جستجوی مقالات مرتبط با کلیدواژه « correlation » در نشریات گروه « آب و خاک »

The purpose of this research is to analyze the quality of groundwater in Khanmirza, Lordegan, Borujen, Ardal, and Kiar cities based on WQI and GWQI indicators based on the Iran Standard and Industrial Research Institute (ISIRI) and World Health Organization (WHO) standard. In this research, 28 samples of groundwater (wells) were collected from different places in Khanmirza, Lordegan, Borujen, Ardal, and Kiar cities from 2020 to 2022 and 10 qualitative parameters HCO3, K, pH, TDS, EC, Ca, Na, Mg, Cl, and SO4 were chemically analyzed in the laboratory. After analyzing the data, the spatial distribution map of the index was prepared for the study area by using the inverse distance weighting interpolation method. The results showed that according to GWQI and WQI indicators, most of the samples were in the good quality category. By examining the Pearson correlation between WQI and GWQI indices and the parameters used, it was found that the two parameters TDS and EC with coefficients of 0.982 and 0.989 have the highest correlation at a significant level of 1% with the WQI index. Also, TDS and Ca parameters with coefficients of 0.975 and 0.979 have the highest correlation with the GWQI index at a significant level of 1%. The results of this research have shown that the combined use of GIS, WQI, and GWQI indicators in evaluating the quality of groundwater and their spatial distribution in the studied area is useful and effective in selecting water resources for drinking purposes.

Drought refers to the lack of rainfall in the long trun, which is one of the most important natural disasters due to its spatial extent and short-term and long-term economic, social and environmental consequences (Nikbakht and Moradi, 2019). Factors affecting the physical, chemical and microbial properties of surface waters: precipitation, geographical location, climate, geology, industrial activities, domestic wastewater, agriculture, mineral pollutants, etc. can be mentioned (Mishra et al., 2017). In addition to drought, land use changes change the hydrological cycle of the basin and upset the balance between rainfall, evaporation, soil permeability and runoff (Farokhzadeh et al., 2016). Land use is one of the most important factors affecting the quality of surface water resources, especially rivers, as land population changes, land use patterns change. Therefore, runoff from rainfall as well as urban wastewater discharge leads to an increase in the amount of nutrients and other pollutants into rivers and surface water sources (Moradi et al., 2012). Tahiru et al. (2020) investigated the impact of land use change and land cover on water quality in a catchment area in the northern region of Ghana. Their results showed that there is a positive relationship between land use change and land cover and water quality parameters. Soltani-Gerdefaramarzi et al., (2021) investigated the effect of land use on surface water quality under both wet and dry periods in the Godarkhosh watershed. The results showed that barren and residential lands had the greatest impact on surface water quality and rangeland and forest land use showed a negative correlation with water quality parameters. Also, a strong significant relationship was found between water quality parameters and land use in dry years. Lei et al. (2021) investigated the effects of land cover, topography, and soil on water flow quality at multiple and seasonal spatial scales in a German lowland catchment. Overall changes in water quality on larger scales were estimated better in the summer. Due to the location of Iran in the dry land belt, most of its area will experience drought during most days of the year, which will cause changes in water and environmental resources. Biology, economic growth and development, agricultural activities, etc. are essential; on the other hands, land use changes have a significant impact on surface water quality. This effect can improve or reduce the quality of surface water. These changes have a great adverse effect on the environment and water resources, so the control and monitoring of surface water for various uses is necessary to make water of good quality available to the public. One of the main sources of drinking water, agriculture and industry in Isfahan province is the Eskandari watershed and the Plasjan river. Therefore, paying attention to water resources is one of the appropriate and necessary management measures at the level of the entire basin. Therefore, in the current research, land use changes during two periods of drought and drought have been investigated on the quantitative and qualitative parameters of the Plasjan River.

Water shortages in a defined area and in a certain period are called drought. This phenomenon is time dependent rather than aridity, and it is quitely temporary. drought in various regions of Iran in arid, semi-arid and even humid areas shows different forms and causes great damage. Drought is calculated using indices such as precipitation and evapotranspiration. The teleconnection is also a new branch of synoptic climatology, which recognizes the relationships between phenomena and climatic elements such as rainfall, drought, and temperature in remote locations. In other words, teleconnection patterns are the occurrence and continuation of large scale models of circulation abnormalities and air pressure that extend over a wide geographical range. These patterns are also oscillatory behavior of low frequencies. Teleconnection mechanisms are one of the important issues in justifying the behavior of the climate, and its effects do not always appear in the same form everywhere (Khosravi, 2004). In worldwide, many studies have been done on climate signals in variety ways. Iran is also affected by rainfall systems, which affects the pattern of rainfall and drought in it.

