Effects of temperature and amendments on nitrogen mineralization in selected Australian soils.

The effects of temperature (18, 24, and 37 °C) and form of nitrogen (N) input from various sources (organic-green waste compost, biosolids, and chicken manure; inorganic-urea) on N transformation in three different Australian soils with varying pH (4.30, 7.09, and 9.

Effectiveness of chemical amendments for stabilisation of lead and antimony in risk-based land management of soils of shooting ranges.

This study aims to examine the effectiveness of amendments for risk-based land management of shooting range soils and to explore the effectiveness of amendments applied to sites with differing soil physiochemical parameters. A series of amendments with differing mechanisms for stabilisation were applied to four shooting range soils and aged for 1 year. Chemical stabilisation was monitored by pore water extraction, toxicity characteristic leaching procedure (TCLP) and the physiologically based extraction test (PBET) over 1 year.

Surface complexation modeling and spectroscopic evidence of antimony adsorption on iron-oxide-rich red earth soils.

Few studies have investigated surface complexation of antimony (Sb) on natural sorbents. In addition, intrinsic acidic constants, speciation, and spectroscopic data are scarce for Sb sorption in soil. Only simple sorption models have been proposed to describe the sorption of Sb(V) on specific mineral surfaces.

Differential effect of coal combustion products on the bioavailability of phosphorus between inorganic and organic nutrient sources.

In farming systems, all the applied phosphorus (P) is not available to plants because they are either adsorbed in soil or lost to the environment through leaching or runoff. The effect of coal combustion products (CCPs) for enhancing the bioavailability of applied phosphorus (P) in soil was examined separately for inorganic (KH2PO4 - PP) and organic (poultry manure - PM) P treatments, where fluidised bed combustion (FBC) ash emerged as the most effective amendment. Greenhouse study was conducted by growing mustard plants on FBC amended soils under leaching and non-leaching setups.

Bioavailability and ecotoxicity of arsenic species in solution culture and soil system: implications to remediation.

In this work, bioavailability and ecotoxicity of arsenite (As(III)) and arsenate (As(V)) species were compared between solution culture and soil system. Firstly, the adsorption of As(III) and As(V) was compared using a number of non-allophanic and allophanic soils. Secondly, the bioavailability and ecotoxicity were examined using germination, phytoavailability, earthworm, and soil microbial activity tests.

Phosphorus-arsenic interactions in variable-charge soils in relation to arsenic mobility and bioavailability.

Phosphorus (P) influences arsenic (As) mobility and bioavailability which depends on the charge components of soil. The objective of this study was to examine P-As interaction in variable-charge allophanic soils in relation to P-induced As mobilization and bioavailability. In this work, the effect of P on arsenate [As(V)] adsorption and desorption was examined using a number of allophanic and non-allophanic soils which vary in their anion adsorption capacity.

Chemodynamics of chromium reduction in soils: implications to bioavailability.

Chromium toxicity in soils can be mitigated by reduction of Cr(VI) to Cr(III) which is influenced by the presence of free Cr(VI) species in soil solution, and the supply of protons and electrons. In this study, the effects of Cr(VI) adsorption (i.e.

Using biochar for remediation of soils contaminated with heavy metals and organic pollutants.

Soil contamination with heavy metals and organic pollutants has increasingly become a serious global environmental issue in recent years. Considerable efforts have been made to remediate contaminated soils. Biochar has a large surface area, and high capacity to adsorb heavy metals and organic pollutants.

Concomitant reduction and immobilization of chromium in relation to its bioavailability in soils.

In this study, two carbon materials [chicken manure biochar (CMB) and black carbon (BC)] were investigated for their effects on the reduction of hexavalent chromium [Cr(VI)] in two spiked [600 mg Cr(VI) kg(-1)] and one tannery waste contaminated [454 mg Cr(VI) kg(-1)] soils. In spiked soils, both the rate and the maximum extent of reduction of Cr(VI) to trivalent Cr [Cr(III)] were higher in the sandy loam than clay soil, which is attributed to the difference in the extent of Cr(VI) adsorption between the soils. The highest rate of Cr(VI) reduction was observed in BC-amended sandy loam soil, where it reduced 452 mg kg(-1) of Cr(VI), followed by clay soil (427 mg kg(-1)) and tannery soil (345 mg kg(-1)).

Lead immobilization and bioavailability in microbial and root interface.

A range of both soluble and insoluble phosphate (P) compounds have been used to immobilize Pb in solution and soil. However, these compounds have limitations because of low solubility or leaching of P. Phosphate solubilizing bacteria (PSB) can be used to enhance the solubility of insoluble P compounds.

Impact of urease inhibitor on ammonia and nitrous oxide emissions from temperate pasture soil cores receiving urea fertilizer and cattle urine.

New Zealand's intensively grazed pastures receive the majority of nitrogen (N) input in the form of urea, which is the major constituent of animal urine and the most common form of mineral N in inorganic N fertilizers. In soil, urea is rapidly hydrolyzed to ammonium (NH4(+)) ions, a part of which may be lost as ammonia (NH3) and subsequently as nitrous oxide (N2O), which is a greenhouse gas. Two glasshouse experiments were conducted to study the effect of a urease inhibitor (UI), N-(n-butyl) thiophosphoric triamide (NBPT), commercially named Agrotain, applied with urine and urea on urea hydrolysis and NH3 and N2O emissions.

