Journal of Water and Soil
Year:2012 | Volume:26 | Issue:1|Papers Count:27

Lack of using a standard method for the evaluation of watershed management measures in Iran did not provide a base for comparing the results of various applied technologies in the watershed management. This study introduces the results of applying WOCAT programme for the assessment of bio-mechanical alternatives, which have been done in DEJKORD region in the Duroodzan watershed, northwest of Fars Province. This programme provides a complete data set of physical characteristics of the watershed, applied measures, human environment, maintenance and problems. The results of this research indicate that the creation of the Watershed union and the implementation of various technologies of soil and water conservation, such as the plantation of almond and apple trees on the countor lines instead of annual rainfeed crops such as wheat and barley on hills with 8 to 30% slope, control of erosion with various biological and mechanical methods, and capacity building of the rural people in 1377, are the most dominant causes of the success of the Watershed Management project. The first successful sign of this project is the significant reduction of surface runoff and soil erosion. By employing these technologies, 15, 000 hectares of the destroyed national resources with the cultivation of wheat and barley, was changed into dry and irrigated Almond (10, 000 hectares) and Apple (5000 hectares) gardens. The management and executing of these technologies were carried out by a Watershed Management union composed of 8000 members. The Ratio of B/C after the implementation of these technologies is 5.2 and the ratio of income from the new technologies (cultivation of fruit trees) to the previous one (sowing wheat and barley dry) is 15. The second effect of this project is reversing the trend of migration process from rural to municipal areas. Many young people are now back to the region. The success of this project has caused the extension of the technologies to the neighbor regions. The last success of this project is executing sustainable development for the region. The availability of concise and comprehensive information provided a scientific base for using the application of WOCAT in DEJKORD.

To evaluate the effects of soil compaction on tuber yield and quality and uptake of nutrients by potato plant, an experiment with completely randomized design and three replications was conducted in greenhouse of Soil Science Department, Zanjan University, Zanjan, Iran. In this experiment, potato tubers were sown in a loamy soil with different levels of compaction or bulk density. The bulk densities of soils used in this study were 1.3 (control), 1.56 and 1.8 gr/cm3 respectively. The results of analysis of variance of data showed that potato yield and the concentrations of macro- and micronutrients, in leaf and tuber, decreased as the level of soil compaction increased. The decrease in concentration was greater for N, P and K than the other nutrients. Comparison of means showed that potato yield was 6.32 kg/m2 for control treatment which was significantly more than those treatments with higher bulk densities (5.87 and 5.13 kg/m2 respectively). The tuber yield of control was respectively 7 and 19% higher than those of treatments with densities of 1.56 and 1.8 g/cm3. The highest mean for tuber number was obtained for control and it decreased by 46.1 and 47.5% in treatments with densities of 1.56 and 1.8 g/cm3 respectively. The difference in tuber number was not significant between second and third levels of compaction. The highest tuber length and diameter were measured in control treatment and the size of tuber decreased as the compaction level of soil increased. The leaf concentrations of macro- and micro- nutrients were higher in control treatment than the treatments with higher bulk densities compaction and the decrement of concentration with compaction was greater for macronutrients than micronutrients. The tuber concentrations of nutrients were also decreased by increasing soil compaction and the highest decrement in N, P and K concentrations were 52.3, 34.7 and 45.6% respectively. The result of this study indicate that soil compaction restricts root growth and development and thereby decreases plant uptake of nutrients, potato yield, size and number of tubers and leaf and tuber concentrations of macro- and microelements.

Hydrodynamic models are suitable tools for understanding hydraulic behavior of large and complex networks which can evaluate network performance and improve their operation and management. FLDWAV model is a kind of hydrodynamic model with wide capability which basically has been developed for using in rivers. The model is included by routing different methods considerable variety of boundary condition and accessible source code hence it can be used in unsteady flow of irrigation and drainage network. The purpose of this study is testing and accommodating the results of FLDWAV model with experimental data, thus the elongated trapezoidal channel was constructed and by the use of collected observation data was evaluated model performance and its application for irrigation and drainage networks. Two hydrographs were produced with different properties and their data was compared with several testing model results from simulating unsteady flows in channel without calibration and with calibration. The results show that FLDWAV model is suitable for simulation of unsteady flow with eligible accuracy. Open source model prepares capability to accommodate model with different conditions in experimental structure and according to multiple advantages its application is advisable in operation improvement and rehabilitation of irrigation networks.

