Journal of Water and Soil
Year:2012 | Volume:26 | Issue:2|Papers Count:28

In order to study the effect of three irrigation methods (drip, and furrow and basin) on four cultivars of edible onion long-days, during an experiment was carried out in Neyshabur Agricultural Research Station for two years (2004 and 2005). The main-plots were three methods of irrigation and the sub-plots were four cultivars of onion (red, Azarshahr Kashan white, red and white Neyshabour). That thay were studied in the strip-plot design based on the randomized complete block with three replications, and means of results based on a Duncan multiple range tests were evaluated. The results showed that, the percentage of seeds what were green in drip irrigation method was better than other methods of irrigation. The basin irrigation method had the lowest percentage of green product, but the percentage of green cultivars was no significant difference. In three methods of irrigation, change the ratio of length to width of bulb was similar to others and during the growing season, with a ratio decreased to approximately. The number of multifetal onions in the basin irrigation method had a significant increase to other methods of irrigation and drip irrigation method had the lowest number of multifetal onions. In different methods of irrigation and cultivars, thickness of onion bulb was significant differences with each other and in drip irrigation method, the thickness of the layers of union bulb increased. In basin irrigation, onions had lowest thichness of layer. In the Study of interactions, the yield of Kashan white variety in furrow irrigation to basin irrigation method increased about 47%. And the average yield of white Kashan variety, in drip irrigation was 30% more than basin irrigation method. The average yield of drip irrigation method was 7.2% less than the yield of furrow irrigation method and 27% higher than furrow irrigation method. Water use efficiency in drip irrigation to basin and furrow irrigation methods, was higher about 28 and 52 percent respectively. Generally, drip irrigation method was the best treatment for all onion cultivars.

To study the effects of different levels of phosphorus and inoculation with plant growth promoting rhizobacter (PGPR), Pseudomonas fluorescent, on tuber yield and quality of potato a factorial experiment with completely randomized design and three replications was performed in greenhouse of Soil Science Department, Zanjan University, Zanjan, Iran. In this experiment, potato tubers were sown in planting boxes using a loamy soil and factorial combinations of four levels of phosphorus and two levels of PGPR. The phosphorus levels were 0, 15, 30, and 45 mg/kg soil and treatments with and without PGPR were also included in the experiment. The results showed that potato yield and leaf concentrations of macro-elements, except potassium, increased as the levels of soil phosphorus increased. But the leaf concentrations of micro-elements decreased as the soil phosphorus levels increased. The potato yield and leaf concentrations of macro- and micro-elements increased in PGPR inoculated treatments. The interactive effects of phosphorus and PGPR levels were significant on potato yield and dry matter content of tuber and these traits increased as the phosphorus and PGPR levels increased. The interactive effects of phosphorus and PGPR levels were also significant on leaf concentrations of macroelement, except nitrogen, but not on leaf concentrations of micro-elements. The results of this study indicate that potato yield, size, number and dry matter content of tuber and leaf concentrations of macro-elements, except potassium, increase with increasing soil phosphorus levels up to 45 mg/kg soil. But the leaf concentrations of micro-elements decrease as the soil phosphorus levels increase. Inoculation with PGPR improved potato yield and quality of tubers.

Now days, Use of sewage sludge (SS) in agriculture as inexpensive source included macro and micro nutrient has been attended. Purpose of experiment performance was comparison of SS application with fertilizer treatment (F) on some nutrient bioavailability in three textural classes of a calcareous soil after harvesting corn. A factorial experiment was carried out in a completely randomized design with two factor and three replications under greenhouse conditions. Results indicated that soil total nitrogen (TN), available phosphorous (P) and potassium (K) were increased significantly by addition of SS in all three soil textures. TN and available P were significantly lower in fertilizer treatment compared with SS amended soil in all three soil textures. Addition of SS in increasing soil K was lower than the increase in soil P or TN which is probably due to the low content of K in SS. Soil DTPA extractable iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn) significantly increased with SS application in all three soil textures and was higher than fertilizer treated soil textures. Based on nutrient bioavailability in soil textures after harvesting corn, especially at high rates of SS, addition of most nutrients are not necessary for next crop. Concentration of DTPA extractable cadmium (Cd) and Lead (Pb) were not detectable in soil textures amended with SS after harvesting corn, therefore, low content of Cd and Pb in utilized SS reveals that reaching a toxic level of these elements in soil is unexpected. However, if frequently high levels of SS are applied, soil test is recommended for monitoring heavy metals concentration amended soils. Nutrient security of corn and eliminate of Fe and Zn deficiency in calcareous soils are advantages of SS application in agricultural land. Prior to any SS recommendations, the results need to be verified under field conditions.

