Balwant Singh

Balwant Singh
The University of Sydney

PhD University of Western Aust

About

208
Publications
68,697
Reads
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10,194
Citations
Additional affiliations
May 1998 - December 2015
The University of Sydney
Position
  • Professor (Associate)
August 1993 - May 1998
University of Reading
Position
  • Lecturer/Research Fellow
March 1986 - February 1991
University of Western Australia
Position
  • PhD Student

Publications

Publications (208)
Article
Soil organic matter (SOM) decomposition and stabilisation are largely affected by microbial carbon use efficiency (CUE), which is defined as the proportion of substrate carbon (C) uptake that microbes use for growth. Microbial CUE varies due to substrate quality and availability differences, but this may also depend on soil properties, such as pH,...
Article
The interactions of plastics and soil organisms are complex and inconsistent observations on the effects of plastics have been made in published studies. In this study, we assessed the effects of plastic exposure on plants, fauna and microbial communities, with a meta-analysis. Using a total of 2936 observations from 140 publications, we analysed h...
Article
Full-text available
Soil organic matter (SOM) plays a central role in the global carbon balance and in mitigating climate change. It will therefore be important to understand mechanisms of SOM decomposition and stabilisation. SOM stabilisation is controlled by biotic factors, such as the efficiency by which microbes use and produce organic compounds varying in chemist...
Chapter
The increasing production and use of conventional plastics, including in agricultural systems, has generated over 6500 million tonnes of plastic waste over the last 70 years. Over two–third of this waste had been deposited in landfills and natural environments including soils. However, the existence, persistence and impacts of plastics on soil prop...
Article
Soil organic carbon (SOC) is the largest terrestrial C stock and soils' capacity to preserve OC varies with many factors including land use, soil type and depth. We investigated the effect of land use change on particulate organic matter (POM) and mineral-associated organic matter (MOM) in soils. Surface (0-10 cm) and sub-surface (60-70 cm) soil sa...
Chapter
Oxide minerals (include oxides, hydroxides, oxyhydroxides and hydrated oxides) are primary and secondary minerals of Si, Fe, Mn, Al and Ti. Secondary oxides, particularly of Fe, Al and Mn, are perhaps the most reactive and important components in many soils due to their large specific surface area and strong sorption capacity for many essential and...
Article
Full-text available
This article investigates a novel data fusion method to predict clay content and cation exchange capacity using visible near-infrared (visNIR) spectroscopy, portable X-ray fluorescence (pXRF), and X-ray diffraction (XRD) techniques. A total of 367 soil samples from two study areas in regional Australia were analyzed and intra- and interarea calibra...
Article
Biochar amendment causes immediate increases in soil organic carbon (SOC), but long-term effects are unclear. Biochar properties change with time (biochar aging) potentially affecting how efficiently SOC remains in soil after decomposition, indicated by microbial carbon use efficiency (CUE, the ratio of microbial growth over carbon uptake). Effects...
Article
C CP-MAS nuclear magnetic resonance (NMR) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopies were compared for evaluating their potential to characterise the influence of land use change on organic carbon (OC) chemistry of particulate organic matter (POM) and mineral associated OM (MOM) fractions of different soil types. Surf...
Article
Full-text available
Although association between mineral and biochar carbon have been speculated in some studies, still there is no direct evidence for the influence of individual clay minerals on the mineralization of biochar carbon in soils. To address this, we conducted an incubation study using monomineralic soils constituted by separately mixing pure minerals, i....
Preprint
Full-text available
Abstract. Soil organic carbon (OC) is the largest terrestrial C stock and soils' capacity to preserve OC varies with many factors including land use, soil type and depth. We investigated the effect of land use change on particulate organic matter (POM) and mineral-associated organic matter (MOM) in soils. Surface (0–10 cm) and sub-surface (60–70 cm...
Article
Lime is a common amendment to overcome soil acidity in agricultural production systems. However, plant root effects on lime and soil carbon (C) dynamics in acidic soils under varied temperature remain largely unknown. We monitored root effects of soybean on the fate of lime applied to an acidic soil at 20 and 30°C in growth chambers. Soil respired...
Article
The added value of biochar when applied along with fertilizers, beyond that of the fertilizers themselves, has not been summarized. Focusing on direct comparisons between biochar additions (≤ 20 t ha‐1) – separately considering the addition or not of inorganic fertilizers (IF) and/or organic amendments (OA) along with biochar – and two different co...
