مجله تحقیقات آب و خاک ایران
سال پنجاه و دوم شماره 2 (پیاپی 62، اردیبهشت 1400)

A significant part of the nitrogen fertilizers due to the high solubility in water, penetrates into the lower parts of the soil and become unavailable to the plant. To prevent nitrogen losses, various methods have been used, of which coatings is the most widely used methods to reduce the rate of dissolution in water. The objective of the current study was to produce novel slow release fertilizers (SRFs) using starch-based polymer nanocomposites (in terms of environmental compatibility and degradability) and to investigate the comparative efficiency of these samples on the growth and nutritional responses of tomatoes. Firstly, two formulations of urea fertilizer coated with starch-based polymer nanocomposite reinforced with biochar nanoparticles (A) and pristine polymer without nanoparticles (B) were synthesized. Then, the effects of two levels (180 and 420 kg/ha or 60 and 140 mg/kg) synthesized SRF samples (A and B) and un-coated urea granule fertilizer (as a control) on morphological characteristics of tomatoes were investigated. A factorial design based on the completely randomized blocks with three replications was performed at Agricultural Biotechnology Research Institute, Karaj. The results showed that the presence of nanoparticles increases the release time of urea from the coating layer, and it was prolonged with increasing the amount of NCNPs because of favorable interfacial polymer-filler interactions. So that, the nitrogen release rate from sample A, at pH= 2, 6 and 10, was respectively decreased 49.46, 18.52 and 45.13% as compared to sample B. Moreover, application of SRF samples increased nitrogen use efficiency, nitrogen agronomic efficiency and apparent nitrogen recovery. So that, the nitrogen use efficiency in fertilizer treatments A and B with usage of 420 kg/ha was respectively increased 7/85 and 14/68% compared to urea fertilizer.

Estimating runoff created by rainfall is a very important step in water resources planning, especially in ungauged River Basins. Therefore, research on models simulating the river flow with minimum error in the river basins is necessary. In this study, rainfall-runoff simulation of Minab watershed was done using data mining methods and their performance was compared to present the proper one. For this purpose, eight data mining algorithms including Model Tree (MT), Random Forest (RF), Support Vector Machines (SVM), Bayesian Ridge Regression (BRR), Gaussian Process (GP), Extreme Gradient Boosting (XGB), Artificial Neural Network (ANN), and Multivariate Adaptive Regression Splines (MARS) were used. Coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE) and Taylor diagram were used to evaluate the model performance. The results indicated that the MARS model had the best performance among the all models to simulate the monthly discharge of the Minab watershed. Also, the SVM model with (RSME =7.73) has a good performance. The other models also performed relatively close to each other (The XGB model with 9.98 had the highest and the MARS model with 7.7 had the lowest RMSE). Then, by entering the values of sea level temperature (PGSST) in the simulation process, the effect of this parameter on the simulation results was investigated. The results showed that PGSST values did not improve the runoff simulation results in the study area.

Plant water requirement or evapotranspiration (ET) is one of the main components of water balance and a key factor in irrigation planning to improve water use efficiency of agricultural lands. Different methods have been proposed to determine evapotranspiration directly using lysimeter and indirectly using computational methods. Evaporation pan is one of the indirect, simple and suitable methods for estimating the evapotranspiration of the reference plant and the main plant, which shows the combined effects of atmospheric parameters such as air temperature, air humidity, radiation and wind. In this study, using 20-year meteorological data (1999-2018) of the all synoptic stations in Kurdistan province, the value of pan coefficient was estimated using the methods Cuenca (1989), Raghuwanshi & wallender (1998), Modified Snyder, Mohamed et al (2008), Allen and Pruitt (1991), Snyder (1992), Orang (1998), Pereira (1995), Christiansen (1990) and FAO-24 (1997). In order to evaluate the accuracy of estimating evapotranspiration obtained from pan evaporation mehod, the FAO Penman-Mantith 56 method was used. To evaluate the accuracy of the models and to select the best one, four indicators; (RMSE), (MAE), (MBE) and t-test were used. The final results showed that on a daily, monthly and seasonal basis, the methods of FAO-24 (1997) and Christiansen (1990) had the best performance and the methods of Raghuwanshi & Wallender (1998) and Allen and Perot (1991) had the worst performance.

