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

The purpose of this study was to investigate the effect of sewage sludge on the uptake of some heavy metals by Quinoa (Chenopodium quinoa L.) from the tailings of Mouteh Gold Mine. For this purpose, the effects of 0, 20 and 40 ton ha-1 sewage sludge on the concentration, uptake, bioconcentration and translocation factor of Pb, Cd and Ni in the three cultivars of Quinoa (Q29, Red carina and Titicaca) were investigated. According to the results, the effect of Quinoa cultivar, different levels of sewage sludge and the interaction effects of treatments on the Pb and Ni concentration of roots and shoots, root Cd concentration and bioconcentration and translocation factor of Pb were significant. In the Titicaca cultivar, application of 40 ton ha-1 of sewage sludge significantly increased root and shoot Ni concentration and root Cd concentration, and significantly decreased shoot Pb concentration and bioconcentration and translocation factor o Pb. In the Red carina cultivar, the concentration of root and shoot Pb, biological accumulation factor of Pb, root Cd concentration and shoot Ni concentration of plants treated with 40 ton ha-1 of sewage sludge were significantly higher than control treatment. Also, application of sewage sludge significantly reduced translocation factor of Cd and increased total uptake and biological accumulation factor of Ni. In general, the highest shoot Pb concentration, total Pb uptake, biological accumulation factor of Cd, and translocation factor of Cd and Ni were observed in cultivar Q29. Whereas, shoot Cd and root Ni concentrations of the Red carina and Titicaca cultivars were significantly higher than the Q29 cultivar. Based on the results, Q29 cultivar has good accumulation ability for the studied heavy metals and can be a suitable species for the remediation of contaminated soils.

To evaluate the effects of different levels of sewage sludge and sewage sludge-derived hydrochar a greenhouse experiment was performed in a factorial combination based on a completely randomized design with three replications and three factors of organic matter at three levels (control, 10g sewage sludge, and 10 g sewage sludge-derived hydrochar per kilogram), nitrogen at two levels (0, and 250 mg per kg soil as urea), and copper at three levels (0, 10, and 250 mg Cu per kilogram as copper sulfate). The results showed that by applications of sewage sludge and its hydrochar, the dry matters of shoot and root, tillers number, spikes number, leaves number, leaf length, leaf width, plant height, and stem diameter were significantly increased as compared to the control and the amount of this increase in the presence of sewage sludge was greater than that of hydrochar. Also, the using of 250 mg N per kilogram increased the mentioned characteristics relative to the control. The soil contamination Cu significantly reduced the tillers number, spikes number, leaves number, and root dry matter as compared to the control. The use of sewage sludge hydrochar and N fertilizer reduced the Cu toxicity and increased rice tolerance to Cu toxicity by reducing the Cu concentration in rice shoot. To achieve rice optimum growth in both Cu contaminated and non-contaminated conditions, the use of 10 g sewage sludge or sewage sludge-derived hydrochar and 250 mg N per kilogram soil can be recommended at similar conditions.

Today, the use of organic wastes as fertilizers to improve the physical, chemical and biological properties of soil is common. In this study, to investigate the effect of the sewage sludge on the growth and concentration of chlorophyll, nitrogen, phosphorus and potassium in quinoa plant, a factorial experiment was conducted based on a completely randomized design with three replications in a calcareous soil with electrical conductivity of 13.1 dS m-1. Treatments included three genotypes of quinoa (Red carina, Titicaca, Q29) and three levels of sewage sludge (0, 20 and 40 t ha-1). The results showed that the effects of the quinoa genotype, different levels of sewage sludge and the interaction of treatments on the root dry weight, shoot P concentration and chlorophyll concentration were significant. Also, the sewage sludge had a significant effect on the shoot length, shoot dry weight and shoot nitrogen concentration. By increasing the level of the sewage sludge, root length, shoot length, shoot dry weight and shoot N concentration were increased, on average, by 44.7 %, 48.8%, 42.0% and 46.6%, respectively. Also, application of 40 t ha-1 sewage sludge significantly increased the chlorophyll concentration and shoot P concentration in Q29 and Titicaca genotypes. According to the results of this study, application of sewage sludge can increase the growth of quinoa by improving its nutrition.

To study the effect of different amounts of municipal compost and sewage sludge on soil properties and wheat, a field experiment was conducted in Ruddasht research station in Isfahan, for five years. Five treatments including 25 and 50 t/ha/year of municipal solid waste compost and 15 and 30 t/ha/year of sewage sludge and control treatment (non-application of organic fertilizer) were used in a randomized complete block design with three replications for five years. The organic fertilizer application increased organic matter in the soil. Also, the application of organic fertilizers, especially at higher levels, increased phosphorus, potassium, iron, copper, manganese, zinc, cadmium and lead in the soil. Also, the application of organic fertilizers increased signifivantly phosphorus, potassium, nitrogen, iron, copper and zinc in the grain and straw of wheat. The concentration of these elements increased significantly with application of organic fertilizers after five years. For manganese, this trend was reversed due to the antagonistic relationship with the iron element. The concentration of lead and cadmium in the plant was so low that it could not be measured by atomic absorption. In general, municipal waste compost and sewage sludge increased the soil organic matter and the concentration of nutrients in the plant, especially in terms of micronutrients such as zinc and iron.