High energy losses by hydraulic jump cased these phenomena known as dissipater energy through water conveyance channels. Basin bottom roughness is an important factor for control, reducing length and conjugated depth and increase energy losses by hydraulic jump. In this study the effects of cross triangular roughness space on hydraulic jump is investigated. Total of 126 experiments were carried out on rough bed with different distance in the Froude number of incoming flow was varying between 4 to 13.7. Comparing the final result showed that secondary depth and hydraulic jump length will decrease considerably on rough bed in compare to smooth bed. The energy loss will increase and it will be intensified by climbing Froude number. The nondimensional flow profile of hydraulic jump follows a unified curve. It was also revealed that the increase in height and spacing of rough elements decrease the length of jump, length of rollers and the sequent depth. It is found the bed shear stress is 10 times bigger than that on smooth bed.

The CSM-CERES-Maize model was calibrated and evaluated by using the field and weather data set of a two-year field experiment previously carried out on silage corn at the Agricultural Research Center in Varamin. The data set included soil, crop, and weather data of a two-year corn experiment with four irrigation levels and three N fertilization levels. Twelve treatments were arranged in a strip-plot design in a randomized complete block with three replications during the 2003 and 2004 growing season. Data collected in the field included weight of biomass, leaf area index, and important physiological dates such as silking, anthesis, grain filling, and harvest maturity during the growing period. The maximum leaf area index and weight of biomass at physiological harvest, along with anthesis and maturity dates were used in the calibration process. The biomass weight during the growing season was used for the model evaluation. The results indicated that GENCALC tool is capable enough to be applied for determining genetic coefficients of maize with acceptable accuracy. The result of calibration of the model produced the following statistics, root mean square errors (RMSE) for anthesis and maturity dates were 1 and 2 days, 980 and 1313 kg ha-1 for weight of biomass and 0.75 and 0.44 for maximum LAI in the years of 2003 and 2004, respectively. Genetic coefficient required by the CSM-CERES Maize model including P1, P2, P5, G2, G3, and PHINT were found to be 236 (oC), 0.4 (days/hr), 790 (oC), 833, 8.5 (mg/day), and 55 (oC), respectively. The evaluation of the CSM-CERES-Maize showed that the model was able to simulate weight of biomass for the silage maize accurately with root mean square errors (RMSE) ranging from 9 to 1483 kg ha-1 and coefficient of determinations (r2) ranging from 0.86 to 0.99 for all of the 12 treatments for two years. It is concluded that the GENCALC tool was capable of successfully determining the cultivar parameters required by the CSM-CERES-Maize model and that the model itself was well calibrated for the data set used in this study.

Water deficit is on of the factor that limited growth of plant and oxidative process is a secondary stress due to drought. In order to study the effect of exogenous application of hydrogen peroxide on drought tolerance in ornamental amaranth (Amaranthus tricolor L.) an experiment was conducted in greenhouse conditions. The experiment was factorial based on randomized complete design with 3 replications. Different concentration of hydrogen peroxide (0, 2/5 and 5 mM) and three levels of irrigation regime (after 2 (every 78 h), 5 (every 120 h) and 8 (every 192h) days) were treated in this study. results showed a significant difference in traits measured in different irrigation regimes. with increasing irrigation intervals, chlorophyll index, shoot and root dry weight, relative water content (RWC), stomata conductivity (gs), plant height and root volume decreased and increased proline, electrolyte leakage and root length. interaction between hydrogen peroxide content and irrigation with different regimes showed that root volume and root weight were significant in 5% level and chlorophyll index, shoot weight, stomata conductivity, plant height, electrolyte leakage, free proline and root length were significant in 1% level. The final results showed that foliar application of hydrogen peroxide can improved alleviate adverse effects of drought stress in ornamental amaranth by increasing proline in 0.5 mM level and increasing chlorophyll index and shoot dry weight in 2.5 mM level.

