نشریه مدیریت خاک و تولید پایدار
سال نهم شماره 2 (پیاپی 28، تابستان 1398)

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.

Wind erosion is one of the most important land degradation aspects especially in arid and semi-arid regions such as Kerman province. Wind direction and speed are two important erosive factors affecting wind erosion and sediment yield. The purpose of this study was to analyze the erosive winds of the province in order to determine the direction of predominant winds and the status and the potential of wind erosion during different periods of 8 to 11 years.

In this study, wind anemometric data for 8-11 y periods were analyzed using 12 synoptic stations in Kerman province. For this purpose, the WR Plot View software was applied in order to analyze the anemometer data and draw wind roses and storm roses of the selected synoptic stations of the province. Moreover, the sand roses of the studied stations were plotted using the Sand Rose Graph 3 software, accordingly different sand drift potential and direction indices were derived.

The results of wind rose analysis generally indicated that the western and southwestern winds dominated in the western part of the province, whereas the northern winds were more frequent in the eastern part. Storm rose analysis showed that in most stations, the highest erosive winds were mainly blown from the west and south west directions, while at Bam and Shahdad stations the north and at Zarand the southwest and northeast winds were predominate. According to this analysis, the most frequent winds at the speed classes of ≤6.7, 6.7-7.7, and 7.7-9.8 m s-1 were allocated to Jiroft (94.9%), Sirjan (8.0%) and Kahnooj (12.0%) stations, respectively. Among all the stations, Rafsanjan with 10.9%, 5.0%, and 4.1% showed the most frequent winds at the higher speed classes of 9.8-11.8, 11.8-13.9, and ≥13.9 m s-1, respectively. The analysis of resultant drift direction (RDD) implied that sand transport for the western stations of the province was mainly toward east and northeast directions, for Zarand station was from northwest to southeast and for Shahdad and Bam stations was from north to south directions. The minimum amount of total drift potential (DPt) was found at Baft and Jirof stations by 398 and 400 v.u., respectively, while Rafsanjan station with 1665 v.u. experienced the highest value of this index. Except for Baft and Jiroft stations with moderate wind potential, the other stations showed high wind potentials. The analysis of uni-directional index (UDI) indicated that except for Jiroft and Zarand stations which had high variability with multi-directional winds, for the other stations moderate variation with bi-directional winds and oblique angle were observed.

It was concluded that although wind erosivity analysis gives valuable information on wind erosion situation and sediment transport, it is necessary to be considered and used the threshold velocity as well as soil erodibility databases in order to achieve a more accurate analysis of wind erosion in the province.

The deficiency of available phosphorus (P) is considered as a main problem in Iran’s soils. In order to increase the available P, chemical fertilizers are used. However, P in chemical fertilizers are transformed into less available forms over time. To improve the efficiency of P fertilizers, organic amendments could be effective. Sewage sludge contains an abundance of organic matter and nutrients and is used to improve the productivity of farmland and enhance yield. This study conducted to investigate the effect of the interaction of sewage sludge and P fertilizers on availability and mineral of P and maize (Zea Mays L.) indices in a calcareous soil.

This study was conducted based on factorial experiment in a completely randomized design with 3 replications. The experimental factors were chemical fertilizer (0 and 50 mg/kg of KH2PO4) and sewage sludge (0 and 1 % w/w). The treated soils were kept in 80% of the field capacity in greenhouse condition for one month. The maize (single cross 704) was planted in 3 kg pots under greenhouse of Shahrekord University. After 2 months planting, shoot was removed and maize indices (P concentration, dry matter, and uptake) were determined. Also, after planting, soil sampled from pots and the various fractions of P including (soluble P, Fe-Al bonded P, Ca bonded P, residual P, and organic P) and available (P Olsen and CaCl2 0.01 M methods) were determined.

