• Volume 45,Issue 2,2008 Table of Contents
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    • STOCHASTIC SIMULATION OF THREE-DIMENSIONAL SPATIAL DISTRIBUTION OF SOIL PROFILE TEXTURAL LAYERS IN ALLUVIAL PLAIN, NORTH CHINA

      2008, 45(2):193-200. DOI: 10.11766/trxb200612040232

      Abstract (1694) HTML (0) PDF 752.28 K (3837) Comment (0) Favorites

      Abstract:Complicated variability of the spatial distribution of soil textural layers is a typical characterist ic of alluvial soil.Quantificational description of soil profile structure is crucial to the study of land use and transport of soil water and solute.Based on observation of 139 soil profiles in a 15 km2 region in alluvial plain,North China,a transition probability geostat istical model was used to analyze variability of the spatial distribution of soil textural layers.Results indicate that the distribution of soil textu ral layers is not merely stochastic,but shows a certain tendency of juxtapositional transference.When this model was used in the conditional simulation of indicator kriging method,the final three dimensional geostatistical realization of soil textural layers spa tial distribution reflected the cross correlation between different soil textural layers.The findings may serve as powerful support for further simulation of water movement and solute transport in the regional soil.

    • DETERMINATION ERROR OF WATER CONTENT IN STONY SOIL

      2008, 45(2):201-206. DOI: 10.11766/trxb200611070233

      Abstract (2114) HTML (0) PDF 1.15 M (2576) Comment (0) Favorites

      Abstract:Existence of rock fragments in soil makes it more difficult to measure water content of the soil.Some researchers take rock fragments as fine soil or impermeable media for the convenience of calculation,but this may lead to big errors in some situations.Analysis of these errors was conducted.Indoor experiments were carried out to validate the formula for calculating relative errors.Results indicate that the relative error in measuring water content of fine soil or soil-fragment mixture media was related to rock fragment content and ratio of water content of rock fragment to fine soil.When the ratio was high,big error may result even if the rock fragment content was low; and when the ratio was very low,high rock fragment content also induced great error.In addition,the ratio was not a constant,but varied with their water contents.Therefore,the hydraulic properties of rock fragments need considering in the study on monitoring accurately water regime and simulating quantitatively water and solute transport processes in fields of stony soil.

    • SEM ANALYSIS OF SOIL PORE AND ITS FRACTAL DIMENSION ON MICRO SCALE

      2008, 45(2):207-215. DOI: 10.11766/trxb200610080234

      Abstract (2124) HTML (0) PDF 1.51 M (3715) Comment (0) Favorites

      Abstract:Samples of two soils different in soil texture were collected and scanned with a scanning electron microscope(SEM) producing SEM images in the scale ranging from 0.1 to 127.8 μm for analysis of size and number of pores and their distributions.The mass fractal dimension Dm and the surface fractal dimension Ds of soil pores are obtained from the measured data.The analysis shows that the certain correlativity of Dm existed with soil texture,bulk density,porosity and pore-size distribution.The finer the soil texture,the larger the bulk density,the lower the porosity,the higher the percentage of small pores,and the larger the Dm.Dm displayed a significant linear regression relationship with soil bulk density and soil porosity of soil.Ds reflects the degree of irregularity of the pore-solid interface in soil,and the larger the Ds the more irregular the soil pore profile.The distribution of Ds was found in agreement with a total normal distribution in soil pore.Both Dm and Ds was sensitive to variation of management pattern and tillage system of soils and they may be cited as useful indicators for soil management.

    • MAGNETIC PROPERTIES OF URBAN SUBGRADE SOIL AND THEIR PEDOGENETIC IMPLICATIONS

      2008, 45(2):216-221. DOI: 10.11766/trxb200701070235

      Abstract (1579) HTML (0) PDF 398.06 K (2248) Comment (0) Favorites

      Abstract:Magnetic properties can be simply,rapidly and accurately measured,and their pedogenetic implications are significant.In this study,63 soil samples collected from 11 subgrade soil profiles distributed in the downtown area of Nanjing were tested for low-frequency susceptibility,frequency dependent susceptibility,free iron oxide,active iron oxide,particle size distribution,organic carbon,pH and calcium carbonate equivalents.Results show that magnetic mineral and soil-forming processes were highly diversified due to heterogeneity of parent materials and artificial input.Magnetic minerals were mainly derived from fly ash,automobile exhaust and so on High pH and carbonate content retarded formation of fine magnetic minerals in urban en vironment.Magnetic susceptibility combined with other pedogenetic properties is very useful in illustrating the soil-forming processes in urban areas.