The purpose of this study was to investigate the relationship between NINO4 and NAO indices with meteorological droughts in synoptic stations in the southern part of the Caspian Sea. For this purpose, data of rainfall were obtained monthly from the Meteorological Organization of Iran. Then, SPI was calculated for different time scales of months including 1, 3, 6, 9, 12, 15, 18, 24, 48. The next step was to obtain the values of the Ocean Atmospheric indices, including NINO4 and NAO, at the monthly scale from the Australian Meteorological Organization. For analysis, the MINITAB16, SPSS16 was used. In this case, the simultaneous and asynchronous relationship between the time series of SPI and the NAO and NINO4 indices was determined. In this stage, Spearman's correlation test and cross-correlation function were determined. In the next step, regression modeling was done. In this way, regression models for the time series of SPI were calculated taking into the simultaneous and asynchronous state of the NAO and NINO4 indices. The lag times were 1-6, 12, 24, 48 months. Finally, errors for regression models were determined at all stations to select the best model.

The results showed relationships between NAO with SPI different series at Ardabil and Babolsar stations in January, April, August and December; the NINO4 with SPI at Ardebil station in all months except October and December. Also, the results of regression equations showed that in SPI time series of NINO4 with the highest coefficient, the highest and NAO with lowest coefficient, had the lowest effect on drought in studied areas. In this case, the Ardabil has the highest coefficient in SPI24 months. At the end, the error statistics including RMSE, R, R2, CE were calculated for model reliability and calculation of errors.

In this case, the best model was found at the Gorgan station by calculating the error statistics. The result suggests that these stations are neighbor to the Caspian Sea, which has affected the rainfall and drought pattern of the regions. This can also be the result of the universality of the Enso phenomenon that affects the world's climate. In order to obtain better results, it is recommended to study the precipitation and temperature pattern of these areas with other Ocean Atmospheric indices such as SOI and AO. Regarding the fact that the distant teleconnection indices do not occur in all directions in one way, it is suggested to study rainfall and temperature pattern of other parts of Iran in relation to climate signals. This study is also in line with another study by researchers who through statistical and synoptic methods have investigated the relationship between climatic factors such as rainfall and temperature with climatic signals. Study of other researchers determine that there is a significant relationship between the annual rainfall of Iran and the South Oscillation Index. temperature pattern of these areas with other Ocean Atmospheric indices such as SOI and AO. Regarding the fact that the distant teleconnection indices do not occur in all directions in one way, it is suggested to study rainfall and temperature pattern of other parts of Iran in relation to climate signals. This study is also in line with another study by researchers who through statistical and synoptic methods have investigated the relationship between climatic factors such as rainfall and temperature with climatic signals. Study of other researchers determine that there is a significant relationship between the annual rainfall of Iran and the South Oscillation Index.

Dust phenomenon is one of the destructive and common phenomena in arid and desert areas of Iran and the world that has harmful effects on human life and the environment. The purpose of this study is to statistically investigate the number of dust occurrences for the period 1990 to 2016 for the whole of Iran. In this study, the number changes of dust occurrences in months of the studied years (1990-2016) were analyzed at 30 stations in the country, and the correlation between stations at four regions and the whole country was investigated. The results of the occurrence number of dust in different seasons in the country indicated that the highest and lowest occurrence of dust in the country were in summer and winter, respectively. The highest and lowest dust levels were on July and December, respectively, in most stations in the country compared to other months. Also, the results showed that Zabol and Zanjan had the highest and lowest dust levels with 3666 and 130 events during the year, respectively. Most of the stations in the country had a significant correlation in terms of dust occurrence at the level of 95 and 99%, which indicates that almost most of the country have similar conditions in terms of dust storm. The results also showed that the stations that were geographically close to each other had a higher correlation coefficient.