The results showed that interaction between P fertilizer and sewage sludge on P extracted by Olsen method wasnot significant (p>0.05), while in P extracted by CaCl2 0.01 M was significant (p<0.05). The results revealed that by addition the 50 mg/kg P, P-Olsen and P-CaCl2 increased 21.4 and 60%, respectively, while 1% sewage sludge application P extracted by Olsen and CaCl2 0.01 M methods increased 83.2 and 200%, respectively. The effect sewage sludge (except residual P) and chemical fertilizers on all P fractions were significant (p<0.01). In addition, the interaction between chemical fertilizer and sewage sludge was only significant on Ca -bound P (p <0.05). The effect of sewage sludge on P fractions was more remarkable than chemical fertilizer and their interaction effect. By addition 50 mg/kg P fertilizer, P concentration in maize and the dry matter increased 8.2 and 25.9%, respectively. Similarly, in comparison with without sewage sludge, by sewage sludge application these indices increased 4.9 and 194%, respectively. The interaction of sewage sludge and P fertilizers was significant on maize uptake (p<0.05). The P uptake increased 32.5% in sewage sludge + 50 mg/kg P fertilizer compared to 1% sewage sludge and increased 170 % compared to 50 mg/kg P fertilizer.

The results showed that the effect of chemical P fertilizer application on extracted P by Olsen method wasn’t related to sewage sludge application. In treated soil with sewage sludge, available P considerably increased compared to treated soils with P fertilizer that could be attributed to different impact of treatments on P fractions. Also, the effect of chemical fertilizer application on uptake of P was related to sewage sludge rates.

Potatoes producers in Iran are widely use nitrogen, phosphorus and potash fertilizers for tuber production, but the tuber yield is less than the potential in desirable conditions. In this high cost and low efficiency farming system, soil microorganisms can play an important role in improving fertilizer efficiency and reducing costs. In addition to physical and chemical properties, soil quality has a close relationship with biological aspects. The aim of the present work was to evaluate the positive effects of potassium, phosphate solubilizing bacteria and nitrogen-fixing bacteria on potato growth, tubers yield and its dry matter, as well as saving the chemical fertilizers for healthier crop production. Materials and Methods This study was conducted as a split plot experiment in a randomized complete block design with three replications at Research Farm of Ferdowsi University of Mashhad, Iran in the 2016 cropping season. Treatments included nine fertilizer programs including; phosphate solubilizing bacteria (Phospho-powerbacter dayan), potassium solubilizing bacteria (Peta-powerbacter dayan), free-living nitrogen-fixing bacteria (Nitro-bacter dayan), phosphate solubilizing bacteria + Triple super phosphate fertilizer, potassium solubilizing bacteria + potassium sulfate fertilizer, free-living nitrogen-fixing bacteria+ nitrogen fertilizer with a source of urea 46%, phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria, phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria + triple super phosphate + potassium sulfate + nitrogen and control (without biological and chemical fertilizer) as main plots and two potato cultivars (Fontane and Sante) as subplots.

The highest leaf area index observed in Fontane cultivar and phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria. In Sante cultivar, tow treatments including free-living nitrogen-fixing bacteria alone and phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria showed the highest leaf area index. The highest Fontane shoot biomass was produced in phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria treatment and in Sante cultivar was observed in free-living nitrogen-fixing bacteria + Nitrogen fertilizer treatments. Application of phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria simultaneously caused an increase in the number of tubers per plant in both cultivars. Fontane in potassium solubilizing bacteria + potassium sulfate fertilizer produced the highest tuber yield, which it was 37% more than control treatment. The highest tuber yield in Sante cultivar was obtained by application of phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria + triple super phosphate + potassium sulfate + nitrogen, which was 36% more than control treatment. The highest of dry matter percentage, specific gravity and starch content in both cultivars were obtained in treatment of all bacteria with chemical fertilizers and the lowest of these characteristics was observed in control treatment. The lowest reducing sugars was obtained in the phosphate solubilizing bacteria + Triple super phosphate and phosphate solubilizing bacteria in Fontaneh and Sante cultivars, respectively. The best DPPH radical scavenging activity in Fontaneh was observed in treatment of all bacterias and in Sante cultivar in applying free-living nitrogen-fixing bacteria. The highest and lowest total phenol content was observed in control treatment and application of potassium solubilizing bacteria + potassium sulfate fertilizer with 75% difference, respectively.

