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Wetting Rate and Clay Content Effects on Interrill Erosion in Ultisols of Southeastern china

Pedosphere 2010年第1期20卷 129-136页

作者： YAN Feng-Ling, SHI Zhi-Hua , CAI Chong-Fa and LI Zhao-Xia key laboratory of subtropical agriculture & environment, ministry of agriculture, huazhong agricultural university, wuhan 430070 (china) [a] key laboratory of subtropical agriculture & environment Ministry of Agriculture Huazhong Agricultural University Wuhan 430070 (China)

An aggregate stability test and a simulated rainfall test were conducted on four representative Ultisols from southeastern china. The soils selected, with clay contents ranging between 117 and 580 g kg-1 , were derived from shale and Quaternary red clay. The stability of aggregates (2–5 mm in diameter) obtained from the soil samples were determined by the Le Bissonnais method. For determination of infiltration, runoff, and erosion, the soil samples were packed in 30 cm × 60 cm trays, wetted at rates of 2, 10, and 60 mm h-1 , and then exposed to simulated rainfall at 60 mm h-1 for 1 h. The results indicated that both aggregate stability and slaking caused by fast wetting increased with increasing clay content. The effect of wetting rate (WR) on infiltration and seal formation varied with clay contents. In the soil with low clay content (sandy loam), the infiltration rate was affected slightly by WR due to low aggregate stability and slaking. In the soils with medium clay content (silt clay loam and clay), WR affected infiltration significantly due to the high aggregate slaking force. In the soil with high clay content, the effect of WR on infiltration was significant, but not as evident as in the soils with medium clay content, which may be related to high aggregate stability by wetting partially compensating for slaking force. The effect of WR on soil loss was similar to that of runoff, but more pronounced. The findings from this study indicated that the relationship between wetting rate and clay content should be considered when predicting interrill erosion in Ultisols.

关键词： aggregate stability infiltration seal formation

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Relation of lead adsorption on birnessites with different average oxidation states of manganese and release of Mn^(2+)/H^+/K^+

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Journal of environmental Sciences 2009年第4期21卷 520-526页

作者： ZHAO Wei, FENG Xionghan, TAN Wenfeng, LIU Fan, DING Shuwen key laboratory of subtropical agriculture Resource & environment, ministry of agriculture of china, huazhong agricultural university, wuhan 430070, china. [a]key laboratory of subtropical agriculture Resource & environment Ministry of Agriculture of China Huazhong Agricultural University Wuhan 430070 China

The characteristics of Pb^2＋ adsorption on the surface of birnessites with different average oxidation states （AOS） of Mn, synthesized under acidic and alkali conditions, were investigated. The results indicated that the amount of adsorbed Pb^2＋ increased with the increase of Mn AOS in birnessites. The amount of Pb〉 adsorbed positively correlated with the amount of released Mn^2＋, H^＋, and K^＋（r = 0.9962 〉 0.6614, n = 14, ct = 0.01）. The released Mn^2＋, H^＋, and K^＋ were derived mostly from the corresponding cations adsorbed on the vacant sites. The maximum amount of adsorbed Pb^2＋ increased with the increasing vacant cation sites, leading to an increase of the total amount of released Mn^2＋, H^＋, and K^＋, and the increased likelihood for two Pb^2＋ adsorbed in the region of one side of a vacant site.

关键词： pb^2+ adsorption birnessite vacant site cation release

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Analysis of the contribution of acid phosphatase to P efficiency in Brassica napus under low phosphorus conditions

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Science china(Life Sciences) 2010年第6期53卷 709-717页

作者： ZHANG HaiWei1,2,HUANG Yu2,YE XiangSheng2 & XU FangSen1,2 1 National key laboratory of Crop Genetic Improvement,huazhong agricultural university,wuhan 430070,china 2.key laboratory of subtropical agriculture and environment,ministry of agriculture,huazhong agricultural university,wuhan 430070,china 1. National key laboratory of Crop Genetic Improvement Huazhong Agricultural University Wuhan 430070 China2. Key Laboratory of Subtropical Agriculture and Environment Ministry of Agriculture Huazhong Agricultural University Wuhan 430070 China

To understand whether genotypic variation in acid phosphatase (APase) activity in rapeseed (Brassica napus L.) induced by phosphorus (P) deficiency has impact on P efficiency,soil APase activity in the rhizosphere for rapeseed P-efficient genotype 102 and P-inefficient genotype 105 was measured against organic and inorganic P sources in the pot experiment,and the activities of root-secreted APase and leaf intracellular APase were investigated in different P-starvation periods in the nutrient *** activity of root-secreted APase in *** was induced under low P ***,P nutrition and P uptake efficiency of the plants supplied with organic P were not directly related to the activity of root-secreted APase due to several confounding factors affecting APase *** higher activity of leaf APase improved P remobilization in plants and played important roles in enhancing P use efficiency,shown by the significant correlation between leaf APase activity and P use efficiency in a rapeseed recombinant inbred population of 135 lines.