Accurate estimation of water requirements of plants is a key factor in controlling several hydrological processes including: planning and management of water resources, especially in arid and semi-arid regions (Laaboudi et al., 2012; Wen et al., 2015) water pricing and water requirement for Irrigation (Yassin et al., 2016). In this study, multivariate regression methods and gene expression planning were evaluated to estimate reference evapotranspiration. For model input data, the Khorramabad Synoptic Station information including: maximum and minimum temperatures, maximum and minimum relative humidity, sunny hours and monthly wind speeds in the range of 1983-2017(420 months) were used. Based on the relationship between input and output parameters, six input patterns were determined for modeling.70% of the data were used for training and 30% were used for model validation.The results of multivariate regression showed that the proposed model had acceptable accuracy with R2 = 0.952.The analysis of model coefficients showed the greatest effect of maximum temperature with a coefficient of 0.604 on reference evapotranspiration. Gene expression planning results showed that the fifth pattern with four main operators was R2 = 0.958 and RMSE = 0.704 in the training phase and R2=0.977 and RMSE = 0.615 in the test phase had better performance.

Drought occurs due to lack of humidity and deficiency in precipitation amount. Therefore, it is important to recognize and investigate the effective factors on precipitation deficiency and consequently drought occurrence. Enso is a phenomenon of climatic teleconnection that can affect weather in different regions of the world. Enso is one of the important large-scale phenomena affecting the temporal and spatial distribution of rainfall and consequently the drought that occurs in the tropical Pacific. The objective of this research was to investigate the effect of Enso on meteorological drought in the midwest of Iran.

First, precipitation data of synoptic stations in 14 locations were obtained in the west of Iran. Then, SPI values was calculated at different time scales of 1, 3, 6, 9, 12, 15, 18, 24, and 48 month using the spi-sl-6.exe software package. In the next step, using the data of Enso including Nino1+2, Nino3, Nino3.4, and Nino4, the Spearman correlation test was simultaneously performed in the Minitab16 program. Then, the asynchronous relationship was investigated with the cross-correlation function between Enso and SPI in time series of months 1 to 48 in SPSS16. Finally, linear regression modeling was performed. Multivariate regression test with simultaneous and delayed states of 1-6, 12, 24, and 48 months was used based on the stepwise method.

Results are presented in three sections: simultaneous, asynchronous relations, and regression equations. Results showed a high correlation between seasons of autumn and spring with indices of Nino4, Nino3.4, Nino3, and Nino1+2. In addition, the asynchronous relationship was better than the simultaneous mode. Better significance in the asynchronous mode is due to the effect of Enso on weather and drought in Iran. Considering the p-value <0.05, it was shown that the highest significance was observed between Enso indices and drought index in Bushehr station. In addition, in a number of stations, including Arak, Urmia, Shiraz and Hamedan, no significant relationship was observed in their simultaneous state. The regression analysis showed that Nino4, Nino3.4, Nino3 and Nino1+2 indices had the highest effect in different time series of SPI with the highest positive and negative coefficients of atmospheric oceanic index in all stations. The results showed that high correlation between Enso and SPI can affect predicting climatic conditions, drought, floods, planning, and crisis management in watershed scale.

Enso can be used as predictors of long-term climatic factors such as precipitation and temperature. Enso phenomenon in Nino1 + 2, Nino3, Nino3.4 and Nino4 regions can be used as predictors of climatic factors such as rainfall for long-term forecast of precipitation and finally drought and wet season in different parts due to the universal Enso phenomenon. It seems that due to the mechanism of the Enso phenomenon and its relationship with natural disasters, further studies can be effective in predicting climatic conditions, drought and floods in Iran which ultimately can be used in predicting hydro-climatic events.

Soil temperature is one of the important parameters in meteorological agriculture and affects many soil biological processes. Unfortunately, due to the lack of soil temperature data in many regions of the country, this issue has always been discussed in agricultural projects. In the present study, practical equations were created to estimate the monthly soil temperature using the correlations between different meteorological parameters and soil temperature in five agricultural stations in different cities of Fars province (Shiraz, Abadeh, Darab, Zarghan, and Jahrom) at depths of 5, 10, 20, 30, 50, and 100 cm. In this regard, multivariate linear regression equations have been used. According to the results, the following parameters affected soil temperature: in Abadeh, meteorological variables of wind speed, rainfall, and maximum temperature; in Darab, relative humidity, wind speed, air pressure, rainfall, maximum temperature, and minimum temperature; in Jahrom, variables of wind speed, air pressure, maximum temperature, and minimum temperature; in Shiraz, the variables of sunshine hours, wind speed, air pressure, rainfall, maximum temperature, and minimum temperature and in Zarghan city, the variables of sunshine hours, wind speed, air pressure, rainfall, maximum temperature, and minimum temperature. In general, fewer parameters are needed in all stations to estimate soil temperature at depths of 5 and 10 cm, and the importance of meteorological parameters and their effective role in estimating soil temperature increases with increasing depth. Also, the effect of meteorological variables on soil temperature is not the same in different climates. According to the coefficients related to the equations, the highest and the lowest effect on soil temperature at different depths, are the maximum temperature and sunshine hours. With increasing depth, regression coefficients decrease as well. In all stations, regression coefficient at depths of 5 and 10 cm has been calculated between 0.98-0.99, and at depth of 100 cm has been calculated between 0.87-0.92, shows decreased about 10% of this coefficient with increasing the depth. According to the results and equations obtained for each station and different climates in Fars Province, this equation can be used to estimate soil temperature in areas without data.

