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Combined Heavy Metal Pollution in Red Soil

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Pedosphere 1996年第4期6卷 305-312页

作者： CHENHUAIMAN ZHENGCHNURONG lmcp，instituteofsoilscience AcademiaSinicaNanjing210008China lmcp，instituteofsoilscience Academia

The effects of combined heavy metal pollution of red soil on the growth of wetland rice and the transfer of Pb, Cd, Cu and Zn from soil into plants were studied by greenhouse pot experiment. The results showed that the plat yields were markedly affected by heavy metals, with the exception of Pb, in soils under the experimental conditions, without taking into consideration all the interactions among the elements. The concentrations of the elements in plants were mainly affected by the specific element added to the soil. The effect of interactions among the heavy metals was very significant either on plant yields or on the concentration of the elements in plants. The risk assessment of a combined pollution by heavy metals in the soil is discussed preliminarily in terms of the relative pollution equivalent.

关键词： heavy metals rice risk assessment soil

Simulation of Methane Oxidation by Paddy Soils in a Closed System

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Pedosphere 1996年第4期6卷 313-320页

作者： CAIZUCONG YANXIAOYUAN lmcp，instituteofsoilscience ChineseAcademyofSciencesNanjing210008China lmcp，InstituteofSoilScienc

Methane oxidation by paddy soils in a closed system could be simulsted by the equation where xo and x are the CH4 concentrations at time zero and t, respectively; k1 and k2 are constants related to the constant of first-order-kinetics. According to the equation the change of soil ability to oxidize CH4 could be estimated by the equstion The results showed that the soil ability to oxidize CH4 varied, depending on the initial CH4 *** initial CH4 concentration stimulated soil ability to consume CH4, while low concentration depressed the ability. This characteristic of paddy soil seemed to be of considerable significance to self-adjusting CH4 emission from flooded rice fields if there exist oxic microsites in the soil.

关键词： methane oxidation paddy soils simulation

Study on Variation in ^(15)N Natural Abundance. Ⅰ. Characteristics of Variation in ^(25)N Natural Abundance of Forest Soils

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Pedosphere 1991年第3期1卷 277-281页

作者： SUNGUO－QING XINGGUANG－XI 等 lmcp，instituteofsoilscience AcademiaSinicaNanjing210008（China） lmcp，instituteofsoilscience Academi

INTRODUCTION A lot 0fwork has been done on the variation of natural ^(15)N abundance in soils andtheir N components (Chen et al., 1964). However, these reports mostly concerned thegeochemical mean of natural ^(15)N abundance, and only a little work has been done on thecharacteristics of variation of the natural ^(15)N abundance in different ecosystems and itsrelationship with the properties and conditions of soil, which is the aim of our recent re-

关键词： forest soil 15N natural abundance

Use　of　New　Water　Soluble　Surface　Film－Forming　Material　to　Reduce　Ammonia　Loss　from　Water　Solution

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Pedosphere 1996年第4期6卷 329-334页

作者： YINBIN SHENRENFANG 等 lmcp，instituteofsoilscience AcademiaSinicaP.O.Box821Nanjing210008China lmcp，InstituteofSoilScien

A new water soluble surfaCe film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laborstory. Results showed that the new film formed by the material was not only more effective in reducing ammonia loss than any other films tested but also much cheaper. The optimum amount of addition of the new film-forming material was about 10times the theoretical amount to form a monomolecular film. Under the experimental conditions, the new film could effectively depress the ammonia volatilization for at least 6 days. The cumulative ammonia loss rates for different films were fitted to a simple logistic equation, and some important parameters such as the cumulative loss, and the maximum and average volatilization rates were calculated. The effect of different films could be, therefore, compared quantitatively, indicating the new film was most effective in depressing ammonia volatilization.

关键词： ammonia loss logistic equation surface film-forming material

Degradation of Soil Properties due to Erosion on Sloping Land in Southern Jiangsu Province,China

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Pedosphere 2004年第1期14卷 17-26页

作者： ZHANGYan PENGBu-Zhuo GAOXiang YANGHao lmcp InstituteofSoilScienceChineseAcademyofSciencesNanjing210008（China） DepartmentofUrbanandResourcesScience NanjingUniversityNanjing210093（China）

Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the 137Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer.

关键词： ^(137)Cs coarser soils nutrients soil degradation soil layer

Particle Size Distribution of Kaolinite and Halloysite in Weathering Products of Granite and Its Implications for Pedogenesis

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Pedosphere 1997年第3期7卷 211-218页

作者： WANGYONGJIN等 YANGHAO 等 DepartmentofGeography NanjingNormalUniv.Nanjing210097（China） lmcp，instituteofsoilscience AcademiaSi

The kaolins collected from a profile of weathered granite at Yichun County, Jiangxi Province have been subjected to particle size fractionation by the conventional sedimentation method and examined by XRD,SEM and TEM. All of them exhibit a mixture phase of poorly crystallized kaolinites and halloysites (0.7 nm) occurring as the main clay minerals. Electron micrographs reveal that plate kaolinites are the principal constitution in the coarse fraction, and more tubular and curled halloysite (0.7 nm) in the fine fraction. Both of them show normal probability curves in particle size distributions. The ratios of kaolinite and halloysite (0.7 nm) in different size fractions are examined by X-ray diffraction with a series of X-ray patterns characterized by three main peaks at d(001), d(002) and d(020),varying in intensity. Therefore, an index Qhm, expressed as (Id(001) + Id(002))/(2×Id(020)), is designed to indicate relative ratios of the two clay minerals in a number of mixture phases. Because kaolinite and halloysite (0.7nm) commonly occurred, respectively, in low and medium leaching microenvironment, the index Qhm can be used to indicate weathering and *** of a weathering crust.

