JWSS - Journal of Water and Soil Science

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Waste tire rubbers are considered one of the environment pollutants. Increased production of these pollutants has led to more serious consideration of ways to reduce the harms caused by their accumulation in the environment. Therefore, the effects of incorporation of waste rubber crushed particles in two sizes of 1-2 and 3-5 mm and the amounts of 0, 5, 10 and 20 Mg ha-1 in a calcareous soil (0-30 cm depth) on some chemical properties of soil was investigated in Isfahan University of Technology research field (Lavark). This experiment was performed using seven treatments along with a non amended control treatment in a randomized complete block design with three replications in 1387. Eight months after incorporation, soil samples were collected for laboratory analyses. Results of ANOVA tables show that soil pH, electrical conductivity, percentage of total nitrogen and DTPA-extractable concentrations of cadmium, lead, copper and iron were not significantly affected by application of rubber particles. Incorporation of rubber particles into the soil significantly increased soil organic carbon and carbon to nitrogen. Increases in the DTPA-extractable Zn in soils treated with 10 and 20 Mg ha rubber particles in fine and coarse sizes were significant in comparison with the control soil. DTPA-extractable Zn content in the soil treated with 10 and 20 Mg ha 3-5 mm waste tire rubbers particles was about two and three times higher than that in the control treatment, respectively. The results of this study showed that in short-time, incorporation of crushed tire rubbers particles had no significant effect on most chemical properties of the soil but increased the available Zn content. In this regard, further studies to monitor the effects of adding waste rubber crushed particles on organic matter mineralization, plant toxicity and physical properties of soil in long-term are recommended.

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This study was carried out to investigate zinc (Zn) and cadmium (Cd) concentration in paddy soil and rice grain produced in central and southwest Iran in relation to soil and plant factors, and their intake in peoples diet was also assessed. Rice crops and associated surface soils (0-30 cm) were collected from 136 fields in Isfahan, Fars and Khuzestan provinces. The result, showed the DTPA-Zn concentration in more than 50% of paddy soils was less than its critical deficiency concentration (2 mg kg-1). The grain Zn concentration in more than 54% of the rice samples was less than 20 mg kg-1. The measured Cd concentrations in paddy soils and edible part of rice exceeded the world health organization (WHO) value in more than 12% of the samples. By considering the average daily rice consumption of 110 g per capita, the Zn intake from rice consumption was estimated about 10% needed for female and male adult. Diet intake analysis did not indicate any excessive dietary intake of Cd when Cd mean of concentrations in rice grain was 0.04 mg/kg, but based on the results of risk analysis, it is more than safely level for contaminated rice.

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Cow manure and sewage sludge add heavy metals to soil. Organic and inorganic fractions in these compounds can immobilize heavy metals such as lead (Pb) and affect their bio-availability. This investigation was conducted to compare the effects of organic and inorganic fractions of sewage sludge and cow manure on distribution of lead chemical forms in soil as a completely randomized design. Treatments consisted of application of 10% (w/w) enriched sewage sludge and cow manure (6 g Pb kg-1 organic amendments). Another treatment was also used in which soil Pb concentration was increased to 600 mg kg-1 soil using Pb(NO3)2 salt. To compare the effects of organic and inorganic fractions, organic carbon, iron oxide and easily reducible iron and manganese were removed from cow manure and sewage sludge, and were added to the soil by 10% (w/w). The samples were incubated at 23-25ºC for 111 days and their moisture was maintained at 80% water field capacity. More than 50% Pb in Pb(NO3)2 treatment was in exchangeable fraction, while for cow manure and sewage sludge treatments more than 40% Pb was found to be in oxide fraction. Application of cow manure and sewage sludge increased the Pb in oxide fraction by 14.8 and 17.5%, respectively. Removing organic carbon fraction of cow manure and sewage sludge increased the Pb bound to residual fraction by 12% and 14% respectively. Removing iron oxide fraction of sewage sludge and cow manure decreased the Pb bound to oxide fraction by 8% and 13%, respectively. Removing easily reducible iron and manganese decreased the oxide fraction of Pb by 16% and 14%, respectively. It is concluded that, despite relatively high amounts of organic carbon in the sludge and manure, inorganic fractions of these materials have more significant effects on availability of Pb in soil.