Waterlogging is an important factor, affecting soil properties. This research was conducted to evaluate the effect of waterlogging on secondary soil clay minerals, as well as manganese (Mn) of paddy soils with long-term rice cultivation in Fars province. In each region, two soil profiles in paddy and non-paddy fields were digged on calcareous parent materials and the same landform in a pairwise manner. Analysis of the clay mineralogy indicated that the long-term rice cultivation seems to have an influence on the quantity of clay minerals, as indicated by higher smectite in paddy soils. But, higher chlorite, illite and palygorskite was found in non-paddy soils. Clay minerals were probably affected more by parent materials and less by the aquatic condition. Chlorite and illite were observed in both paddy and non-paddy soils and increased with depth due to their presence in parent rocks. Transformation of illite to smectite in the A horizon increased relative abundance of smectite but it decreased with depth. The results showed that the paddy soils have more available Fe and Mn (extracted by DTPA), total Fe and Mn (extracted by HNO3), and poorly crystalline Fe and Mn oxides (extracted by Ammonium oxalate), compared to the non-paddy soils and the surface horizons of paddy soils showed the highest rates. Also, the long-term cultivation of rice decreased the content of pedogenic (extracted by Citrate-Bicarbonate-Dithionite) and crystalline Mn oxides.

One of the most important issues that has always threatened the health of human societies is the contamination of food with heavy metals and reaching the danger limit. To conduct this research in a case study and laboratory work, the amounts of heavy metals (Cd, Zn, Cu, Pb, Mn, Ni and Fe) and their Target hazard quotient of human health through salt consumption of Maharloo Lake and Korsia salt mine were investigated for both child and adults groups. For this study, Maharloo Lake and Korsia salt mine were sampled and their heavy metals were determined. The daily intake of metals was determined and compared with the reference value. The target hazard quotient, THQ for all metals of Maharloo Lake salt for adults and child was less than one. This means that the hazards of the proposed metals are within the acceptable limits. For korsica salt, the THQ for lead metal (for child group) was more than one and for other metals (child and adult groups) was less than one, indicating that non-cancerous adverse effects were likely to occur in childs. Among the proposed metals, the highest THQ was obtained for lead metal and the lowest one for zinc metal for Maharloo salt and korcia salt mine. The Hazard index for adults and child was less than one for Maharloo salt and more than one for Korsia salt, indicating that there are adverse effects of non-cancerous diseases due to the consumption of heavy elements caused by the consumption of this salt. Salt consumption threshold for hazard level 1, which is negligible in terms of chronic hazard, for Maharloo Lake salt, for child and adults were 1003.8 and 4133.4 mg/day and for Korsica salt for child and adults were 13.2 and 543.5 mg/day, respectively.

As regards Iran is covered by many arid and semi-arid regions, the formation of soil-pedogenic features are very important and effective to have a better understanding of the topics of the soil sciences in these regions. Parent material is one of the main factors controlling soil properties in arid and semiarid regions. Basalt and volcanic glass are among igneous rocks that contain minerals susceptible to weathering minerals. Their weathering products are deposited as secondary minerals and different cations in the soil and the consumption of weathering products accelerate the weathering, soil formation and evolution during these processes. In this study, morphological and physicochemical properties of eight soil profiles formed on basalt rocks in semiarid region of middle Alborz were investigated and micromorphological properties were studied in six thin sections. Micromorphological observations showed different evidences of the occurrence of weathering processes. Formation of hypocoating and nodules of iron oxide and manganese, cubic microstructure and its evolution in different soils from semi-angular to angular cubic, layered clayey clusters indicating periodic deposition of this. Also, the layers were in favorable conditions, and the formation of a variety of pedogenic carbonate effects such as nodules, coating and hypocoating, cavities filled by micritic and sparite crystals were suggested alternating dry and wet periods, and the effect of these periods on progresses in weathering processes. One of the unanticipated consequences in the micromorphological study was the large volume of clay produced in some soil profiles due to the greater weathering intensity of volcanic glass.