According to the population growth and increasing production of urban waste, environmental hazards of these wastes are on of the most important challenges in most cities that the safest way to prevent them from accumulating is to add them to the agriculture lands. This case is especially considered in countries with dry climates because of lacking organic matter in soils. Due to the high consumption of vegetables in the country and the use of sewage sludge as soil fertilizer, the risk of soil pollution for the peresence of heavy metals in soil and plant may threaten human and creature health. Consequently, studies need to be conducted to evaluate the effect of different levels of sewage sludge on of zinc (Zn), cupper (Cu), cadmium (Cd) and lead (Pb) concentration in root and shoot of radish (Raphanus sativus) and and basil (Ocimum basilicum) vegetables.

This study aims to investigate the effect of domestic sewage sludge on concentration of zinc (Zn), cupper (Cu), cadmium (Cd) and lead (Pb) in radish (Raphanus sativus) and and basil (Ocimum basilicum) vegetables. A pot experiment in greenhouse was conducted at Ferdowsi University of Mashhad, Faculty of Agriculture, in 2018. The experiment was performed in a completely randomized design with three replications. Sewage sludge was consumed at five levels (0, 10, 20, 40, 80 t ha-1) during plant growth. Available form of heavy metals in soil samples was extracted by DTPA 0.005 M solution. total concentration of heavy metals in sewage sludge and soil measured by Aqua regia method and concentration of plant metals measured by dry digestion method.

The results indicated that the use of the sewage sludge in different treatments levels had significant impact (p < 0.05) on the concentration on of these heavy metals in the two plants studied. increase of sewage sludge enhanced metals concentration in shoot and root rather than control plant. particularly for Zn, in root and shoot in both plants. Increase in concentration metals in the two plants were followed Zn> Cu> Pb> Cd in both roots and shoots, The metals uptake in radish was drastically higher than basil. the value of all the metals at 10 t sludge per ha were lower than permissible concentration and at 80 t per ha were higher than permissible concentratoin for all of them.

in general, application of different levels of sewage sludge in soil caused changes in soil chemical properties including decrease of soil pH, increase of electrical conductivity, and soil organic carbon. Also, in the treatment of last level of sewage sludge, two plants were toxic and in the lowest level of treatment of sewge sludge, no toxicity and damage were observed in the plants. However, continuously application of the sludge at 10 t per ha did not plluted the plants, should be recommended cautiously As the results of the study indicate, application of the lowest level of sewage sludge should also be performed with constant precision and monitoring.

Today, the use of biochar in the sustainable management of soil fertility, has been drawing the attention of the scientists as a multi-purpose and environmentally friendly strategic idea. There are several scientific reports implying the outstanding positive effect of biochar on soil fertility and plant growth. On the contrary, some inconsistent reports have mentioned negative or no effect of biochar. Therefore, it is necessary to investigate the effect of any biochar on the soil and plant before any widespread use of any kind. In the present study, the effect of three different biochar and their raw materials on potassium availability and corn growth was studied.

The study was carried out as a two-part-experiment, including laboratory and greenhouse parts. In both parts of the study, treatments included the control (soil without any biochar or its feedstock), Municipal Waste Compost (MWC), Biochar of Municipal Waste Compost (BMWC), Sewage Sludge (SS), Biochar of Sewage Sludge (BSS), Cow Manure (CM), and Biochar of Cow Manure (BCW). In each study, application rates of treatments to the soil, were 1% w/w. In the laboratory part, the effects of the treatments on available-K and parameters of Quantity/Intensity (Q/I) ratio of potassium were investigated. Also the effects of the treatments on plant growth, K-concentration and K-content of corn were investigated in the greenhouse part.

The CM and its biochar, highly increased the available-K by highly increasing the potassium-Q/I parameters compared to the control. While the SS and its biochar lightly increased the available-K by lightly increasing the potassium-Q/I parameters. The CMW and its biochar, intermediately increased the available-K by intermediately increasing the potassium-Q/I parameters compared to the control. Treatments could improve could improve the growth, k-concentration and k-content of corn compared to the control, excepting of MWC in the case of the plant growth, and SS and BSS in the case of k-concentration. Totally, the descending order of treatments in terms of increasing K-availability was as the follows: 1-BCM, 2- CM, 3-BMWC, 4-MWC, 5-SS and BSS, 6-control. The descending order of treatments in improving plant growth conditions and increasing dry weight of the plant was as the follows: 1-CM, 2-BSS and SS, 3- BMWC, 4- BCM, 5- Control and MWC.

Considering the superiority of BMWC to MWC, in terms of affecting on K- availability and plant dry weight, BMWC can be preferred to MWC. Considering the superiority of BCM to CM in terms of the effect on K-availability, K- concentration and content of plant compared to the control, meanwhile its decreasing effect on plant growth compared to CM, it seems that some considerations such as salinity and nutritional balance must be carefully considered and managed in the case of BCM application. Despite the similarity of BSS and SS in terms of increasing plant growth, BSS application can be preferred to SS because of the more value of PBCK, and consequently, the more continuously K-supply.