Role of organic amendment application on greenhouse gas emission from soil.

Globally, substantial quantities of organic amendments (OAs) such as plant residues (3.8×10(9) Mg/yr), biosolids (10×10(7) Mg/yr), and animal manures (7×10(9) Mg/yr) are produced. Recycling these OAs in agriculture possesses several advantages such as improving plant growth, yield, soil carbon content, and microbial biomass and activity.

Carbon storage in a heavy clay soil landfill site after biosolid application.

Applying organic amendments including biosolids and composts to agricultural land could increase carbon (C) storage in soils and contribute significantly to the reduction of greenhouse gas emissions. Although a number of studies have examined the potential value of biosolids as a soil conditioner and nutrient source, there has been only limited work on the impact of biosolid application on C sequestration in soils. The objective of this study was to examine the potential value of biosolids in C sequestration in soils.

Carbon storage and soil CO2 efflux rates at varying degrees of damage from pine wilt disease in red pine stands.

We evaluated the carbon (C) storage and soil CO2 efflux rates of red pine (Pinus densiflora S. et Z.) stands damaged by pine wilt disease (PWD) in Korea.

Denitrification and N2O:N2 production in temperate grasslands: processes, measurements, modelling and mitigating negative impacts.

In this review we explore the biotic transformations of nitrogenous compounds that occur during denitrification, and the factors that influence denitrifier populations and enzyme activities, and hence, affect the production of nitrous oxide (N2O) and dinitrogen (N2) in soils. Characteristics of the genes related to denitrification are also presented. Denitrification is discussed with particular emphasis on nitrogen (N) inputs and dynamics within grasslands, and their impacts on the key soil variables and processes regulating denitrification and related gaseous N2O and N2 emissions.

Sorption-bioavailability nexus of arsenic and cadmium in variable-charge soils.

In this work, the nexus between sorption and bioavailability of arsenic (As) and cadmium (Cd) as affected by soil type, soil pH, ageing, and mobilizing agents were examined. The adsorption of As and Cd was examined using a number of allophanic and non-allophanic soils which vary in their charge components. The effect of pH and ageing on the bioavailability of As and Cd was examined using spiked soils in a plant growth experiment.

Recycled water sources influence the bioavailability of copper to earthworms.

Re-use of wastewaters can overcome shortfalls in irrigation demand and mitigate environmental pollution. However, in an untreated or partially treated state, these water sources can introduce inorganic contaminants, including heavy metals, to soils that are irrigated. In this study, earthworms (Eisenia fetida) have been used to determine copper (Cu) bioavailability in two contrasting soils irrigated with farm dairy, piggery and winery effluents.

Landfills as a biorefinery to produce biomass and capture biogas.

While landfilling provides a simple and economic means of waste disposal, it causes environmental impacts including leachate generation and greenhouse gas (GHG) emissions. With the introduction of gas recovery systems, landfills provide a potential source of methane (CH4) as a fuel source. Increasingly revegetation is practiced on traditionally managed landfill sites to mitigate environmental degradation, which also provides a source of biomass for energy production.

Heavy metal toxicity to bacteria - are the existing growth media accurate enough to determine heavy metal toxicity?

A new minimal medium was formulated considering the limitations of the existing media for testing heavy metal sensitivity to bacteria. Toxicity of cadmium and copper to three bacteria was investigated in the new medium and compared with three other media commonly used to study the effect of the toxic metals. Based on speciation data arrived at using ion-selective electrodes, the available free-metal concentration in solution was highest in the MES-buffered medium.

Effect of soil type on distribution and bioaccessibility of metal contaminants in shooting range soils.

Shooting ranges from Department of Defence sites around Australia were investigated for extent of metal contamination. Shooting range soils contained concentrations ranging from 399 to 10,403 mg/kg Pb, 6.57 to 252 mg/kg Sb, 28.

DDT remediation in contaminated soils: a review of recent studies.

Over the past few decades significant progress has been made in research on DDT degradation in the environment. This review is an update of some of the recent studies on the degradation and biodegradation pathways of DDT and its metabolites, particularly in soils. The latest reports on human toxicity shows that DDT intake is still occurring even in countries that banned its use decades ago.

Improving bioavailability of phosphorous from cattle dung by using phosphatase immobilized on natural clay and nanoclay.

The high P retention of acidic Andisols makes necessary to increase our technological approaches in pasture management in the animal system production. Here, we evaluated the clay- or nanoclay-acid phosphatase complexes for improving phosphorus mineralization from degraded cattle dung. We implemented an immobilization mechanism of acid phosphatase (AP) using natural clays (allophanic and montmorillonite) and nanoclays as support materials.

The influence of biochar and black carbon on reduction and bioavailability of chromate in soils.

The widespread use of chromium (Cr) has a deleterious impact on the environment. A number of pathways, both biotic and abiotic in character, determine the fate and speciation of Cr in soils. Chromium exists in two predominant species in the environment: trivalent [(Cr(III)] and hexavalent [Cr(VI)].