to evaluate different presented methods in the literature in estimation of saturated water content. Since soil organic matter is considered as an effective parameter on the soil structure, in this study its influence in the estimation of saturated water content is studied. For this purpose, in the first case without considering the value of organic matter, different methods such as soil total porosity, Vereecken et al., Mayr and Jarvis, and Scheinost et al., were evaluated. In the second case, the measurement of organic matter was used in prediction of saturated water content. Then beside the other methods mentioned above, Wösten et al. model as well as two linear and nonlinear models of Rajkai et al. were evaluated as well. In the first and second cases 443 and 309 soil samples from three data bases e.g., Cornelis et al., UNSODA and GRIZZLY were used, respectively. The results showed that when organic matter increased, saturated water content increased as well. In the first and second cases, the smaller values of RMSE and AIC showed that the Vereecken et al. model predicted saturated water content more accurately than the other methods. The obtained results also indicated that models in which organic matter is considered as an input parameter could not estimate saturated water content as accurately as Vereecken et al. model estimated.

This study was conducted to determine the impacts of plastic mulch, drip irrigation method and different amount of water and their interactions on yield, water use efficiency (WUE) and quality characteristic of tomato (Mobile cultivar). The study was conducted in Torogh Agricultural Research Station, Razavi Khorasan province. The study was done during 2007-2008. Experimental design was randomized complete blocks (RCBD) in split split plot with three replications. Design treatments included different amount of water (60, 80 and 100% water requirement) in main plot, drip irrigation method (surface and subsurface) in sub plot and mulch (with/without mulch) in sub-sub plot. The combined analysis showed that irrigation water amount, irrigation method and mulch treatments had significant effect on yield and WUE (P≤0.01). Yield in 60, 80 and 100% water requirement treatments was 31.141, 54.575 and 62.265 ton/ha, respectively, which showed significant difference. The highest WUE (7.881 kg/m3) was in 80% irrigation treatment, followed by 60 and 100% (with 5.925 and 7.232 kg/m3), respectively. There was significant difference between yield in surface and subsurface drip irrigation (that was 43.380 and 55.274 ton/ha), respectively. Water use efficiency in subsurface drip irrigation was 7.927 kg/m3 that was greater than surface drip irrigation. Yield in mulch and without mulch treatment was 55.641 and 42.714 ton/ha, respectively. Application of mulch increased water use efficiency about 30 percent. Subsurface drip irrigation with 80% water use and using of mulch was the best treatment.

Fluoride (F-) is an essential element for human and some animals. The fluoride concentration in irrigation water is an important index for water quality. The objective of the present study was to determine spatial variability of fluoride in groundwater and soils of some areas in Arak plain. Therefore, during two seasons, autumn (2007) and the end of spring (2008), 87 and 92 water samples were collected from the wells, in the study area, respectively. Furthermore thirty soil samples were taken from the same positions. Fluoride concentrations in groundwater and soil samples around Arak city was measured by Ion Selective Electrode (ISE) method. The results show that the average fluoride of water samples during two seasons ranged from 0.3 to 0.06 mg/L which is below the standard level (1.5). These values were suitable for irrigation. Generally, spatial distribution in groundwater and isopiezometry maps indicated that fluoride increased where groundwater flow lines were centralized. Besides, fluoride concentration has increased in the rural zones and discharge areas. Average concentrations of fluoride in agricultural and industrial areas were 1.5 and 7.5 mg/Kg respectively. Maximum concentration of fluoride belonged to industrial areas with 26.5 mg/Kg showing significant difference in 1% scale in comparison with agricultural zone. There was negative correlation between fluoride with lime values and positive correlation with pH.