    • EXTRACTION OF SALINIZED SOIL INFORMATION IN ARID AREA BASED ON ETM+ DATA

      2008, 45(2):222-228. DOI: 10.11766/trxb200607260236

      Abstract (1961) HTML (0) PDF 872.80 K (2551) Comment (0) Favorites

      Abstract:The eco-environment of the arid region in West China is quite feeble.It is of great practical significance to accurately and automatically extract salinized soil information to the monitoring of soil salinization and the study on dynamic variation of soil salinization.Remote sensing(RS) technology demonstrates a number of advantages in studying soil salinization in arid area.But how to extract salinized soil information accurately from RS images is the basis of the study.An arid area typical of the Wigan-Kuqa River Delta Oasis in the north of the Tarim River Basin of Xinjiang,China,was selected as an example for the study.Seven-spectrum-band Enhanced Thematic Mapper-plus(ETM+) images dated August 1,2001 were used against the data obtained from field investigation of the soil features of the area,and analysis of typical soil RS soil information,to extract NDVI(Normalized Difference Vegetation Index) and PC3(third principal component),which were specified as major characteristic variables for information extraction of non-salinized soil and salinized soils,respectively.And MNDWI(Modified Normalised Difference Water Index),TM1 and TM7 were cited as supplementary characteristic variables.An information extraction model,using the decision-tree classification method was established and applied to classification of RS images.Results show that the RS information characteristics-based automatic information extraction of salinized soils is feasible and capable of yielding information higher in identification accuracy.

    • REMOTE SENSING MONITORING OF SOIL MOISTURE IN THE YELLOW RIVER DELTA

      2008, 45(2):229-233. DOI: 10.11766/trxb200612180237

      Abstract (1831) HTML (0) PDF 1.25 M (7058) Comment (0) Favorites

      Abstract:The Yellow River Delta is very important to our country in economy,agriculture and so on.To study how remote sensing data could be used to evaluate soil moisture distribution in the Yellow River Delta,a remote sensing TM data model for soil moisture was established based on all band Landsat-5 TM images,field investigation of soil moisture regimes and other related data with the aid of the research technique combining remote sensing,mathematics and modeling,the pixel decomposition method to extract soil moisture spectrum information by removing interference of vegetation,the soil moisture spectrum method and the regression analysis.The TM data model was further verified against the study area.Results indicate that the findings conform to the reality.The TM data model is thought to be applicable and workable to monitoring and evaluating of soil moisture distribution.

    • SOIL ENVIRONMENTAL QUALITY AND REMEDIATION IN YANGTZE RIVER DELTA REGION Ⅴ.POLLUTION STATUS AND SOURCES OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGRICULTURAL SOILS OF TYPICAL DISTRICTS

      2008, 45(2):234-239. DOI: 10.11766/trxb200610220238

      Abstract (1747) HTML (0) PDF 1.24 M (2645) Comment (0) Favorites

      Abstract:The contents and sources of 15 USEPA priority PAHs in agricultural surface soils(0~20 cm) of typical districts,Wuxi and Taizhou in the Yangtze River Delta were studied.The results showed that the PAHs pollution was heavy in agricultural soils of Wuxi district and the sum of 15 PAHs contents ranged from 1 058 to 9 500μg kg- 1.The composition of PAHs was mainly 4 to 6 rings and the main sources were petroleum and combustion of petroleum,grass,wood and coal.In agricultural soils of Taizhou district,the PAHs pollution was light and the sum of 15 PAHs contents ranged from 128 to 604μg kg-1.The composition of PAHs was mainly 3 to 6 rings and the main sources were petroleum and petroleum combustion.