Article
Full-text available
Soil amendment with biochar is shown to be a low-cost carbon sequestration option while its properties contribute to nutrient dynamics. The properties of biochar can be purposely modified using different techniques including chemical oxidation. A change in biochar functionality, to an equivalent state of natural aging, could alter plant nutrient us...
Article
Full-text available
Soil mineral composition affects soil behavior, but field estimation of mineral composition has proved difficult. To investigate the potential of predicting soil mineral composition in situ, 15 soils representing diverse mineral composition from New South Wales, Australia, were scanned with visible near-infrared (VisNIR) and portable X-ray fluoresc...
Article
There has been great interest in biochar application to soil for long‐term carbon (C) sequestration. However, the interactive priming of organic C mineralization, including shifts in microbial community structure and the persistence of biochar in a clayey soil amended with biochar and labile organic matter (LOM) over a relatively long period (i.e....
Article
Full-text available
An exhaustive meta-analysis of 132 long-term (≥ 10 years) studies worldwide was carried out to determine the effects of the use of organic amendments (OA) and OA + inorganic fertiliser (IF) on soil nutrient fertility. The responses of (1) crop yield [over the whole duration of the period (yieldm) and at the end of the experiment (yieldf)], (2) soil...
Article
Full-text available
Background- Soil amendment with biochar can increase biological nitrogen fixation (BNF) and improve growing conditions for legumes, while such effects may alter when biochar properties change with time (biochar aging). Methods - We examined BNF and competitiveness of legumes in a mixed pasture (dominated by clover, Trifolium repens) after 26 month...
Article
This study was aimed to evaluate the role of minerals in the preservation of organic carbon (OC) in different soil types. Sequential density fractionation was done to isolate particulate organic matter (POM, <1.8 g cm⁻³) and mineral associated OM (MOM: 1.8–2.2, 2.2–2.6 and >2.6 g cm⁻³) from four soils, i.e., a Ferralsol, a Luvisol, a Vertisol and a...
Article
This study evaluated the effectiveness of dry ashing of soils and subsequent spectral subtraction procedure in comparison with alternative chemical methods in accentuating organics for diffuse reflectance infrared Fourier transform (DRIFT) spectroscopic analysis of soil organic matter composition. Chemical oxidation of soil with sodium hypochlorite...
Conference Paper
Full-text available
Biological nitrogen fixation (BNF) by clover (Trifolium repens) is an important mechanism of nitrogen (N) addition to pastures contributing up to 545 kg N ha-1 yr-1. Amendment of soil with biochar, a form of pyrogenic carbon (C) rich material, could increase BNF and improve growing conditions for clover while increasing C storage in the soil. In ac...
Article
Full-text available
Biochar, a form of pyrogenic carbon, can contribute to agricultural and environmental sustainability by increasing soil reactivity. In soils, biochar could change its role over time through alterations in its surface chemistry. However, a mechanistic understanding of the aging process and its role in ionic nutrient adsorption and supply remain uncl...
Article
The effect of macadamia nut shell biochar on nitrogen, potassium, phosphorus, magnesium, calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment. The treatments combined two fertiliser rates (50 and 100% rate of the commercial mix commonly used in forestry nurseries) with...
Article
Allometric equations remain essential to the estimation of forest biomass and carbon (C) stocks. However, such equations have mainly been developed for American and European forests, and transferring them to other species or eco-regions is problematic. There are large forested areas in the eastern Himalayas, but we lack all but the most rudimentary...
Article
Full-text available
Biochar is pyrolysed biomass and largely consists of pyrogenic carbon (C), which takes much longer to decompose compared to the biomass it is made from. When applied to soil, it could increase agricultural productivity through nutrient retention and changing soil properties. The biochar-mediated nutrient retention capacity depends on the biochar pr...
Article
Bauxite residue sand (BRS) is the primary growth medium for rehabilitating Alcoa’s residue storage areas in south-west Western Australia. Successful revegetation of highly alkaline BRS can be hindered by its low nitrogen (N) use efficiency. Biochar, a carbon (C)-rich material, has been suggested to have the potential to improve water and nutrient r...
Chapter
Full-text available
Biochar has unveiled a new avenue for carbon (C) sequestration and has shown the potential to increase agricultural productivity. Although there is still debate about the mineralization rate of biochar and its role in sustaining soil fertility after fresh biochar amendment, oxidized or aged biochar has shown strong positive effects on crop producti...