关键词： Brassica napus APase activity P remobilization P efficiency low-P stress

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Interaction Between Charge Characteristics and Cu^(2+) Adsorption-Desorption of Soils with Variable or Permanent Charge

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Pedosphere 2002年第4期12卷 321-328页

作者： LI XUEYUAN, LING WANTING and HE JIZHENGkey laboratory of subtropical Soil Resources and environment, Chinese ministry of agriculture, huazhong agricultural university, wuhan 430070 (china) Chinese ministry of agriculture Huazhong Agricultural University Key Laboratory of Subtropical Soil Resources and Environment Wuhan 430070

Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and permanent charge (brown soil) and the relationship between them were studied by means of back-titration and adsorption equilibrium respectively. The amount of variable negative charge was much less in variable-charge soil than in permanent-charge soil and increased with the pH in the system, but the opposite trend occurred in the points of zero charge (PZCs). The amount of Cu2+ ions sorbed by permanent-charge soil was more than that by variable-charge soil and increased with the increase of Cu2+ concentration within a certain range in the equilibrium solution. The amount of Cu2+ ions desorbed with KC1 from permanent-charge soil was more than that from variable-charge soil, but the amount of Cu2+ ions desorbed with de-ionized water from permanent-charge soil was extremely low whereas there was still a certain amount of desorption from variable-charge soil. The increase of PZC of soils with variable or permanent charge varied with the increment of Cu2+ ions added. When the same amount of Cu2+ ions was added, the increments of PZC and variable negative surface charge of permanent-charge soil were different from those of variable-charge soil.

关键词： adsorption-desorption Cu2+ ion permanent-charge soil variable-charge soil variable negat surface charge

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Binding and Transformation of Extracellular DNA in Soil

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Pedosphere 2005年第1期15卷 16-23页

作者： CAIPeng HUANGQiao-Yun ZHANGXue-Wen CHENHao StatekeylaboratoryofagriculturalMicrobiology CollegeofResourcesandEnvironmentHuazhongAgricultureUniversityWuhan430070China StatekeylaboratoryofagriculturalMicrobiology CollegeofResourcesandEnvironmentHuazhongAgricultureUniversityWuhan430070China／／CollegeofScienceHuazhongAgricultureUniversityWuhan430070China CollegeofScience HuazhongAgricultureUniversityWuhan430070China

DNA is the genetic material of various organisms. Extracellular DNA adsorbed or bound on surface-active particles in soils has been shown to persist for long periods against nucleases degradation and still retain the ability to transform competent cells. This paper reviews some recent advances on the binding and transformation of extracellular DNA in soils, which is fundamental to understanding the nature of the soil, regulating biodiversity, and assessing the risk of releasing genetically engineered microo…

关键词： adsorption binding extracellular DNA soil transformation

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Effects of Phosphate Adsorption on Adsorption-Desorption and Availability of Cu and Zn Ions in Ultisols and Alfisols

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Pedosphere 2000年第4期10卷 355-362页

作者： LIXUEYUAN DONGYUANYAN 等 keylaboratoryofsubtropicalSoilResourcesandenvironment ChineseMinistryofAgricultureHuazhongAgriculturalUniversityWuhan430070China keylaboratoryofsubtropicalSoilResourcesandenvironment ChineseMinistr

Surface charge, secondary adsorption- desorption and form distribution of Cu2+ and Zn2+ in Ultisols and Alfisols having adsorbed phosphate were studied by potentiometric titration, adsorption equilibrium and sequential extraction method, respectively. The soil surface negative charges increased whereas the amount of positive charges decreased with increase of P adsorbed. The soil secondary adsorption capacity for Cu2+ and Zn2+ was positively significantly correlated with the amount of P adsorbed by the soils, which could be described by the Langmuir equation. The amounts of Cu2+ and Zn2+ desorption from soils were decreased after P adsorption by the soils and the relationship between them was linear. After the soils adsorbed P, form distribution of Cu2+ and Zn2+ in soils changed remarforbly.

关键词： adsorption-desorption Alfisol and Ultisol availability Cu2+ and Zn2+ phosphate adsorption

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Poultry Manure Compost Alleviates the Phytotoxicity of Soil Cadmium: Influence on Growth of Pakchoi (Brassica chinensis L.)

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Pedosphere 2010年第1期20卷 63-70页

作者： CHEN Han-Song HUANG Qiao-Yun LIU Li-Na CAI Peng LIANG Wei LI Ming key laboratory of subtropical agriculture and environment of ministry of agriculture Huazhong Agricultural University Wuhan 430070 (China) State key laboratory of agricultural Microbiology Huazhong Agricultural University Wuhan 430070 (China)

The growth performance of pakchoi （Brassica chinensis L.） in relation to soil cadmium （Cd） fractionations was investigated to evaluate the remediating effect of poultry manure compost on Cd-contaminated soil. A yellow-brown soil （Alfisol） treated with various levels of Cd （0 50 mg Cd kg^-1 soil） was amended with increasing amounts of compost from 0 to 120 g kg^-1. Compost application transformed 47.8%-69.8% of soluble/exchangeable Cd to the organic-bound fraction, and consequently decreased Cd uptake of pakchoi by 56.2%-62.5% as compared with unamended soil. Alleviation of Cd bioavailability by compost was attributed primarily to the increase of soil pH and complexation of Cd by organic matter including dissolved organic matter. In general, the improvement of pakchoi performance was more pronounced in higher Cd-contaminated soil. Addition of large amount of compost also favored the anti-oxidative capability of pakchoi against Cd toxicity. This low cost remediation method seems to be very effective in the restoration of Cd-eontaminated soils.