    • BIOAVAILABILITY OF SOIL HEAVY METALS IN THE YANGTZE RIVER DELTA——A CASE STUDY OF KUNSHAN CITY IN JIANGSU PROVINCE

      2008, 45(2):240-248. DOI: 10.11766/trxb200610110208

      Abstract (2177) HTML (0) PDF 1.10 M (3432) Comment (0) Favorites

      Abstract:Bioavailability of soil heavy metals refers to the degree of absorption and accumulation of soil heavy metals by organisms and toxicity to organisms.Kunshan City,typical of the Yangtze River Delta,was chosen as case for study on bioavailability of soil heavy metals.A total of 126 soil samples were collected and analyzed.Results show that available Cd ranked first in concentration,and its bioavailability reached up to 63.75%.Significant differences were observed in bioavailability of heavy metals between different function zones,Cd,Cu,Ni,Pb and Co were the highest in the smelting and plating industry zone,Cr in the chemical industry zone and Zn in the vegetable production zone.Differences in bioavailability of Cd,Cr,Cu,Pb and Zn were also found between soil types,which were in a decreasing order of Wushan soil > Qingni Soil > Huangni Soil,as well as between soils of different parent materials which were lined in an order of fluvial and marine sediment > lacustrine sediment.It was also found that the effect of soil forming parent materials was greater than that of soil type on the bioavailability,and that the bioavailability and contents of available heavy metals declined with the depth in soil profile.Marked positive correlation existed between concentrations of heavy metals in rapeseed and concentrations of bioavailable heavy metals in the soil.Zn and Cd showed the highest enrichment coefficient,posing the highest potential risk.Analysis of total concentrations & bioavailability of soil heavy metals and their total concentration in plant revealed that Cd was the dominant pollutant that threatens safety of agricultural production and groundwater.

    • DETERMINATION OF NITROGEN, CARBON AND OXYGEN STABLE ISOTOPE RATIOS IN N2O, CH4, AND CO2 AT NATURAL ABUNDANCE LEVELS BY MASS SPECTROMETER

      2008, 45(2):249-258. DOI: 10.11766/trxb200704250209

      Abstract (1876) HTML (0) PDF 1.02 M (3767) Comment (0) Favorites

      Abstract:The increasing effect of greenhouse gases is arousing more and more concern of the people in the world and soil as both a source and a sink of these trace gases has been studied.Accurate determination of stable isotope composition of these trace gases will help people trace their sources and find out their release patterns.Isotopic mass spectrometers with a fully automated interface for pre-GC concentration(PreCon) of trace gases can be used with high precision to determine stable isotope ratios of carbon,nitrogen,and oxygen in N2O,CH4,and CO2 at atmospheric concentrations.A series of tests including sampling,concentrating,and mass spectrometric determination were conducted,and accurate and reliable results were obtained,confirming that the method is feasible and applicable to air quality monitoring and the study of atmospheric chemistry,plant respiration,and soil gas generation.

