P.C. Brookes

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (166)549.92 Total impact

  • Guoliang Chen, Xingmei Liu, Philip C Brookes, Jianming Xu
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    ABSTRACT: The identification of plants with high arsenic hyperaccumulating efficiency from water is required to ensure the successful application of phytoremediation technology. Five dominant submerged plant species (Vallisneria natans (Lour.) Hara., Potamageton crispus L., Myriophyllum spicatum L., Ceratophyllum demersum L. and Hydrilla verticillata (L.f.) Royle) in China were used to determine their potential to remove As from contaminated water. V. natans had the highest accumulation of As among them. The characteristics of As accumulation, transformation and the effect of phosphate on As accumulation in V. natans were then further studied. The growth of V. natans was not inhibited even when the As concentration reached 2.0 mg L(-)(1). After 21 d of As treatment, the bioconcentration factor (BCF) reached 1300. The As concentration in the environment and exposure time are major factors controlling the As concentration in V. natans. After being absorbed, As(V) is efficiently reduced to As(III) in plants. The synthesis of non-enzymic antioxidants may play an important role under As stress and increase As detoxication. In addition, As(V) uptake by V. natans was negatively correlated with phosphate (P) uptake when P was sufficiently supplied. As(V) is probably taken up via P transporters in V. natans.
    International Journal of Phytoremediation 03/2015; 17(3):249-255. DOI:10.1080/15226514.2014.883496 · 1.47 Impact Factor
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    ABSTRACT: The effect of interactions between soil minerals and organic matter as a function of aggregate size on butachlor sorption was quantified in natural soils with various degrees of organo-mineral aggregation. The smallest size clay microaggregates sorbed most butachlor (58% to 71%) and the fine sand fraction sorbed the least (less than 4.3%). When normalized to organic carbon, butachlor sorption to the clay microaggregates was even smaller than to the silt and sand fractions under specific soil conditions. The sum of sorption to the different fractions was, on average, above 78% greater than sorption to the bulk soils, with the greatest differences in the soils with relatively higher ratios of clay to soil organic carbon (RCO). This suggests that minerals can physically protect favorable sorption sites within soil organic matter (SUM), and inhibit butachlor sorption by influencing SUM physical conformation. Comparisons of changes in butachlor sorption coefficients (both K-d and K-oc) in two different series of soils, with the same mineral components but gradients of total organic carbon (TOC) and RCO values also showed that minerals can directly contribute to soil butachlor sorption processes, which may be even more pronounced in soils with relative higher RCOs. A new adsorption model was proposed and verified to quantify the net contribution of minerals to butachlor sorption, based upon 38 different soils. This study has increased our ability to quantify the positive direct contribution of soil minerals and their negative indirect contribution through associated effects on SOM physical conformation during butachlor sorption in natural soils.
    Geoderma 11/2014; s 232–234:309–316. DOI:10.1016/j.geoderma.2014.05.021 · 2.51 Impact Factor
  • Zhongmin Dai, Philip C Brookes, Yan He, Jian-Ming Xu
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    ABSTRACT: To compensate for the shortcomings of manure biochar, an ignocellulose-based feedstock (rice straw) was added into manure-based feedstock (swine manure) at 3:1, 1:1 and 1:3 (w/w) manure/straw ratios during biochar production within the pyrolysis temperature ranging from 300-700 ˚C. The results showed that the pyrolysis temperatures and the proportions of straw added both influenced the biochar properties. The overall properties of biochars at 300 ˚C, 400 ˚C and 500 ˚C were thoroughly different from those at 600 ˚C and 700 ˚C by principal components analysis (PCA). The XRD, FTIR and SEM spectra suggested that the addition of straw considerably changed the mineral crystals, functional groups and porous structures in manure biochar, respectively. The Zn(Ⅱ) adsorption batch experiments showed that the biochars with more proportions of manure had the largest Zn(Ⅱ) adsorption capacity than other biochars at 300 ˚C, which was attributed to the mineral components, oxygen functional groups and surface areas. To meet varied agronomic and environmental requirements, the different conditions including pyrolysis temperatures and proportions of straw added should be quantitated.