The objective of the present study is to assess the performance of 18 irrigation districts from ten countries in the world using the Benchmarking method and data mining analysis (cluster analysis). Irrigation networks of Dez, Sefidrood, Tajan and Voshmgir from Iran have been compared with 14 irrigation districts from nine other countries. The k- means algorithm was used to analyze the performance indicators, thereby enabling irrigation districts to be classified into seven statistically homogeneous groups. The results showed that the irrigation districts without any canal coverage and irrigation districts with 100% of concrete coverage in the main canal and 50% in the secondary canals may be classified into a homogeneous group due to drainage water recycling system. In other words, canal coverage and drainage water recycling may prepare an appropriate water delivery condition. Land-leveling plays an important role to improve yield production in the irrigation districts. Increasing 1.5 to 2 t ha-1 in yield production for Bani amir district of Morocco and Office du niger of Mali due to the implementation of land-leveling has been experimented. The evaluation indicated that water user association (WUA) is another factor to improve the management process of the irrigation districts. The economic indicators in Voshmgir area have a high value because of the WUAs and managing around 70% of the irrigated areas by them. Lack of these organizations in the Dez irrigation district, increased the amount of annual relative irrigation supply indicator to 3.08. This indicator in Office du niger district with the WUAs is just 0.12. Benchmarking and data analysis techniques are powerful tools to evaluate efficiency in irrigation districts.

Regarding temporal variation of rivers discharge and demands, for suitable use of dam reservoirs stored water, application of operation rule curves is necessary. Operation rules are expressed with rule curves. Application of yield model is one of the methods of operation curve preparation, which correlates reservoir operation with reservoir storage volume in first period. In this study after description Standard Operation Policy and yield model, based on these models two computer programs in FORTRAN language were prepared for reservoir operation. Then based on yield model, Doroodzan dam rule curve achieved based on yield model and results were compared with SOP model. Results showed that sum square of deficit in yield model was significantly 73.27 percent less than SOP model, which expresses model ability in derivation of dam reservoir operation rule curve. Yield model in addition to decrease of water deficiency, supplies absolute demands and distributes deficit uniformly in more years.

Nowadays, soil pollution with heavy metals has become a major problem which their accumulation in plants can directly or indirectly influence on animals and humans life. Lead and cadmium are poisonous metals, with increasing the amount of these metals in environmental pollution; they will be increased in food chain significantly. In this research, three levels of cadmium (0, 100 and 200 mg/kg), three levels of lead (0, 200 and 400 mg/kg) and three levels of native resistance bacteria inoculants (B0: Control, B1: Bacillus mycoides and B2: Bacillus circulans) were examined as a factorial experiment with randomized complete block design (RCBD) in three replications. Then sunflower responses to cadmium and lead toxicity including: heavy metal and micronutrients concentration and their uptakes and finally dry matter weight of sunflower were evaluated in greenhouse condition. Results showed that with increasing cadmium and lead concentration in soil, concentration of these elements in plant root and shoot increased significantly (P<0.05). Therefore, cadmium showed a high ability of translocation from root to shoot. The highest translocation factor (TF) for cadmium which was equal to one occurred in all six treatments and for lead which was 0.716 observed in Cd200Pb400B2. The highest rate of uptake for cadmium and lead in root with use of native bacterial inoculants in Cd100Pb400B1 and Cd0Pb400B1with 260 and 481µg/Pot and in shoot in Cd200Pb200B0 and Cd0Pb400B1 with 377 and 389µg/Pot respectively. Application of resistance and native PGPR improves uptaking rate of nutrient elements and it also helps to increase plant resistance in stress conditions.