Measuring complexity and ways to reduce it in organizations and decision-making processes has become one of the topics of the day. The chaos theory was proposed in the 1960s, and the most effective and most successful effort was made by Edward Lorenz. Towards this, the flow rate of Sefidrood River as the most important river in Guilan Province and the second-longest river in Iran was studied using Chaos theory.

The study area in this research is a sub-basin of the Sefidrood River Basin. After collecting the monthly and annual discharge data of Sefidrood River, the following items were investigated:1- chaotic dynamic systems, 2- phase space reconstruction, 3- determining the time delay, 4- determining the embedding dimension, 5- determining the correlation dimension, and 6- determining the Lyapunov and Hurst exponents.

In determining the delay time using the autocorrelation function (ACF( curve, the appropriate lag is where the graph reaches a value close to zero or about 0.1 to 0.2. An appropriate embedding dimension is an embedded dimension in which the number of false neighbors has reached to about zero. For a lag of 1-month, the delay vectors are concentrated around the diagonal axis of space. Therefore, X(t) and X(t +1) are very close and continuous. Therefore, they will cause the characteristics of the adsorbent structure to be lost. Also in the state (phase) space for the delay time of 100 months, the density of lag vectors is close to the horizontal and vertical axes of the graph and indicates the incoherence and complexity of successive components in the lag vectors and its inadequacy to achieve system dynamics. However, due to the 5 months delay state space obtained from the average actual information (AMI) method, the delay vectors have a better distribution and the state space is well filled with points. The correlation dimension of the monthly time series is 3.37.

The presence of stochastic behavior in the river flow was determined using the correlation dimension test and Hurst exponent. The correlation exponent was saturated after increasing the embedded dimension in an incorrect value equal to 3.37. In addition, the closest correct value to the correlation dimension indicates the minimum variables required to describe the system, which is a value of 4. The obtained Hurst exponent is opposite to 0.5 and according to Hurst studies, it indicates the non-randomness and the presence of chaos in the river. The Hurst exponent obtained in daily scales is between 0.5 and 1 and indicates the existence of long-term memory in this series.

Estimation of evapotranspiration of the reference plant is one of the important components in the design of irrigation systems and water management for irrigation of plants. In this study, four coefficients of evaporation pan Schneider (1992), Aurang (1998), Allen and Perot (1991) and Konica (1989) to estimate the reference evapotranspiration compared to the FAO-Penman-Monteith model using indices RMSE, MAE, AARE, MR and Spearman coefficient were evaluated. Information required for different coefficients for estimation (ETo) was collected from Khorramabad synoptic station. The results of statistical evaluation showed that in the daily period, Orang (1998) and Schneider (1992) pan coefficients with RMSE equal to 1.004 and 1.13 (mm.day-1), respectively, as the most appropriate and Allen and Prot coefficients ( 1991) and Konica (1989) were selected as the most unsuitable coefficients with RMSE of 1.83 and 1.47 (mm.day-1), respectively. On the other hand, the results of statistical evaluation for the 10-day period of Konica (1989) and Schneider (1992) pan coefficients with RMSE of 6.01 and 8.25 (mm.day-1), respectively, as the most appropriate coefficients and coefficients of Allen and Perot (1991) and Aurang (1998) were selected as the most unsuitable coefficients with RMSE of 13.90 and 9.43 (mm.day-1). Spearman correlation test also showed that the results of all coefficients have an acceptable correlation with the reference method.