Due to lack of organic matter in most soils of Iran, use of different organic fertilizers in soil is very important for improving soil fertility, increasing water and nutrient storage capacity in soil, increasing water infiltration, reducing soil erosion and improving plant growth and yield. However, these fertilizers alone cannot provide all the requirements of plants for different nutrients and are not sufficiently available to farmers everywhere. On the other hand, high consumptions of chemical fertilizers cause environmental pollution and increased agricultural production costs. So, in order to increase effectiveness of organic and chemical fertilizers and to achieve sustainable agriculture, integrated application of organic and chemical fertilizers is recommended. The deficiencies of micronutrients in the most agricultural soils often reduce the yield and quality of wheat. Therefore, the appropriate concentrations of these nutrients in wheat are important not only for the optimum yield of the wheat plant and its quality improvement but also for the health of humans and animals. In order to improve micronutrients nutrition of wheat and its quality the integrated management of soil fertility is essential.

This research was carried out to study the effects of urea combining with farmyard manure (FYM), municipal solid waste compost (MSWC) and municipal sewage sludge compost (MSSC) on concentrations of micronutrients and sodium in seed, leaf and stem of wheat. The experiment was done in a randomized complete blocks design with 15 treatments and three replications under field conditions at Khalatposhan Agricultural Research Station, University of Tabriz, Tabriz, Iran. The treatments included were: 1) control, 2) 150 kg urea/ha, 3) 300 kg urea/ha, 4) 30 ton MSWC/ha, 5) 30 ton MSWC/ha + 150 kg urea/ha, 6) 60 ton MSWC/ha, 7) 60 ton MSWC/ha + 150 kg urea/ha, 8) 30 ton MSSC/ha, 9) 30 ton MSSC/ha + 150 kg urea/ha, 10) 60 ton MSSC/ha, 11) 60 ton MSSC/ha + 150 kg urea/ha, 12) 30 ton FYM/ha, 13) 30 ton FYM/ha + 150 kg urea/ha, 14) 60 ton FYM/ha, 15) 60 ton FYM/ha + 150 kg urea/ha. The size of each plot was 2.0 m × 1.9 m. At the end of growth period, the plants were harvested and the concentrations of Fe, Cu, Zn, Mn and Na in their seeds, leaves and stems were measured.

The results showed that the effects of treatments on the concentrations of Fe, Zn, Cu and Mn in different sections of wheat were significant. The application of 300 kg urea/ha significantly increased Fe concentration in seed and stem, Cu concentration in leaf and stem, Mn concentration in leaf and Na concentration in stem as compared with the control. There was a significant positive correlation between Zn concentration in leaf and urea fertilizer level. The use of FYM, MSWC and MSSC significantly increased the concentrations of Fe and Zn in seed, concentrations of Fe, Zn and Mn in leaf and concentrations of Fe, Zn, Cu and Mn in stem relative to the control. The concentrations of Fe, Zn, Cu and Mn in different sections of wheat in integrated treatments especially in combined application of 150 kg urea and 60 ton FYM, MSWC and MSSC per hectare were greater than other treatments while the seed Na concentration in these treatments was lower than other treatments.

In general, in order to decrease chemical fertilizers use and achieving sustainable agriculture, improvement of Fe, Zn, Cu and Mn nutrition of wheat plant, improvement of wheat seed and straw quality, combined application of 150 kg urea and 30 or 60 ton FYM or MSWC or MSSC per hectare could be recommended at similar conditions.