In order to investigate the effects of different irrigation regimes on yield and yield components of three chickpea cultivars, an experiment was conducted during the 2007 growing season at Mashhad. Six irrigation regimes including I1=full irrigation, I2=irrigation at branching, I3=irrigation at flowering, I4=irrigation at pod formation, I5=irrigation at seed filling stage, and I6=dry farming without irrigation (main factors). Three kabuli chickpea cultivars ILC482, Jam, Karaj 12-60-31as (sub factors) in a split block experiment based on randomized block design with three replications. There were significant differencese between supplemental irrigation levels on yield and yield components of chickpea cultivars. The results showed that the supplemental irrigation at flowering had significant higher grain yield (1732 kg/ha), pod number in main and substems, grain number and weight in plant and 100 grain weight, compared to other irrigation regimes. All traits exclude of pod number in main and substems were higher in full irrigation than supplemental irrigation regimes. ILC482 and Karaj 12-60-31 cultivars had the highest and lowest grain and biological yields and harvest index respectively. Grain yield had significant positive correlation With Seed filling rate (r=0.081**) and effective seed filling period (r=0.79**) Grain weight had the highest significant positive correlation (r=0.75**) with grain yield. The results showed taht the flowering stage in chickpea cultivars is the most sensitive stage to drought stress and in deficit water condition supplemental irrigation in this stage may considerably increases yield of chickpea. In tolerance to drought stress and supplemental irrigation conditions ILC482 cultivar was better compared to other cultivars.

One of the ways to increase economic and environmental efficiency of drainage systems is water table management. Water table management consists of, controlled drainage and subirrigation. This study examines the effect of controlled drainage on yield, root distribution pattern and water use efficiency of maize (SC 704) in Karaj. The experiment was performed as a randomized complete design with three replicates including three treatments: free drainage (FD) and controlled drainage with 40 cm (CD40) and 60 cm (CD60) controlled water tables. Lysimetric station is equipped with drainage system and water table control system. Irrigation intervals in all of the lysimeters were based on MAD=0.65 in FD treatment. For all treatments, irrigation depths were determined based on deficiency of soil moisture from field capacity with 70 percent application efficiency. The results showed that 30 percent irrigation losses during implementation of treatments in CD treatments did not cause rise of the water table to the desired control levels, due to extra consumption of plant. So between two water table control treatments there was no significant difference. In free drainage treatment which drainage water discharge was facilitated lower plant consumption were noted. Effect of water table management on yield, irrigation amount, root dry weight and water use efficiency was significant (p<0.01). Volume of drainage water in FD treatment was 34.8 percent of total gross irrigation and in CD treatments was zero percent. Despite the fact that amount of gross irrigation in FD treatment was more than CD treatments, but useful consumption was higher in CD treatments. Dry weight of silage in FD, CD40 and CD60 treatments were 3.94, 6.38 and 6.56 kg/m2, respectively. Total root dry weight of FD treatment compared to CD treatments was 43.7 percent more. Also water table management led to remarkable changes in root distribution pattern in CD treatments compared to FD treatment. Lowest water use efficiency was in FD treatment with 5.32 Kg/m3 while in CD40 and CD60 treatments were 9.87 and 10.16 Kg/m3, respectively. Finally results showed that management strategies of drainage water discharge using controlled drainage, in addition to control of amount of drainage water can be effective on water use efficiency of plants.

Limitations of traditional (conventional) soil surveys and improvement of information technology have lead soil surveyors to invent new methods which are generally called digital soil mapping (DSM). The aim of these methods is the prediction of soil classes or soil properties based on easily-available or measuring environmental variables. The objective of this investigation is to study the efficiency of digital elevation model and its derivates for soil mapping using Soli-Land Inference Model (SoLIM) and credibility of its results in the Borujen area, Chaharmahal-va-Bakhtiari province. Eighteen terrain attributes including height, slope (angle), aspect, curvature, minimum curvature, maximum curvature, tangent curvature, profile curvature, planform curvature, flow direction, flow accumulation, direct radiation, diffuse duration, diffuse radiation, area solar radiation, power index, sediment index and wetness index, were derived from the DEM. These derivates as well as three dominant soil subgroups and seven soil families of the region were used to construct the input data matrix of the model. Results showed an accuracy of 65% and 40% for interpolation and extrapolation of the soils at subgroup level, respectively. The accuracy decreased to half when soil families were considered for credibility of the model. Because of using crisp limitations in American Soil Taxonomy system, assessing soil survey results can be miss-leading partially, whereas using SoLIM model shows well the reality of the soils in the field.