关键词： kaolin-group minerals particle size distribution weathering crust

Nitrogen Forms in Humic Substances

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Pedosphere 1992年第4期2卷 307-315页

作者： ZHUOSU－NENG WENQI－XIAO lmcp，instituteofsoilscience AcademiaSinicaP.O.Box821Nanjing210008（China） lmcp，InstituteofSoilScie

In this paper,the nitrogen forms in newly-formed humic substances,including humic acid (HA),fulvic acid (FA) and humic acid in humin (HAI),were studied by using the ^15N CP-MAS NMR technique in combination with chemical *** show that the majority of nitrogen in HA,FA and HAI was in the amide form with some presented as aliphatic and/ or aromatic amines and some as pyrrole type nitrogen,although the contents of nonhydrolyzable nitrogen in them differed greatly from each other (15-55%).

关键词： fulvic acid humic acid 15N CP-M AS NMR nitrogen forms

Fate of N from Green Manures and Ammonium Sulfate

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Pedosphere 1991年第3期1卷 219-227页

作者： SHISHU－LIAN WENQI－XIAO 等 instituteofsoilscience AcademiaSinicaP.O.Box821.Nanjing210008（China） lmcp，instituteofsoilscience Ac

By means of ^15N tracer technique the fate of N in ammonium sulfate,milk vetch,sesbania and azolla,and the availability of their residual N were studied in a microplot *** showed that a) at the end of the first crop of early rice,both plant recovery and loss of N from ammonium sulfate were the highest whereas those from azolla were the lowest with those from milk vetch and sesbania in between;the sequence was reversed in terms of recovery of N in soil;the net residual N from ammonium sulfate was very low,about 1/7-1/4 of that from green manures,indicating that chemical N fertilizer contributes little to the soil N reserve;b) plant recovery of the residual N was low and it did not always decrease with time;the total plant recovery (from the second to the fifth crops) of the residual N from various test fertilizers was only 8-11% of the total N originally applied;c) the plant recovery of the residual N from ammonium sulfate was the highest,followed by those from milk vetch and sesbania,and that from azolla was the lowest,no matter in which cropping season (from the second to the fifth);N availability ratio showed the same trend,indicating that chemical N fertilizer helps renovate soil organic N,maintain and increase availability of soil N.

关键词： azolla milk vetch N availability ratio sesbania

Effects of Different Lead Compounds on Growth and Heavy Metal Uptake of Wetland Rice

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Pedosphere 1991年第3期1卷 253-264页

作者： CHENHUAI－MAN ZHENGCHUN－RONG 等 lmcp，instituteofsoilscience AcademiaSinicaP.O.Box821Nanjing210008（China） lmcp，InstituteofSoilScie

Effects of different lead compounds, PbCl2, Pb(NO3)2 and Pb(OAc)2, on the rice growth and uptake of lead and some microelements by wetland rice were studied. The results showed that the seed germination, rice seedling growth, chlorophyl content, grain yield and uptake of Pb, Cu, Zn, Fe and Mn by rice plant were affected by the chemical forms of Pb compounds added in soil to a certain degree. The germination rate and the amount of chlorophyl decreased remarkably with increasing Pb concentration, the root extension was restrained obviously by the presence of Pb, and the effect of PbCl2 was more evident than that of Pb(NO3)2 or Pb(OAc)2. The pot incubation test with yellow brown soil and red soil showed that there was no significant regularity in effect of Pb on grain yield, but the difference in the influence of various Pb compounds on yield was clearer. The effect on the amount of Pb in straw and brown rice was in the sequence of Pb(NO3)2> Pb(OAc)2> PbCl2. In case the content of Pb in brown rice was 0.5 mg/ kg, the relative loading capacities of yellow brown soil for Pb added as PbCl2, Pb(OAc)2 and Pb(NO3)2 were 100, 90 and 60 respectively. Pb uptake by wetland rice was closely related to the chemical species of Pb in soil, but there was no comparability among chemical forms of different Pb compounds in the same soil. The uptake of Cu, Zn, Fe and Mn by wetland rice was markedly affected by the addition of Pb, and different Pb compounds varied in their impacts on the uptake of other metals by different organs of wetland rice, e.g. the concentration of Fe in root increased significantly (r = 0.92), while opposite was true for Fe in brown rice (r =-0.92) due to the application of Pb(OAc), in soil. These results demonstrate that the effect of accompanying anions of Pb on the physiological and biochemical processes of wetland rice was rather complex.

关键词： anion loading capacity of soil microelement Pb rice