One of the most important groups of environmental contaminants is petroleum hydrocarbons which usually come from oil and gaseous industrial. In this study, the effects of Zeoplant and Biochar of Bagasse as an organic-mineral and organic amendments were investigated on the soil physical and mechanical properties in Oil fields of Ahvaz. Soil sampling was performed using systematic sampling (randomized in the block), then the soil samples were put in the pots and 2, 4 and 6 % (by weight) of treatments added to the soils. The incubation time was 100 days and during this time the moisture level adjusted on 25 and 50% of field capacity (FC). After incubation, the soil aggregate stability, friability index (FI), Atterberg limits and soil permeability were measured using standard methods. Our results revealed that the mean weight diameter (MWD) was decreased from 1.3 mm for the blank to 0.6 mm for 6% of Zeoplant treatment at 50% of FC. Moreover, for both treatments friability index was increased which was higher for 50% of FC, while for 6% of Zeoplant, FI was declined. Also, the application of 2 and 4% of biochar decreased the MWD as an index of soil aggregate stability. Results depicted that the application of Zeoplant and Bagasse Biochar increased liquid limit (LL) and plastic limit (PL) and consequently decreased the plastic index (PI). In general, the application of organic-mineral treatments to the soil was effective on soil physical and mechanical properties; therefore the quantity and quality of the above treatment must be considered as a component of decision pyramid.

Predicting hydrological parameters, especially rainfall, has played a very important role in water resources management and planning. Therefore, the development of methods giving accurate estimates has always been of interest to researchers. In this study, precipitation data from the Ahvaz synoptic station in the period of 2018-1961 were used to develop Kstar and Gene Expression Programming wavelet hybrid models (WKstar and WGEP). The performance of the applied models was evaluated using statistical indices, including the correlation coefficient (CC), Nash-Sutcliffe (NS), Kling–Gupta (KGE) and the Willmott Index (WI). Initially, the Kstar and GEP individual models were implemented, with a delay in precipitation input up to four months ago and month numbers. Results showed that both models achieved maximum accuracy with a time delay of one month (M1 senario), but their performance was very low and unacceptable. Regarding that both models with the M1 pattern have the best performance, so the M1 inputs decomposed by five different wavelet functions to detail and approximat subsets and were represented to the models. The results showed that the performance of wavelet hybrid models was significantly improved, so that the NS index increased from 0.139 to 0.607. In addition, the best performance of WKstar and WGEP hybrid models was obtained with the inputs of the Daubechies wavelet of order four and the decomposition level two. Also, there was no significant difference between the two developed hybrid models statistically, but using the violin plot it was found that the WKstar model is more suitable for predicting precipitation at the Ahvaz synoptic station.

Mine tailings dams, as one of the important and unavoidable parts of any mine, are considered as a sources of environmental pollution in the areas adjacent to each mine, which has received less attention from an environmental point of view. The present study was conducted to investigate the environmental effects of the tailings dam of Chahar Gonbad copper mine on changes in quantities of some soil pollutants adjacent to the tailings dam of this mine. In this study, according to the location of the region, six samples of sediment from the tailing dam and nine samples of topsoil were collected and the amounts of Pb, Sb, Zn, Cd, As and Cu; as well as soil pollution indices of each element (enrichment factor (EF), Geo-accumulation factor (Igeo), and contamination factor (CF)) were measured and compared with the environmental protection standard. The results of pollutants in sediments showed significant enrichment of Cu and Sb elements in tailings dam sediment samples. Based on the standard values ​​of soil pollution, with the exception of high levels of Cu (38-135 mg kg-1) and As (7.2-17.8 mg kg-1) in some samples, the observed levels of Pb, Zn, Cd and Sb in all soil samples were lower than the environmental protection standards. According to the results of soil pollution indices, the two elements Sb and As had higher EF and Igeo than the other elements, which shows the effect of anthropogenic factors (tailings dam) on amounts of these elements. The results of this study showed, despite the high amounts of Cu in the soil surface samples (due to the nature of the Cu vein deposit in the region), the area adjacent to the dam is not contaminated with other pollutants, although EF of As (4-15.3) and Sb (3-5.9) can be a serious alarm to pollute the area with these elements in the coming years. Based on the obtained results, it is suggested that changes in the pollution of tailings dams as one of the sources of environmental pollution in the areas adjacent to the mines, be continuously assessed and appropriate management measures be applied.