In the present study, the application of bio fertilizers in potatoes showed that these fertilizers could improve physiological, yield and quality characteristics of potato cultivars by using less chemical fertilizers. Generally, application of phosphate solubilizing bacteria + potassium solubilizing bacteria + free-living nitrogen-fixing bacteria + triple super phosphate + potassium sulfate + nitrogen produced the highest potato tuber yield.

With increasing global warming, drought stress and salinity are considered as one of the most important problems in agriculture and soil management. These stresses will change the uptake of nutrients by the plant. In the nature, the plant is under salinity and drought in same time. However, few studies have been carried out on the contribution of each stresses to nutrient variation under mixed treatment. Therefore, this study examines the effects of same amounts of matric and osmotic potentials on variation in some nutrients and their ratios under full and partial irrigation systems in corn leaves and roots.

Experiments with two factors consist of potential-type (osmotic, matric, and combined) and potential levels at four levels (-0.46, -1.12, -1.91, -3.63) performed on the basis of completely randomized design in greenhouse conditions. In order to apply salinity and drought stress to two parts of the root of a plant, a separator structure was used to separate the root into two parts in the pot. To fix the suction of the matric and pots drainage, a handmade tensiometer was used.

The study of variations in nutrient concentration in leaves showed that the partial root irrigation system in the mixed treatment reduced by 11 and 7% concentration of N at levels of -1.12 and -19.9 bar, respectively, compared with the matric potential treatment. Also, P concentration of leaf in mixed treatment compared to the osmotic and matric potentials treatment respectively at level -1.91 bar was increased by 87% and 83%, respectively, and at level -3.63 bar 91% and 95%, respectively. However, the concentration of all nutrients studied in the root was influenced by type, potential level and interaction of these two factors except for phosphorus. In partial irrigation system, the significant variations of N, K, K / N and K / Ca in the section were affected by osmotic potential and total Ca and Mg in the section of matric potential compared with to full irrigation root.

This study showed that in high levels of osmotic and matrix potential in mixed treatments, due to the presence of sufficient water in half of the root, the changes in the nutritional elements are low compared to the isolated osmotic and matric treatments and increase with the potential reduction of these changes. In this case, the most variations in the elements are related to the salinity part the mixed treatment. Therefore, the reduction of the osmotic potential level in the root portion should be accompanied by increased matric potential in the other part of the root, so that it can reduce the nutritional balance of the plant.

Amount of elements in soil affected by parent materials and geochemical and pedogenesis processes. Many studies done about heavy metals concentration in different parent materials and developed soils on them in the world. Mean concentration of elements in soils are similar to mean concentration of them in parent materials, mostly. Difference between element concentrations in parent material and soils developed on them in natural conditions, is derived from pedogenesis processes. Due to the soil pollution with heavy metals is almost permanent and local in any region, this research done about trace element concentration in surface soils with different parent materials in northwest of west Azarbaijan province.

Concentration of some trace elements in 105 surface soil samples developed on 8 different rock mass (Granite, Andesite, Basalt, Ultrabasic, Marl and sand stone, Ghom formation, Lime and Shale) from back slope position, and also their concentration in rock samples in northwest of west Azarbaijan was determined by atomic absorption method. Geo- accumulation index used to estimation of soil contamination to heavy metals.