    Journal of Agricultural and Food Chemistry 10/2014; 62(44). DOI:10.1021/jf504106v · 3.11 Impact Factor
  • Jiajiang Lin, Yan He, Jian-Ming Xu, Zuliang Chen, Philip Charles Brookes
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    ABSTRACT: Vertical variations of pentachlorophenol (PCP) dissipation and microbial community were investigated in a paddy soil with the addition of electron acceptors (NO3-, SO42-) and donors (crop residues). Crop residues enhanced PCP dissipation by supplying dissolved organic carbon (DOC) as an electron donor, while NO3- and SO42- inhibited it. The dissipation of PCP in electron donor treatments resulted in the accumulation of 3,4,5-trichlorophenol (3,4,5-TCP) except for wheat residues. The abundance and diversity of phospholipid fatty acids (PLFAs) decreased with increasing soil depth. The succession of predominant PLFAs shifted from aerobic bacteria to anaerobic bacteria when electron acceptors were changed to electron donors. The saturated/monounsaturated fatty acids (S/M) ratio increased with soil depth, which probably implied that nutrient turnover rate declined after the accumulation of 3,4,5-TCP. Our results showed that the addition of electron donors and acceptors modified the microbial communities, which then further influenced the degradation pathway of PCP.
    Journal of Agricultural and Food Chemistry 09/2014; 62(41). DOI:10.1021/jf502746n · 3.11 Impact Factor
  • Kongcao Xiao, Lu Yu, Jianming Xu, Philip C. Brookes
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    ABSTRACT: Purpose Initial soil pH determines the direction and magnitude of pH change after residue addition. This study aimed to evaluate the relative importance of initial soil pH and rate of residue application in determining subsequent pH change, nitrogen (N) mineralization, and soil-exchangeable aluminum (Al). Materials and methods An incubation experiment was conducted for 102 days on a Plinthudult soil and a Paleudalf soil, where pH gradients were produced after application of direct current (DC). Rates of vetch applications were 0, 5, 15, 30, and 50 g kg−1 soil. Results and discussion Increasing rates of vetch application caused greater increases in soil pH, but no consistent increase in soil pH at higher initial pH range (4.40∼6.74), because of nitrification. There was a positive correlation between alkalinity production and the initial soil pH at day 14, while correlations became negative at days 56 and 102. Mineral N accumulated as NH4+–N in low pH soils, due to limited nitrification, while NO3−–N dominated in higher pH soils. Application of vetch decreased KCl-extractable Al, probably because of complexation of Al by organic matter and precipitation of Al as a result of increased pH, reductions in Al concentration increased with increasing rates of vetch application. However, this amelioration effect on Al concentration weakened with time in higher pH soils. Conclusions Application of vetch residue can significantly increase soil pH and concentrations of mineral N and reduce exchangeable Al. These amelioration effects are enhanced with increased rate of vetch addition and vary with time depending on the initial pH of the soil.
    Journal of Soils and Sediments 09/2014; 14(9). DOI:10.1007/s11368-014-0909-1 · 2.11 Impact Factor
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    ABSTRACT: Biochars produced from swine manure (SM), fruit peels (FP), Phragmites australis (PA) and Brassica rapa (BR) were applied at different rates to a sandy loam soil at 70% moisture. Phospholipid fatty acid (PLFA) measurements showed that feedstock type, biochar type and application rate significantly affected the soil microbial communities. PLFAs derived from bacteria, fungi, actinomycetes, G + ve and G − ve bacteria and sulfate reducers were higher with FP biochar at 3% and 1% weight: weight (wt:wt), respectively, followed by SM at 1% and PA biochar at 3%, than in the control soil. The control soil also contained higher concentrations of certain iso:anteiso PLFAs, which are indicative of environmental stress, than did biochar treated soils. Protozoa PLFAs only increased in PA 3% and BR 1% treatments. Redundancy analysis illustrated the relationships between microbial communities and chemical properties within biochar types and addition rates to soil. The analysis indicated that different biochars induced different chemical changes such as increased pH, dissolved organic carbon and total carbon and nitrogen in soil and changed the microbial community structure. These properties may be used as indicators of both soil improvement and C sequestration.
