جستجوی مقالات مرتبط با کلیدواژه « آلودگی خاک » در نشریات گروه « زراعت »

Heavy metal contamination in soil refers to the excessive accumulation of elements called heavy metals, which are capable of causing significant levels of biological toxicity. These metals, in concentrations higher than of tolerable threshold of plants, often cause metabolic disorders, inhibition of growth and physiological process and eventually lead to death of plants. Lead (Pb) and zinc (Zn), as the two common coexisting mineral heavy metals around the world, accumulate in the soil due to mining activity and can adversely affect the crop productivity, the agro-ecosystem components and ultimately the human and environmental health. Biochar, as a potent soil amendment agent, is often obtained by pyrolysis of agricultural organic wastes such as crop residues under low oxygen pressure condition. Trichoderma harzianum, as a plant growth promoter, has capability in stimulating plant growth under varying environmental stresses and therefore, inoculation of plant roots with this fungus could be a conceivable approach to cope with the heavy metal stress. Hairy vetch (Vicia villosa Roth) is a winter annual forage species that shows better growth performance than the other forage legumes such as alfalfa or clover under the severe environmental conditions, especially winter frost and drought.phosphorus supplementation and their interactions on the growth, physiology and P, Pb and Zn uptake by hairy vetch in heavy metal-polluted soil.

The experiment was carried out in the greenhouse of Faculty of Agriculture and Natural Resources of Mohaghegh Ardabili University as a factorial experiment based on a completely randomized design (CRD) in three replications. Heavy metal contaminated soil was collected from wheat fields around Angouran village (Angouran Rural District, Angouran District, Mahneshan County, Zanjan Province, Iran), downstream of the Zanjan's lead and zinc processing plant (Calcimin® Co.; 36°34'13.2"N 47°37'21.4"E), from a depth of about 0 to 25 cm. Two levels of biochar application (non-biochar control, 5% peanut hull-derived biochar), two levels of Trichoderma inoculation (non-inoculation control and inoculation with conidial suspension) and three levels of P supplementation (0P, non-supplementation; 11P, 11 mg P.kg-1 and 22P, 22 mg P.kg-1) were applied as the three experimental factors. The feedstock of peanut hull (PH) used in the present experiment were purchased from the local market. After thorough washing, PHs were air-dried and then well ground with a lab-scale mill and sieved using a 100 mesh sieve size. T. harzianum Rifai - T22 isolate acquired from the Laboratory of Plant Pathology, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili was revived on PDA (potato dextrose agar) medium and further incubated for at least one week at 28 °C. This experiment was conducted in an open-air vegetation yard with mean day/night temperatures of 25/17 °C, respectively. The experiment lasted for 50 days, in the period from May 16, 2020 (sowing the seeds) until July 5, 2020 (final sampling). In each plastic pot (25 cm in diameter × 20 cm in height), pre-filled with the pot mixture according to the treatments, 20 surface-sterilized hairy vetch (Vicia villosa Roth., Local landrace from Ardabil, Iran) seeds were sown and irrigated with tap water (EC = 0.21 dS m-1 and pH = 7.2) to 100% field capacity. Throughout the experiment, all the pots were re-irrigated when the soil water content dropped to 70% of the field capacity.

Application of biochar and Trichoderma fungus at not using phosphorus (P0), resulted in higher aerial biomass. Trichoderma fungus alone or with P11 level had a better result in increasing plant height. The concentration of chlorophyll a was in highest level by biochar combined Trichoderma, and P0 phosphorus applied, as well as the application of Trichoderma caused the highest concentration of chlorophyll b. The changes in relative leaf water content ranged from 85.5 to 90.5% among the treatment combinations. Phosphorus consumption at the maximum level (P22) showed the same effect in improving leaf protein compared to the P0 level. Moderate phosphorus consumption (P11) combined with biochar and Trichoderma caused the highest soluble sugar content. The highest proline content of leaves was obtained by using Trichoderma without applying biochar and phosphorus. The use of biochar alone or with Trichoderma could improve the amount of phosphorus absorption as much as the use of phosphorus fertilizer alone. Combined application of biochar and Trichoderma fungus with P11 and P22 fertilizer levels increased phosphorus absorption by 41.6% and 22.3% respectively compared to P0 level. Trichoderma fungus had no significant effect on the amount of Pb and Zn absorption in the aerial parts, but biochar significantly reduced their absorption in the aerial parts of Hairy vetch plants.

Based on the results, the application of biochar alone or in combination with Trichoderma fungus improved the vegetative traits and physiological characteristics, including increasing the concentration of photosynthetic pigments, the relative content of leaf water and soluble sugar, the content of protein and proline in the cluster flower vetch. Phosphorus absorption increased significantly when using biochar and Trichoderma. It seems that biochar helps to increase photosynthesis by creating suitable conditions in soil porosity, humidity, increasing cation exchange capacity and reducing the concentration of heavy elements, with better absorption of elements and thus improving plant growth and development. Trichoderma fungus with biological control increases the availability of elements including phosphorus by increasing the transfer of sugar and amino acids and creating induction resistance and stimulating the growth of beneficial microorganisms, and by making changes in the physiological characteristics, it increases the resistance of the plant against the stress of heavy elements.