关键词： contamination heavy metal plant remediation

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Effect of Cobalt-Doped Framework on Formation of Todorokite from Layered Manganese Oxides with Mg^(2+)/Co^(2+) Ions as Template

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Pedosphere 2011年第6期21卷 730-737页

作者： CUI Hao-Jie LIU Fan TAN Wen-Feng FENG Xiong-Han Institute of Urban environment Chinese Academy of Sciences Xiamen 361021 （China） key laboratory of subtropical agricultural Resources and environment Ministry of Agriculture Huazhong Agricultural University Wuhan 430070 （China）

Cobalt （Co） exists in significant quantities in naturally occurring manganese （Mn） oxides and alters the growth of Mn oxide crystals. Four-layered Mn oxides, Na-buserite （Na-bus） and three Co-doped Na-buserite samples prepared from oxidation of Mn（OH）2 with 5%, 10%, and 20% Co/（Mn ＋ Co） molar ratios （5Co-Na-bus, 10Co-Na-bus, and 20Co-Na-bus）, were used to prepare todorokite, a common Mn oxide on the Earth＇s surface, using Mg2＋/Co2＋ ions as a template. The results showed that todorokites could be obtained by reflux treatment of Mg2＋-exchanged non-doped Na-buserite and three Co-doped Na-buserites at atmospheric pressure. However, the formation of todorokites was prohibited by reflux treatment of Co2＋-exchanged Na-bus, 5Co-Na-bus, and 10Co-Na-bus samples. Instead, todorokite was obtained by the reflux treatment of Co2＋-exchanged 20Co-Na-bus samples under atmospheric pressure. X-ray photoelectron spectroscopy analysis showed that doped Co existed as Co3＋ in the MnOs layers of doped Na-buserites. The amount of substituted Co3＋ in the MnO6 layers may play a key role in the conversion of buserite to todorokite using Co2＋ ions as a template.

关键词： Mn oxide Na-buserite reflux treatment transformation tunnel structure

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Isothermal Microcalorimetry:A Review of Applications in Soil and environmental Sciences

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Pedosphere 2007年第2期17卷 137-145页

作者： RONG Xing-Min HUANG Qiao-Yun JIANG Dai-Hua CAI Peng LIANG Wei key laboratory of subtropical agricultural Resources and environment Ministry of Agriculture Huazhong Agricultural University Wuhan 430070 （China）

Isothermal microcalorimetry provides thermodynamic and kinetic information on various reactions and processes and is thereby a powerful tool to elucidate their mechanisms. Certain improvement in isothermal microcalorimetry with regard to the studies on soil and environmental sciences is briefly described. This review mainly focuses on the use of microcalorimetry in the determination of soil microbial activity, monitoring the toxicity and biodegradation of soil organic pollutants, the risk evaluation of metals and metalloids, the heat effect of ion exchange and adsorption in soil, and environmental researches. Promising prospects for the applications of the technique in the field are also discussed.

关键词： environment isothermal microbial activity microcalorimetry soil

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Induced temperature-dependent DNA degradation by C60 without photoactivation

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Science Bulletin 2011年第Z2期 3100-3107页

作者： WANG Chang 1,2 , LIN Yan 2 , WANG Ying 3 , LIANG Yong 1,3* , MENG LingZhi 4 , ZHANG Jie 2 , ZHOU QunFang 1 & JIANG GuiBin 1 1 State key laboratory of environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, china 2.key laboratory of subtropical agriculture and environment of the ministry of agriculture, huazhong agricultural university, wuhan 430070, china 3 School of Medicine, Jianghan university, wuhan 430056, china 4 Department of Chemistry, wuhan university, wuhan 430072, china

This study shows that C60can degrade pBR322 plasmid DNA at room temperature without photoactivation. The degradation was enhanced by increasing incubation temperature, reaction time or C60concentration. We also found that superoxide radical anions （O 2 · ） were formed in the C60solution. Superoxide dismutase significantly inhibited DNA cleavage and O 2 · generation induced by C60. These results suggest that DNA cleavage was caused by the formation of reactive oxygen species induced by C60at room temperature. Furthermore, we demonstrate that the DNA degradation was significantly inhibited by acid amide chemicals such as formamide, and by increased ionic strength of the reaction solution. These results indicate that the DNA conformation stability and the surface properties of C60are important factors regulating DNA degradation. We propose that C60can bind DNA, decrease DNA conformation stability, and induce the formation of reactive oxygen species and DNA cleavage at room temperature. Our results provide a possible explanation for the genotoxicity of C60, which should be considered in future use of this particular nano-material.

关键词： C60 DNA degradation reactive oxygen species genotoxicity

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