    Geoderma 08/2014; s 226–227:270–278. DOI:10.1016/j.geoderma.2014.01.023 · 2.51 Impact Factor
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    ABSTRACT: A greenhouse study was conducted to investigate the effects of inorganic (phosphate rock, single superphosphate and calcium magnesium phosphate) and organic amendments (peat, straw manure and pig manure) on the uptake of lead (Pb) and trace elements by Chinese Cabbage (Brassica chinensis) grown in an acidic red soil. The application of all organic amendments increased the soil pH while inorganic amendments such as single superphosphate did not. Both inorganic and organic amendments decreased the availability and uptake of Pb while the organic amendments were superior to the inorganic (phosphate) amendments in reducing the availability of the more labile (soluble and exchangeable Pb) forms of soil Pb. More Pb was taken up by roots than shoots with all soil amendments. Among the organic amendments, straw manure and pig manure caused the largest decrease in Pb availability at 456.5 and 457.3mgkg(-1), respectively, when a high level of 30g organic amendments kg(-1) was applied. The organic amendments greatly increased the fraction D targeted to Fe-Mn oxides bound Pb, and decreased the fraction A (water-soluble), B (exchangeable), and C (carbonate-bound), thereby decreasing the solubility and mobility of Pb in soil. The organic amendments also significantly improved the concentrations of Fe, Mn, Cu and Zn in the soil and shoots (except Fe in shoots and/or roots), which are essential for plant nutrition. The organic amendments of straw and pig manure lowered the availability and uptake of Pb but not that of other trace metals. Thus, these amendments have the potential to remediate Pb-contaminated soils in situ.
    Chemosphere 06/2014; 119C:177-183. DOI:10.1016/j.chemosphere.2014.05.081 · 3.50 Impact Factor
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    Hua Qin, Philip C Brookes, Jianming Xu, Youzhi Feng
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    ABSTRACT: A greenhouse experiment was conducted to investigate the effects of zucchini (Cucurbita pepo L.), inoculated with the arbuscular mycorrhizal (AM) species Acaulospora laevis, Glomus caledonium, and Glomus mosseae, on the soil bacterial community responsible for Aroclor 1242 dissipation. The dissipation rates of Aroclor 1242 and soil bacteria abundance were much higher with the A. laevis and G. mosseae treatments compared to the non-mycorrhizal control. The biphenyl dioxygenase (bphA) and Rhodococcus-like 2,3-dihydroxybiphenyl dioxygenase (bphC) genes were more abundant in AM inoculated soils, suggesting that the bphA and Rhodococcus-like bphC pathways play an important role in Aroclor 1242 dissipation in the mycorrhizosphere. The soil bacterial communities were dominated by classes Betaproteobacteria and Actinobacteria, while the relative proportion of Actinobacteria was significantly (F = 2.288, P < 0.05) correlated with the PCB congener profile in bulk soil. Our results showed that AM fungi could enhance PCB dissipation by stimulating bph gene abundance and the growth of specific bacterial groups.
    Environmental Science and Pollution Research 06/2014; 21(22). DOI:10.1007/s11356-014-3231-y · 2.76 Impact Factor
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    ABSTRACT: Temporal and spatial changes in the annual and seasonal temperatures in a typical basin of the Qiantang River were analysed based on the time series databases of daily temperatures from 14 meteorological stations. Both the Mann–Kendall (MK) trend test and simple linear regression analyses were employed to detect trends in the mean and extreme temperatures. The temperature changes during the three periods of 1960–1990, 1960–2000 and 1960–2006 were investigated at each meteorological station and over the entire basin as an average. The spatial and temporal changes were characterized by significant warming throughout the region, with the minimum temperature (Tn) increasing the most, particularly after 1990. Various percentiles of extreme temperatures, as well as their corresponding frequencies, were chosen to explore the trends of extreme climate change in this region. Linear regression analyses showed a significant warming trend in cold events both on an annual and seasonal basis, especially in the winter. Conversely, the hot events were dominated by an insignificant warming trend (p > 0.05). When comparing the time series before and after 1990, trend shifts were apparent in both the mean and extreme temperatures, particularly in the spring and winter. In addition to the large-scale circulation, regional factors may have influenced the observed climate change in the studied region. Climate change has already influenced human society by, for example, increasing the frequency of haze in the study region. We conclude that the warming here is mainly attributed to changes in the minimum temperature.