Article
Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescribed burn offs for fire management. The objective of this study was to elucidate mechanistic interactions of copper (Cu²⁺) and nickel (Ni²⁺) with different chars produced by pyrolysis (green waste, GW; blue-Mallee, BM) and forest fires (fresh-burnt by pre...
Data
Full-text available
Fertilizer use efficiency is often low due to low retention capacity of nutrient ions in the soil. Biochar, a form of pyrogenic carbon, can be applied to soil as it can potentially reduce nutrient losses by adsorbing cations and anions on its surfaces. The sorption of ions is primarily governed by surface characteristics of biochars. When biochar a...
Data
Full-text available
Biochar is pyrolysed biomass resistant to biodegradation, and when applied to soils, it could increase agricultural productivity through increased nutrient retention. The biochar-mediated nutrient retention capacity depends on the biochar properties, which change with time. Here, we examined biochar effects after 21 months of application (at 20 t h...
Article
Application of biochar to soil has potential to reduce greenhouse gas (GHG) emissions, store C for long-term and provide agronomic benefits. However, the extent of these benefits are dependent on the type of biochar used and the environmental system in which it has been placed. While there are a large number of laboratory and glasshouse experiments...
Article
Full-text available
We used diffuse reflectance Fourier-transform infrared (DR-FTIR) spectroscopy, X-ray diffraction (XRD), and chemical and isotopic analyses to characterize the light fraction of four contrasting soils (control and biocharamended soils) to determine changes in biochar properties after aging. Two Eucalyptus saligna Sm. wood biochars, produced at 450°C...
Article
Full-text available
Liming has important implications for N dynamics in acidic soils planted with legumes that are not fully understood. We used a 15N tracer (K15NO3) to examine N dynamics in a Chromic Luvisol planted with soybean with and without lime in environmentally-controlled chambers set at 20�C and 30�C (full factorial design). Liming increased total N and 15N...
Article
High-altitude soils potentially store a large pool of carbon (C) and nitrogen (N). The assessment of total C and N stocks in soils is vital to understanding the C and N dynamics in terrestrial ecosystems. In this study, we examined effects of altitude and forest composition on soil C and N along a transect from 317 to 3300 m a.s.l. in the eastern H...
Article
Producing robust seedlings for forest plantation establishment is important as early growth influences potential yield and propagation is a significant budget component. The reputed benefits of biochar as a soil amendment may assist the growth and establishment of seedlings while simultaneously allowing for a reduction in fertiliser application. Th...
Chapter
This chapter provides an overview of biochar research within Australia with consideration given to the regional land-use diversity in defining both the dominant feedstock materials used and the dominant target systems. Carbon sequestration and greenhouse gas (GHG) mitigation have been strong underlying themes of Australian biochar research, with co...
Article
The use of gypsum to ameliorate soil sodicity is a typical practice in Australian agriculture. However, the longevity of ameliorative effect due to gypsum application is often short, due to the rate of dissolution and subsequent leaching by rainfall and/or irrigation. Gypsum was combined with chicken manure/wheat straw compost, during the compostin...
Article
Full-text available
The potential of mid-infrared spectroscopy in combination with partial least-squares regression was investigated to estimate total and phosphate-extractable arsenic contents in soil samples collected from a highly variable arsenic-contaminated disused cattle-dip site. Principal component analysis was performed prior to mid-infrared partial least-sq...
Article
Biochar has been proposed as a suitable component for growing media; however, little research has been done on the effects of biochar-amended media on ornamental plant growth. We investigated the effects of four rates of application of Eucalyptus saligna wood biochar [0, 2.5, 5.0, or 10.0% (w/w)] in combination with three rates of a controlled-rele...
Article
Full-text available
Land-use and management practices on limed acidic and carbonate-bearing soils can fundamentally alter carbon (C) dynamics, creating an important feedback to atmospheric carbon dioxide (CO2) concentrations. Transformation of carbonates in such soils and its implication for C sequestration with climate change are largely unknown and there is much spe...
Article
Recent studies have shown both increased (positive priming) and decreased (negative priming) mineralisation of native soil organic carbon (SOC) with biochar addition. However, there is only limited understanding of biochar priming effects and its C mineralisation in contrasting soils at different temperatures, particularly over a longer period. To...
Article
Two primary factors controlling dissolution rate of lime and gypsum chemical ameliorants are magnitude and frequency of water infiltration. Thus, it could be expected that longevity of these amendments is reduced under irrigated-systems, relative to dryland-systems. This paper examines efficacy of single and combined applications of lime and gypsum...