    • EFFECTS OF LONG-TERM FERTILIZATION ON LABILE ORGANIC CARBON IN SOIL AGGREGATES IN RED PADDY SOIL

      2008, 45(2):259-266. DOI: 10.11766/trxb200609050210

      Abstract (1824) HTML (0) PDF 569.19 K (3219) Comment (0) Favorites

      Abstract:A long-term field experiment has been carried out for 23 years in Jinxian County Institute of Red Soil in Jiangxi Province(116b20c24°E,28b15c30°N).One of the aims of the experiment is to study effects of longterm fertilization on labile organic carbon pool in soil aggregates in red paddy soil.It is designed to have the following treatments,i.e.1) Zero fert ilization(CK),2) chemical fert ilizers alone(NPK),3) organic fertilizers alone(OM),and 4) combinat ion of chemical and organic fertilizers(NPKM).Results show that content of labile organic carbon in soil aggregates decreased with soil depth.Long-term application of fertilizer,especially in Treatment NPKM,increased content of labile organic carbon in soil aggregates,thus preserving and improving quality of the soil carbon pool.Content of labile organic carbon and percentage of soil labile organic carbon to total soil organic carbon differed between aggregates different in size fraction.In terms of content of potent ial mineralization carbon(PMC) and percentage of PMC to total soil organic carbon,aggregate size fractions followed a decreasing order of 0.25~1 mm,1~3 mm,> 3 mm,0.05~0.25 mm,and < 0.05 mm,whereas in terms of percentage of content of dissolved organic carbon(DOC) to total soil organic carbon,they did a decreasing one of 0.05~0.25 mm,0.25~1 mm,1~3 mm,> 3 mm,and < 0.05 mm.Contents of PMC and DOC in aggregates were significantly related to content of SOC(p< 0.01) in A horizons of all treatments,and in soil P horizon as well,except for the size fraction of 1~3 mm(p< 0.05).Micro-aggregates(< 0.25 mm) was higher than macro-aggregates(> 0.25 mm) in stability.

    • VARIATION OF NITROGEN USE EFFICIENCY OF RICE DIFFERENT IN GENOTYPE AND ITS EVALUATION

      2008, 45(2):267-273. DOI: 10.11766/trxb200610160211

      Abstract (2686) HTML (0) PDF 626.91 K (3810) Comment (0) Favorites

      Abstract:Nuse efficiency of rice is key to its overall yield potential,and efforts to improve the key potential must be guided by a thorough understanding of the process that governs N use efficiency.Field experiment was conducted to assess differences in grain yield,Naccumulation,and N physiological use efficiency between 177 genotypes of rice japonica(71 semilate varieties(130~150 d) and 106 late varieties(151~172 d) under two levels of N supply(0 and 180 kg hm-2) in 2003.Grain yield and N accumulation increased with the N rate,while physiological N use efficiency decreased.Significant differences in grain yield,N uptake and N physiological use efficiency were observed between genotypes within the same variety group under the same N application rate.Based on grain yield under two N rates,genotypes within each group were divided into four types,such as efficient-efficient,inefficient-efficient,inefficient-inefficient,and efficient-inefficient.High N use efficiency(NUE) cultivars produced high yields when N was applied,and low NUE cultivars low yields.Thus genotypes which have promising traits for improved N uptake and N physiological use efficiency are identified.Those with higher N physiological use efficiency were lower in N concentration in straw at maturity.Further study is needed to elucidate mechanisms involved in high N uptake and N physiological use efficiency.

    • RELEASE CHARACTERISTICS OF AMMONIUM FROM POLYMER-COATED COMPOUND FERTILIZERS

      2008, 45(2):274-279. DOI: 10.11766/trxb200610310212

      Abstract (1613) HTML (0) PDF 1.91 M (2532) Comment (0) Favorites

      Abstract:Mono-component and multi-component coated controlled release fertilizers were used to check the characteristic of ammonium release in the static water treated with different temperatures and granule radii.The results showed that the release rate of ammonium increased significantly under high temperature and small granule radius.Moreover,the components of fertilizer core had a significant influence on ammonium release, because different components of fertilizer core had variable ions,which would change the saturate concentration of ammonium related with the impetus of ammonium release.The lag and linear period of ammonium release were also influenced by temperature,granule radius and components of fertilizer core.The activation energy was introduced as a sensitivity indicator of release rate change under different temperatures.The activation energy was also directly related with the granule radius and components of fertilizer core.The release profiles of coated fertilizer could be evaluated by the lag period,linear period,decay period and the activation energe,which gave new thoughts for the development and application of coated fertilizer.

