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Mineralization of Nitrogen in Hydromorphic Soils Amended with Organic Wastes
CMA Iwegbue, FN Emuh, AO Bazunnu, O Eguavoen
Journal of Applied Sciences and Environmental Management , 2011,
Abstract: This paper present the results of nitrogen mineralization in hydromorphic (wetland) soils of the Niger Delta amended with organic wastes. The organic wastes amended soil generally showed a decrease in total inorganic (NO3-N+NH3-N) released within first 14 days, which increased thereafter. The nitrogen mineralized during 58 day of incubation ranged from 82.15 mg kg-1 to 281.60 mg kg-1 for fadamal soil, 54.50 mg kg-1 to 197.30 mg kg-1 for meander belt soil and 98.50 mg kg-1 to 320.00 mg kg-1 for Mangrove soil (mangal acid sulphate soils). The order of cumulative nitrogen released in the waste amended soil followed the order: sewage sludge>kitchen waste> poultry manure> oil palm waste> cow manure. Total mineralized N indicated negative correlation with total organic N and C:N ratio
Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation  [PDF]
Raymond A. Wuana,Felix E. Okieimen
ISRN Ecology , 2011, DOI: 10.5402/2011/402647
Abstract: Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern. 1. Introduction Soils may become contaminated by the accumulation of heavy metals and metalloids through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition [1, 2]. Heavy metals constitute an ill-defined group of inorganic chemical hazards, and those most commonly found at contaminated sites are lead (Pb), chromium (Cr), arsenic (As), zinc (Zn), cadmium (Cd), copper (Cu), mercury (Hg), and nickel (Ni) [3]. Soils are the major sink for heavy metals released into the environment by aforementioned anthropogenic activities and unlike organic contaminants which are oxidized to carbon (IV) oxide by microbial action, most metals do not undergo microbial or chemical degradation [4], and their total concentration in soils persists for a long time after their introduction [5]. Changes in their chemical forms (speciation) and bioavailability are, however, possible. The presence of toxic metals in soil can severely inhibit the biodegradation of organic contaminants [6]. Heavy metal contamination of soil may pose risks and hazards to humans and the ecosystem through: direct ingestion or contact with contaminated soil, the food chain (soil-plant-human or soil-plant-animal-human), drinking of contaminated ground water, reduction in food quality (safety and marketability) via phytotoxicity, reduction in land usability for agricultural production causing food insecurity, and land tenure problems [7–9]. The adequate protection and restoration of soil ecosystems contaminated by heavy metals require their characterization and remediation.
Plant Response to Salmon Wastes and Sewage Sludge Used as Organic Fertilizer on Two Degraded Soils Under Greenhouse Conditions
Celis,José; Sandoval,Marco; Barra,Ricardo;
Chilean journal of agricultural research , 2008, DOI: 10.4067/S0718-58392008000300007
Abstract: the potential toxicity of urban sewage and farmed salmon sludge, as well as their fertilizer potential, was evaluated by a battery of tests carried out with lettuce (lactuca sativa l.) and annual ryegrass (lolium multiflorum lam.) cv. winter star. wastes were evaluated in a patagonian soil (andic cryofluvent) and a granitic soil (ultic palexeralf). the treatments were municipal sewage sludge (mss), salmon ground-farming waste (psw) and salmon lake-farming waste (lsw) at different rates: 25, 50, 75, 100 and 150 t ha-1. bioassays in lettuce were conducted for germination index (gi), radicle and hypocotyl structure length. test in ryegrass were conducted for aboveground biomass yield. the phytotoxicological results from patagonian soil showed significant differences (p ≤ 0.05) among sludge, where the highest values for gi, radicle and hypocotyl length were for lsw, followed by psw. results from granitic soil showed no significant differences among sludge added. in both soils, mss treatment at application rate of 150 t ha-1 presented the smallest radicle length, not showing development of the hypocotyl structure. biomass data indicated that mss, psw and lsw sludge can be applied at 25 to 150 t ha-1 on patagonian soil and only lsw sludge on granitic soil. however, its addition should be complemented with n and k inorganic fertilizer to increase pasture yield. mss and psw sludge applied at 150 t ha-1 was clearly detrimental for crop yield, especially when applied to granitic soil.