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The task of modern agriculture is to safeguard the production of high quality food, in a sustainable natural environment under the precondition of pollution not exceeding accepted norms. The sustainability of current land use in agro-ecosystems can be assessed with respect to heavy metal accumulation in soils by balancing the input/ output fluxes. The objectives of this study were to model accumulation rate and the associated uncertainty of Zn in the agro-ecosystems of 3 arid and semi-arid provinces (Fars, Isfahan and Qom). Zinc accumulation rates in the agro-ecosystems were computed using a stochastic mass flux assessment (MFA) model with using Latin Hypercube sampling in combination with Monte-Carlo simulation procedures. Agricultural information including crop types, crop area and yield, kind and number of livestock, application rates of mineral fertilizers, compost and sewage sludge and also metal concentration in plants and soil amendments were used to quantify Zn fluxes and Zn accumulation rates. The results indicated that Zn accumulates considerably in agricultural lands of the studied townships especially in Najafabad (3009 g ha-1yr-1). The major Zn input routes to the agricultural soils (and due to agricultural activities) were manure and mineral fertilizers and the major part of the uncertainty in the Zn accumulation rate resulted from manure source.

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Due to soil and plant zinc (Zn) deficiency and its effect on reducing yield and quality of agricultural products, application of Zn fertilizers has been intensified in recent years. To achieve optimum fertilizer management, knowledge of factors affecting Zn availability in soil and its uptake by plant is required. Therefore, this study was carried out to investigate the effect of certain soil physiochemical properties on Zn availability in soil and its uptake by corn. The experiment was laid out in a completely randomized design with factorial combination and three replicates in the research greenhouse of Isfahan University of Technology, in winter 2009. In this greenhouse experiment, 11 soil series were exposed to two Zn levels (0 and 15 mg Zn kg−1 in the form of zinc sulfate). The results indicated that Zn application significantly increased the dry matter weight and shoot and root Zn concentration of corn, although the magnitude of this increase varied depending on the soil type. There was no significant correlation between the DTPA-extractable Zn and the uptake of this nutrient element by corn. There was a negative significant correlation (P < 0.05) between the equivalent calcium carbonate content and available P with the DTPA-extractable Zn. A significant linear relationship (R2 = 0.31) was found between the buffer capacity of soil for Zn and clay content. According to the results obtained from the stepwise regression analysis, the DTPA-extractable Zn and buffer capacity of soil for Zn were not correlated with other measured soil properties.

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Iron chlorosis is an important disorder of plane trees (Plantanus orintalis L.) in green space of Isfahan city. Before using reclamation methods for correcting Fe chlorosis, it is necessary to find a suitable index for evaluating plant Fe status. Therefore, activity of glutathione peroxidase (GP) enzyme and concentration of carotenoids and chlorophyll a and b pigments, as physiological indices of active Fe, were compared to total Fe concentration in leaves to evaluate Fe status in plane trees. For this purpose, severity of chlorosis of plane trees at different regions of Isfahan city was recorded. Then, 73 trees with different severity of chlorosis symptoms were selected and their leaves were sampled on July 2009 and 2010. Concentration of Fe, chlorophyll a and b and carotenoids in leaves as well as activity of GP enzyme were measured. Results showed large variation in leaf Fe concentration between young and old leaves and also between leaves with different chlorosis severity symptoms. No correlation was found between leaf Fe chlorophyll concentration and severity of chlorosis symptoms. Also, concentrations of chlorophyll a in young and old leaves with very severe chlorosis symptoms were 44 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of chlorophyll b in young and old leaves with very severe chlorosis symptoms were 40 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of carotenoids varied among young and old leaves with different severity of chlorosis symptoms. Activity of GP in young leaves was also reduced by intensifying severity of chlorosis symptoms. According to the result of the present study, activity of GP enzyme and leaf concentration of carotenoids and chlorophyll a, as suitable physiological indices of active Fe, had close correlation with severity of Fe chlorosis in plane trees. Also, deficiency of active Fe in leaves is a probable reason of chlorosis symptoms in plane trees.