One of the technologies that deal with efficient use of water is sprinkler irrigation systems. If farmers are to continue the use of sprinkler systems which may be crucial in agricultural development, educational programs should be tailored to their needs. Therefore, the main purpose of this study was to analyze educational needs of farmers equipped with sprinkler irrigation. Furthermore, this study sought to investigate the appropriate teaching strategies that should be used by extension educators when teaching sprinkler irrigation systems. Finally, this study focused on competencies needed by adult educators as perceived by farmers. The target population of this descriptive survey design consisted of farmers who were equipped with sprinkler irrigation systems (N=75). An accessible sample of 63 farmers participated in this study (86% response rate). Using Borich Need Assessment model, four educational needs emerged. Namely, distinguishing different components of the system, system maintenance, knowledge on different sprinkler irrigation methods, and their relative advantages and disadvantages were prioritized by farmers. Moreover, farmers ranked face to face training, demonstration farms, and workshops as their top three preferences for receiving training for sprinkler system. Finally, farmers believed that sprinkler irrigation educators should be competent in different design systems and their components as well as competence in diffusion of innovations. The result of this study has major implications for sprinkler irrigation development programs. First, extension agents should train farmers on technical issues related to irrigation systems. If educational needs of farmers are to be met, extension agents with competencies in irrigation systems are suggested. Moreover, they also need to use face-to-face education when training farmers.

Zinc (Zn) is an essential plant nutrient. Knowledge about distribution of Zn between its different chemical forms is useful in understanding the chemistry of this element in soil and also in development of soil testing procedures. The present study was conducted to obtain such information about distribution of zinc forms in 20 soil samples of Lorestan province by the use of a sequential extraction procedure to extract different zinc forms in these soils and determination of relations between those and some of soil properties. The percentages of distribution of Zn forms with respect to sum of obtained forms were 0.35 for carbonated bound, 0.41 for exchangeable+water soluble, 0.79 for amorphous Fe-oxide bound, 3.03 for organic bound, 3.97 for crystalline Fe-oxide bound and 91.43 for residual (Mnox bound form was not detected and ignored). Correlation coefficient of equivalent carbonate calcium percent was negative with all the Zn forms (with the exception of organic bound) but with exchangeable+water soluble and Fe-oxides bound was significant. The relation between the available P with Fe-oxides bound and residual form obtained significant. The correlation of organic matter percent of soils with organic bound form was negative and significant. The extractable Zn with DTPA also showed significant correlations with Fe-oxides bound and residual Zn forms. There were significant correlations between some of Zn forms and this result probably showed the existence of a dynamic relationship between them in the soils.

Rice can be cultivated in various soils but soil with heavy texture and low permeability is more appropriate for its growth than other types of soil texture. It’s assumed that existence of zeolite in soil can be effective for moisture retention and avoiding of occurrence of crack in soil. In order to investigation of the effect of zeolite on moisture status and hydraulic properties of Guilan province’s paddy’s soils, zeolite factor was conducted in four levels (0, 8, 16, 24 tons per ha) in five stages of soil moisture (saturation, appearance of capillary crack, final crack, returning from final crack to capillary crack, destruction of crack) in three replications as factorial based on complete randomized block design in a soil texture (Silty clay) as the dominant texture in Guilan area in Iran’s Rice Research Institute. Results showed that moisture in saturation stage did not change much by adding zeolite, while in capillary crack stage, moisture storage has increased to 7% and in final crack stage, it has increased to 17%. So you see, after a cycle of dry and wet, the amount of moisture and bulk density has not turned back to its primitive amount, also the volume of inflammation in soil’s moistening trend is far lower than the volume of subsidence in soil’s drying trend and the soil has not turned back to its primitive volume. Finally, the effect of zeolite on the volume of consumable water has been significant at five percent statistical level.