Due to zinc deficiency of agricultural lands and fertilizer application problems, use of zinc efficient cultivars is considered a suitable way for the compensation of this deficiency and increasing the yield of the agricultural products. In this research, zinc efficiency of eight common bean cultivars was studied based on the seed yields in two treatments of zinc fertilizer (0 and a 10 mg/kg per soil treatment) in greenhouse condition. The concentration and the uptake of the micronutrients and phosphorus as well as yield component of various cultivars in the two levels of fertilizer was measured. The results showed that the G01437 cultivar with 93% and the Cardinal cultivar with 46% had the most and least zinc efficiency, respectively. The cultivars with more zinc efficiency in the zinc deficient treatment had more seed weight, seed numbers and pod numbers, whereas the response of the cultivars with less zinc efficiency to the zinc application was higher. In the treatment of zinc sufficiency among various cultivars, these characteristics had less difference. The concentration and the uptake of zinc with zinc application increased in all of the cultivars. This increase was more in the cultivars with higher zinc efficiency. The concentration of the other elements with zinc application decreased while their uptakes increased except in the cultivars with higher zinc efficiency. Overall, due to ability of produce higher yield in zinc deficiency conditions, using of the cultivars with higher zinc efficiency is a suitable strategy for the compensation of zinc deficiency in agricultural lands.

Siderophores are low molecular weight organic ligands excreted by aerobic soil microorganisms and some plants roots to acquire Fe. Siderophores may also complex other metals such as Cd, therefore, may influence bioavailability, toxicity and mobility of Cd in soils. The main objective of this study was to investigate the effects of desferal siderophore (DFOB) on adsorption of Cd on montmorillonite. The adsorption of Cd on montmorillonite was studied as a function of pH (Cd concentration: 1mg L-1) in the range of 3-7.6, and as a function of metal concentration (Cd concentration in the range of 0.1-1 mgL-1) in the absence and presence of siderophore (DFOB concentration 250 mM) using a 24 h batch equilibration experiments. The results of adsorption envelopes (pH dependent experiments) showed that the siderophore deceased sorption of Cd onto montmorillonite at pH³5. The results of equilibrium test (isotherms) revealed that removal of Cd from solution was affected by siderophore at both pHs. Siderophore decreased adsorption of Cd by the mineral. The Freundlich and Langmuir isotherms were described satisfactorily equilibrium data. The values of Freundlich (KF) and Langmuir (KL) bonding constants were greater in suspensions without siderophore as compared to suspensions containing siderophore. These values are indication of competition between siderophore and the clay surfaces for Cd ions.

Precipitation is one of the most important climatic factors with high variations in time and space. Determination of the amount of precipitation in different locations is particularly very important. For this reason, to estimate precipitation in various regions of Golestan province, different interpolation methods have been used. Precipitation data of 32 rain gage stations with 26-years period were selected. First the accuracy and homogeneity of data were evaluated by using statistical tests. Then, to determine the best model of spatial pattern of annual precipitation in Golestan province, six methods of IDW, GPI, LPI, RBF, Kriging and Co-Kriging have been used. The criteria of statistical error were used to evaluate the results and to select the most suitable method of interpolation. The results showed that Geostatistics methods were better than deterministic methods, and among the geostatistical models, Kriging give better results (MAE=60.49) than Cokriging (MAE=64.46). Also in cases of using the deterministic methods, RBF and IDW have more accurate results than LPI and GPI. The lowest MAE (60.49) was recorded in Kriging method with spherical model and the highest MAE (288.96) was obtained in GPI method with power 5.