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Zinc (Zn) is an essential trace element for plants as well as for animals and humans. There is a significant relationship between soils, plants and humans Zn status in a certain agro-ecosystem. The objectives of this study were to assess Zn status of soils in 3 arid and semiarid provinces of Iran and to model the relationship between wheat grain Zn and agro-ecosystem parameters. About 137 soil and wheat samples were collected randomly from the agricultural soils of Fars, Isfahan and Qom and were analysed in laboratory. Modeling the relationship between wheat grain Zn and agro-ecosystem parameters was done using least square based and robust methods. The results indicated that total Zn concentration of soils (range, 21-149 mg kg-1 mean, 75.2 mg kg-1) was in normal ranges. The DTPA-extractable Zn concentrations were below the critical level (0.8 mg kg-1) in 16% of the surveyed fields. The Zn concentration in 80% of wheat grains was sufficient (more than 24 mg kg-1) with respect to plant nutrition (range, 11.7-64 mg kg-1 mean, 31.6 mg kg-1). However, Zn bioavailability for consumers was generally low in more than 75% of the samples. This is because of high phytic acid to Zn molar ratio (more than 15). Soil DTPA-extractable Zn and available P were entered in to most of regression models significantly. Regression analysis showed that most of models fitted to wheat grain Zn concentration and soil Zn and influenced by agro-ecosystem parameters had a weak prediction power, despite their high determination coefficient. This means that factors other than those considered here have a strong influence on the uptake of Zn by wheat in these soils.

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Limited information is available about the effect of preceding crop residues on bioavailability of zinc (Zn) in calcareous soil and its accumulation in wheat grain. In this experiment, residues of five crops including safflower (Carthamus tinctorius L.), sunflower (Helianthus annuus L.), bean (Phaseolus vulgaris L.), clover (Trifolium pretense L.) and sorghum (Sorghum bicolor L.) were incorporated into a calcareous Zn-deficient (0.5 mg kg-1) soil. A treatment without crop residue was also used in the experiment. This experiment was conducted in research greenhouse of Isfahan university of technology in 2010. Two wheat cultivars (Triticum aestivum cvs. Backcross and Kavir) differing in Zn-efficiency were studied in the experiment. Incorporating crop residues into the soil resulted in an increase of grain Zn concentration in both wheat cultivars although this increase was dependent on the preceding crop type. The greatest increase of grain Zn concentration occurred in the sorghum residues treatments. Although application of crop residues significantly decreased grain phytic acid to Zn molar ratio (as Zn bioavailability criteria for consumers), this ratio was still higher than 15, the critical Zn bioavailability level for consumers in foods. According to the results, despite the increase in the total Zn content, the bioavailability of Zn in wheat grain was not affected by crop residue treatments.

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This research was carried out in a hydroponic culture to investigate the effect of Zn nutrition on phytosiderophore release by roots of three bread wheat genotypes (Triticum aestivum L. cvs. Rushan, Kavir, and Cross) differing in Zn-efficiency. The wheat seeds were germinated in sterile sand and two weeks later the plants were transferred to nutrient solution containing different Zn levels. Phytosiderophore released by plant roots was collected ten days after applying Zn treatments and measured using resin-Cu-mobilization test. A month after their transfer to nutrient solution, the plants were harvested and Fe and Zn concentrations in root and shoot were measured, and total amounts (uptake) of these nutrients were determined. Zinc addition increased concentration and total amount of Fe and Zn in shoot in Rushan genotype, while it had no significant effect on concentration and total amount of Zn in shoot and root of Kavir and Spring Back-Cross-Rushan genotypes. Addition of Zn to the nutrient solution decreased concentration and total amount of Fe in shoot of all wheat genotypes. On the other hand, Zn nutrition increased root Zn concentration in Rushan and Kavir genotypes, while it resulted in significant decrease of root Zn concentration in Back-Cross-Rushan genotype. Effect of Zn nutrition on the amount of phytosiderophore release by roots of wheat genotypes was different. Zinc nutrition resulted in an increase of phytosiderophore release by roots of Rushan, while it had no significant effect on phytosiderophore release in other wheat genotypes.

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In a pot experiment, the effect of soybeans, mung beans and beans on the corn and sunflowers in a cadmium contaminated soil was studied in a completely randomized design with three replications. The treatments consisted of intercropping of corn and mung bean corn and beans, corn and soybean, sunflower and mung bean, sunflower and beans, sunflower and soybean monoculture of corn, and monoculture of sunflower. There were significant effects of cocropping of companion crops on shoot dry weigh, the concentration of cadmium and zinc and the chlorophyll content of corn and sunflower. In this study the shoot weight of corn grown with bean and soybean and that of sunflower grown with bean plants was decreased as compared to the related monocultures. The concentration of cadmium was increased in the corn grown with soybean or mungbean and in sunflower grown with soybean. Co- cropping with bean plants had no significant effects on the concentration of cadmium in corn or sunflower. Among companion crops, the concentration of cadmium was higher in bean plants compared to those of soybean and mungbean plants. The chlorophyll content in the leaves of corn plants grown with mungbean was increased with an increase in cadmium concentration. However, this trend was not observed in other treatments. The results of this study show that co- cropping with either soybean or mungbean may increase cadmium uptake by corn and sunflower which in turn may increase the risk of inflowing of toxin cadmium into the food chain. However, further study needs to re-evaluate the effect of these companion crops on the distribution of cadmium in the edible parts of corn and sunflower.