Agricultural scientists have developed considerable interest in modeling and generation of rainfall as new ways of analyzing rainfall data and assessing its impact on agriculture. A combination of Markov chain and gamma distribution function is recognized as a simple approach and is demonstrated to be effective in generating daily rainfall data for many environments. Thus the availability of the weather data limits the applicability of the simulation method. When these model parameters are evaluated over time and at different places, however, certain general characteristics are revealed. First, the transitional probability of a wet day followed by a wet day tends to be greater but parallel to the transitional probability of a dry day followed by a wet day. This phenomenon leads to a linear relationship of the transitional probabilities to the fraction of wet days per month. Second, the beta parameter, which is used to describe the amount of rainfall, is related to the amount of rain per wet day owing to the positive skew ness of the rainfall distribution. Based on these relationships, a simple method is introduced, by which model parameters can be estimated from monthly summaries instead of from daily values. The suggested method, therefore, provides a convenient vehicle for applying weather simulation models to areas in which its use had been impossible because of the unavailability of long series of daily weather data.

Soil classification is a simple tool which is useful to improve human knowledge and to transfer the experience and technology obtained from landscape. The objective of the present research is to compare the efficiency of Soil Taxonomy and WRB in saline soils of different areas in Kerman province. Soil climatic units of the province were separated and based on the area covered by each climatic unit, several pedons were studied. Finally, 12 saline pedons were selected. Results showed that WRB can better express field conditions from both horizontal and vertical dimensions for classification of saline soils of arid areas due to various qualifiers used and more flexibility of this system in reflecting effective properties in soil nomenclature. Besides, adding new "Calcic Natrisalids" and "Calcic Petrosalids" subgroups to Soil Taxonomy from one hand, and "Petrogypsic", "Hypergypsic", "Episalic", "Endosalic", and "Aquic" qualifiers to prefix qualifiers of Solonchaks reference group of WRB from the other hand, can better correlate subgroups of Soil Taxonomy with second level classes of WRB.

One of the major aspects of water resources management in the arid and semi-arid regions is the use of unconventional water sources such as effluents from wastewater treatment plants. As a result, assessment of water supply potential as well as fertilizer values of these unconventional water sources is an important issue in any comprehensive resource management program. In this study, the water supply potential and fertilizer values of the effluents from the City of Mashhad wastewater treatment plants (Olang, Parkand-Abad #1 & Parkand-Abad #2) was assessed based on: 1) the effluents' nitrogen and phosphorus contents, 2) common types of agricultural crops in the region (wheat, barley, tomato), and 3) the crops water and fertilizer requirements over their growing season. The results of this research indicated that the water supply potential of the effluents from above mentioned wastewater treatment plants for irrigation of wheat, barley and tomato are equivalent to 962, 870 and 729 hectares, respectively. Moreover, based on the results of the integrated model used in this research, the use of the effluents can provide 87.2, 74.4 and 133.6 kg.ha-1 available nitrogen and 36.7, 31.7 and 62.0 kg.ha-1phosphorus for wheat, barley and tomato, respectively. In terms of economic assessments, the water value of the effluents corresponded to 89.6×106 Rials for wheat, 67.4×106 Rials for barley, and 125.0×106 Rials for tomato. In terms of fertilizer value, the corresponding economic assessment represented values of 1.97×109, 1.44×109, and 4.68×106 Rials. In general, the net results of the economic analysis performed indicated that the use of the effluents from the City of Mashhad wastewater treatment plants in agriculture can reduce the cost of production by 33, 31 and 28 percent for wheat, barley and tomato, respectively.