Highest amount of clay was observed in soils derived from Andesite and Basalt and then sedimentary rocks. Highest amount of total Fe (27231.25 mg/kg), Mn (730 mg/kg), Cu (28.5 mg/kg) and Zn (50.25 mg/kg) was observed in Andesite rock. Total Ni (1937.50 mg/kg), Co (92.50 mg/kg) and Cr (786 mg/kg) is more in ultrabasic rock compared to other rocks. The highest and least concentration of soil total Fe was observed in soils developed on ultrabasic (22062.42 mg/kg) and Ghom formation (6885.42 mg/kg) parent materials, respectively. High Mn concentration is in soils derived from igneous rocks. The highest of Cu (53.17 mg/kg) and Zn (67.75 mg/kg) concentration was observed in soils developed on Andesite and Granite rocks, respectively. Amount of Ni (1667 mg/kg), Co (94.89 mg/kg) and Cr (304.09 mg/kg) in soils derived from ultrabasic parent material is more than others. Positive and significant correlation was observed between studied trace elements in soils and parent materials.

Significance of the entry of trace elements in region soils is parent materials. Fe pollution in soils was not observed compared to global soils, but some of soils were infected to Mn element. Also, most soils were affected to Ni and about of half of them to Cr and Co in the region according to Iran̕̕̕ʼs standard. Keywords: Contamination, Trace elements, Igneous rock, Sedimentary rock, Surface soil.

Determination of different chemical forms of copper in soil is important in the evaluation of copper availability for plants, soil fertility management as well as plant nutrition. Availability of copper for plants depends on the relative distribution of different chemical forms of copper. Copper relative distribution in soil is a function of physical and chemical properties of soil such as the amount of organic matter, CaCO3 content, soil pH, clay content and CEC. Sequential extraction is one procedure to estimate the chemical forms of elements such as copper in soil that is considered as the perfect method for the description of elements behavior in soil. This study was done to determine different chemical forms of copper in some calcareous soils of Rafsanjan, relationship between these chemical forms and with physical and chemical characteristics of studied soils and also relation of different chemical forms of copper with plant responses (growth parameters and Cu concentration and uptake) of pistachio seedlings.

Eleven soil samples with different physical and chemical properties from different parts of Rafsanjan region before and after cultivation were fractionated by sequential extraction (Sposito et al.) to estimate the quantities of copper in exchangeable, sorbed, organic, carbonate and residual forms. The greenhouse experiment was carried out as a completely randomized design on 11 soil samples in three replications and each replication in three observations in pots containing 4 kg soil. After 8 months, pistachio seedlings were harvested and soils were air dried. Chemical forms of copper in soil samples were extracted by method of Sposito et al. and Cu concentration in plant tissues (leaf, stem and root) were determined by atomic absorption spectrometry.

Sequential extraction results indicated that exchangeable and sorbed forms of copper before and after planting were negligible, organic Cu 9.1 and 17.6 %, carbonate Cu 9.8 and 20.8 % and residual Cu 80 and 61.4 % respectively. After planting the amount of residual copper significantly decreased whereas organic and carbonate forms significantly increased. The highest correlation coefficient in soil samples, after cultivation was observed between carbonate Cu and stem Cu concentration (r=0.542**).

Organic and carbonate forms of copper could have an important role in pistachio seedlings nutrition, although their availabilities in soils are low. Generally, the pattern of copper distribution in soil samples before and after planting was as follows: Residual Cu > carbonate Cu> organic Cu> exchangeable Cu> adsorbed Cu

Presence of pesticides in ground water resources has grown in the past few years and has become an intensive and burning issue of discussion. Groundwater contamination not only affects the health of human beings as it is being directly used for drinking purpose, but also can act as source of contamination for food chain, when used for irrigation. Awareness of the fate of the use of soil pesticides is necessary to reduce the mobility of these compounds in the soil and protect the environment. present study reports the effect of organic manure and biochars amendments on adsorption and metribuzin downward mobility in soil columns.

organic amendments (manure and biochr) was added to soil at a level of 1% and the effect of soil (T), soil + manure (TM), soil + biochar (TB) treatments on adsorption and leaching of metribuzin pesticide was studied under saturated and unsaturated moisture conditions. Adsorption experiment with Batch method and soil leaching experiment with Soil column method were conducted in Laboratory of Gorgan Agricultural Sciences and Natural Resources university with two replications.