Least limiting water range (LLWR), a proposed soil physical quality index, is the range of soil water content at which plant growth is least limited by water potential, aeration and soil mechanical resistance. The slope of the soil water retention curve at its inflection point (Si) is also considered as a soil physical quality index which controls important soil physical behaviors. The purpose of this study was to assess the effects of electrical conductivity (EC) and sodium adsorption ratio (SAR) of the prepared solutions as irrigation water on LLWR and Si in two clay loam and sandy loam soils under laboratory conditions. The treatments consisted of applying irrigation waters with three levels of EC (0.5, 4 and 10 dS m-1) and four levels of SAR (1, 5, 15 and 25). Soil columns were arranged and irrigated with the prepared solution for 12 weeks during six wetting and drying cycles. At the end of this period LLWR, Si and soil aggregate stability indices including MWD, WAS, DC and saturated hydraulic conductivity (KS) were measured. Analysis of variance showed that the effect of soil texture, SAR and EC on LLWR was significant (P£0.01) and increase in SAR and EC lead to decrease in LLWR. Increase in SAR from 1 to 25 resulted significant (P£0.01) decrease in Si index while Si remained unaltered by EC of the irrigation water. DC, WAS and Ks than two indicators LLWR and Si most affected by irrigation water EC and SAR.

Regarding to water resources limitation and knowing this matter that about 40% of the world's land is managing by dry farming system, therefore improving management of dry farming system is important issue. This paper is intended to assessment the effects and variations of rainfall on the annual dry farming of wheat, base on the least number of rainfalls. Hamedan state has been chosen as a case study and for covering all rainfalls, four weather station, located in areas under dry farming system have been selected. For best assessment, the new index as indicator of Time-Rain (RTI) has been introduced. This indicator has the combined capabilities of assessing the changes of both factors of time and amount of rainfall on the annual dry farming yield. The effect of each intermittent rainfall on the annual dry farming yield of wheat is calculated by using the multi regression that defined base on the RTI index. The results show, the differences and the effects of each intermittent rainfall have been indicated better by using RTI index. The rainfalls in autumn and winter are more reliable and knowing the effects and impacts of those rainfalls are more practicable. This research also indicates that importance of the autumn and winter rainfalls are depends on the climate of region.

Stilling basins with different layout of rough and appurtenances are commonly used to reduce the excessive energy of exiting flow downstream of hydraulic structures through the phenomenon of hydraulic jump. This paper deals with an experimental investigation on the effect of vertical trapezoidal cross bars on the characteristics of hydraulic jump. total of 126 runs are conducted where the Froude number of incoming flow to the basin ranged from 3.9 to 13.7.Three different heights (t) were selected for the rough elements with four different longitudinal spacing (s).The results showed that the non dimensional profile of the jump could be defined with a unique equation. It was also revealed that the sequent depth, length of hydraulic jump and roller length are reduced while the energy loss is increased, comparing with classic jump. These effects are intensified as the Froude number of incoming flow, the height and spacing of the rough bars increased. It is found the bed shear stress is 3.2-9.6 times bigger than that on smooth bed. The investigation resulted in some empirical relations to define the sequent depth, energy loss and bed shear stress for different flow conditions on used rough beds.

Considering the production of more than 2 million tons of sulfur per year and in order to create a basis for application of agricultural sulfur in plant nutrition and farmland reclamation, the National Petrochemical Company of Iran, has produced an agricultural Sulfur enriched with iron (Fe), zinc (Zn) and manganese (Mn). There is little information available on the quality of these products and the reaction of these fertilizers in soil and available sulfur for plant. The present study was conducted to investigate oxidation potential and sulfur release in soil and influence on changes in rate of sulphate and available micronutrients in a calcareous soil. Soil sample was collected from vicinity of Karaj city and agricultural sulfur with Thiobacillus inuculant was throughly mixed with 1 kg of soil at the equivalent rates of 0, 300 and 600 kg.ha-1. The samples as randomized complete design with three replications were incubated under 25oC and 80% of field capacity for 180 days, and in time periods (45, 90, 135 and 180 days after incubation) subsampled. Sulphate, iron, zinc and manganese concentrations were determined. The results showed that incubation time has a significant effect on changes in available sulfur, iron, zinc and manganese. In general, regardless of the type of agricultural sulfur, the different level of fertilizers increased sulphate, zinc and manganese concentrations. Type of fertilizer only had significant effect on zinc concentration. The mean increase of available Zn for agricultural sulfur containing zinc was 3.2 times.