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Phytoremediation is one of the best methods for cleaning heavy metal contaminated soils. In this method, tolerant plants with high absorption potential are used to clean up the pollutant. The purpose of this greenhouse study was to find the most suitable plants with the highest Zn translocation factor and shoot concentration. Soil samples were collected from zinc and lead Bama mine in Isfahan province, Iran. To compare the hytoextraction power, Heliantus annus.L., Thlaspi caerulescens, Trifolium pretense L. and Amaranthus retroflexus were planted in 8 kilogeram pots. The experiment was conducted in completely randomized design with three replications. After seventy days, plants root and shoot were harvested and Zn concentration was measured. The result showed that Thlaspi caerulescens had significantly higher root and shoot Zn concentration (3125 and 4041 mg kg-1, respectively). The highest bioaccumulation factor and translocation factor was observed in Thlaspi caerulescens. Based on this research, Thlaspi caerulescens was one of the suitable Zn hyper accumulators for cleaning up the Zn pollution.

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Organic fertilizers affect soil chemical and physical properties, particularly chemical forms of zinc in soil solid phase and thereby improve soil Zn availability. The present field study was aimed to evaluate the effects of organic and chemical fertilizer (zinc sulfate) on different zinc fractions in soil solid phase of rhizosphere in two successive years in Rudasht Research Field, Isfahan. Treatments consisted of sewage sludge (5 and 10 t ha-1), cow manure (5 and 10 t ha-1), and ZnSO4 (40 Kg ha-1). The control had no added Zn. Three weeks after applying fertilizer treatments, Back Cross genotype of wheat was cultivated in each plot. Our results showed that the organic fertilizers increased Zn concentration in exchangeable fraction (EXCH-Zn), the organically bound Zn form (ORG-Zn), and Zn bound to iron and manganese oxides (FeMnOX-Zn). However, the changes in Zn fractions were dependent on the fertilizer type. Positive and significant correlation between EXCH-Zn, ORG-Zn, and FeMnOX-Zn, and the total Zn uptake by wheat indicated that these pools of Zn in solid phase are labile pools with a significant role in supplying Zn for plants.

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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.

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In this work, the effect of raw and modified bentonite and zeolite with trivalent iron on the stabilization of water-soluble and adsorbed arsenic in a calcareous soil was studied. Raw and modified bentonite and zeolite were added to the soil in different weights in a completely randomized block design with three replications and kept to field capacity soil moisture content of 80% for 8 weeks. The concentrations of water-soluble and adsorbed arsenic, water-soluble and absorbed phosphorus in soil and soil pH were measured. Treatments significantly affected the mobility of arsenic and phosphorus in soil. Raw zeolite and bentonite in different levels increased arsenic mobility (about 107 to 325 % and 259 to 350% respectively). Despite the change in surface properties of zeolites modified with iron, this treatment at different levels increased arsenic mobility in soils by about 124 to 246%. Bentonite modified with iron had the greatest effect on reducing arsenic mobility in soil (about 91%). Phosphate mobility was similar to arsenic in different treatments.

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Zinc deficiency is the most widespread micronutrient disorder in the production of wheat (Triticum aestivum L.) and other cereal crops. An experiment was conducted in greenhouse, in 2013, using the sterile sand-perlite (2:1 v/v), to study the effects of two beneficial microorganisms on growth and nutritional status of wheat (Nicknejad cultivar). The study was arranged as factorial in a completely randomized design with three replications. The experimental factors consisted of Piriformospora indica (E0: Uninoculated E1: Inoculated), Pseudomonas putida (E0: Uninoculated E1: Inoculated) and Zinc (Zn0: 0 Zn1: 2µM ZnSO4 ). The results showed that inoculation by P. putida increased shoot dry weight at both levels of zinc, but this increase was observed for root dry weight only without zinc application. The iron concentration of shoot was decreased as a result of inoculation by P. putida at both levels of zinc. However, P. indica inoculation increased iron concentration in zinc application, but had no significant effect without zinc application. At both levels of zinc, the highest P, Zn, chlorophyll a and b concentrations were achieved by inoculation with P. indica. Inoculation by P. putida reduced P concentration at both levels of zinc but it reduced Zn, chlorophyll a and b concentrations only with zinc application. The results of this research showed that despite negative effect of P. putida on nutrient uptake, inoculation by P. putida and/or P. indica plays an important role in the promotion of wheat growth in zinc deficiency conditions.