Predicting Mineral N Release during Decomposition of Organic Wastes in Soil by Use of the SOILN_NO Model  [PDF]
Trine A. Sogn,Lars Egil Haugen
Applied and Environmental Soil Science , 2011, DOI: 10.1155/2011/161079
Abstract: In order to predict the mineral N release associated with the use of organic waste as fertilizer in agricultural plant production, the adequacy of the SOILN_NO model has been evaluated. The original thought was that the model calibrated to data from simple incubation experiments could predict the mineral N release from organic waste products used as N fertilizer on agricultural land. First, the model was calibrated to mineral N data achieved in a laboratory experiment where different organic wastes were added to soil and incubated at 15°C for 8 weeks. Secondly, the calibrated model was tested by use of NO3?? leaching data from soil columns with barley growing in 4 different soil types, added organic waste and exposed to natural climatic conditions during three growing seasons. The SOILN_NO model reproduced relatively well the NO3?? leaching from some of the soils included in the outdoor experiment, but failed to reproduce others. Use of the calibrated model often induced underestimation of the observed NO3?? leaching. To achieve a satisfactory simulation of the NO3?? leaching, recalibration of the model had to be carried out. Thus, SOILN_NO calibrated to data from simple incubation experiments in the laboratory could not directly be used as a tool to predict the N-leaching following organic waste application in more natural agronomic plant production systems. The results emphasised the need for site- and system-specific data for model calibration before using a model for predictive purposes related to fertilizer N value of organic wastes applied to agricultural land. 1. Introduction In order to achieve sustainable food production there is a high focus on recycling of nutrients by utilisation of organic waste as a fertilizer in agricultural plant production. Effective and safe use of organic wastes in agricultural plant production requires risks and benefits to be weighed and documented. Heavy metal and organic contaminant accumulation, as well as transmission of pathogenic bacteria, are among the identified risks. These risks are continuously managed by advances in the waste processing technology. On the other hand, obvious positive effects of organic waste application on soil structure, porosity, water retention capability, cation exchange capacity, and biological activity have been identified, for example [1, 2]. The nutrient value of organic waste has shown to be dependent of type of waste, both origin and processing method [3]. A general condition for using organic wastes as fertilizers is the ability to predict their mineralization dynamics during
Biological soil crusts on initial soils: organic carbon dynamics and chemistry under temperate climatic conditions  [PDF]
A. Dümig,M. Veste,F. Hagedorn,T. Fischer
Biogeosciences Discussions , 2013, DOI: 10.5194/bgd-10-851-2013
Abstract: Numerous studies have been carried out on the community structure and diversity of biological soil crusts (BSCs) as well as their important functions on ecosystem processes. However, the amount of BSC-derived organic carbon (OC) input into soils and its chemical composition under natural conditions has rarely been investigated. In this study, different development stages of algae- and moss-dominated BSCs were investigated on a~natural (<17 yr old BSCs) and experimental sand dune (<4 yr old BSCs) in northeastern Germany. We determined the OC accumulation in BSC-layers and the BSC-derived OC input into the underlying substrates for bulk materials and fractions <63 μm. The chemical composition of OC was characterized by applying solid-state 13C NMR spectroscopy and analysis of the carbohydrate-C signature.14C contents were used to assess the origin and dynamic of OC in BSCs and underlying substrates. Our results indicated a rapid BSC establishment and development from algae- to moss-dominated BSCs within only 4 yr under this temperate climate. The distribution of BSC types was presumably controlled by the surface stability according to the position in the slope. We found no evidence that soil properties influenced the BSC distribution on both sand dunes. 14C contents clearly indicated the existence of two OC pools in BSCs and substrates, recent BSC-derived OC and lignite-derived "old" OC (biologically refractory). The input of recent BSC-derived OC strongly decreased the mean residence time of total OC. The downward translocation of OC into the underlying substrates was only found for moss-dominated BSCs at the natural sand dune which may accelerate soil formation at these spots. BSC-derived OC mainly comprised O-alkyl C (carbohydrate-C) and to a lesser extent also alkyl C and N-alkyl C in varying compositions. Accumulation of alkyl C was only detected in BSCs at the experimental dune which may induce a~lower water solubility of BSC-derived extracellular polymeric substances when compared to BSCs at the natural sand dune indicating that hydrological effects of BSCs on soils depend on the chemical composition of the extracellular polymeric substances.
Evaluation of physicochemical properties and distribution of Pb, Cd, Cr and Ni in soils and growing plants around refuse dumpsites in Akure, Nigeria
PO Oviasogie, E Omoruyi, D Okoro, CL Ndiokwere
African Journal of Biotechnology , 2009,
Abstract: The physicochemical properties and distribution of Pb, Cd, Cr and Ni in soils and growing plants around refuse dumpsites in Akure, Southwestern Nigeria were evaluated to ascertain the impact of the wastes on these soil quality indices and edible plants. The soils close to the dumpsites were more acidic (pH, 5.50) compared with the soils away (25.0 m) from the sites. Also there were corresponding increases in the organic carbon and cation exchange capacities of the soil indicating measurable levels of biodegradability of the wastes. Pb, Cd, Cr and Ni have maximum concentrations of 23.00, 2.91, 9.00 and 24.00 mg/kg respectively in the soils. The amount of Cd determined in the soils was consistent with the critical level obtained for agricultural soils. Results obtained from the plant tissues analysed showed that 0.84 mg/kg Pb was detected in the root of Zea mays, while 0.25 mg/kg Ni was obtained in the root of Sorghum vulgare. Talinum triangulare and Amaranthus crucantus did not possess detectable levels of these metals. The present study has justified the need to continually assess the quality of soils, and the concentration of certain heavy/toxic metals in growing plants around refuse dumpsites.
Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils  [PDF]
Tope O. Bolanle-Ojo,Abiodun D. Joshua,Opeyemi A. Agbo-Adediran,Ademola S. Ogundana,Kayode A. Aiyeyika,Adebisi P. Ojo,Olubunmi O. Ayodele
International Journal of Agronomy , 2014, DOI: 10.1155/2014/428569
Abstract: Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+ were carried out on three surface (0–30?cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27?cmolc kg?1) but relatively high base saturations (?50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. The values obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions. 1. Introduction Baseline concentration of heavy metals in soils depends on the local geology. This has been supplemented to various degrees by anthropogenic inputs from industrial processes and operations that generate wastes containing considerable amounts of these metals. Heavy metals are nonbiodegradable and hence environmentally persistent and may accumulate in biota and the soils where they can affect soil properties. They interact with soils in various ways but sorption from aqueous solution onto solid particles is an important process that influences their accumulation and transport in the environment [1]. Thus, heavy metals pollution in soils has become a significant topic of concern. Nowhere has the situation become more serious than in developing countries due to the recent establishment of industries producing wastes and effluents containing heavy metals. This has led to increase in the heavy metal burden of the developing countries where waste management practices are poor and the final metal sink is the soil. Metals may interact with soils in many ways: they may be sorbed by the soil depending on the soil pH, organic matter content, cation exchange capacity, and so forth; the oxidation state of some metals
Composting of Disposal Organic Wastes: Resource Recovery for Agricultural Sustainability
Mohammad H Golabi,Peggy Denney,Clancy Iyekar,
Mohammad H. Golabi
,Peggy Denney,Clancy Iyekar

过程工程学报 , 2006,
Abstract: One of the major problems of agricultural soils in the tropical regions of the Pacific is the low organic matter content. Because of the hot and humid environment, the soil organic matter (SOM) is minimal due to rapid decomposition.Composted organic material is being applied on agricultural fields as an amendment to provide nutrients and enhance the organic matter content for improving the physical and chemical properties of the cultivated soils. In addition land application of composted material as a fertilizer source effectively disposes of wastes that otherwise are buried in landfills. In our soil program at the University of Guam, we are evaluating the use of organic material as an alternative to synthetic fertilizers. Its goal is to develop management strategies and use available resources for improving crop production while conserving resources and preserving environmental quality. Our case study project is designed to improve soil fertility status by using composted organic wastes and assessing how the nitrogen and other essential nutrients contribute to long-term soil fertility and crop productivity without application of synthetic fertilizers. In our pilot project, compost is produced from wood chips,grinded typhoon debris mixed with animal manure, fish feed, shredded paper and other organic wastes. Mature compost is then applied on the field at the rates of 0, 5, 10 and 20 t/ha as a soil amendment on the eroded cobbly soils of southern Guam.Corn is planted and monitored for growth performance and yield. The effect of land application of composted material on the SOM content and overall soil quality indices are being evaluated in this pilot study.
The relation between heavy metals distribution and particle size fractions in some egyptian soils
Monier Morad Wahba
Italian Journal of Agronomy , 2006, DOI: 10.4081/ija.2006.309
Abstract: Soil as a part of the environment receives pollutants from all types of human activities. Heavy metals originating from various organic waste sources and industrial activities accumulate in the soil surface, and their fate depends not only on the types and amounts of waste applied, but on soil properties. Furthermore, soils differ in their retention power for various heavy or trace elements. Twelve soil samples were selected from different sites irrigated with industrial and sewage wastes at Helwan city (Cairo Governorate) in the north and El-Saff (Giza Governorate) in the south. Separation of clay, silt and sand fractions were carried out. Chemical analyses of trace elements in the form of total and available contents (Fe, Mn, Zn and Pb) were determined in each fraction. The obtained results show that the average amounts of heavy metals in different fractions are related to the particle size of the soil especially the fine fraction. Heavy metals content was always in the surface layers higher than sub-surface. All metals were highest in clay fraction followed by silt and sand fractions respectively. This investigation discussed the importance of the fine fractions in the accumulation of heavy metals by coordination number in the lattice structure.
The relation between heavy metals distribution and particle size fractions in some egyptian soils
Monier Morad Wahba
Italian Journal of Agronomy , 2011, DOI: 10.4081/ija.2006.309
Abstract: Soil as a part of the environment receives pollutants from all types of human activities. Heavy metals originating from various organic waste sources and industrial activities accumulate in the soil surface, and their fate depends not only on the types and amounts of waste applied, but on soil properties. Furthermore, soils differ in their retention power for various heavy or trace elements. Twelve soil samples were selected from different sites irrigated with industrial and sewage wastes at Helwan city (Cairo Governorate) in the north and El-Saff (Giza Governorate) in the south. Separation of clay, silt and sand fractions were carried out. Chemical analyses of trace elements in the form of total and available contents (Fe, Mn, Zn and Pb) were determined in each fraction. The obtained results show that the average amounts of heavy metals in different fractions are related to the particle size of the soil especially the fine fraction. Heavy metals content was always in the surface layers higher than sub-surface. All metals were highest in clay fraction followed by silt and sand fractions respectively. This investigation discussed the importance of the fine fractions in the accumulation of heavy metals by coordination number in the lattice structure.
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