Heavy metal pollution is one of the most important global causes of soil pollution. Metallic contaminants, even in low concentrations, are carcinogenic due to their non-degradable nature and their physiological effects on living organisms and humans. Seed germination is one of the most important stages in the life cycle plants that respons to environmental factors such as biotic and abiotic stresses. The objective of this experiment was to assess the germination characteristics, biochemical traits and expression of antioxidant genes in bread wheat genotypes at seedling stage under mercury metal stress. The experiment was conducted in split plots based on completely randomized design with three replications in which mercury stress in four levels (including no-application as control and application of 5, 10 and 15 μM mercury chloride) and wheat genotypes in three levels (including Gonbad, Morvarid and N9108 genotypes) were considered as main- and sub-factors, respectively. The results showed that with increasing mercury chloride stress, germination indices as well as morphological and biochemical traits in all three wheat genotypes had a decreasing trend and this decrease in different genotypes was significantly different. Line N9108 had better conditions under mercury metal stress in terms of all measured traits. The expression of superoxide dismutase and peroxidase genes in line N9108 was also higher than the other genotypes, which can indicate the superiority of this line than the other two wheat genotypes under mercury chloride stress conditions.

Increasing the concentration of different heavy metals, such as lead, copper, cadmium in water, soil and air can pose negative effects on the entire ecosystem and cause harmful health consequences for all forms of life. The major sources of the pollution are chemical fertilizers and pesticides. In order to investigate the contamination of heavy metals such as lead, chromium and cadmium in soil and areal part of saffron plant in Ferdows farms, a completely randomized design was used in autumn 2016. Firstly, the sampling of soil and plants from 4 different stations was done (1-farms nearby residential areas 2-farms in residential areas 3-farms near the road 4-farms without specific use) with 3 replications, it should be noted that from each station 5 subsamples were taken and then mixed. Soil sampling was done at 0-30 and 30-60 cm depths, and the sampling of the plant was randomly taken from three parts of petals, flags and brunette. A total of 24 soil samples and 36 samples from different parts of the saffron plant were transferred to the laboratory. After preparation of the samples, acid digestion was performed for measured by the atomic absorption system. The results showed that the highest mean of the heavy metals concentration in the soil was for chromium (80.64 ± 8.03mg/kg), lead (42.36 ± 3.19mg/kg) and then cadmium (0.9±0.14mg/kg). The significant difference between the different parts of the saffron plant for chromium and copper (Pvalue >0.05) were not observed, however, there was a significant difference for cadmium at 5% level that the highest concentration was for flag 1.08 mg/kg. The highest levels of chromium, lead and the roads observed cadmium in the out of residential areas and the lowest amount of chromium, lead and cadmium were observed by the roads.

The use of phosphate fertilizers in tobacco cultivation is an important step in increasing yield. Since Triple Super Phosphate (TSP) fertilizer has a low amount of cadmium(Cd), phosphorus of fertilizer and salinity of irrigation and soil have interaction effect on the mobility and absorption of this element, therefore the exact determination of the absorbed Cd by the tobacco plant is crucial due to the use of TSP Fertilizer and different irrigation salinity stresses on the fate of absorbed Cd by tobacco and its smoke. Tobacco resistance to the salinity of sodium chloride was under 50 mM, and the salinity of 50 mM and more, reduced the photosynthesis and yield of the tobacco plant.

This study was carried out to investigate the interaction of three factors of TSP, irrigation water salinity, and soil Cd contamination on the Cd in the plant and qualitative characteristics of tobacco in Bardaskan city, 2016 and in the greenhouse condition. Irrigation salinity was at 3 levels of 0, 20 and 40 mM of NaCl, TSP was at two levels of 0 and 1.5 g.kg-1 and soil Cd contamination were at two levels of 0 and 12 mg. kg-1 soil in a factorial arrangement in a completely randomized design experiment. Data were analyzed by SAS statistical software and Tukey test was used to compare the means.

The results of this study showed that the use of TSP in Cd-contaminated soils at 0, 20 and 40 mM salinity levels, increased shoot Cd concentration of the tobacco plant by 3.43, 4.94 and 33.3, 4 times of root Cd concentration and by increasing the salinity, the concentration of Cd in both root and aerial parts of the plant increased. With the increase in salinity from zero to 20 mM, the concentration of Cd in the smoke of cultivated tobacco in contaminated soil with Cd increased by 65% compared to zero salinity. Increasing salinity from zero to 40 mM, increasing the concentration of Cd in smoke Tobacco reached 83.2%. The application of TSP at all salinity levels showed an increase in the dry matter and root growth, concentration and amount of root and shoot Cd.

