Showing 7 results for Fractionation
Majid Hejazi Mehrizi, Hossein Shariatmadari, Majid ََafyuni,
Volume 17, Issue 64 (9-2013)
Abstract
Application of sewage sludge has been considered as an organic fertilizer in arid and semi-arid regions of Iran. This study was conducted to investigate cumulative and residual effects of sewage sludge on soil inorganic fractions and their relation to phosphorus (P) availability. Two levels of application (50 and 100 Mg ha-1) and three consecutive times of sewage sludge application (1, 3 and 5 years) with a control treatment were studied in a randomized complete block split plot design with three replications. Composite soil samples were collected from 0-30 depth at the end of 5th year of application. Increasing the rate and application year of sewage sludge enhanced dicalcium phosphate (Ca2-P), octacalcium phosphate (Ca8-P), apatite (Ca10-P), aluminum phosphate (Al-P), iron phosphate (Fe-P) and available P but decreased occluded P (OC-P). Residual effect of sewage sludge application resulted in increased inorganic fractions in blocks treated for 1 year compared to control. Positive correlations were observed between inorganic P fractions and Olsen P, wheat yield and P uptake (except OC-P). We concluded that inorganic P fractions and P availability increased in sewage sludge amended soil.
H. Motaghian, A. Hosseinpur, F. Raiesi, J. Mohammadi,
Volume 17, Issue 65 (12-2013)
Abstract
Studying the distribution of Zn in the soils allows investigating their mobility and bioavailability. In this research, 10 calcareous soil samples were selected, and sewage sludge-amended (1% w/w) and -unamended (control) soils were incubated for 1 month. Before planting, fractions of Zn were determined, three seeds of wheat were planted in each pot and after 8 weeks, they were harvested. Results showed that all Zn fractions were increased by sewage sludge addition. Results of pot experiment indicated a significant correlation between Zn concentration in wheat with exchangeable (r=0.92**) and Zn associated with Fe and Mn oxides (r=0.76*) in control soils. In addition, significant correlation coefficient was found between Zn associated with Fe and Mn oxides and Zn uptake index (r=0.86**). Moreover, wheat responses were significantly correlated with Zn exchangeable (r=0.71*- 0.84**) in amended soils. Yield was correlated with Zn associated with carbonates and Zn associated with Fe and Mn 0.69 and 0.75, respectively. Zn uptake index was correlated with Zn associated carbonates (r=0.64*). Therefore, the exchangeable and Zn associated with Fe and Mn oxides in control soils and the exchangeable and Zn associated carbonates and Zn associated with Fe and Mn oxides in amended soils could be used as available fractions of wheat.
H. Mahmoudzadeh, M. Sheklabadi, A. A. Mahboubi,
Volume 18, Issue 68 (9-2014)
Abstract
Organic carbon pools and carbon lability directly affect soil biological, physical and chemical characteristics. Besides, capacity of self-organization of soil is related to the organic carbon pools. Sand size fraction (> 50 µm) organic matter is more labile than silt+clay size fraction organic matter. Assessment of this organic carbon variation can be a suitable index to determine soil quality. The aim of present study was to evaluate the impact of land use change on particle size fractions of organic carbon and carbon pool index. In September 2010, soil samples were collected from the three major land use types including wetlands around the lake, wetlands converted to wheat, and alfalfa cultivations. Soil samples were collected from the 0-30, 30-60 and 60-90-cm depths in each of land use. According to the results of particle size fractionation of organic carbon in 0-30-cm layer, the highest and lowest amounts of sand size fraction organic carbon were obtained in wetland (67.01 g.C.kg-1soil) and wheat land use (24.57 g.C.kg-1soil), respectively. Land use change from wetland to alfalfa and wheat caused a decrease of silt+clay size fraction organic carbon in 0-30-cm by 48.39 and 45.14 t.C.h-1, respectively. In the 30-60-cm layer of cultivated land, soil organic carbon storage in silt+clay size particle was more than sand size fraction organic carbon. Results showed that carbon pool index in alfalfa, and wheat land was decreased by 50 and 60% compared to wetland, respectively. And carbon management index in alfalfa and wheat was declined by 44.90% and 66.70%, respectively.
M. Norouzi, A. H. Khoshgoftarmanesh, M. Afyuni,
Volume 18, Issue 70 (3-2015)
Abstract
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.