The most important part of the design and operation of the supplier systems of agricultural water requirement is the estimating of plant water requirement. In this study by using the LARS-WG5 model, downscaled the data of HADCM3 model according A1B, A2 and B1 scenarios that confirmed by IPCC, and was simulated monthly amounts of precipitation, minimum temperature, maximum temperature and sunshine hours in Khorasan Razavi province in the period 2011-2030. Then using OPTIWAT software, reference evapotranspiration and effective rainfall calculated with Hargreaves- Samani and FAO method respectively and finally the water requirement of sugar beet was estimated in monthly scale for the two next decades compared with the base period (1991-2010). The results showed that spring and autumn precipitation in the future period will be increased in all stations except Torbat Jam compared with the base period. Most increase of precipitation equal 26, 21 and 16 percent based in A1B, A2 and B1 scenarios compared with the base period is owned Mashhad Station and will occur in April. Also according simulation of LARS-WG5 model, Minimum and maximum temperatures will increase during 2011 to 2030 and the increase of the minimum temperature is more than maximum temperature. As a result of these changes, the water requirement of sugar beet in 20 next years in most of the city of Khorasan Razavi province will be different compared to the current period. So that the Torbat Jam station under scenario A1B, A2 and B1, respectively 19, 18 and 18 percent and in the Golmakan respectively 15, 17 and 17 percent, water requirement of this plant will increase from the period of development until the beginning of the final period of growth and in Ghuchan, Nishabur and Mashhad will decrease in the middle period of growth. The most amounts of the reducing in water requirement equal 10 percent and belonging to Ghchan station. The results of running OPTIWAT software also showed that in Sarakhs, Gonabad, Kashmar and Sabzevar, would not happen perceptible change in the amount of water requirement of this plant in the next two decades compared with the base period.

Soil quality evaluation is an essential issue in soil management for agriculture and natural resource protection. Soil quality indices are useful tools for determination and comparison of soils quality. Using of principle component analysis in this study we selected 6 important properties as a soil quality minimum data set (MDS) among 18 soil properties (TDS). Then, soil quality of agriculture and pasture lands in DehSorkh region in south of Mashhad city was evaluated by Integrated quality index (IQI) and Nemero quality index (NQI) in two collections of soil properties include MDS and TDS. The results showed that soils of the region had low quality in respect to studied indices and was significant correlation between IQITDS-IQIMDS and between NQITDS-NQIMDS. Generally those results show that determined MDS can be a suitable representative of TDS. In addition, comparison of soil quality indices between agriculture and pasture soils showed that efficiency of TDS collection in determining land use effect on soil quality indices was better than that of MDS.

SPI is based on fitting a gamma distribution to precipitation amounts in selected periods. Based on current research, the gamma distribution may not be fitted to annual precipitation of some regions. In order to evaluate this subject, annual precipitation have been used during 1958- 2007 at 11 Synoptic Stations in Iran. In first step, values of SPI and frequency of different classes of drought severity were calculated. The Kolmogorov–Smirnov test is used to assess the goodness of fitting most appropriate distribution function to annual precipitation. Then, according to equi-probability transformation the values of SPI were modified. The impact of applying most appropriate distribution function was evaluated to change the frequency of different classes of drought severity in Modified Standardized Precipitation Index (MSPI). The results showed that annual precipitation in all stations do not fallow Gamma distribution as appropriate distribution function except for Rasht station. Using appropriate distribution function in a MSPI leads to changing the frequency and/or displacement of different classes in SPI. So displacements occurred in all classes of drought severity at Tehran and Gorgan synoptic stations. The Gorgan station with 15 events has the most changes in frequency classes.

Obligatory modelling of precipitations in various periods, have a lot of problems and weakness because of their casual nature in time and space. Moreover, their uncertainty in predictions, reduce credibility of estimations which have done via these models. Wavelet is one of the novel and very effective methods in analyzing of time series and signals considered in the hydrology in recent years. In this research, precipitation signal has been decomposed via selected mother wavelet, and then the resulted data are used by fitting direct equations to anticipate the precipitation. These mentioned methods are applied in Zarringol station in Golestan province (Iran) for 33 years predict monthly precipitation with 808 mm annually during 1975-76 until 2007-2008. As a result, decomposed signal via wavelet, correlation among observed and calculated data is 84% and the precipitation prediction can be done with more precise. Meaningless of F test in 90% and above verifies this phenomenon.