The results showed that adsorption’s experiment data was matched to the Freundlich model. The adsorption of metribuzin herbicide increased both in TM and TB organic amendment and the Freundlich constant (Kf) for T, TM and TB treatments was 1.2, 2 .3 and 2.6, respectively which were 70% higher in organic amendment treatments than control treatments. Application of manure and biochar at 1% level in soil reduced the downward movement of the pesticide, and maximum concentration of pesticide in the lechate. The total amount of pesticide recovered in TB, TM, T treatments was 77%, 50% and 47%, respectively. Also, the maximum amount of pesticides recovered in unsaturated conditions in treatment T ,TM, TB respectivly were 27%, 10% and 13% less than in compared to saturated conditions.

the application of manure (TM) and biochar (TB) in soil at 1 % level increased the metribuzin retention in the soil and reduced the downward movement of pesticides and affected breakthrough time and maximum concentration of metribuzin in the leachate. Application of biochar in soils is effective in agricultural sustainability and environmental conservation. A better understanding of the benefits of using biochar requires long-term and continuous studies on agro-environmental issues. Also, according to the data of this study, in all treatments. pesticide leaching was higher in saturated conditions than in unsaturated conditions.

In recent years, the use of conservation tillage methods in the world has been widely considered and the use of conventional tillage methods has become obsolete in some parts of the world. Soil conservation tillage systems in arid and semi-arid usually runs. In semi-arid areas, the key to increasing the production of crops is to maximize the penetration of superficial waters. In addition, techniques that lead to a decrease in evaporation from the soil and increase the amount of water available to plants when drought occurs, they are very important. Conventional tillage methods, by increasing energy costs, lead to processes of degradation and reduction of water and soil resources, and long-term effects on soil properties produce undesirable effects and cause the formation of hard layers. The metabolic share and microbial contribution are among the ecophysiological indices that are evaluated to determine the microbial status of the soil.

This research was conducted in 2015 to investigate the effect of different tillage systems on soil biological activity in Golestan province. In this study, in the first stage, three regions were selected from Golestan province in the Gorganroud basin and in the cities of Gonbad, Kordkuy and Bandargaz. From each of these managements, 30 samples were taken at depths of 0-30 cm. Then biological soil properties such as soil microbial respiration, microbial biomass, urease, alkaline phosphatase, acid phosphatase, dehydrogenase and cellulase activity Measured. The experiment was conducted as a completely randomized block with three replications.

The results showed that the effect of tillage treatment in three areas of Gonbad, Kordkuy and Bandargaz on microbial respiration traits, alkaline phosphatase, acid phosphatase, urease, cellulase and dehydrogenase was significant, but there was no significant effect on microbial biomass in Gonbad region. The results of the comparison of mean values indicated that soil biological activity was affected by different tillage systems in the three studied areas. In all three studied areas, the rate of respiration in conventional tillage systems was higher than that of no-till and conservation tillage systems. While in the no-till system, due to reduced organic matter decomposition, the amount of microbial biomass was higher than the other two systems. Considering the differences in enzymatic activity in different regions in different systems, the results showed that alkaline and acid phosphatase enzymes activity, urease and cellulase activity in the Gonbad region in the conservation tillage system was higher than of two other systems While in the Kurdkuy region the activity of these enzymes in the conservation tillage system was less than the other two systems. In the Kurdkuy and Bandargaz regions, the activity of the dehydrogenase enzyme in the conservation tillage system was more than the other two systems, while in the Gonbad region the activity of this enzyme in the no-till system was more than the other two systems.

Different tillage systems affect the level of biological and enzymatic activity of the soil, which was also dependent on the area, so that the microbial biomass of the soil decreased with decreasing moisture content and soil organic matter. Also, according to the results of this study, it was determined that the conventional tillage s system in terms of biological and enzymatic activities in all three areas, especially the Gonbad area, had less efficiency and more efficient no-till and conservation tillage systems, although in areas the different situations were different. Key words: tillage, enzymatic activity, conservation tillage and organic matter