Due to its especial geographic condition, Iran, as a semi-arid country, suffers from water shortage for domestic, industrial and agricultural usages. As limited water supplies, the use of non-conventional water resources, such as industrial or municipal wastewater, is a common practice in many parts of the world including Iran. It is estimated that at least 20 million hectares in 50 countries are irrigated with raw or partially treated wastewater. Also, it is estimated that the potential volume of wastewater in urban and rural areas of Iran will be 4369 and 823 million m3, respectively. On the other hand, the use of sewage sludge in agricultural soils has been widespread in many countries around the world, also in Iran. The use of sewage sludge in agricultural has been shown to improve the soil’s characteristics such as organic matter, nutrients, porosity, aggregate stability, bulk density and plant productivity. Despite the growing interest in wastewater and sewage sludge usage, excessive use of them may have some harmful effects such as human health problems, runoff and leaching of nutrients to surface and groundwater, undesirable chemical constituents, pathogenesis, accumulations of heavy metals in plants and soils, negative environmental and health impacts. So, wastewater and sewage sludge use should be under controlled conditions to minimize the health risks of pollution to agricultural products, soil. Heavy metals are extremely persistent in the environment; as they are non-degradable and thus, readily accumulated at toxic levels. Metals can also accumulate in the soil at toxic levels due to long term use of wastewater. There is potential for inorganic nutrients and heavy metals present in wastewater and sewage sludge that transfer in the soil column and pollutant surface and groundwater. Today, medicinal plants are cultivated commercially in the polluted environments where soil, water and air contain rather high levels of pollutants. These plants appear to be a good choice for phytoremediation since these species are mainly grown for secondary products (essential oil) thus, the contamination of the food chain with heavy metals is eliminated. Aromatic and medicinal plants also have a demonstrated ability to accumulate heavy metals. The Mint (Mentha spicata) is a medicinal plant which has received considerable economic importance due to the large demand for its essential oil in food, pharmaceutical, cosmetic and hygiene industries. The purpose of this study was to determine the leach of heavy metals (Zn, Pb, Niand Cd) from the wastewater and sewage sludge to the soil column under Mint cultivation. This study was conducted at the Bu-Ali Sina University greenhouse located in Hamedan, western Iran. The experiment was run in May 2015- February 2016), including 5 months for soil preparation (in lysimeters) and 5 months for crop cultivation and harvesting. To evaluate the use of wastewater and its sewage sludge on on transferring heavy metals in soil column under Mint cultivation, a factorial experiment based on completely randomized was designed with three replications in 27 lysimeters. The factors included three types of watering: tap water (W1), raw wastewater (W2) and treated wastewater (W3), and three sewage sludge levels: 0 (S1), 50 (S2) and 100 tha-1 (S3). Therefore, 9 treatments (W1S1 to W3S3) were considered for investigation. 27 volumetric lysimeters were applied as cultivation beds (26 × 30 × 30 cm). The soil had two layers: the upper layer (0 to 50 cm) with sandy loam texture, and the bottom layer (50 to 110 cm) with sandy clay loam texture. After beds preparation, Mint (Mentha spicata) was planted in them. The raw and treated wastewaters as well as sewage sludge were prepared from wastewater treatment plant of Hamedan. Overall, 13 irrigation programs with 10-day intervals were applied. Zn, Pb, Ni and Cd concentrations in leachate were measured after each watering. The results showed the effect of watering and sewage sludge on heavy metals concentration of drainage water was statistically significant. Also, the result showed that wastewater and sewage sludge increase all (except Cd) leached heavy metals comparing to the control. In all treatments, concentrated Zn, Pb, Ni and Cd in the soil profile ranged from 0 to 1.66, 0 to 0.05, 0 to 0.05 and 0.0 to 0.0 mg/l, respectively. The concentrations of all heavy metals in drained water, was very lower than the FAO standard. By performing continuous irrigations, the trends of heavy metals (zinc, lead and nickel) were irregular schema (especially the use of wastewater and sewage) at different times. The first five irrigations showed an upward and the others showed a downward path.

Human activities, including the use of sewage sludge as fertilizer, cause excessive accumulation of heavy metals in the soil. The conversion of sewage sludge to biochar is a potential way its disposal and is a cost-effective technology for the remediation of soils contaminated with heavy metals and the environment due to the reduction of bioavailability of heavy metals. Also, using biological methods such as the use of soil organisms, including earthworms, is a new and promising way to improve contaminated soils. Several studies have been done about the effects of biochar and earthworms on fractionation of heavy metal at the world, but a report has not yet been presented about the effect of integrated application of biochar and earthworms on fractionation of copper and zinc elements. Therefore, the present study was carried out to investigate the effect of pyrolysis temperature change and application rate of biochar on the Copper (Cu) and Zinc (Zn) fractions and their uptake by E. fetida earthworms in a contaminated calcareous soil from the area surrounding the old Ahangaran lead-zinc mine.

The experiment was carried out as a factorial experiment based on completely randomized design with three replications under environmental conditions of the laboratory of Soil Sciences Department of Bu-Ali Sina University in Hamedan. Experimental factors included earthworms Eisenia fetida species in 2 levels (with and without earthworms) and biochar produced from sewage sludge at two different temperatures of 300 and 600 ° C in 4 levels (0, 2, 4 and 8%) were added to contaminated calcareous soil. 12 earthworms were introduced into each container, and the containers were stored in a climatic chamber with 16 hours of light and 8 hours of darkness at 25 ° C for 42 days. The method of sequential extraction was used to investigate the fractionation of Cu and Zn. Statistical analysis of the data using SPSS and MSTATC software and means comparison was performed by the Duncan test at 5% probability level.

According to the results of the analysis, activity of the earthworm in the soil treated with biochar produced at 300 °C had no significant effect on the amount of copper and zinc in the exchangeable fraction. While reduced the amount of Cu and Zn in the exchangeable fraction and increased the amount of Cu and Zn in the residual fraction of the soil treated with biochar produced at a temperature of 600 °C. Increasing the application rate of biochar significantly reduced the amount of copper and zinc in the exchange sector, as this decrease was evident in the biohazard produced at a temperature of 600 °C. So, the activity of the earthworm at a level of 8% biochar produced at a temperature of 600 °C resulted in a decrease of the amount of exchangeable copper from 0.391 to 0.256 in comparison to the absence of earthworms. The concentration of exchangeable zinc decreased from 242.1 mgkg-1 in control treatment to 0.579 and 0.283 mgkg-1 in 8% biochar produced at 300 and 600 ° C treatments, respectively. Due to low motility of heavy metals in soils treated with biochar, the concentration of Cu and Zn in the body of the earthworm has decreased and this trend was higher in the biochar produced at 600 ° C compared to the biochar produced at 300 ° C . Therefore, heavy metals fractionation could be changed as a result of the activity of earthworms in soils treated with biochar, this trend indicates that the distribution of the metals in biochar-amended soil is gradually shifting from the more labile fractions to the more stable fraction.