    • ATMOSPHERIC NITROGEN DEPOSITION IN AGRECOSYSTEM IN RED SOIL REGION OF JIANGXI PROVINCE

      2008, 45(2):281-287. DOI: 10.11766/200612040213

      Abstract (2181) HTML (0) PDF 931.31 K (3308) Comment (0) Favorites

      Abstract:During the period from December 2004 to November 2005,atmospheric deposition was monitored at the Yingtan Red Soil Ecological Station,Chinese Academy of Sciences,in Jiangxi Province.Observation data were analyzed with focus on concentrations of nitrogen oxidants and nitrogen deposition flux.Over the farmland,the concentrations of NH3,NOx,organic nitrogen(ON) were 24.6,3.54,and 7.2 μg m-3,respectively,in the atmosphere,4.16,4.64 and 0.92μg m-3,respectively,in aerosols,and 0.89,0.73 and 0.26 mg L-1,respectively,in precipitation.The total nitrogen deposition is N 6.26 g m-2,of which 3.19 g m-2 or 51% was dry deposition,and 3.07 g m-2 or 49% wet deposition,and 5.47 g m-2 or 87.4%,inorganic nitrogen and 0.79 g m-2 or 12.6% organic nitrogen.Compared with other types of landuse,such as grassland,forest and lake,farmland receive more atmospheric nitrogen deposition in Jiangxi Province,which will have significant impact on nitrogen balance within the farmland ecosystem.

    • DYNAMICS OF SOIL ORGANIC SULFUR MINERALIZATION IN BLACK SOILS OF NORTHEAST CHINA AND ITS AFFECTING FACTORS

      2008, 45(2):288-295. DOI: 10.11766/trxb200610140214

      Abstract (1956) HTML (0) PDF 1.65 M (2527) Comment (0) Favorites

      Abstract:An open incubation method was used.Samples of black soils,collected from different areas(Beian,Hailun,and Gongzhuling) and plots of a long-term fertilization experiment,were incubated aerobically at 20℃ or 30℃,respecfively to study characteristics of organic S mineralization in the soils.Results show that in aerobic incubation,cumulative organic Smineralization increased with the time going on,followed the first-order kinetic model.The cumulative organic S mineralization in the first 4 weeks accounted for 50%~62% of the total mineralization in 14 weeks.The black soil in Gongzhuling was the highest in S supply capacity,and stronger in S supply intensity and quicker in organic S mineralization rate than in Hailun and Beian.The higher the temperature,the higher the mineralization potentiality of organic S,the higher the velocity constant of mineralization reaction,and the shorter the half-life period.In terms mineralization potential of organic S in the long term fertilization experiment,the treatments were in the order of M > MNPK > NPK > CK,showing that organic fertilizer was the major source of soil organic S,and improved soil S supply capacity.

    • EVOLUTION OF FERTILIZATION RATE AND VARIATION OF SOIL NUTRIENT CONTENTS IN GREENHOUSE VEGETABLE CULTIVATION IN SHANDONG

      2008, 45(2):296-303. DOI: 10.11766/trxb200611220215

      Abstract (2981) HTML (0) PDF 526.98 K (4421) Comment (0) Favorites

      Abstract:Shandong Province is the main vegetable producing region in China,with its greenhouse coverage account ing for nearly 50% of the country's.In the period from 1994 to 1997,the mean annual fertilization rate on greenhouse vegetable in Shandong was N 1 351 kg hm-2,P2O5 1 701 kg hm-2 and K2O 539.6 kg hm-2.In comparison with the application rate in 2004,the application rates of nitrogen and phosphorus fertilizers decreased,but of potassium fertilizer and organic manure in creased significantly in 2007.Apparent balance of soil nutrients showed that soil N,P and K was gaining by a large margin.Re gardless of high fertilization rates,fertilizer recovery rates were still quite low.The apparent fertilizer recovery rate of nitrogen,phosphorus and potassium was 21 33%,2 82% and 61 34%,respectively,in greenhouses in Shouguang City in 1997.Soil pH in the greenhouse showed a declining tendency as compared with that in the open field,while the content of organic matter a reverse one.The content of soil available nitrogen varied sharply from area to area,averaging 205 4 mg kg- 1,and the content of available P had a similar tendency and averaged 2252 mg kg-1,showing an obvious build up effect and an extremely positive relationship with greenhouse age(r= 0.550**,n= 35).The highest content of available K was up to 369.7 mg kg-1,which also demonstrated an obvious build up effect.The older the greenhouse,the higher the content of available potassium(r=0.502**,n=35).The content of soluble calcium was 337 9 mg kg-1 in the surface soil,and the content of soluble magnesium was 67.8 mg kg-1.Generally the content of soil trace elements,except boron,in the greenhouse was higher than in the open field,respectively.