In 40 mM irrigation water, TSP caused the highest shoot Cd concentration in tobacco plant compared to the control, and the combined effects of both salinity and TSP factors were more than each of them separately. In all three levels of irrigation salinity, RF, TF and EF increased in the presence of TSP. The highest RF amount was observed with 1.71% in Cd-contaminated soil without TSP and in salinity of 20 mM irrigation water. As the salinity levels increased, EF increased, but the RF increased to 20 mM, and then the decrease was observed. With increasing salinity of irrigation water from 0 to 20 mM NaCl, Cd content of plants grown in Cd-contaminated soils increased by 33.7%, but this increase for 40 mM was 26.31%. With increasing sodium chloride irrigation up to 20 mM, Cd content of the tobacco plant increased. The application of TSP in high salinity of irrigated water and Cd-contaminated soils caused more Cd absorption by tobacco plants, so in which soil and water conditions, fertilization should be restricted.

In recent years a major part of agricultural lands has been contaminated with heavy metals as a result of industrial activities, ore mining, smelting, irrigation with sewage and fertilization which has reduced soil quality and plant products health. This study was conducted to investigate some plant responses of two bean cultivars (Khomein and the G01437) to cadmium and lead in a calcareous soil under greenhouse conditions. In a factorial experiment based on completely randomized design, cadmium in the form of cadmium nitrate four levels of zero, 20, 40 and 80 mg/ kg soil and lead as lead nitrate in zero, 50, 100 and 200 mg/ kg levels were added to pots. Then seeds of the two mentioned bean cultivars were planted. Plants dry weight, concentration and uptake amounts of cadmium and lead in shoots and roots were determined after harvesting. Analysis of variance showed that main and interaction effects of cadmium and lead were significant on dry weight of roots and shoots (p<0.01). The effects of treatments on the uptake responses, however, were varied. Plant cultivars had a significant effect on cadmium and lead uptake in shoots and roots. Shoots cadmium uptake in Khomein cultivar was greater than G01437, while Cadmium uptake in the roots was greater in G01437 than in Khomein. The greatest uptake of cadmium in the shoots was observed in the zero lead + 80 cadmium treatment in Khomein (9.40 micro g per pot) and its lowest amount was obtained from 50 lead + zero cadmium treatment in G01437 (1.27 micro g per pot). Translocation factor (TF) of cadmium and lead and BRS index was decreased by increasing the cadmium and lead concentrations in soil.

Investigating and identifying soil contaminants soil are essential. A wide range of techniques are available for the removal of metal ions from polluted environments. Each of them has advantages and disadvantages based on simplicity, flexibility, efficiency of processes, cost, technical and maintenance problems. Therefore, easy, effective, economical and environmentally friendly techniques for treatments are needed. Use of organic absorbents is one of the newest and most appropriate cost techniques. In this study, soil was treated with citrus peel as low cost organic immobilizers in order to investigate the time effect on decreasing mobility of Ni and Zn. The soil was artificially contaminated with Ni and Zn in separate containers. Both elements were incorporated at a dose of 600 mg l-1 and then citrus peel was added to soils at the rate of 5%. Sampling of treatments was in 1h, 1, 3, 7, 14, 21, 28 days of incubation. The experiment was done with 2 treatments including polluted soil samples with and without citrus peel as control in completely randomized design. Statistical analysis done using the SAS software (version 9.1) and Duncan test was performed at 5% level. Results indicated that at the first time of incubation, the pH of soils decreased due to the presence of citrus peel and increased the availability of metals. But the prolonged incubation time led to increasing metal adsorption onto organic adsorbent surfaces and decreasing the metal concentration in exchangeable fraction. Mean Zn concentrations in the control soil and soil treated with citrus peel, were 107.8 and 98.3 mg kg-1 and mean Ni concentrations were 144.5 and 134.4 mg kg,-1 respectively. Differences in control and the citrus peel treatment for both elements were significant.

Heavy metal pollution in soil and environment can be reduced by their immobilization. The effects of chemical amendments as zeolite with three levels, 0 (Z1), 5% (Z2) and 10% (Z3) and triple super phosphate with three levels, 0 (P1), 0.25% (P2) and 0.5% (P3) on mine wastes collected and uptake of Pb and Zn by plant and wheat growth were determined. The mine waste was from Bama mine around Esfahan with very high total concentration of Pb (2300 mg kg-1) and Zn (16500 mg kg-1). Dry weight and concentrations of Pb and Zn by wheat in amended soils were studied under greenhouse conditions. Result showed that the application of amendments zeolite and phosphorous decreased Pb concentration in above ground plant biomass and Pb concentration was increased in wheat root. The interaction effect of zeolite and phosphorous on Pb concentration in above ground plant biomass and root was not significant. But in case of Zn element, only phosphorous amendment resulted in concentration reduction in above ground plant biomass and increased concentration in wheat root. The interaction effect of zeolite and phosphorous on Zn concentration reduction of above ground plant biomass and increase in Zn concentration of root were not significant. Moreover, wheat growth in the treated mine waste was superior to its growth in untreated mine waste. Zeolite did not show any effect on wheat growth. However, the interaction effects of zeolite and phosphorous on increasing of wheat above ground and root dry weight were significant.