JWSS - Journal of Water and Soil Science

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During 1998-99, a field experiment was conducted to investigate the effects of residual Processed Municipal Waste Leachate (PMWL) on growth and yield of wheat (variety Roshan). The treatments consisted of residual amounts of 0, 150, 300 and 600 t/ha of PMWL and a residual N, P, K, and Zn fertilizer treatment in a randomized block design with 3 replications. In 1998, rice seedlings were transferred to 34 m plots. After harvesting the rice, wheat was seeded in the same plots without any new treatment. Processed municipal waste leachate and fertilizers were applied during the rice growth. Residual effects of PMWL increased the amounts of available macro- (N, P and K) and micronutrients (Fe, Cu, Zn and Mn) in soil which, in turn, promoted the grain and straw yield of wheat compared to the control. Straw and grain yield increased from 1.67 and 3.50 t/ha in control to 3.93 and 12.80 t/ha in 600 t/ha of PMWL, respectively. The residual effects of PMWL had no significant effect on heavy metals concentrations in plant. The effects of residual PMWL in the soil were proportional to the amount of leachate applied. However, more investigations are recommended to fully understand heavy metals effects on soil, plant, and environment.

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A factorial experiment with two levels of Zn (0 and 1.5 mg Zn kg^-1), five salinity levels of irrigation water (0, 60, 120 and 180 mM NaC1, and 120 mM NaNO₃) in three replications was conducted. Wheat (Triticum aestivum cv. Roshan) was seeded in pots. After plant harvesting, zinc and cadmium concentrations were determined in the shoot. Activities of metal species in the soil solution were predicted using the computer program MINTEQA2. Treating the soil with NaC1-salinized water increased total concentration of cadmium (Cd_T) as well as Cd²⁺, CdC1⁰₂, and CdCl⁺ species whereas, NaNO₃ treatment had no significant effect on Cd_T. Shoot Cd concentrations were positively related to Cd_T and soil solution Cl^- but negatively related to Zn_T. Application of Zn-fertilizer decreased Cd and increased Zn concentrations in shoot, significantly. The results of this experiment showed that Cl^- has an effective role in increasing mobility of soil Cd and its uptake by plant.

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The management and application of organic wastes in agricultural lands decreases environmental risks and increases utilization of these matters. The objective of this research was to investigate and compare the effect of polyacryl factory sewage sludge (PSS), municipal compost (MC) and cow manure (CM) on soil properties and on yield and growth of maize (single cross 704, Zea mays L.). The treatments were control (without any organic waste) and application of PSS, MC, and CM at two rates (15 and 45 t ha-1). This research was done in the research farm of Isfahan University of Technology (Lavark-Najafabad). The experimental design was a randomized, complete block with three replications. Treatments were incorporated into the soil before the maize planting (on 23 June 2008) and soil sampling was performed after 132 days (Simultaneously with maize harvesting). Application of the organic wastes resulted in significant increase soil organic matter (SOM), total nitrogen (TN) and saturated hydraulic conductivity (Ks) and significantly decreased bulk density. However, saturated hydraulic conductivity was decreased by application of PSS. Application of 15 and 45 t ha-1 of PSS reduced Ks more than 14% and 42%, respectively, compared with control however, the reduction was significant only in the plots which received 45 t ha-1 of PSS compared with control. The results of plant yield and growth showed that leaf area index (LAI), plant length, biological yield, 1000 seed weight and seed yield increase due to the application of organic wastes.

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Micronutrients such as Fe and Zn in adequate level are essential for plant growth cycle and impose a vital role in increasing yields of most agricultural crops. Using organic wastes such as sewage sludge, compost and manure is a proper practice for returning organic matter and some nutrients into the soil, particularly in arid and semi-arid regions. The objective of this study was to determine the effects of sewage sludge, compost and cow manure on availability of Fe and Zn in soil and their uptakes by corn, alfalfa and targetes flower. A completely randomized design with three treatments (sewage sludge, compost and cow manure at 25 Mg/ha) was used. Application of sewage sludge, compost and cow manure significantly increased availabile Fe and Zn of the soil. The application of organic wastes increased the dry matter yield of the plants. Fe and Zn concentration of plants shoots in organic amendments treatments were significantly greater than blank. The highest mean concentration of Fe in plant tissues was obtained in the cow manure and the highest mean concentration of Zn in plant tissues was obtained in the compost treatment.

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The petroleum refinery sludge is an important source of environmental pollution. Burning and burying of the sludge may have adverse effects on environment and human health. Thus, other mechanisms for decreasing the toxic effects of hydrocarbon substances in the sludge must be used. In this study, Isfahan refinery sludge was dewatered, air dried and mixed by 0, 10, 20, 30 and 40% w/w ratio with two calcareous soils, viz., Mahmoud Abad (Typic Haplocalcids with clay texture) and Bagh Parandegan (Anthropic Torrifluvents with silty loam texture). Different mixtures of soil and sludge were farmed for 21 days and irrigated on a daily basis to field capacity. Then, 100 seeds of Tallfescue (Festuca arundinacea) and Agropyron were planted in polluted soils with 3 replicates in 3 kg pots for 5 months. Result showed that Tallfescue and Agropyron yields decreased in sludge contaminated treatments. In the 40% sludge treatment, Tallfescue decreased the total petroleum hydrocarbons content by 65 percent. The highest degradation for agropyron was in the 30% sludge treatment which showed about 55% reduction in total petroleum hydrocarbons. The 40% sludge treatment resulted in the minimum yields of root and shoot plants. The highest degradation of TPHs occurred in the Tallfescue rhizospher of 40% sludge. Maximum degradation of TPHs on the Agropyron rhizospher was in 30% sludge mixed with Bage parandegan soil, but maximum yield of plant was in 20% sludge. Our study shows that Tallfescue rhizospher is most effective for decreasing TPHs, and that the phytoremediation in soils with more clay can adsorb and fix the toxic components and then at higher levels of pollutions can let the plants grow.

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This study was conducted in Rudasht Research Farm Isfahan, to evaluate tolerance to iron (Fe) deficiency of 30 spring wheat genotype, using split plots in a randomized complete block design with three replications. Main plot consisted of two Fe levels (0 and 20 kg Fe ha-1 applied as FeEDDHA at planting and beginning of vegetative growth). Grain yield increased by 14% following the application of 20 kg Fe ha-1 as FeEDDHA. Application of Fe significantly increased grain yield of all wheat genotypes except for Rushan. The result indicated that Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Tolerance Index (STI) were the most suitable indices for identifying and selecting Fe-deficiency tolerant wheat genotypes. By using both treatments with and without added Fe, grain yield showed significant (P < 0.01) positive correlation with MP, GMP and STI. The STI could divide the studied wheat genotypes in different groups based on both their response to fertilization and grain yield potential. Therefore, the STI was the best index to identify Fe deficiency tolerant genotypes. Based on the three indices, Ghods and Falat genotypes were the most tolerant and sensitive genotypes to Fe deficiency, respectively

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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.