    International Journal of Climatology 03/2014; 35(1). DOI:10.1002/joc.3962 · 3.40 Impact Factor
  • X. Zhu, H. Chen, W. Li, Y. He, P. C. Brookes, J. Xu
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    ABSTRACT: In the space of just a few years, nanotechnology has become a topical subject not only in academia, but also in the daily lives of people. In order to investigate the properties of natural nanoparticles (NNPs) and to obtain a better understanding of their environmental behaviour and impacts from a new perspective, transmission electron microscope (TEM), zeta potential analysis and time-resolved dynamic light scattering (DLS) analysis were used to examine the main properties and aggregation kinetics of NNPs extracted from Chinese soils added to various concentrations of the electrolytes NaCl, CaCl2 and LaCl3. The NNPs that were less than 100 nm remained stable for 100 days. The classic Derjaguin-Landau-Verwey-Overbeek (DLVO) model partially revealed the aggregation behaviour of NNPs, in which ionic strength, composition and size may play important roles. The influence of hematite and natural organic matter (NOM) was demonstrated by aggregation kinetics and critical coagulation concentrations (CCC). The size of NNPs could also change the maximum total potential energy of interactions in the systems (VT(h)). These factors make the aggregation of NNPs in electrolytes different from that of soil colloids and influence the environmental behaviour of NNPs.
    European Journal of Soil Science 03/2014; 65(2). DOI:10.1111/ejss.12118 · 2.39 Impact Factor
  • Xingmei Liu, Jian Zhou, Wanlu Li, Jianming Xu, Philip C Brookes
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    ABSTRACT: Our aim was to test the effects of simulated acid rain (SAR) at different pHs, when applied to fertilized and unfertilized soils, on the leaching of soil cations (K, Ca, Mg, Na) and Al. Their effects on soil pH, exchangeable H(+) and Al(3+) and microbial community structure were also determined. A Paleudalfs soil was incubated for 30 days, with and without an initial application of urea (200 mg N kg(-1)soil) as nitrogen (N) fertilizer. The soil was held in columns and leached with SAR at three pH levels. Six treatments were tested: SAR of pH 2.5, 4.0 and 5.6 leaching on unfertilized soil (T1, T2 and T3), and on soils fertilized with urea (T4, T5 and T6). Increasing acid inputs proportionally increased cation leaching in both unfertilized and fertilized soils. Urea application increased the initial Ca and Mg leaching, but had no effect on the total concentrations of Ca, Mg and K leached. There was no significant difference for the amount of Na leached between the different treatments. The SAR pH and urea application had significant effects on soil pH, exchangeable H(+) and Al(3+). Urea application, SAR treated with various pH, and the interactions between them all had significant impacts on total phospholipid fatty acids (PLFAs). The highest concentration of total PLFAs occurred in fertilized soils with SAR pH5.6 and the lowest in soils leached with the lowest SAR pH. Soils pretreated with urea then leached with SARs of pH 4.0 and 5.6 had larger total PLFA concentrations than soil without urea. Bacterial, fungal, actinomycete, Gram-negative and Gram-positive bacterial PLFAs had generally similar trends to total PLFAs.