Chemical fertilizers can supply all the nutrients required by plants, but their high consumptions cause environmental pollution and increased agricultural production costs. Organic fertilizers can improve the biological, physical, and chemical properties of soil and improve soil fertility and productivity. However, these fertilizers alone cannot provide all the requirements of plants for different nutrients. In addition, these fertilizers are not sufficiently available to farmers everywhere. So, in order to increase effectiveness of organic and chemical fertilizers, to decrease environmental pollutions and to achieve sustainable agriculture, integrated application of organic and chemical fertilizers is recommended. Nitrogen (N), phosphorus (P) and potassium (K) are essential elements for plant nutrition and growth. Wheat as a strategic crop is the most important cereal and plays a very important role in human and animal nutrition and health. The deficiencies of N, P and K in the most agricultural soils often reduce the growth and yield of wheat. Therefore, the appropriate concentrations of these nutrients in wheat seed, leaf and stem are important not only for the optimum growth of the wheat plant and its quality improvement but also for the health of humans and animals. This research work was carried out to study the effects of combining farmyard manure (FYM), municipal solid waste compost (MSWC) and municipal sewage sludge compost (MSSC) with different levels of urea on seed, leaf and stem yields of wheat (Triticum aestivum L.) cultivar Alvand and concentrations of N, P and K in seed, leaf and stem in a randomized complete blocks design with 15 treatments and three replications under field conditions at Khalatposhan Agricultural Research Station, University of Tabriz, Tabriz, Iran. The treatments included were: 1) control (without fertilizers), 2) 150 kg urea/ha, 3) 300 kg urea/ha, 4) 30 ton MSWC/ha, 5) 30 ton MSWC/ha + 150 kg urea/ha, 6) 60 ton MSWC/ha, 7) 60 ton MSWC/ha + 150 kg urea/ha, 8) 30 ton MSSC/ha, 9) 30 ton MSSC/ha + 150 kg urea/ha, 10) 60 ton MSSC/ha, 11) 60 ton MSSC/ha + 150 kg urea/ha, 12) 30 ton FYM/ha, 13) 30 ton FYM/ha + 150 kg urea/ha, 14) 60 ton FYM/ha, 15) 60 ton FYM/ha + 150 kg urea/ha. The size of each plot was 2.0m × 1.9m. At the end of growth period, the plants were harvested and different sections of wheat plant (seed, leaf and stem) were separated and the yield of each section was determined. The concentration of N in seed, leaf and stem were then measured by Kjeldahl method. After dry ashing of the seed, leaf and stem samples, the concentrations of P and K in their extracts were measured by spectrophotometer and flame photometer instruments, respectively. The results showed that application of 300 kg urea/ha increased the wheat grain yield and concentrations of N, P and K in seed, leaf and stem but it decreased the stem yield. Application of 150 kg urea/ha had no significant effect on the leaf yield but its integration with 60 ton MSWC/ha significantly increased the leaf yield of wheat. The combining of 150 kg urea with 30 and 60 ton FYM, MSWC and MSSC per hectare increased yields of wheat stem and seed and their N and P concentrations as compared with the control and application of solely organic fertilizers. The use of FYM, MSWC and MSSC significantly increased the wheat grain yield and concentrations of N, P and K in seed, leaf and stem relative to the control but their effects on yields of leaf and stem depended on the type and rate of organic fertilizer. The highest yields of grain, stem and leaf and the highest concentrations of N, P and K in wheat grain, stem and leaf were observed under combined application of 150 kg urea and 60 ton FYM, MSWC and MSSC per hectare. The minimum yields of seed, leaf and stem and the minimum concentrations of N, P and K in different organs of wheat plant were observed in the control treatment. The average wheat yield component was in the order of seed > stem > leaf. The mean concentrations of N, P and K in different sections of wheat were in the order of seed > leaf > stem, seed > leaf > stem and stem > leaf > seed, respectively. The grain yield of wheat had positive and significant correlations (p<0.01) with concentrations of N, P and K in different organs of wheat, which indicates the role of N, P and K nutrition of wheat plant in increasing its seed yield. The wheat seed had higher concentrations of N and P and lower concentration of K compared to leaf and stem. In general, in order to decrease nitrogen fertilizers use, enhance N, P and K nutrition of wheat plant, improve wheat seed quality, decline environmental pollution and increase wheat yield, application of 150 kg urea and 60 ton manure per hectare is recommended. However, if there is not enough manure, 150 kg urea and 60 ton municipal solid waste compost or municipal sewage sludge compost per hectare can be applied at similar conditions.