In order to evaluate the effects of fertilization and tillage methods on soil microbial community and sunflower yield, a field experiment was carried out in Sanandaj. The experimental design was a split plot with three replications. Main plots consisted of no tillage (T1), minimum tillage (T2) and conventional tillage (T3). Six methods of fertilization including (N1): 15 t FYM ha-1; (N2): 10 t compost ha-1; (N3): 75 kg triple super phosphate ha-1+150 kg Urea ha-1+50 kg Sulfate potassium; (N4): 10 t FYM ha-1+5 t compost ha-1, (N5): 10 t FYM ha-1+5 t compost ha-1+25 kg triple super phosphate ha-1+75 kg Urea ha-1+25 kg Sulfate potassium and (N6): control were arranged in sub plots. Results showed that the maximum number of bacteria (109.1×106) in dry soil was obtained from the no tillage system. Also, co application of farmyard manure and compost increased bacteria number and phosphatase, urease, catalase, and cellulases activities. All soil enzyme activities decreased significantly with application of chemical fertilizers. The activity of phosphatase (acid and alkaline) and cellulase tended to be higher in the no tillage treatment compared to conventional tillage (51, 27 and 83% respectively). The significantly highest grain yield and oil yield were detected in N5 treatment. The highest grain yield (3701 kg/ha) was produced in minimum tillage system.

Amongst different kinds of frosts, radiation frost is very important; because of frequency occurrence and is controllable well with active protection methods in agricultural sector. Along with radiation frost monitoring, Precise forecasting of the minimum temperature and hourly estimation of its variations (trend) during the nights with frost event for starting and ending time determination of the active protection methods is satisfied. Therefore, using an experimental forecasting model, which can calibrate to meet local conditions and have a simple application, it seems essential. Thereafter, this study aimed at predicting the minimum temperature using a simple regression model and estimating the temperature trend during these kinds of nights. In this paper, using hourly synoptic data of Mashhad station for January, February and March during 1999-2010, meanwhile separating radiation frost from advection frost, dew point temperature and dry temperature two hours after sunset embedded for developing the prediction model of minimum temperature. Then, according to the predicted minimum temperature, the temperature trend during the night hours with radiation frost event was incident prediction. In the significant confidence level of 99 percent, Pearson correlation coefficient value between observed and predicted minimum temperatures based on developed model was 0.93. The amount of root mean square error (RMSE) for the developed model is 1.63oC and the amount allowed this model predicted 76 percent. In forecasting the occurrence of temperatures during the nights with radiation frost event in 2010, the amount of RMSE is 0.7oC and correlation coefficient is more than 0.90 (significant at 0.01) respectively.

Surface soil shear strength (SSS) is among the most important and needed parameters that is required in soil erosion simulation and prediction. Lack of the SSS is often a problem in erosion simulation at watersheds. Because of SSS high variability and too sampling, SSS are too difficult, too time consuming, and/or too expensive to measure directly. Therefore it is necessary to measure indirectly. This study was conducted to predict this parameter using kriging, PTFs, SSPFs methods and their combination. In this reason, the study was conducted in central Zagros region on water erosion susceptibility with an area of 23562 ha (rangeland and degraded-rangeland landuse). Based on the maps of geology, topography, landuse and soil capability, 14 Land Unit Tracts (LUT) was created. A total of 90 samples were collected in triplicates in order to determine sample variability of each LUT. Soil samples were collected from the 0-10 cm of soil depthes. Routinely measured (available) parameters for surface shear strength PTFs and SSPFs included soil surface and subsurface attributes in addition to topographic and vegetation attributes: particle size distribution, soil organic carbon, gravel, slope, aspect, elevation and normalized difference vegetation index (NDVI) were used. Three MLR PTFs (pedotransfer functions) and SSPFs (soil spatial prediction functions) were tested and investigated in this study. Spatial variability of parameters was investigated using semivariograms and the ratio of nugget to total semivariance. Krigin method was used to create map of the needed data. Interpolated easily-obtained parameters by kriging maps are subsequently input into PTFs and SSPFs to predict surface soil shear strength. The performances of the models were evaluated using mean absolute error (MAE) between the observed and the estimated values, root mean square error (RMSE), Geometric standard deviation of the error ratio (GSDER), and Geometric mean of error ratio (GMER). Results showed that the performance of PTFs and SSPFs as compared to combining kriging-PTFs and SSPFs was similar. All of the parameters were moderately spatially dependent.