    Environmental Science and Pollution Research 02/2014; 21(10). DOI:10.1007/s11356-014-2573-9 · 2.76 Impact Factor
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    Timothy E. Crews, Philip C. Brookes
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    ABSTRACT: We compared inorganic and organic P fractions to a soil depth of 92 cm in two long-term Classical Experiments at Rothamsted Research in the U.K. The predominant soil-forming factor that differentiated the sites was vegetation type. The Broadbalk plots feature annual wheat and have been in continuous production since 1843, while the Park Grass plots feature perennial grassland vegetation that has been hayed every year since 1856. To evaluate the long-term effects of annual versus perennial vegetation on soil P forms, we carried out Hedley P fractionations and microbial biomass-P fumigation-extraction analyses on soils from fertilized and unfertilized treatments of both experiments. In both P-fertilized and unfertilized soils we found an inverse relationship between pool sizes of actively cycling Po (0.5 M bicarbonate + 0.1 M NaOH fractions) and recalcitrant Pi (hot conc. HCl + final digest fractions) with Po dominant in the perennial hay meadow and recalcitrant Pi dominant in the annual wheat. Microbial biomass-P in the surface horizons of fertilized and unfertilized perennial hay meadow was an order of magnitude greater than in annual wheat. To investigate how P fractions changed through time we conducted Hedley P fractionations on archived soils sampled from Broadbalk wheat in 1893, and Park Grass hay meadow in 1876. Since 1893, unfertilized Broadbalk soils experienced almost no change in P fractions in the surface 23 cm, but substantial depletion in labile and recalcitrant Pi and Po in deeper strata. The Park Grass perennial vegetation showed greater depletion of surface soil fractions over time. When fertilized for over 100 years, almost all P fractions in the surface 23 cm were enriched in both crop types, but below 70 cm, only the active Po pool in Park Grass showed a substantial increase under fertilization. Even when fertilized, low available or occluded Pi fractions in both annual and perennial systems were substantially depleted below 70 cm. Our findings suggest that herbaceous perennials maintain a greater proportion of native or fertilizer-P in relatively available organic forms compared to annual wheat. By reducing the fraction of P held in recalcitrant forms, P fertilizer requirements could be reduced
    Agriculture Ecosystems & Environment 02/2014; 184:168–181. DOI:10.1016/j.agee.2013.11.022 · 3.20 Impact Factor
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    ABSTRACT: Because the in situ incorporation of rice straw into paddy fields enhances CH4 emissions, the ex situ (or shifted) incorporation of rice straw into uplands may provide an alternative way of mitigating CH4 emissions and increasing crop productivity and soil organic carbon (SOC) accumulation. To evaluate the efficiency of this practice, three field trials were conducted in flooded paddies (FP), paddy-upland rotation (PU), and upland (UL) cropping systems in Taoyuan county, a subtropical region of China. All trials had three fertilization treatments: no fertilizer (Nil), chemical fertilizer only (NPK) and combined application of chemical fertilizer and rice straw (NPK + R in FP and NP + R in PU and UL). Results showed that the responses of crop yields to NPK in the UL trial (yields increased 2.4 to 4.1-folds relative to Nil) were greater than those of rice (increased 1.65 to 1.80-folds) in the FP and PU trial. Compared with NPK treatment, NPK + R constantly increased the grain yields of rice in the FP trial by 10% averagely, but not in PU trials. The effects of NP + R treatment on crop yields in the UL trial were significant (p < 0.05) during the first 5–6 years. NPK treatments increased the SOC accumulation at a rate of 0.48 Mg ha−1 yr−1 in the FP trial and 0.35 Mg ha−1 yr−1 in the UL trial, but not in the PU trial. NPK + R treatments resulted in SOC accumulation rates of 1.00, 0.68, and 0.24 t ha−1 yr−1, and 9.11%, 6.56%, and 6.45% of the total straw C input was converted to SOC in the FP, UL, and PU trials, respectively. The results suggested that the incorporation of rice straw was highly efficient on SOC accumulation and crop productivity in the uplands (as shown in the UL trial). We therefore recommend the ex situ incorporation of rice straw in the upland neighboring paddy fields as a way of utilizing excessive rice straw in the hilly area of subtropical China.
    Agriculture Ecosystems & Environment 02/2014; 184:51–58. DOI:10.1016/j.agee.2013.11.019 · 3.20 Impact Factor
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    ABSTRACT: Vallisneria natans (Lour.) Hara, a widely distributed submerged aquatic plant, is a promising species for arsenic (As) removal from contaminated water. We investigated the effects of pH on the accumulation, subcellular distribution and detoxification of As in V. natans. The results showed that the optimum pH for submerged V. natans growth is close to 7.0. The accumulation of As in the plant increased with the increase of pH (p < 0.05). This may have been due to arsenic/phosphate transporters with a higher affinity for the more highly electronegative AsO4 (3-) than for HAsO4 (2-) and H2AsO4 (-). After As(V) was accumulated by plants, more than 80 % was reduced to As(III), but As reduction decreased with increased pH. The majority of accumulated As and reduced As(III) (47 %-66 %) was found in the vacuoles. Higher As concentrations in vacuoles could be considered as an important mechanism for As detoxification in submerged plants.