Global warming is strongly linked to the increase in greenhouse gas emissions to the atmosphere. One of the most efficient ways to reduce the amount of atmospheric CO2 is to produce a lot of biomass and convert the biomass into a biochar. Biochar is an organic carbon-rich solid that can be obtained from pyrolysis of various organic materials. In other words, biochar can be produced via thermal degradation of many organic materials such as vegetation biomass, animal waste, sewage sludge, etc. in absence or lack of oxygen. Biochar is more resistant to microbial degradation than its feedstock and has a mean resistance time of several decades. In connection with the use of biochar, the most researches have been done in non-fertile and highly weathered soils. The most significant effects of biochar application, have been also observed in strongly acidic soils. In many arid and semi-arid regions of the world, including Iran, the soil organic matter content is low. The lack of organic resources and their instability in the soil are considered as some of the most important challenges in improving soil fertility and plant growth and yield. To improve soil fertility by using insufficient existing organic resources, stabilizing organic matter by converting it into the biochar can be a fundamental strategy. If this strategy is applied in our country with calcareous soils, it is necessary to study the effects of different biochars on calcareous soils from different aspects .In this regard, in the present study, the effect of three types of biochar in a calcareous soil has been investigated in comparison with their feedstock.
The effects of three types of biochar and their feedstock in a calcareous soil were investigated in a 6-months period of incubation. A completely randomized design in the form of split plot experiment, was carried out. The main plots were consisted of Control, Municipal Waste Compost (MWC) and its biochar (BMWC), Sewage Sludge (SS) and its biochar (BSS) and Cow Manure (CM) and its biochar (BCW). The sub plots consisted of five sampling times as 10, 30, 60, 120 and 180 days after the beginning of incubation. Application rate of each treatment per kilogram of soil was calculated based on having the same weight of organic carbon content. So that all treatments contained 2.2 grams of organic carbon. After mixing the treatment with soil and adjusting the humidity to the moisture content of the field capacity (FC), they were transferred to the cans (with 3 holes embedded on their doors) and kept at 25°C in the incubator. During the 6-month incubation period, soil moisture was set at FC levels at intervals of two to three days. Sub samples were taken at five times. After air drying the sub samples, the chemical parameters such as EC of 1:2.5 extract, pH of 1:2.5 suspension, available phosphorus (extracted with sodium bicarbonate 0.5N) and available potassium (extracted with ammonium acetate 1N) were measured. After data collection, statistical analysis was performed using SAS software.
The soil texture was sandy loam with 21% of clay, 7% of silt and 72% of sand. Soil CaCO3 content and soil organic carbon content was 16% and 0.23% respectively. Available forms of potassium and phosphorous in soil were 76 and 6.3 mg kg-1, respectively. According to the results, under the influence of each treatment, the variation of soil available P, showed a significant increasing trend with the time. Changes in available potassium and soil pH were not significant over the time. Variation of soil salinity with time although showed an increasing trend but was not significant. Comparison of the effects of treatments showed that both biochars and their feedstock could significantly increase the available phosphorus and potassium in soil. In this regard, the effect of biochars was more pronounced than their feedstock. Among the feedstock, ranking for enhancing effect on available P, was SS > CM > MWC and among the biochars, it was BCM > BSS > BMWC. Ranking for enhancing effect on available K, was CM > MWC > SS and BCM > BMWC > BSS among the feedstock and biochars respectively. The increase in available phosphorus and potassium due to the use of biochars were much higher than that of total phosphorus and total potassium added by biochars. The soil pH decreased as a result of the application of each treatment compared to control. In this regard, the significant difference between biochars and their feedstock were not seen. Probable presence of some amounts of pyrogenic carbon with biochars can be one of the reasons for soil pH reduction. Electrical conductivity of 1:2.5 extract of soil was increased by all treatments compared to the control. Except for BSS, two other biochars significantly increased soil salinity more than their feedstock. This increasing effect on soil salinity can be partially due to the existence of some amount of ash accompanied with biochars.
Application of biochars derived from cow manure, sewage sludge or municipal waste compost in this experimental conditions, led to a significant increase in the amount of available phosphorus and potassium in soil compared to control and their feedstock. Therefore, the use of these biochars can have a high potential for reducing the consumption of some chemical fertilizers. From this point of view, the order of the superiority of the coal was as follows: biochar of cow manure > biochar of municipal waste compost> biochar of sewage sludge. The conversion of any of these feedstock to biochar did not have an effect on their potential for soil pH changes. Except for biochar of sewage sludge, in two other biochar, the potential for increasing soil salinity was higher than the feedstock. Considering that the durability of biochar in soil is much higher than that of its feedstock, it is possible to use suitable biochars such as those examined in this study as a great potential for the sustainable improvement of soil fertility and for reducing the use of chemical fertilizers in our country's agriculture. This requires extensive field researches for other soil properties in different soil and water conditions, with different kinds of biochars and crops.