This research was carried out to study the sorption of lead (Pb) and cadmium (Cd) at surface and sub-surface horizons of ten Palygorskitic soils in eastern Isfahan province. Physical, chemical and mineralogical properties of the selected soils were measured. Sorption characteristics of Pb and Cd were estimated from sorption isotherms using Langmueir, Ferundlich and linear equations. According to the mineralogical results, smectite, mica, palygorskite, chlorite, kaolinite and quartz exist in all of the studied soils. Ferundlich and linear adsorption isotherms and Ferundlich, Langmueir and linear adsorption isotherms were able to describe the lead adsorption and cadmium adsorption, respectively, Ferundlich isotherm showed higher R2 for both of the elements. Parametern in Ferundlich equation for Pb and Cd was in the range of 0.22-1.52 and 1.95-4.61, respectively. Distribution coefficient (KF) for Pb and Cd was in the range of 2679-114815 and 353-1369 Lkg-1, respectively. Maximum sorption of cadmium (b) was in the range of 1250-2000 mgkg-1. The constant related to binding energy (k) was in the range of 0.30-2.50 Lmg-1 for cadmium. In linear model, distribution coefficient (Kd) for Pb and Cd was in the range of 4188-64605 and 33-678 Lkg-1, respectively. In general, lead sorption was higher than cadmium sorption in the soils of the area. Correlation coefficients between sorption isotherms parameters and soil physico-chemical properties showed that calcium carbonate equivalent, organic mater, cation exchange capacity and clay percentage are the most important soil properties for Pb and Cd sorption.

Aqua Crop model is a powerful tool and valuable for improvement of water management in the field and calculating water productivity. Simplicity, necessity for minimum input data and acceptable accuracy are the advantages of this model. In this research in order to evaluate and analyze the sensitivity of Aqua Crop model, field data under soybean planting in Karaj area were used. This experiment was conducted in 2008 in form of randomized complete block design in three replications and four furrow irrigation treatments including: full irrigation (at 100 percent of the soil moisture deficit compensation), conventional deficit irrigation at 75 and 50 percent of the soil moisture deficit compensation and partial root drying at 50 percent of the soil moisture deficit compensation. The results showed that Aqua Crop model can simulate crop yield, crop evapotranspiration and soybean water use efficiency acceptably. The results of this research based on sensitivity coefficient rates (Sc) show that input data of the model don’t have any sensitivity to date of emergence, initial soil moisture and irrigation water depth in full irrigation treatment.

The purpose of this study was to asses the potential impact of physical and biological changes on soil hydraulic properties in the prepared soil columns. A clay loam (CL) and a sandy loam (SL) soil, were used for the two types of repacked and repaired soil columns. For this purpose the soil was passed through a 8-mm sieve and poured into large cylinder. In total, 24 columns were prepared out of which 8 columns were used as repacked columns and the rest (16 columns) were installed in the field under effects of wetting/drying and freezing/thawing cycles (physical changes). Of the physically changed columns 8 columns were subjected to earth worm activity (biological changes). All experiments were conducted with four replicates. Applied experimental treatments (averaged over physical and biological changes and soil texture) caused a decrease in bulk density (6.5%) and an increase in macropore (39.8%), mesopore (32.8%), micropore (20.0%), filed capacity (28.4%), wilting point (7.5%), available water content (43.3%) and the volumetric water content at 5 cm matric suction (28.1%) through soil columns. The grater values of these properties were shown in clay loam soil which confirms the greater affinity of clay in regeneration of soil structure and soil pore improvement. These changes verify the effects of wetting and drying and freezing and thawing cycles in modification of soil structure.

Quantity-Intensity (Q/I) curves of potassium and their derived parameters provide general information about soil K availability and fertilizers management. This study was conducted to compare the Q/I parameters in soils of Mobarakeh and Shahrekord plains in Isfahan and Chaharmahal-va-Bakhtiari Provinces, respectively. The Q/I plots showed the common forms described in the literature but high variations were observed in the soils with respect to Q/I parameters. Results showed the following Q/I parameters for the surface soils (A horizon) of Mobarakeh and Shahrekord plains, respectively: the potassium activity ratio at equilibrium (AR0): 0.0278 to 0.1067 and 0.0174 to 0.0811 (mmol.l-1)0.5, the immediate available K (DK0): 0.728 to 2.62 and 0.56 to 4.05 mmolkg-1, the difficulty available K (KX): 1.57 to 1.71 and 3.69 to 5.25 mmol.Kg-1 and the potential buffering capacity (PBCK): 13.6 to 26.27 and 30.97 to 49.96 mmol.kg-1/ (mmol.L-1)0.5. Correlation coefficients showed a significant difference (r=0.86) between PBCK and CEC for Mobarakeh soils whereas no significant difference was observed for Shahrekord soils. A significant difference was also observed among AR0, K0 and exchangeable potassium for both of the soils studied.