Chapter
Full-text available
In this chapter, a biochar classification system related to its use as a soil ammendment is proposed. This document builds upon previous work: Standardized product definition and product testing guidelines for biochar that is used in soil (IBI, 2012) (aka IBI Biochar Standards), Guidelines for biochar production: European Biochar Certificate (EBC,...
Article
The oxidation of surface functional groups on biochar increases its reactivity and may contribute to the cation exchange capacity of soil. In this study, two Eucalyptus wood biochars, produced at 450°C (B450) and 550°C (B550), were incubated separately in each of the four contrasting soils for up to 2years at 20°C, 40°C and 60°C. Carbon functional...
Article
Significant amounts of sulfuric acid (H2SO4) rich saline water can be produced by the oxidation of sulfide minerals contained in inland acid sulfate soils (IASS). In the absence of carbonate minerals, the dissolution of phyllosilicate minerals is one of very few processes that can provide long-term acid neutralisation. It is therefore important to...
Article
Full-text available
The current knowledge about the content and composition of soil organic matter (SOM) associated with particle size fractions in Thai soils is generally scarce. This study was conducted by sampling 25 soils (each at 3 depths, n=75) with different texture and mineralogy. The samples were analyzed for organic carbon (OC) and total nitrogen (total N)....
Article
Positive relationships between temperature and soil respiration rate are widely observed, but it remains unclear if the relationships are due to increases in soil organic matter mineralisation (R (om) ), or in root and rhizosphere respiration (R (roots) ), or increases in both. This study aims to determine the relative sensitivity of R (om) and R (...
Article
Batch experiments were conducted to evaluate the sorption-desorption behaviour of 14C-labelled carboxylic acids (citric and oxalic) and amino acids (glutamic, alanine, phenylalanine and lysine) on 2 pure minerals (kaolinite, illite, montmorillonite, ferrihydrite and goethite). The sorption experiments were complemented by ATR-FTIR spectroscopy to g...
Article
Intensive greenhouse industry wastes large amounts of nutrient-rich green waste through improper disposal practices. Converting this greenhouse waste into biochar for soil application offers a viable option to recycle nutrients and long-term C storage. This study was carried out to evaluate the agronomic potential of a biochar produced from tomato...
Conference Paper
Full-text available
Although low molecular weight organic compounds (LMWOC) (e.g., carbohydrates, carboxylic acids and amino acids) represent a small portion of soil organic carbon, they are considered key contributors of a number of soil processes. LMWOCs are labile form of soil organic carbon that are easily utilized by microbes and also highly susceptible to leachi...
Article
Full-text available
The purposes of the research were (1) to estimate the ability of wheat Triticum aestivum L. to uptake antimony (Sb) from contaminated soil and water, (2) to study effects of Sb bioaccumulation on the plant development and distribution of macro- and trace elements in the plants, and (3) to compare uptake of Sb and some other elements by wheat seedli...
Data
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Conference Paper
Full-text available
Batch experiments were conducted to evaluate the sorption-desorption behaviour of 14 C-labelled carboxylic acids (oxalic and citric) and amino acids (glutamic acid, lysine, alanine and phenylalanine) on phyllosilicates (kaolinite, illite and montmorillonite) and Fe oxides (ferrihydrite and goethite). Sorption data fitted well with the non-linear Fr...
Article
Full-text available
Organo-mineral interactions are important for the cycling and preservation of organic carbon (OC) in soils. To understand the role of soil mineral surfaces in organo-mineral interactions, we used a sequential density fractionation procedure to isolate <1.6, 1.6–1.8, 1.8–2.0, 2.0–2.2, 2.2–2.6, and >2.6 g cm −3 density fractions from topsoils (0–10 c...
Article
Full-text available
In this study, nine Oxisols and five Ultisols from Thailand were used to determine the association of major and trace elements with iron (Fe) oxides. The Fe oxides were concentrated and the association of elements (Al, Ca, Cu, Cr, Mg, Mn, Ni, Pb, P, Si, V, Ti, Zn) with Fe was evaluated using batch dissolution in 1 M HCl at 208C. The dissolution beh...
Article
Full-text available
Biochar has been recognised as an effective amendment for the remediation of contaminated soils; however, there is limited knowledge on the effects of biochar ageing in soil on its adsorption behaviour for cationic and anionic species. Biochars are considered to develop negative charge from oxidation with ageing, which may create additional interac...