In this research, using direct measurement method, the flow pressure in the composite channel with vegetation has been measured. The vegetation used in this study was made of PVC. Five different diameters with values ​​of 20, 25, 30, 40 and 50 mm, two longitudinal distances of 12 and 15 cm and two transverse distances of 6 and 8 cm according to the regular and irregular arrangement and the location of vegetation as the proposed variables were used in this study. For direct measurement of force, a special type of hydraulic flume called "knife edge hydraulic flume" was used. Based on the results of the experiment, it was found that with increasing vegetation diameter, the flow force increases, which is due to increasing the volume and reduction of the cross-sectional area of the vegetation. In addition, due to the effect of longitudinal and transverse distances of vegetation, it can be said by increasing these distances, the flow force rate showed a decreasing trend. This is due to the reduction of vegetation volume and the secondary flows caused by vegetation cover.

Periphyton or periphytic biofilms are microbiomes consisting of a complex matrix including autotrophic and heterotrophic types such as algae, bacteria, fungi, protozoa, metazoa, etc. Periphytic biofilms are commonly found in many aquatic ecosystems such as the sea, lakes, rivers, streams, ponds and paddy fields and play an important role in primary production, food network interactions such as carbon cycle, phosphorus and some other nutrients. Periphytic biofilms respond quickly to environmental changes, especially nutrients and light, and can be used as an indicator of disturbances and adverse conditions in aquatic ecosystems. In recent years, research interests in using periphyton for controljng the non-point source pollution, treating contaminated water, and interferencing nutrient have increased. Although the effects of periphyton on water quality and its relationship to water flows have been investigated by researchers, our understanding of their function in paddy fields and their effect on nutrient cycles is limited. In the present article, an attempt has been made to present a summary of the research done on periphyton and their effect on the nutrient cycle, especially on rice plants' growth in paddy fields.

The application of hydrological models in watersheds has always been considered by water resources researchers. This subject is of special importance in arid and semi-arid regions due to the greater complexity of hydrological processes in these region. In this research, the efficiency of WetSpa distributed hydrological model in Menderjan semi-arid basin has been evaluated and the sensitivity analysis and uncertainty analysis of the model parameters have been performed using PEST software.  Moreover, the efficiency of the Extended Kalman filter in improving the results has been investigated. The Nash-Sutcliffe coefficient for the calibration and validation periods was 0.63 and 0.58, respectively, confirming that the WetSpa model has a good performance in runoff simulation in Menderjan basin. The results of sensitivity analysis also show the high sensitivity of Kg and K_ss parameters and the low sensitivity of G_max and P_max parameters in the study area. Moreover, the results of uncertainty analysis are generally consistent with the results of sensitivity analysis and indicate the high certainty of sensitive parameters and the low certainty of non-sensitive parameters. The results of applying Kalman filter also show the improvement of the results. So that the Nash-Sutcliffe coefficient increased from 0.63 to 0.71 in the calibration period and from 0.58 to 0.69 in the validation period.

In order to investigate the effect of different organic fertilizers on yield and some physiological characteristics of potato under drought stress conditions, an experiment was conducted in the form of split plots, based on randomized complete block design with three replications in 2018 at Baraan region in Isfahan. The applied treatments include drought stress based on the fraction of Allowable Water (AW) or Management allowed Deplition (MAD= 45% as a control, 55%, 65% and 75% in main plots) and organic fertilizers including vermicompost (7 ton ha-1), municipal waste compost (15 ton ha-1), cow manure (50 ton ha-1) and control (without fertilizer application) were in the sub-plots. Results showed that the drought stress reduced yield and its components and reduced leaf chlorophyll content (p≤0.01). Comparison of means showed that potato yield in vermicompost treatment without drought stress reached 33 tons per hectare. Intraction of vermicompost and irrigation after 65% depletion of AW (reduction of 20% in water consumption), led to the production of 23 tons per hectar potato. Under these stress conditions, compost treatment also resulted in potato production of 21 tons per hectar. The interaction of vermicompost and irrigation after 75% depletion of AW (30% reduction of water consumption), Leaf chlorophyll reached 12 mg/g, the same as situation at no application of vermicompost and drought stress. Also, the highest amount of proline was measured in the interaction of MAD=65% and compost and vermicompost treatments with 21.2 and 24 mg/g, respectively. In general, the application of organic fertilizers could help to reduce the negative effects of drought stress.