Gh. Rahimi, F. Noroozi Goldareh,
Volume 24, Issue 4 (2-2021)
Abstract
Earthworms are soil organisms commonly used in environmental studies and biological toxicology. Therefore, the present study aimed to investigate the role of Eisenia Fetida earthworms on the bioavailability of zinc and copper in the contaminated soils. This study was carried out on a contaminated soil sampled from the Ahangaran mine 26 kilometers far from the city of Malair and its surrounding areas. In this experiment, 12 earthworms with the average weight of 0.3 -0.6 g were selected for each soil sample. The worms were exposed to a metal contaminated soil for 42 days. After the test time, Zinc (Zn) and Cupper (Cu) concentrations were measured in different fractions of the soil. The results showed that cow manure, carrot pulp and vermicompost significantly reduced (at the level of 5%) 62.2, 80 and 65.2 mg / kg of the metal zinc concentration in carbonate, respectively, as compared to the treatment control. Earthworms significantly increased zinc (81.45 mg kg) in the carbonate fraction. On the other hand, there was a significant increase in the amount of exchangeable copper with the addition of organic fertilizer to worm, as compared to the control sample. This increase was significant (at the level of 1%) in the treatment of Vermicompost (1.27 mg / kg) and carrot pulp (1.32 mg / kg), as compared to control.
S. F. Hashemi, R. Zalaghi, N. Enayatizamir,
Volume 26, Issue 1 (5-2022)
Abstract
This study investigated the effect of the inoculation of the soil with some phosphorus solubilizing microorganisms (PSM) on inorganic P fractions in sandy soil enriched with inorganic and organic amendments. A factorial experiment arrangement was performed in a completely randomized design with three replications, using two factors: microorganisms (control, Entrobacter cloacae, Brevundimonas, and piriformospora indica) and amendments (control, (5%) apatite, (5%) apatite + (3%) zeolite, (5%) apatite + (1%) molasses). A 60-days incubation was performed after the application of treatments. Inorganic P fractionation and alkaline phosphatase activity of soil were measured at the end of the experiment. Phosphorus distribution in soil was as follow: octacalcium phosphate > apatite P > dicalcium phosphate > Olsen p > aluminium phosphate > iron phosphate. The application of apatite increased all of the P mineral fractions. The application of zeolite-appatie was very effective and although did not increase Olsen P (probably because of the low cation exchange capacity of soil), had a significant effect (p<0.05) on other P forms and caused dicalcium phosphate to increase (69.2%) and apatite P and octaclcium phosphate to decrease (34.8% and 60.0%, respectively) compared to apatite application. Application of molasses resulted in significant increases in dicalcium phosphate and octacalcium phosphate (48.9% and 29.3%, respectively) and decreases in apatite P and Olsen P (62.1% and 63.9%, respectively). Microbial inoculation resulted in a significant increase in Olsen P and dicalcium phosphate and a decrease in octacalcium phosphate and apatite P; showing the ability of these organisms to increase the phosphorus availability. Entrobacter and Piriformospora indica were more effective than Brevundimonas. It seems that microorganisms in different substrates had used different mechanisms; such that in apatite and apatite-molasses treatments microbial inoculation resulted in an increase in alkaline phosphatase activity, but in zeolite-apatite treatment, pH had decreased indicating the organic acid production by microorganisms.
F. Khafi, A.r. Hossienpour, H. Motaghian,
Volume 26, Issue 2 (9-2022)
Abstract
One of the significant factors affecting biochar properties is the pyrolysis temperature. This study aimed to investigate the effect of pyrolysis temperature on the properties and fractionation of Zn and Pb in biochars produced by sewage sludge. Biochars were prepared at temperatures of 300 to 700 °C and the physicochemical properties, availability, and fractionation of Zn and Pb were investigated. The results showed that pH, pHzpc, percentage of calcium carbonate, cation exchange capacity, specific surface area, and porosity in biochars were higher than in the feedstock. By increasing biochar production temperature, the mentioned properties increased. FT-IR revealed that the OH functional group is present in free form, either in the structure of C-OH and -COOH and aliphatic-CH2 groups in the sewage sludge. By converting sewage sludge to biochar, the intensity of these peaks decreased. In contrast, peaks representing complex aromatic structures appeared. The availability of Zn and Pb in biochar was reduced as compared to sewage sludge. The results of fractionation indicated that sewage sludge has bio-availability and toxicity of Pb and Zn. the amount of oxide and residual fractions of these two metals increased by converting sewage sludge to biochar at different temperatures. Therefore, it seems that biochar production from sewage sludge reduces the toxicity and bio-availability of Zn and Pb. Also, by incrementing the temperature of production, the bio-availability potential (bonding with organic matter), and non-toxicity (residual) of these metals increased.