The main purpose of this research was assessing climate change impact on temperature, precipitation, maize biomass and water productivity values and trend in 2010-2039 in Pakdasht. According to this, required data for crop model (AquaCrop) calibration was collected from an experiment field in Pakdasht, south east of Tehran and climatological data were taken from Pakdasht and Aminabad meteorological station. An ensemble of nine AOGCMs (Atmosphere-Ocean General Circulation Model) in corporation with A2 emission scenario was used in order to incorporate uncertainties of these models. Using Bayesian-Mont Carlo approach, temperature and precipitation CDFs were generated for risk levels of 25, 50 and 75%. Data obtained from AOGCMs were downscaled by means of “Change factor” method and input data for AquaCrop were produced then biomass values for future period of 2010-2039 were simulated. Results showed 7.8, 6.8 and 6.2% reduction in full irrigation and 20.8, 18.9 and 17.8% reduction of deficit irrigation treatment due to 25, 50 and 75% risk level, correspondingly. Descending trend of biomass and consequently water productivity were for most probably due to temperature and rain variability increment.

Reducing evapotranspiration (ETc) is one of the ways to reduce water use in agriculture. Creating or putting mulch on the soil surface can reduce ETc. Establishing a cover crop between harvest and cultivation of the main crop can produce enough mulch on the soil surface. An experimental study carried out to assess different impacts of no tillage system under crop mulch (DSM) compared with conventional tillage (CT) in the Southeast of France (being in a Mediterranean climate) from 2000 to 2007. In this paper, the impacts of DSM on the ETc were studied. Zero flux plane method was used to determine ETc. The results showed that mulch reduced ETc for corn, sorghum and durum wheat from 29 to 118 mm as compared with CT. This reduction resulted in saving approximately a water depth application of 30 mm, being considerable in a context with water deficiency.

Now days, water allocation issue is the main problem of decision makers and stakeholders in the majority of catchment basins. The stream flow is the most important information for simulation and modeling of water resources systems allocation. In the other hand, in recent years, trend of stream flows decreased in downstream because of development of agriculture lands and enhancement of stream flows withdrawals. In this study, allocation of water resources systems has investigated under conditions of existing trend and detrending of stream flow by using MIKE BASIN model. In this study, allocation of water resources system has been done for trend, first detrended (in order to management of upstream) and second detrended (in order to management of downstream) time series in Soofi Chai basin. In order to detect the trend of annual stream flow, has been also used non-parametric methods such as Mann-Kendall, Theil-Sen and Spearman Rho. The results showed a decreasing significant trend of Soofi Chai stream flow at 95% confidence level but, there was no significant trend in the Chekan Chai stream flow. Moreover, the results of model simulation, showed that the relative deficit percent of consumption nodes has increased in first detrended status and has decreased in second detrended status relative deficit percent in comparison with existing trend status, respectively. As, for agricultural nodes 1 and 2 has decreased 18 and 1.9 percent, respectively in comparison with first detrended status. In addition, this relative deficit for these nodes has increased 42 and 25 percent in comparison with second detrended status.

One possible means of achieving better agronomic management is the use of crop models for yield prediction under different conditions. Accurate prediction of crop yield is essential for suitable water management in arid and semi arid regions. The objective of this study was developing a model for grain yield prediction of canola based on simulated leaf area index under water stress conditions. In this study, leaf area index was simulated based on cumulative temperature and water stress index. Soil water balance was also simulated based on root zone depletion, actual evapotranspiration, runoff from the soil surface and deep percolation. The model used crop and soil data and meteorological data including daily maximum and minimum air temperature (oC), precipitation (mm) and solar radiation (MJ.m-2d-1). The model was developed based on the 2004-2005 growing season data for Zarfam cultivar under full irrigation and water stress conditions, and validated with 2005-2006 growing season data. The simulation results showed that across all water levels, model performed well for grain yield simulation based on simulated LAI.