More than half of the agricultural lands in arid and semi-arid climates are rainfed. Many climatic variables affect the yield of rainfed crops, among them rainfall is the most important variable. The aim of the present study is to determine the yield functions of rainfed wheat in Tabriz, Sarab and Maragheh stations located in the east of Lake Urmia basin, considering the changes of climatic variables during different stages of rainfed wheat growth. In order to model the yield using multivariate regression method, some precipitation variables such as, number of effective precipitation events, vegetation precipitation deficit, reference precipitation and evapotranspiration deficit in rainfed conditions during six stages of rainfed wheat growth including germination; End of germination until the beginning of flowering; Flowering stage; Finishing flowering until the seeds start to fill; Seed filling stage and whole growing season were used. In general, based on the obtained results, precipitation fluctuations have the greatest effect on wheat yield. Therefore, identifying the precipitation regime and analyzing its characteristics is important for assessing yield fluctuations of rainfed crops. Among the growth stages, the fluctuation of the proposed traits in the whole growth season has a greater role in determining yield functions. Yield functions were determined using variables that had a significant correlation with yield. For this purpose, 22-year and 3-year data were used for calibration and validation, respectively. The results of the model efficiency coefficient and normalized root mean square error indicated better effeciency of Enter method in the Sarab (EF=0.55 and NRMSE=0.19) and the Moderate accuracy of Stepwise method in estimating the rainfed wheat yield in Maragheh and Tabriz. In Maragheh and Tabriz, the Stepwise method with average relative error values of 21% and 15.6%, respectively, and in Sarab, the Enter method with an average relative error of 16.5% had better results in yield fitting.

Investigation:

 of relationship between base flow index and flow duration curve indices at national scale in Iran Rahim Kazemi1 *Jahangir porhemmat2, Forood Sharifi3 1Assistant Prof., Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran 2,3 Prof., Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran Abstract:

Recognizing and understanding the relationship between the different components of the catchments can help improvement and development of predictions in ungagged catchments. The true value of the base flow is unclear, and since the flow duration curve (FDC) is generated using observational data, therefore recognizing and analyzing the relationships between FDC and the base flow index (BFI) leads to achieving information for optimal use of FDC indices as the estimating parameter of BFI. The purpose of this study is to investigate and identify the relationship between BFI and FDC indices in catchments of different climates of Iran.

First, by preparing the climate map of the country and its intersection with the border of the 4th order of watersheds, the catchments located in each climatic zone were separated. Then, at least 30 stations with appropriate statistics and the common period of 1976-2011 were selected in each climatic zone. The FDC was prepared using long-term daily stream flow data, and indices of, Q2, Q5, Q10, Q15, Q20, Q50, Q75, Q90, extracted. The index of the last inflection point of FDC at the zero slope of FDC was extracted using coding in MATLAB. Then BFI was calculated using one parameter recursive digital filtering algorithm and using long-term daily stream flow data. Finally, regression relationships between the average annual FDC indices and BFI in different climatic zones were computed and analyzed.

The results showed that the highest correlation between FDC and BFI in catchments of very humid region with a coefficient of determination of 0.84 was related to first part of FDC, but in both humid and semi-humid regions, the highest correlation were related to the last part of FDC with 0.63 and 0.69 coefficient of determination. The highest coefficient of determination (0.85) between FDC index at the zero slope point (QFinal) and the BFI were related to the catchments of very humid region. Correlation between end-of of FDC indices with BFI in catchments of humid, semi-humid, Mediterranean and semi-arid climate zones were strong relation and could be recommended for regional analysis, forecasting and estimation purposes in ungauged catchment. However, in the catchments of the arid region, this relationship was exceptional, and indices of first part of FDC play this role. In very humid region, the coefficient of determination of FDC indices with BFI was reliable and usable.

In overall conclusion, it is noteworthy that the correlation between the endpoint FDC indices with the average annual BFI in the humid, semi-humid, Mediterranean and semi-arid climate zones were strong, reliable and recommended for regional analysis, forecasting and estimation in ungagged catchments. However, in the catchments of the arid region, this relationship was exceptional, and first part of FDC indices play this role, and have the highest correlation. In catchments located in very humid region, the coefficient of determination of all indices with the BFI has the ability to be trusted and used. The overall results in the catchments of all climatic zones show FDC indices as a reliable and predictive parameter of BFI. 