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Arbuscular mycorrhizal fungi (AMF) are widespread endosymbionts in terrestrial ecosystems and their exudates have important effects on soil properties. A greenhouse experiment was conducted with six AMF treatments including four exotic species inoculums (Funneliformis mosseae ,Claroideoglomus claroideum  and Rhizophagus irregularis and a mixed isolate of three species), one mixed native AMF species treatment and a sterilized soil (control) with four salinity levels (1, 5, 10 and 15 dS m^-1). AMF increased the soil (EEG) and total (TG) extractable glomalin, and also the hot water (HWC) and diluted acid (DAC) extractable carbohydrates compared to control treatment in all salinity levels. The native AMF species had the greatest effects on EEG, TG, HWC and DAC at 10 and 15 dS m^-1. Soil EEG and TG concentrations were higher in the mixed exotic AMF treatment than in each AMF species. The greatest glomalin concentration was related to F. mosseae at 1, 5 and 15 dS m^-1 but at 10 dS m^-1 the greatest glomalin concentration was related to C. claroideum. The greatest carbohydrate concentration was related to F. mosseae at 1 and 5 dS m^-1 but at 15 dS m^-1 significant differences were observed among the three AMF species. Our results showed that there is an interaction between salinity and different AMF species, and a combination of them determines the function of AMF.

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This study was conducted to determine some mineral content concentrations in soils and plants of three elevation classes (1500, 2200 and 3000m) and two phenological stages of flowering and seedling in north facing slopes of Sabalan rangelands. Soil samples from the depth of 20cm and plant samples using 1×1m plots with 10 replications were collected. After sample preparation, the concentrations of minerals such as calcium, phosphorous, sodium, potassium, ion, copper, zinc and magnesium were determined using spectrophotometer and flame photometer. Data was analyzed by SAS9.1 software using a Completely Randomized Design with a Generalized Linear Model procedure. Results showed that elevation had a significant effect on Ca, Fe, Cu, Zn and Mn of soil and P, Na, K, Mg and Mn of plants in the study areas (P&le0.05). Growing stages had a significant effect on all elements of plants except Ca (P&le0.05). Moreover, results showed that in three elevation classes the high demand minerals' concentrations were higher at the starting seedling stage in comparison with the flowering stage. In contrast, the low demand minerals' concentrations in three elevation sites were higher in the flowering stage in comparison with seedling stage. Interaction effect of elevation and growing stage was also significant in relation to all elements except Ca (P&le0.05).

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In order to assess the status of the iron (Fe) chlorosis of plane trees in green space of Isfahan city, the chlorosis intensity of 73 trees in different regions was recorded as (1): low (less than 5% of leaves), (2): moderate (less than 50% of leaves), (3): severe (more than 50% of leaves), and (4): very severe (more than 95% of leaves). The whole leaf (with petiole) samples were taken from the top and bottom of each tree, separately, during 2008 and 2009. Then selected chemical properties of the leaves were analyzed.  The results showed that in more than 95 and 71% of the young leaves, Fe concentration was less than the critical deficiency level (202 mg/kg). Concentration of Fe in the older leaves of all plane trees even those with slight symptoms of chlorosis was less than the critical level (382 mg/kg). No significant relationship was found between the leaf zinc concentrations and intensity of iron chlorosis. In more than 92 (in the first year) and 87% (in the second year) of the plane trees, Zn concentration of young leaves and in all trees, Zn concentration of old leaves were less than the critical deficiency concentration (23 mg/Kg). The comparison between concentrations of Cu in the leaves with its critical deficiency level showed that more than 90% of young and old leaves accumulated toxic levels of Cu in both sampling years. In regard with the sufficient range of P, about 79% of the trees in the first year and 53% in the second year accumulated excess levels of this nutrient in their young leaves. This condition was slightly modified for the older leaves so that excessive concentration of phosphorus in mature leaves was not observed in the first year and in the second year, only about 29% of the samples had concentrations higher than critical levels. 

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