To study the effect of different amounts of municipal compost and sewage sludge on soil properties and yield of maize after one and five years of consumption, a scientific experiment was conducted in Rudasht irrigation and drainage research station of Isfahan, Iran. The applied treatments of 25 and 50 t/ha of municipal compost and 15 and 30 t/ha of sewage sludge and control treatment (non-application of organic fertilizer) before planting, were used in constant plots in a randomized complete block design with three replications. As a result of organic fertilizer consumption, the pH decreases and concentrations of some essential elements concordant with the lead element increased significantly in the soil. The amounts of micro and macro elements were also increased in harvested corns. It was clear that the concentrations of those elements have increased in soil and corn after five years compared with one year of organic fertilizer consumption. The yield of corn was increased significantly by five year of fertilizer usage in comparison with control treatment

Application of sewage sludge in agricultural lands as a fertilizer is a suitable selection for solving management problems of sewage sludge disposal, besides its economic benefits. One of the main limiting factors to use sewage sludge is its high content of heavy metals such as lead and cadmium. Biochar with organic ligands can create complex with heavy metals and makes them immobile in soil, and reduces their transport to plants. The aim of this study was to investigate the influence of the Biochar on lead and cadmium uptake from a Paper Factory sewage sludge by the Sunflower (Heliantus annus). For this purpose, a factorial greenhouse experiment as a complete randomized design with three replications was conducted. Four levels of sewage sludge with 0, 15, 20 and 25 (g kg-1 of the soil) and four levels of Biochar with 0, 5, 10 and 15 (g kg-1 of the soil) were used in order to investigate the sewage sludge influence. The results showed that the use of sewage sludge led to a significant increase of the lead and cadmium concentrations in the Sunflower shoots and roots. The results also showed that application of Biochar led to a significant decrease (at 1% probability level) of lead and cadmium concentrations at the shoots and roots of Sunflower.

Zinc (Zn) is one of the essential micronutrients for plant growth and its deficiency frequently occurs in calcareous soils. But, a suitable extractant for estimation of plant-available Zn in calcareous soils, amended with sewage sludge, has not been presented yet. The aim of this research was to assess several chemical extractants (7 extractants) for estimation of available Zn in calcareous soils amended (1% w/w) and unamended with sewage sludge. Results showed that Mehlich 3 and Mehlich 1 extractants extracted the highest and the lowest concentrations of Zn in both amended and unamended soils, respectively. All wheat indices (wheat yield, Zn concentration and Zn uptake) increased by sewage sludge addition. Besides, the results indicated that in unamended soils, significant correlations were found (r=0.65*- 0.91**) between extracted Zn using AB-DTPA, DTPA-TEA and Mehlich 3 extractants and different wheat indices. On the contrary, in sewage sludge-amended soils, only the correlation between extracted Zn using Mehlich 2 and Zn concentration was significant (r=0.83**). According to this study findings, the suitable extractant for extracting wheat-available Zn is thoroughly different in calcareous soils amended and unamended with sewage sludge.

Soil compaction is one of the most prevailed limitations for crop growth. The use of organic matters as fertilizer on agricultural soils can reduce the effects of soil compaction and provide the nutrients for the plants. So, a factorial experiment was carried out in a randomized complete blocks design with three replications. The first factor was the source and amount of organic fertilizer (farmyard manure, sewage sludge compost and municipal solid waste compost and each of organic fertilizers at three levels of 0, 15, 30 g/kg soil) and the second factor was two levels of soil compaction (1.2 and 1.7 g/cm3). Results showed that application of all three types of organic fertilizers at both levels of compaction caused an increase in plant dry matter, leaf length and width, stem diameter, leaf chlorophyll index, RWC and WUE, and the maximum of these characteristics was obtained by application of 30 g organic fertilizers. Soil compaction caused a decrease in plant growth and above mentioned characteristics except number of leaves per plant. Application of organic fertilizers and increasing their levels reduced negative effects of soil compaction on corn growth characteristics and WUE; so that at the soil compaction level of 1.7 g/cm3, the corn growth in the 30 g of each fertilizer was greater than the 15 g of them. In order to increasing WUE and corn growth, application of 30 g of farmyard manure or sewage sludge compost or municipal solid waste compost per kg soil can be recommended at similar conditions.

Application of sewage sludge as a cheap and waste material is increasing for supporting plant essential elements especially in the soils of arid and semiarid regions. In the present greenhouse research, the effect of Ardabil municipal sewage sludge on N, P, K, Pb, Cr, Ni and Cd concentrations in soil and plant and also spring wheat yield and growth indices was studied as a randomized complete block design with 5 treatments and 4 replications. Treatments were: zero (control), 30, 60, 120 and 180 tons of sludge/ha. The results showed that all rates of sludge application (30 to 180 tons/ha) significantly increased organic carbon (21.94 to 176 percent), total nitrogen (81 to 310.34 percent), extractable phosphorus (16.7 to 123 percent) and extractable potassium (5.34 to 117.8 percent) in the soil under growth of wheat. The concentration of nitrogen, phosphorus and potassium in grain increased significantly in 180 tons/ha treatment about 36.04, 112.34 and 86.64 percent compared with control, respectively. Sewage application increased grain yield and wheat growth indices such as shoot dry weight, height, and grain weight and leaf area. The effect of sludge application rates on the concentration of Pb, Cr, Ni and Cd was not significant in soil. Generally, with consideration the high electrical conductivity of used sludge, the 120 tons/ha treatment can be recommended as suitable application rate for improving chemical quality of soil.