Reference evapotranspiration (ETo) is an important agrometeorological parameter for climatological and hydrological studies, as well as for irrigation planning and management. The FAO-56 Penman-Monteith combination equation (FAO-56 PM) has been recommended by the Food and Agriculture Organization of the United Nations (FAO) as the standard equation for estimating reference evapotranspiration (ETO). This method considers many parameters related to the evapotranspiration process; net radiation (Rn), air temperature (T), vapor pressure deficit (VPD), and wind speed (U). This paper examines the potential of FAO-56 PM equation in estimating the ETO under difference conditions from limited weather data. For this study, full weather data sets were collected from nine difference weather stations from Iran. FAO-56 reduced-set PM ETO estimates were in closest agreement with FAO-56 full set PM ETO estimates at the most of locations. The difference between FAO-56 full set PM ETO estimates and FAO-56 PM reduced-set ETO estimates generally increases by increasing the number of estimated weather parameters. Overall results indicate that FAO-56 reduced-set PM approaches mostly provided better results compared to Turc equation, adjusted Hargreaves equation and artificial neural networks. This fact strongly supports using the FAO-56 PM equation even in the absence of the complete weather data set. The minimum and maximum air temperature data and local default wind speed value are the minimum data requirements necessary to successfully use the FAO-56 PM equation under humid and arid and semi-arid conditions and the minimum and maximum air temperature data daily and wind speed data daily are the minimum data requirements under extremely arid conditions.

Unsteady flow causes a lot of problems for optimal operational of irrigation networks, hence precise understanding of this flow is necessary. Therefore in this study a computer model has been developed to simulate the unsteady flow produced by delivery and disturbance of water and immediate variation of input discharge in irrigation network. Present model solves partial differential equations of 1-D unsteady flow (Saint- Venant equations) by finite differencing method. Water surface elevation at junction location is calculated implicitly by using of matrix properties and influence line technique. Result of model verification showed developed model simulates water surface profile of positive surge in a trapezoidal channel after sudden closure of end gate. Also developed model for unsteady flow, can simulated steady sate gradually varied flow in a complex loop with a very high accuracy. Additionally there are relatively good agreement between the result of present model with results of ICSS model for simulation of unsteady flow in a single channel (E1R1 channel of Dez network) with different kind of check and intake structures. After model verification, main channel of Darband irrigation network with 14 kilometer length with five secondary channels simulated integrate. Simulation results showed that without any operational performance, 25% sudden reduction of input discharge to main channel reduces discharge of secondary channels between 18.68 to 26.15 percent. Additionally 4.42 hours take place until the effect of unsteady flow fluctuation is disappeared at the location of SC5 channel’s intake.

Soil organic carbon (SOC) is a very important component of soil that supports sustainability and quality in all ecosystems, especially in semi-arid region, and is so important for climate change mitigation. This study was conducted to determine optimum interpolation method for draw SOC spatial variability in a semi-arid region from west of Iran. Cross validation results indicated that ordinary Kriging, Co-Kriging with calcareous percent as secondary variable and RBF with Spline with tension function and optimized parameters, were more efficient to interpolate SOC contents when all data in all land use were applied for interpolating. After division land uses, best interpolation methods were co-Kriging with secondary variable included: surface gravel percent, calcareous percent and soil degradation classes for rangelands, agriculture and forest lands respectively. Exponential model was suitable semivariogram model for all geostatistical methods in all land use types. Optimum lag size and measurement errors in all methods were 750 to 1000 meters and 35-65%, respectively. Application of polygonal Kriging analyses spatial structure of SOC with land use discrimination and abrupt borders between different land use types. But polygonal Kriging did not improve efficiency indices in interpolation, significantly. Estimation error specially increased in south part of ranges because of differences in anisotropy direction and trend existence from data in this location and base variogram in polygonal Kriging.