Drip irrigation, because of its high efficiency on sloping lands is a suitable irrigation system in most countries around the world. Wetting pattern recognition formed by a source point which is called “wetting pattern is very important in drip irrigation. The wetting pattern depends on the soil texture and structure, the volume of applied water, the discharge of emitters and the land slope. In this research the effects of slope and irrigation time on wetting pattern were assessed for constant discharge equal to 4 liters per hour. Experiments were performed on lands with 0, 5, 15 and 25 percent slopes with silt –loam soil texture in three irrigation times of 2, 4 and 6 hours, in 3 replications. So based on the results of experiments and the measurements, table 6 and 7 were presented for designing of drip irrigation system in silty-loam soils. According to results of table 6 on sloping lands in silty-loam soils, applying 6 hours of irrigation time and locating the emitters 56 to 65 centimeters apart from each other, from the point of view of wetted area overlapping gives an appropriate result. Table 7 results show that using the double row arrangement for laterals on sloping lands give high wetting area. If drip irrigation system is used for cultivating on sloping lands with the slope of 5 to 25 percent the place of planting should be done 10 to 25 centimeters below the place of emitter was achieved.

In drought monitoring, different indices usage may leads to different results. In this study, Meteorological variable statistics from 5 synoptic stations of Mashhad, Tehran, Tabriz, Kermanshah and Shiraz among 50 years periods, 1957-58 to 2006-07 were used. In order to evaluate meteorological drought indices, 8 indices such as: RAI, SIAP, DI, PN, *SPI, CZI, SZI and *RDI (Select) were examined. In this study, in order to Promote them, by utilizing 50 metrological variable related to precipitation, evapotranspiration and number of rainy days, a new multivarate method for detect dry and wet years was established based on Chang threshold and Scalogram model. Then based on mentioned years as criteria of important dry and wet years and applying a new statistical criteria as “Total Accuracy (TA)”, appropriate index was selected. In 3 synoptic stations of Mashhad, Tehran and Shiraz, TA value for *RDI (Select), was equal to 0.46, 0.51 and 0.51 respectively. In Tabriz station TA value of 3 indices, *SPI, CZI, SZI was equal to 0.88 and in Kermanshah station TA value of CZI index was equal to 0.64. These indices used as proper index for each station.

This study was conducted in order to investigate the effect of topography and groundwater on soil genesis along a catena, in Yasouj region. Soils ranged from well drained at the top of the slope to poorly drained with a high water table, at the base of the slope. Six soil profiles in different soil physiographic units were dug, described and sampled. Undisturbed soil samples were collected for micromorphiligical and electron microscopy studies. The results exhibited that carbonate dissolution, translocation and formation of secondary carbonates; removal of Fe-Mn oxides from mineral and their distribution in soil matrix as well as clay eluviation were the main soil genesis processes along the catena. The highest amount of carbonate depletion from soil surface was noticed in lowland and plateau physiographic units. Secondary calcium carbonates were observed as micrite and sparite crystals, needle shaped nodules and cytomorphic types. The shrink/swell characteristics on wetting and drying cycles may be the main factor explaining destruction of the clay coatings in some argillic horizons. Fe-Mn oxides exhibited different redoximorphic features along the catena as affected by topography and groundwater level.

Iron bioreduction in ferric minerals is an important process in behavior and bioremediation of contaminants. Organic matters are effective factors in bioreduction of ferric iron by iron reduction bacteria. They enhance iron reduction in hematite by two mechanisms: complexation and electron shuttling. An experiment was conducted under laboratory conditions in the form of a completely randomized design with 12 treatments and 3 replications to examine the function of AQS (as an electron shuttling) and ferrozine (as a complexing agent). The treatments included two controls (with and without Shewanella sp) and 5 levels of ferrozine (0.5, 1, 1.5, 2 and 2.5 mM), and 5 levels of AQS (10, 20, 30, 40 and 50 mM) in the presence of Shewanella sp in anaerobic chamber. The greatest amount of biological reduction of ferric iron was occurred in 2 mM ferrozine and 50 mM of AQS treatments. Ferrozine after 5 days and AQS after 1 day showed the greatest impact on bioreduction of ferric iron in hematite. So both complexation and electron shuttling had additive effect on the bioreduction of hematite.