As there are some health and environmental concerns about wastewater, dewatered sludge, increase in green waste, and restricted legislation about burning them outdoors, environmental health engineers are investigating to find a simple, cost effective and efficient method. This is aimed to have healthy, safe and sustainable disposal of such materials. Co-composting of sludge and green waste is a newly developed process which can help us to achieve this goal. This study was to investigate the most suitable ratio of dewatered sludge to green waste from Chonibieh wastewater treatment plant in Ahvaz, Iran, and assess the feasibility of co-composting of this waste. So, dewatered sludge was composted with green waste as a bulking agent in three different ratios (1:1, 2:1, 3:1: green waste: dewatered sludge W:W). Then composting proceeded in pilot vessels (M1, M2, M3) for 23 days. The C/N ratio, the percentage of total nitrogen, phosphorus, total organic carbon, humidity and pH were tested in certain periods and compared with the national standards. This study showed that in M1, M2, M3 pilots, all parameters (except for total phosphorus) including C/N ratio, percentage of total nitrogen and total organic carbon, humidity, pH could meet class 1 national standard in Iran. Moreover, this compost product could meet the EPA microbial standards, class A. So, the product of this compost process is completely stabilized and could be used in agricultural lands.

The ability of different soil tests in predicting soil phosphorus (P) is important in soils amended with municipal sewage sludge. The objective of the present study was to evaluate several chemical extractants to estimate available P for bean growing in 10 calcareous soils amended with municipal sewage sludge from Chaharmahal-Va-Bakhtiari province under the greenhouse conditions. For this purpose, the soil samples were incubated with sludge at a rate of 39-ton sludge ha–1. The amount of available P of the soil samples was determined by Olsen, Colwell, ammonium bicarbonate-DTPA, 0.01 M calcium chloride, BrayІ, ІІ, Mehlich І and ІІ methods. A pot experiment in a completely randomized design was conducted to evaluate the bean plant indices. The results showed that the amount of extractable P with the above methods decreased in the following order: Colwell> Bray ІІ> Mehlich ІІ> Olsen> Ammonium bicarbonate DTPA> Mehlich І> Bray І> 0.01M chloride calcium. The extractable P with 0.01M chloride calcium, Mehlich І, ІІ Colwell and Olsen methods correlated significantly with plant indices (P concentration and P uptake). Thus, mentioned methods could be used to estimate plant-available P in the soils amended with sewage sludge.

Management of organic and inorganic treatments may have positive or negative effects on soil quality, plant growth and human nutrition. The objectives of this study were to determine the effects of organic and inorganic zinc fertilizer application on soil quality indicators and wheat yield. This research was conducted at Agricultural Research Station Roudasht, Isfahan, Iran. Sewage sludge and cow manure (5 and 10 t/ha), ash rubber (1 t/ha), powder rubber (200 kg/ha), ZnSO4 (40 kg/ha) were applied and wheat was cultivated. Soil samples were collected at tilling and harvest stages. After taking samples and measurements of the soil parameters, we determined the critical limits for each category and class rating for the each soil parameters, and the soil quality index was calculated. The results showed sewage sludge and rubber ash were significantly effective in increasing soil bioavailable Zn compared to other treatments. Application of sewage sludge and cow manure at 10 ton/ha improved soil quality. The expanded soil quality index can help better understand the effect of fertilizers on soil. A positive and significant relationship between soil quality indicators and Zn uptake and wheat yields was also observed. Our results indicate that addition of 10 t/ha sewage sludge as fertilizer can significantly improve soil quality, supplying the necessary amount of Zn for wheat growth.

Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, and 60 ton/ha) of different organic compounds including municipal waste compost, sewage sludge, cattle manure, and wheat straw to gether with control treatment in three replications were applied into loamy soil. The treated soils were kept for 6 months at 70% of field capacity moisture in greenhouse condition. Then soil quality determined based on non-linear score function by using of 14 physical and chemical indicators. The results showed that the score of control treatment was 52.7, which it belong to class 4, i.e. low quality. Addition of different organic matter into studied soil led to improve soil quality score and soil quality class was increased one to 2 degrees. Among the studied treatments, the highest score of soil quality was obtained in 60 ton/ha sewage sludge and 30 and 60 ton/ha compost. Also, addition the other organic treatments cause to increase the quantitative soil quality score in relation to control, and soil quality class increased one degree. Among the studied indicators, iron (Fe), Manganese (Mn), zinc (Zn) micro-nutrients, aeration porosity (AC), and mean weight diameter of aggregates (MWD) were the important limiting indictors in degrading the soil quality in control treatment, and applying the compost and sewage sludge increased their scores.