In this study, for study the effect of rainfall changes on groundwater quality in dry and semi-arid climate of Isfahan province, six basins with high concentration of wells and meteorological stations were selected. Data from 72 meteorological stations of Isfahan province during the statistical period of 2003-2013 and data from 350 wells were used to study the changes in groundwater quality. Subsequently, data with the lowest quality of EC, Ca, Mg, pH, Na, Cl parameters were recorded in Excel software, and ArcGIS software and the changes were zoned. In studying the meteorological drought, rainfall of September as the representative of the driest months of Isfahan, DIP software, analysis of time series 6, 12, 18 and 24-month and the time series with the highest correlation in the zonation were used. Then a correlation time series was zoned in different sections of the six study basins in ArcMap software. The results of Pearson statistical method showed a positive correlation between the drought of meteorology and groundwater quality in the 18-month time series. In summary, with the negative trend of precipitation, the positive trend of salinity, calcium, magnesium, acidity, chlorine and sodium in groundwater was observed from the western areas to the eastern regions. The results show that the minimum variation of millimeters in rainfall from a basin to another basin in Isfahan province affects groundwater quality in each of the six basins and leads to a downward trend in groundwater quality following drought events.

Conveyance and Water distribution irrigation canals are hydraulic structures that transport water supplied from sources such as diversion dams for drinking, agricultural, industry or other purposes. These canals are usually lined by materials such as: concrete, stone with sand cement mortar, asphalt, to prevent water seepage losses along the flow path. Concrete lining that is used in irrigation canals is an unreinforced concrete with a thickness of 5 to 10 cm. Basic requirements of good hardened concrete are: satisfactory compressive strength and sufficient durability (Aba, 2005). After the implementation of each engineering structure, it is necessary to evaluate the project to determine the optimal performance and quality of implementation. Evaluation of the quality of irrigation canal linings is often carried out by the destructive and costly method of coring and carried out various experiments in the laboratory. Although destructive method yields relatively exact and straightforward results from the desired parameters, it also has some side problems that are sometimes difficult to recover. The problems of destructive test (DT) method with coring and destructive method are associated with damage of project, high cost, need the expert group and equipment, time-consuming and sometimes stoppage of project operation. Non-destructive testing (NDT) methods can be used to prevent these complications. Electrical, ultrasonic and Schmidt hammer tests are among non-destructive testing. Nowadays, non-destructive testing of concrete has an effective and practical function in the repair of concrete structures. Non-destructive testing of concrete by providing data on various existing structures allows experts to judge and decide on the performance, needs and methods of repair and restoration of concrete structures. The indicator of evaluation of the quality of concrete lining in irrigation canals in different environmental conditions is the same as the other structures based on the amount of compressive strength (Anon., 2014). The failure of hardened concrete due to repeated cycles of thawing- freezing in cold air in hydraulic structures (such as irrigation canals that can absorb water and saturated) is more probable than other concrete structures (Ramazanianpour and Shahnazari, 1988).

In this study, in order to establish a relationship between non-destructive testing (NDT) of Schmidt's Hammer number with destructive testing (DT) of compressive strength and water absorption parameters, 13 sections from 3 main conveyance canals were studied in Nahre Shaban irrigation network in Nahavand City. At all sections, non-destructive testing of Schmidt's Hammer accomplished for determining the rebound number, then from the same points, 12 and totally 156 cores were provided from 3 canals. Next relationship between rebound numbers (RN) with each of the parameters of laboratory experiments on the linings was investigated. The study area in this study was 6 km from the main canal of the irrigation network of Nahre Shaban in 3 sections of Ghaleqabad, Shaban and Jahanabad in Nahavand City. This canal is divided by diversion dam of Sha'ban with height of 3.5 m which was constructed in a section with coordinates of (X = 262862, Y= 3775625) during 1985 and 2001. Table 1 presents the characteristics of the main canal at the location of the Ghaleh Ghobad river section on the Shaban network. The coordinates of each section of the canal intended for coring were determined using GPS; these coordinates are presented for the 13 points in the selected canals in Table 2.

The average yield per hectare of lemon orchards in Iran, compared with the global average, has considerable distance. In general, environmental factors, especially soil and nutritional factors play a crucial role in the performance and growth of plants. That which agents will create more restrictions on Plant, it can be important on plant product management and its quantity improvement. To identify the nutritional status of lemon orchards in Hormozgan and determine the direct and indirect effects of factors affecting yield, the three major regions of the province (in terms of lemon gardens) reviews, the Hashtbandi, central Minab and Rudan and in each region 20 lime orchards (total 60 orchards) were selected. Then yield, some soil properties at two depths, irrigation water characteristics and nutrient concentration in leaves and some fruit quality parameters of lemon trees were determined. Data analysis and interpretation showed, in general, there was no nitrogen, phosphorus and potassium deficiency in most orchards, while an excess of chlorine and boron concentration caused yellowing and leaf margin burn in most orchards. Correlational studies showed that most of the characteristics (like clay, leaf chlorine and boron concentration) were significantly correlated with yield, had a negative impact on that. The result of path analysis showed that leaf chlorine concentration had the highest direct effect on the yield (90 %), while a direct impact of total calcium and magnesium was below one percent on the yield. Generally, the most negative effect on yield was by clay, water boron concentrations, and leaf chlorine concentration that the significant portions of these effects were direct. So it is recommended in order to increase yield that solutions be considered that directly mitigate the harmful factors.