    Bulletin of Environmental Contamination and Toxicology 01/2014; 92(4). DOI:10.1007/s00128-013-1195-0 · 1.11 Impact Factor
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    ABSTRACT: Understanding organic carbon mineralization and its temperature response in subtropical paddy soils is important for the regional carbon balance. There is a growing interest in factors controlling soil organic carbon (SOC) mineralization because of the potential for climate change. This study aims to test the hypothesis that soil clay content impedes SOC mineralization in subtropical paddy soils.A 160-day laboratory incubation at temperatures from 10 to 30 °C and 90% water content was conducted to examine the dynamics of SOC mineralization and its temperature response in three subtropical paddy soils with different clay contents (sandy loam, clay loam, and silty clay soils). A three-pool SOC model (active, slow, and resistant) was used to fit SOC mineralization.Total CO2 evolved during incubation following the order of clay loam > silty clay > sandy loam. The temperature response coefficients (Q 10) were 1.92 ± 0.39, 2.36 ± 0.22, and 2.10 ± 0.70, respectively, for the sandy loam soil, clay loam soil, and silty clay soil. But the soil clay content followed the order of silty clay > clay loam > sandy loam. The sandy loam soil neither released larger amounts of CO2 nor showed higher temperature sensitivity, as expected, even though it contains lower soil clay content among the three soils. It seems that soil clay content did not have a dominant effect which results in the difference in SOC mineralization and its temperature response in the selected three paddy soils. However, dissolved organic carbon (DOC; representing substrate availability) had a great effect. The size of the active C pool ranged from 0.11 to 3.55% of initial SOC, and it increased with increasing temperature. The silty clay soil had the smallest active C pool (1.40%) and the largest Q 10 value (6.33) in the active C pool as compared with the other two soils. The mineralizable SOC protected in the silty clay soil, therefore, had even greater temperature sensitivity than the other two soils that had less SOC stabilization.Our study suggests that SOC mineralization and its temperature response in subtropical paddy soils were probably not dominantly controlled by soil clay content, but the substrate availability (represented as DOC) and the specific stabilization mechanisms of SOC may have great effects.
    Journal of Soils and Sediments 01/2014; 14(1):1-9. DOI:10.1007/s11368-013-0781-4 · 2.11 Impact Factor
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    ABSTRACT: This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass occurred within 4 days of BCP application-indicating rapid adaptation of the soil microbial community. Increases in biomass-N suggest that microbes were partly mechanistic in the immobilisation of N in soil. Straw, meadow-grass and BCP were subsequently incorporated into experimental soil mesocosms of depth equal to plough layer (23 cm), and placed in an exposed netted tunnel to simulate field conditions. Leachate was collected after rainfall between the autumn of 2009 and spring of 2010. Treatment with BCP resulted in less total-N transferred from soil to water over the entire period, with 32.1, 18.9, 13.2 and 4.2 mg N kg(-1) soil leached cumulatively from the control, grass, straw and BCP treatments, respectively. More than 99 % of nitrate leaching was prevented using BCP. Accordingly, soils provided with crop residues or BCP showed statistically significant increases in soil N and C compared to the control (no incorporation). Microbial biomass, indicated by soil ATP concentration, was also highest for soils given BCP (p < 0.05). These results indicate that field-scale incorporation of BCP may be an effective method to reduce nitrogen loss from agricultural soils, prevent nitrate pollution of groundwater and augment the soil microbial biomass.