In order to investigate the effect of irrigation water salinity on Quality & Quantity Indices of Cherry Tomato (cv. Halil) in Hydroponics, a factorial experiment was conducted on the basis of a randomized complete block design with electrical conductivity at four levels of (A) 0.1, (B) 1.3, (C) 3.2 and (D) 5 dSm-1 and four replications. Growth indices like total yield, mean fruit weight and dry matter percentage, leaf area index (LAI), dry matter percentage of leaf, height and dry weight of plant, EC& PH of fruit juice, total soluble solids of fruit (TSS) and Vitamin C content of fruit juice were recorded during 9 months experiment since September 2010 to May 2011. Results indicated that total yield, mean fruit weight, leaf area index (LAI), dry matter weight of leaf and plant, plant height and fruit juice PH were significantly reduced with increasing salinity level, while dry matter percentage of fruit, EC, total soluble solids (TSS) and Vitamin C content of fruit juice were increased. Also, according to the results the highest total yield was found by treatment (A) with 6.78 kg/plant. Treatments (B) and (C) showed no significant differences at 5% probability level. Results demonstrated that in zones like the region of this research without fresh water that it’s not feasible-because of any reasons among them inappropriate price of crop production from an economical point, energy costs or water resources shortage- to use water refining systems, it’s possible to plant the cherry tomato in soilless culture systems by water resources with salinity level up to 3.5 dsm-1. Finally, the lowest total yield was found by treatment (D) with 3.62 kg/plant that was significantly different with all of other treatments.

Parent materials as one of the major soil formation factors, have a great effect on soil properties. Binaloud zone, around Mashhad, has such a good geological variability and is a suitable location to study residual soils. The aims of this study were to characterize morphological, physical and chemical properties of soils derived from different parent materials in Binaloud zone and to investigate the concept of residual soils based on their evolution. Two soil profiles in the summit of granitic, ultrabasic and metamorphic rocks were sampled from genetic horizons. Physical and chemical properties including texture, equivalent CaCO3, organic matter, gypsum, pH, CEC and EC were measured for genetic horizons. Coarse texture and shallow depth of the soils indicate the low weathering intensity and formation of cambic, calcic and gypsic horizons is majority of soil development in the area. Granite and ultrabasic soils had the most amounts of sand and clay, respectively and metamorphic soils were in between. CEC varies from 7.8 in metamorphic soils to 35.9 cmol (+) kg-1 in ultrabasic soils. The lack of correlation between CEC and clay content suggests that clay type has more important effect than amount of clay on CEC. According to rocks composition, the presence of considerable amount of gypsum and CaCO3 in the soils cannot attribute to weathering. As wind has an important role in this arid region, gypsum and CaCO3 have probably been added to soil profiles by wind activity. In conclusion, based on obtained results, the studied soils cannot be considered completely as residual soils.

Having sufficient knowledge about dry spells occurrence is essential to efficient management and planning of water resources usage. To reach this goal, this study was conducted to assess the continuity and frequency of dry spells, with using daily rainfall data of 12 synoptic stations of Khorasan province in the available period to end of 2007. Dry spells’ relative occurrence frequency and also occurrence probabilities with the Markov chain for all stations were determined seasonally and annually. Results of seasonally comparison of two mentioned methods show better efficiency of the Markov chain to estimate the dry spells of winter and autumn than spring, summer and also annual ones. Also it has more precise results in long (20-30 days) dry spells than the medium and short (less than 20 days) periods. To assess the spatial variation of dry spells, the difference of frequency and Markov chains’ mean values were zoned, both seasonally and annually. Results indicated that the Markov chain is an efficient method for dry spell studding and its results is very close to the reality. One could conclude of the zoning maps which the difference of Markov and observation method was so small in the north of the case study, but increases gradually towards the southern regions.