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.

Nowadays, around the world, environmental impacts, as one of the most important dimensions of sustainable development, play a significant role in strategic decision makings. Water resources management is one of the most sensitive measures due to its bi-directional relationship with sustainable development and also as a facilitator of this path, especially in arid and semi-arid regions. One of the main purpose of the LCA approach is to assess the environmental impact of emissions. In this study, environmental compatibility of mechanical watershed management measures to manage water resources is investigated by using this approach. Therefore, material flow, energy and environmental impacts of all stages of the life cycle of one unit of flood spreading system (located in Daefeh watershed in Rafsanjan plain) were analyzed based on IMPACT 2002+ method available in the Simapro software. The results showed that the earthen structure of the flood spreading system with 8.37 kPt environmental impact is the hot spot of this system (Mostly due to the earthworks), including 91.34% of environmental burdens in the construction phase and 55.2% of the total emission effects. The findings of this research showed that the environmental consequences of emissions during the life cycle of this system were 15.2 kPt. Construction process stage (with the highest amount of environmental burdens in each impact category except for resource depletion) 39.2%, use stage 31.3%, extraction and productivity of materials 23.3% and transportation stage 0.93% of Environmental burdens were allocated in this study. The environmental consequences of emissions in the categories of adverse effects on human health, climate change, resource depletion and ecosystem depletion of the flood spreading system are 6.63, 3.54, 3.06 and 1.94 kPt, respectively. Also the results of this study will be useful for evaluating the environmental effects of different structures. Finally, it is suggested that in the integrated watershed management, which is responsible for protecting our nation's natural resources, life cycle assessment approach be developed and the green building approach could be implemented, such as selecting the design discharge with environmental considerations, selecting quantities and types of environmentally friendly materials.

Local scouring around the bridge pier is the leading causes of their destruction. Thus, to reduce and control this phenomenon, numerous researches have been done and many solutions have been suggested. These solutions are classified in two parts, direct and indirect protections methods. In this study, by definition different scenarios, both protection methods and their combined effects were investigated. In this research, cable around piers, as an indirect method, and sill as a direct method were used. Different locations of the sill (front and back of the pier) and the cable around the pier with relative pitch equal to 0.33, 0.50 and 0.67 in clean water conditions were investigated. In the best case, the pier with a front sill and a relative cable pitch of 0.33, has the least amount of scouring. This pier has the highest amount of scour depth reduction with 63% among the other scenarios. In this regard, the pier with a back sill and a relative cable pitch of 0.33, showed 45% reduction in scouring. This indicates that under the same conditions, with the sill movement from the back to the front of the pier, scouring depth parameter improved 18 percent.

In this research, the interaction of Pb stress, salicylic acid (SA) and biochar (BC) on growth parameters of basil crop (Ocimum basilicum L.) were investigated. This experiment was conducted as a factorial, based on a complete randomized design with three replications in greenhouse of Razi University. Treatments included canola biochar at three levels (0, 1 and 3% by weight), SA at three levels (0, 100 and 200 μM) and Pb at three levels (0, 100 and 200 mg/kg Pb(NO3)2). Results showed that the highest plant height, stem diameter, fresh and dry plant weight, leaf area, fresh and dry root weight, and root volume were observed in the treatment of 200 μM SA, 3% BC and Pb control. Also, the simultaneous application of SA and BC reduced Pb concentration in basil, so that the lowest one (0.67 mg/kg) was found in the treatment of 200 μM SA, 3% BC and Pb control. In contrast, the highest proline content (44.4 mmol/g) was obtained in 200 mg/kg of Pb and control of SA and BC. In general, the application of SA and BC could significantly reduce Pb-induced stress on growth characteristics in basil.