    Water Air and Soil Pollution 01/2014; 225(2):1831. DOI:10.1007/s11270-013-1831-7 · 1.69 Impact Factor
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    ABSTRACT: Many soil microbes exist in biofilms. These biofilms are typified by variable quantities of extracellular polymeric substances (EPS: predominantly polysaccharides, glycoconjugates, and proteins) and the embedded microbial cells. A method to measure soil-EPS (the biofilm exclusive of microbial cells) has not yet been described. The present work investigates the potential of five extraction methods to estimate changes in soil-EPS content. A rationale for selection of appropriate EPS extraction and methodology is discussed, including the crucial consideration of both intracellular and extracellular contamination. EPS was developed in situ by provision of labile C (glycerol) to the microbial biomass of a moist soil and then applying desiccation stress. Only two out of the five extraction methods showed statistically significant increases in polysaccharide production responding to substrate addition. Humified organic matter, estimated by its humic acid equivalent (HAE) was used to indicate the degree of extracellular contamination, and/or creation of humic artefacts – both of which affect detection of changes in EPS. The HAE concentration was very high when applying original and modified methods designed to extract glomalin related soil protein (GRSP). Extraction methods involving heating with dilute sulphuric acid appeared to overestimate EPS-polysaccharide. Using microbial ATP as an indicator of cell-lysis, confidence could only be ascribed to EPS extraction with cation exchange resin. Using this method, the expected increases in EPS-polysaccharide were clearly apparent. The HAE/protein ratios of EPS extracts were also lowest with cation exchange – indicating this method did not cause excessive contamination from humified soil organic matter or create related artefacts. FULL ARTICLE AVAILABLE OPEN ACCESS: http://www.sciencedirect.com/science/article/pii/S0038071714000261
    Soil Biology and Biochemistry 01/2014; · 4.41 Impact Factor
  • Soil Science Society of America Journal 01/2014; 78(5):1606. DOI:10.2136/sssaj2013.08.0340 · 2.00 Impact Factor
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    ABSTRACT: Purpose A laboratory incubation under constant temperature and humidity was conducted to estimate the impacts of nitrogen (N) fertilizers on the acidification of two acid soils (Plinthudult and Paleudalfs) in south China. Materials and methods The experiment had three treatments, i.e., control (CK), addition of urea (U), and addition of ammonium sulfate (AS). We measured soil pH, nitrate (NO3−), ammonium (NH4+), exchangeable hydrogen ion (H+), and aluminum ion (Al3+) concentrations at various intervals during the 90 days of incubation. Soil buffering capacity (pHBC) was also measured at the end of the experiment. Results and discussion The application of N fertilizers resulted in soil acidification. The U treatment caused greater acidification of the Plinthudult soil than the AS treatment, while there were no differences between U and AS treatments on the acidification of the Paleudalfs. At the end of the trial, the pHBC of Plinthudult in AS treatment was greater than that in CK and U treatments, which may be due to the buffering system of NH4+ and NH4OH. However, the pHBC of Paleudalfs was unchanged between treatments. The dynamics of exchangeable H+ and Al3+ corresponded to that of soil pH. Correlation analysis showed that both soil exchangeable H+ and soil exchangeable Al3+ were significantly related to soil pH. Conclusions Application of urea and ammonium sulfate caused acidification in both soils and increased soil exchangeable Al3+ and H+ concentrations in the Paleudalfs. The application of urea increased exchangeable Al3+, and ammonium sulfate increased pHBC in the Plinthudult.
    Journal of Soils and Sediments 01/2014; DOI:10.1007/s11368-013-0695-1 · 2.11 Impact Factor

Publication Stats

14k Citations
549.92 Total Impact Points


  • 2014
    • Chinese Academy of Sciences
      Peping, Beijing, China
  • 2013–2014
    • Zhejiang University
      • College of Environmental and Resource Sciences
      Hang-hsien, Zhejiang Sheng, China
  • 2004–2014
    • Rothamsted Research
      • Department of Sustainable Soils and Grassland Systems
      Harpenden, England, United Kingdom
  • 2009
    • Lund University
      • Department of Biology
      Lund, Skane, Sweden
  • 2006
    • Kenya Agricultural Research Institute
      Nairoba, Nairobi Area, Kenya
    • China Agriculture University-East
      Peping, Beijing, China