Hydraulic conductivity is one of the most important soil physical properties for determining infiltration rate, developing irrigation and drainage systems, and other hydrological processes. The objective of this study was to compare the multiple constant head (MCH), the simplified falling-head (SFH) and the tension infiltrometer (TI) methods for measuring field saturated hydraulic conductivity (Kfs) in some vertisols and entisols. Therefore, Kfs was measured in soils with different shrinkage and swelling ration in wet and dry initial moisture conditions. The results showed that because of the preferential flow at the dry initial moisture condition measurement of Kfs was not possible by MCH and SFH methods. While, TI method provided measuring of this parameter throughout by of preferential flow. At the wet initial moisture condition, the measured Kfs values by SFH and MCH methods were higher than those obtained by TI method. However, the correlations between measured Kfs values by the mentioned methods were significantly positive. The highest observed correlation coefficient was between MCH and SFH methods (r=0.97) and the lowest one obtained between FSH and TI methods (0.73). Statistical analysis of t-test showed that there was no significant difference between Kfs values measured with the three methods at the wet initial condition (P<0.05). Considering the adventages of SFH and TI methods, they can be recommended as suitable methods for measuring Kfs in swelling soils.

There are different ways to control flood damages, which one of these methods is flood zoning (floodplain limits analysis). In this procedure, the floodplain limites were determined by simulating river hydraulic behavior for different return periods. In other hand, the soil and specifically plant coverage were the most effective factor for determining the manning roughness coefficient (n). So, it is expected that the seasonal plant coverage changing affect on manning roughness coefficient and also flood hydraulic behavior forecasting. In this study, a part of Atrak River was selected to study the effect of a season in determining of manning roughness coefficient for prediction of flood hydraulic behavior, due to vegetation cover changes. The manning roughness coefficient was determined separately in winter and summer times. The quantitative and qualitative results were shown that a season affected on determination of manning coefficient, and also its caused changes on “n” values on left and right river banks. Additionally, for determining the floodplain limits the fluctuations on vegetation cover, were effective. Finally, vegetation cover caused some changes on flood zones, velocity, depth, shear stress, distribution of flood flow volume in river system and also floodplain limits for various return periods.

Investigation of earth channel seepage is always taken into account by researchers due to water losses, reduction of soil quality around the channel and for canal lining issues. In this Present research a computer model has written in with seepage amount in an earth channel with natural cross section is calculated by solving general equation of water movement into isotropic or anisotropic soil under saturation condition by numerical finite volume method. Location of pheriatic seepage line using deformed mesh with tray and error is determined. Also amount of seepage is determined by means of Darsy relation and using of calculate head in boundary junctions. Evaluation of model accuracy viewpoint programming, seepage discharge and location of pharisaic seepage line calculated for a circular channel compared with results of analytical conformal mapping method. The results showed location of pheriatic seepage line and wide of seepage area overlaps in tow methods. Also difference between calculate seepage discharge by tow mentioned method decreases with increasing distant of ground water surface table from channel bed. Additionally to model verification two earth channel named Lolham and Shikhsarmast in Nazloo area of Uromiye province were selected and seepage discharge was determined by site measurement. Also the result of falling head hydraulic conductivity test showed hydraulic conductivity of bed material of Lolham and Shikhsarmast channels are 3.5 and 1.77 meter per day, respectively. Then cross section coordinate points and hydraulic conductivity as the only input data entered to model and amount of seepage has calculated that has less than 5% difference with measurement values. After model verification, constant coefficient of empirical relation for seepage calculation has modified using result of model running.

Unfavorable fertility and microbial activity are two limitations of saline sodic soils. This study focused on variation of nitrogen, phosphorous and potassium macronutrients and microbial respiration in ameliorating process of calcareous saline sodic soil. The experiment was factorial based on CRD using 6 soil treatments consist of control, cattle manure, pistachio residue, gypsum, and their combination; 2 water treatments (with and without sulfuric acid) and 3 replicates, which was conducted in laboratory conditions by soil column. Four intermittent irrigation steps with one month intervals and one pore volume were applied. Microbial respiration was measured during leaching operations, while at the end of experiments, macronutrients concentrations of nitrogen, phosphorous and potassium were determined at different depths. The results showed that both organic matters similarly added higher amounts of nitrogen to the soil compared to control and gypsum treatments. At the end of reclamation experiments, absorbable phosphorous decreased with depth for all of the treatments except to gypsum. The results also indicated that control and gypsum had the least while pistachio treatment showed the highest efficiency in improving availability of three study macronutrients. Additionally, in comparison to the untreated irrigation water, application of sulfuric acid in conjunction with irrigation water, led to an increase in absorbable phosphorous and potassium content. Investigation of microbial respiration showed that respiration rate was lower for control while, cattle manure found to have the highest rate. The findings of this research reveal that among different amendments, pistachio residue have the highest efficiency in increasing availability of macronutrients.