The phenomenon of evapotranspiration causes water and moisture losses from water, soil and vegetation levels. Due to the small amount of atmospheric precipitation and water resource constraints in Iran, it is important to calculate it through a suitable method. The present research attempts to evaluate the Reference crop evapotranspiration (ETo) and investigate its relationship with land use. Also long-term land use changes was considered its effects on evapotranspiration changes in the Saqqez catchment. In this study, the long-term mean values of temperature, humidity, sunshine and wind speed data at seven meteorological stations and evaporation pan data of Saqez station were used to determine the appropriate ETo estimation method. TM, ETM and Landsat 8 satellite data and ENVI and GIS techniques were used to extract land use classes during the years 1992-2013. The results of the research indicate that the best method for this region as the cold and moderate climate was FAO radiation and Blaney-Criddle with R2 = 0.89 and Nash –Sutcliffe = 0.86 and R2 = 0.94 and Nash –Sutcliffe = 0.92 in Bijar and Sanandaj station respectively. The results of land use changes indicate that the main changes in land use related to the reduction of area in the rangelands and the increase of area in urban areas, water coverage, agricultural land and garden lands. Also, the results of correlation between evapotranspiration and land use indicate that the highest correlation (0.96) was obtained on agricultural lands and the least correlation (0.38) was observed in the surface area of the rivers.

The rate of metal transfer from the solid phase to solution is an important factor governing their concentration in the soil solution and its availability. In this research, the release rate of Zn in contaminated soils from Isfahan was studied using solutions citric acid, oxalic acid and malic acid 0/01 M during the period of 2 - 504 hours and its relationship with soil characteristics was investigated. The results showed that low molecular weight organic acids could release Zn in the contaminated soils. The Zn released by acids was in the order citric acid> oxalic acid> malic acid. Variation range of Zn released a solution of citric acid, oxalic acid and malic acid, which was 38/9 -21173, 25/2 - 26761 and 25/5 – 20650 mg/kg of soil. Zn released in citric acid solution was higher than that of the two acids. Based on the determination coefficient and standard error estimates done by the kinetic equations, the release of Zn of the contaminated soils and three acid solution was described by the first order equation, elovich, parabolic diffusion and power function, with a high coefficient of determination and a low standard error. Correlation results showed that for the Zn release with the index of Zn usability, there was a significant correlation at 5% level. Showed Multivariate regression model showed that Calcium carbonate, pH and EC affected characteristics of Zn desorption.

Zinc is one of the essential micronutrients for plants, mining and industrial activities leading to pollution of heavy metals, including zinc metal contamination in soils. In addition to the total concentration, knowledge of the Zinc fractions is necessary to assess the mobility of zinc in the soils. One of the sequential extraction methods is Tessier method. sequential extraction with plant cultivation simultaneously, is the appropriate approach for assessing the mobility of toxic metals. Therefore this study was conducted to evaluate the chemical forms and determine their relationship to the physical and chemical properties of soils in some fields under cultivation in Khorasan Razavi province.
The experiment was conducted in a completely randomized design with factorial arrangement includes 4 levels of contamination (0, 500, 1000 and 1500 (mg/kg)) and 10 soil types from different regions of Khorasan Razavi province of 0-30 cm depth in the range of electrical conductivity 1 up to 15 ds/m, with three replications at Research greenhouses of Ferdowsi University of Mashhad. An example of mining waste was prepared as a source of pollution. The soil samples were kept at field capacity moisture for 6 months. Then air-dried soil samples were used for planting borage and determine the Zinc fractions. Then soil samples were air dried and used for planting borage and determining the Zinc fractions. Texture, cation exchange capacity, organic carbon, electrical conductivity, pH and Available phosphorus and potassium were measured in the saturation extract. DTPA-extractable Zinc was measured by atomic absorption spectrometry. Borage was planted in greenhouses in 3 kg pots with three replications. During flowering, the plants were harvested and dry digestion method was used to measure the concentration of Zinc. Chemical forms and Pseudo total concentration of zinc in the samples were determined using Tessier and digestion by HCl and HNO3 acids (3:1) methods respectively. The concentration of the extracts was measured by atomic absorption spectrometry. Statistical analysis was done using Minitab and Excel softwares.
Chemical Forms Average of zinc in soils was as follows:Exchangeable In this study, the residual, carbonate and organic fractions are dominant form of zinc in soils, respectively. With increasing level of contamination, percentage of residual zinc decreased and percentage of other fractions increased, particularly organic and carbonate. Increasing the availability of zinc, is a threat to the environment. There is a high correlation coefficient between different fractions of Zinc with each other and with the pseudo total, amount of plant and available plant zinc showed that there is a dynamic relationship in the soil systems. There is a higher correlation coefficient between the available zinc and carbonate and organic fractions of soils, which indicate available plant zinc, are mainly derived from carbonate and organic fractions.