Puccinellia distanseis perennial forage, belongs to poaceae family, grow in waterlogged lands with relatively high salinity. In this research, the growth of Puccinellia distance plants with Caspian Sea, Incheh and Ajigol saltmarshs and runoff water in Golestan province were investigated to evaluate the potential of withstanding this plant with these salty waters. The highest electrical conductivity (EC) and total dissolved solid (TDS), material was observed in Ajigol saltmarsh, Incheh runoff waters had the medicated, and Caspian Sea indicated the lowest values. Plants were cultivated in sand culture and waterlogged in Hoagland nutrient solution prepared from complete, two and four times diluted of these waters. The Hoagland nutrient solution created from tap water of Gorgan city was used as control. Plants were harvested after two months growth before reproductive stage. The result indicated that Puccinellia distanse plants are not able to withstand in even four times diluted water of Ajigol and Incheh saltmarshs, however, it could resist in Caspian Sea and runoff water. The highest growth of plants was observed in four times diluted runoff water that indicated even more dry mass compared to control (Gorgan city tap water) that may related to high concentration of nitrogen compounds specially nitrate in this water. The results indicated Puccinellia distance plant has a certain ability to withstand to salinity and could utilized for reclamation of seashore and lowlands of runoff water accumulation.

To estimate actual evapotranspiration of grass, an experiment was a weather stationat, the Faculty of Agriculture, Ferdowsi University of Mashhad in 1389 year. In this experiment, actual evapotranspiration grass Deficit irrigation at different levels (5 levels) with a single branch sprinkler system, at two-day period was measure the water balance method. Also was estimated the reference crop evapotranspiration with FAO Penman, Hargreaves-Samani and pan evaporation methods. Coefficients calculated for each plant with water level and Five Fuzzy model was provided for estimating actual daily evapotranspiration. In these models was considered FAO Penman evapotranspiration as the output model. Performance models were compared using RMES, MAE, MBE, t and R2/t. The results showed that evapotranspiration values calculated in terms of standard methods of FAO Penman and Hargreaves - Samani, compared with the water balance method, respectively, 17 and 14 percent more than had been estimated. With analysis of evapotranspiration values in non-standard conditions were found to reduce grass Deficit irrigation is the actual evapotranspiration, The difference amounts to 20 percent evapotranspiration Deficit irrigation conditions was not a significant effect on evapotranspiration. Fuzzy model output results also showed that the fuzzy models developed using the combined model (PMF56) had a high Match and the ability to estimate actual evapotranspiration are included in the daily scale.

In order to study the effect of salinity and silicon application on biomass of shoots and root of fenugreek (Trigonella foenum- graceum L.), a greenhouse experiment was conducted at Research Greenhouse of Ferdowsi University of Mashhad using completely randomized desgin with ten replications. Employed two factors consisted of four levels of salinity using NaCl (0.0, 60, 120 and 180 mM) and two levels of silicon (0.0 and 1.5 mM sodium silicate). Shoot and fruit and root biomass and K content in shoots significantly decreased with increasing salinity, while Na content significantly increased with increasing salinity. Application of silicon imposed a positive effect on preventing high accumulation of Na and increased K content in shoots.

In order to study of the effects of irrigation methods and different water supply levels on the yield of cucumber, an experiment was conducted in Varamin Agriculture Research Center. The statistical model was a split plot design based on RCBD. The main factor was irrigation methods in three different levels (as Tape in 30cm depth, Tape in surface of soil and surface drip irrigation). The sub factor was different water application levels (as 100, 75 & 50 percent of water requirement). The results indicated that, surface drip irrigation and Tape in 30 cm depth method with 100% water application level and Tape in surface with 75% water application level had the highest yield respectively. There were no significant differences between mean yields. The methods of Tape in depth and Tape in surface with 75% and 50% water application levels had the highest water use efficiency. The results showed that the Tape in surface with 75% water application is the best treatment and it can be recommended to farmers in water scarsity conditions.

The effects of air pollutants on the agricultural crops have been studied extensively at the recent years. It is important to estimate the crop yield loss due to the effect of air pollution distribution caused by the sources such as factories, refineries and industries on different crops. In this study the dispersion of the pollutants emission from point sources in the atmosphere was modeled based on Gaussian model in MATLAB environment. It is necessary to say that according to the complexity of the phenomenon mentioned, dispersion from sources of pollution and the weather conditions, the necessity of modeling of this process is of great importance. After developing the mathematical model to estimate pollution plume, its performance accuracy was verified using some observational data. To show the application of the proposed model some hypothetical examples were given and the model results were analyzed.