Quantitative investigation of soil compaction seem essential to improve agricultural management practices for reducing difficulties related to compaction in the environment and crop production systems. Soil compaction can be significantly reduced with changes in physical and hydraulic characteristics of soil, water infiltration and availability of air and water to plants. Sum effects of the above may lead to reduced soil quality. This research was performed to study the effect of compaction on physical and hydraulic properties of a loamy soil in Khuzestan province in southern Iran. A completely randomized block was designed with three replications, applying Blank (No teraffic passing), once, twice, three times, four times and eight times of tractor passings. Physical parameters such as; bulk density, total porosity, Mean Weight Diameter index and soil moisture characteristic. hydraulic parameters including hydraulic conductivities (saturated and unsaturated), number of pores and percent flow through them with effective porosity was determined in the field using disc infilterometer in four potentials (0, -3, -5 and -15 cm of water). Our Results revealed that soil physical and hydraulic properties changed significantly (P<0.01) with compaction. This effect was highest with eight times tractor passing. Soil bulk density in this treatment showed a increased 5.5 percent compared to blank. The value of total porosity and aggregates greater than one millimeter decreased 6 and 70 percent respectively with 8 tractor passings when compared to blank. Results of disc Infilterometer showed that coarse and medium size pores, percent flow through pores and saturated and unsaturated hydraulic conductivities of 8 times tractor passings relative to blank decreased 85, 62.5, 47, 71, 66.5 percent respectively. The highest compaction effect was observed at 0-20 cm depth. From this depth downward no changes was seen in soil physical characteristics due to compaction.

Recent researches show foliar applied methanol increases growth and development of numerous C3 crops in warm and arid growing conditions. So an experiment was carried out in split plot based on randomize complete block design with three replications during 2009 growing season at Mashhad Ferdowsi University, Agricultural Station. Irrigation (100, 75 and 50 percent of water requirement) was main plot and foliar application of methanol (0, 20, 40 and 60 volume percent) was subplot. Each concentration of methanol spryed on chickpea shoots after podding with 10 days interval. The results showed that the effects of foliar application of methanol on yield and yield components were significat. Spray of 60 percent methanol affected biological yield, yield and yield components more than other treatments. So that increased number of pods, 100-grain weight, number of secondary branch per plant, plant height, seed weight, seed number per plant and harvest index.

Crop reference evapotranspiration (ETo) is an important agrometeorological parameter for water resources and hydrological studies, as well as for irrigation planning and management. There are several methods to estimate ETo, but their performance in different environments are not the same. The FAO Penman–Monteith (FAO PM) method has been considered as a universal standard method to estimate ETo for more than a decade. In some situations, using FAO PM is limited due to lack of input variables. In these cases, calculating ETo using FAO PM method with estimated variables is introduced, that has recommended by the FAO paper No.56. So, the purpose of this study is evaluating FAO PM performance to estimate ETo with missing data on wind speed, net radiation and saturation vapor pressure deficit, in Khorasan Razavi province. Empirical methods of ETo estimation including Priestley-Taylor, Hargreaves and Thornthwaite that require less input data, were calibrated for the region. Meteorological data from 10 synoptic stations in Khorasan Razavi province were collected to compare estimates of ETo using FAO PM method, by means of full and missing data. The results showed that when the net radiation and wind speed data are missing, again FAO PM Method is a good option for estimating evapotranspiration in Khorasan Razavi province, so that the RMSE value is less than 0.71 mm day-1. Also, Priestley–Taylor method is a good option to estimate ETo, when wind speed and vapor pressure deficit are missing, especially when this method was calibrated according to local conditions (RMSE=0.56 mm day-1). When only temperature data are available, adjusted Hargreaves and modified Thornthwaite methods were better options to estimate ETo than the FAO PM method, since RMSEs from these methods (0.57 and 0.63 mm day-1, respectively) were smaller than FAO PM (RMSE=0.88 mm day-1).