Land utilization has tremendously increased as a result of growing population. Therefore, it is necessary to utilize lands according to their potential to increase their productivity and sustainability. As assessing the land suitability is a multifactorial issue, it needs a special technique to assess all the factors simultaneously. In this way, multi-criteria decision making methods (such as Analytic Hierarchy Process) are widely used. In this study, AHP and FAO methods of land suitability evaluation for rainfed wheat were compared for some lands in Kuhin area. Based on the study of 23 soil profiles, 1/40000 aerial photo interpretation of the region, and taking into account the characteristics of soil morphology, 16 soil units (land units) were determined in the area and land evaluation was performed on these units. Nine criteria including: %CaCo3, %OC, %gravel, soil depth, texture, apparent CEC, pH, %slope, and climate (precipitation of the growing season, monthly rainfall, vegetative stage, mean temperature of the growing season, and mean temperature of the vegetative stage) were selected. Then, these criteria were compared in terms of decision matrix. Comparison of AHP and FAO land indices showed that AHP index for all land units was much more than that of FAO. Maximum and minimum calculated land indices were 72.5 (land unit 5) and 48.52 (unit 11), respectively. The correlation coefficients between land index and observed yield in the study area for AHP method and FAO method were 0.858 and 0.739, respectively.

In order to provide a database, it is essential having access to accurate information on soil spatial variation for soil sustainable management such as proper application of fertilizers. Spatial variations in soil properties are common but it is important for understanding these changes, particularly in agricultural lands for careful planning and land management.
To this end, in winter 1391, 189 undisturbed soil samples (0-30 cm depth) in a regular lattice with a spacing of 500 m were gathered from the surface of Miankangi land, Sistan plain, and their physical and chemical properties were studied. The land area of the region is about 4,500 hectares; the average elevation of studied area is 489.2 meters above sea level with different land uses. Soil texture was measured by the hydrometer methods (11), Also EC and pH (39), calcium carbonate equivalent (37) and the saturation percentage of soils were determined. Kriging, Co-Kriging, Inverse Distance Weighting and Local Polynomial Interpolation techniques were evaluated to produce a soil characteristics map of the study area zoning and to select the best geostatistical methods. Cross-validation techniques and Root Mean Square Error (RMSE) were used.
Normalized test results showed that all of the soil propertiesexcept calcium carbonate and soil clay content had normal distribution. In addition, the results of correlation test showed that the soil saturation percentage was positively correlated with silt content (r=0.43 and p 0.01) and negatively correlated with sand content (r=0.48 and p According to the produced maps soil electrical conductivity with coefficient of variation of 102.99 and low effective range (935 meter) showed a very high spatial variability which mostly depended on the soil type of Miankangi region. The content of calcium carbonate with an average of 18.66 percentage a relatively high figure and indicates calcium carbonate precipitation as one of the most soluble salts in the soil.Miankangi soils acidity in the neutral range (8.13) is alkaline. That is due to very low coefficient of variation obtained for pH, alkalinity of soil can be seen from its inherent feature. In addition, the high concentration of dissolved substances in studied soils represents further expansion of salinity in irrigated lands in the study area, which leads to reduce in soil quality and health due to irrigation and fertilization. Accordingly, it needs a proper management, implementation of targeted programs for prevention, and overcoming the salinity problems for the sake of improving the soil quality, as well as, achieving sustainable agricultural development in this region.