Heavy metal pollution in soil and water resources has become a serious problem not only in the production of healthy agricultural products, but also in the ecosystem health. Microbially induced calciumcarbonate precipitation (MICP) is a low-cost and environmentally friendly methods for reducing water resources and soil pollution. The aim of this study was to isolate native and efficient bacteria in the biological production of calciumcarbonate in order to remove zinc from contaminated solution. Isolating and screening native bacteria, producing urease and L-asparaginase, was accomplished.  Then, the changes in ammonia, pH and electrical conductivity (EC), as well as removal of zinc from the contaminated solutions were studied using these two efficient isolated bacteria in the presence of sporocarsina pasteurii. The results showed that in the presence of all three bacteria, the amount of produced ammonia, pH and EC in the culture media increased significantly compared to the ones in the control (without bacterial inoculation) (p < /em>≤0.05). The efficiency of isolated urease-producing strain in removal of zinc from the contaminated solution was almost equal to that of sporosarcina pasteurii, while the efficiency of isolated L-asparaginase-producing strain was more. Sporosarsina pasteurii removed 51.32, 65.94 and 70.36% and urease producing strain removed 65.49, 68.07, and 71.46 of zinc in the solutions containing 0.5, 2 and 4 mM Zn, respectively. However, L-asparaginase-producing strain removed 96.29, 93.88, 97.06 and 97.32% of zinc in solution containing 0.5, 2, 4 and 8 mM Zn, respectively. Therefore, it seems native urease- and L-asparaginase-producing bacteria can be useful and efficient in Zn bioremediation of contaminated solutions by MICP process.

Taleghan Dam is the main supplier of required water to the agricultural sector of Qazvin plain. The amount of water allocated from Taleghan Dam to this plain has decreased for various reasons, including increasing the allocation of drinking water to Tehran. The reduction of allocated water and the fluctuation prices of agricultural products due to the time lag between the farmer's decision to cultivate and offer it to the market, make farmers to be uncertain to their future earnings. In order to deal with the uncertainty of the prices of agricultural products and their livelihood, despite the reduction of allocated water, farmers have started to discharge the groundwater by stabilizing the cultivated area and combining the cultivation pattern. In this study, in order to increase farmers' resilience and preserve groundwater resources, water distribution pattern with price prediction and simultaneous water cultivation and distribution pattern with price prediction has been optimized using genetic algorithm. For predicting the price of agricultural products with guaranteed purchase such as wheat, barley, sugar beet and rapeseed the ANN model was ued. For predicting the price of maize, tomato, alfalfa, peas, beans, potatoes, corn and lentils, the reverse demand function method was used. The price elasticity of demand for maize, tomato, alfalfa, peas, beans, potatoes, corn and lentils were estimated -0.508,-1.111,-0.954,-0.914,-0.374,-0.529,-0.363 and -0.332, respectively. MAE and RSME indeces indicated the ability of reverse demand function and ANN in price forecasting. The results also showed that the use of water distribution optimization models with price forecasting will increase revenue by 25% and the simultaneous optimization model of water cultivation and distribution model with price forecasting will increase network revenue by 160% compared to the current situation.

Sewage sludge is a semisolid residual material resulting from the sedimentation of the suspended solid during the wastewater-treatment processes. Since large amounts of sludge are being produced, different ways of disposal have been introduced. One tempting option is to use it as fertilizer in agricultural fields due to its high contents of inorganic nutrients and organic materials. However, the presence of contaminants considerably restricts the application of sewage sludge for the fertilisation and reclamation of soils. Because of the high toxicity of organic pollutants and their irreparable effects on the environment, the aim of this study was to investigate the diversity of organic pollutants in sewage sludge, their limit values for agricultural lands, and the fate of them in the soil. Also methods of analysis of organic trace compounds have been compiled. Some of the most frequently detected contaminants in sewage sludge are polycyclic aromatic hydrocarbons, polychlorinated biphenyls, di-ethylhexylphthalate, nonylphenol and nonylphenol ethoxylates, linear alkylbenzene sulphonates, adsorbable organic halides, polychlorinated dibenzodioxins and furans. These pollutants in the soil may undergo sorption by mineral particles, degradation by soil organisms or transportation with water or soil particles over long distances. Extraction of the sludge sample, subsequent clean-up of the extract and final analysis by either gas or liquid chromatography are methodologies for determining the concentration of organic pollutants in sewage sludge. Novel techniques in extraction such as ultrasonic extraction, microwave-assisted extraction, and pressurized liquid extraction require less solvents reagents and smaller sample siz, are more automated and reduce the number of analytical steps. This study show a better understanding of variety of organic pollutants in sewage sludge, their analytical methods and limit values that is imperative to restricting legislation and specification suitable properties of sludge for land application.