    • NUTRIENT ELEMENT DISTRIBUTION IN ORGANS OF HEPTACODIUM MICONIOIDES IN DIFFERENT COMMUNITIES AND ITS RELATIONSHIP WITH SOIL NUTRIENTS

      2008, 45(2):304-312. DOI: 10.11766/trxb200611010216

      Abstract (1764) HTML (0) PDF 798.01 K (3283) Comment (0) Favorites

      Abstract:Based on investigations and results of Twinspan classification,20 plots in the Dapanshan Nature Reserve were sorted into five different kinds of communities.To well understand nutrient element distribution of Heptacodium miconioides and its relationship with soil nutrients in those five communities,five nutrient elements in five organs of H.miconioides sampled during its anthesis were measured.Results show:1) Nutrient contents in the plant differed somewhat from community to community,but the differences were not significant by related samples nonparametric test(p > 0.05).And the variation coefficients of N,P or K were higher than of Ca or Mg.2) Among the organs N,P or K content declined in the order of leaf > bark > branch > stem,while Ca or Mg in the order of bark > leaf > branch > stem,and the total content of the five elements was in the order of leaf > bark > branch > stem.The differences were significant by related samples nonparametric test(p < 0.01).The variation coefficient of the mean content of the same element in different organs was in the order of leaf > bark > branch > stem.3) No close relationship was found between soil nutrient contents and the five elements in H.miconioides,indicating the variation of the nutrient contents in the plant in different communities was not dominated by the soil nutrient contents,but by other habitat conditions,like thickness of the soil layer,exposure of rocks,etc.

    • CHANGE IN MICROBIAL BIOMASS AND ITS CONTROLLING FACTORS IN DEGRADED SOIL AFTER REFORESTRATION OF Pinus massoniana

      2008, 45(2):313-320. DOI: 10.11766/trxb200611070217

      Abstract (2084) HTML (0) PDF 1.06 M (2208) Comment (0) Favorites

      Abstract:Reforestation of degraded soil can improve soil quality through litter fall,but little is known about interactions between soil microbial biomass and soil physical and chemical properties.The objectives of this study are to determine effects of litter fall on physical and chemical properties and microbial biomass of a degraded soil 18 years after reforestation of Pinus massoniana and to analyze controlling factors on change in soil microbial biomass.Compared with the plot of eroded bare land,the reforested plot showed significant improvement in its measured soil properties,including soil porosity,proportion of water stable aggregate(> 0.25 mm),soil organic carbon and total nitrogen and soil microbial biomass irrespective of whether litter was removed or not.Magnitude of the increases varied with soil depth,slope position and litter management,being larger in the surface than subsurface soils,on the hilltop and foot-slope than on the middle slope.Compared with the treatment of litter preservation,the treatment of litter removal resulted in lower magnitude of the increases.Path analyses showed soil organic carbon content,was the most important factors affecting soil microbial biomass,followed by soil porosity,and then litter,which had some indirect effect through its contribution to soil porosity and soil organic carbon content.The findings of the study suggest that improving soil structural properties is important to recovery of soil microbial biomass.

    • APPLICATION OF PLFA ANALYSIS IN DETERMINATION OF SOIL MICROBIAL COMMUNITY STRUCTURE IN WOODLAND,CROPLAND AND GRASSLAND IN FARMLAND-PASTURE INTERLEAVING ZONE OF NORTH CHINA

      2008, 45(2):321-327. DOI: 10.11766/trxb200610230218

      Abstract (1451) HTML (0) PDF 916.09 K (2402) Comment (0) Favorites

      Abstract:Soil samples were collected from woodland,rain-fed cropland,irrigated cropland and grassland in Wuchuan County,Inner Mongolia in early May of 2002 in the study on distribution characteristics of soil microbial phospholipid fatty acids(PLFAs).Soil microbial biomass carbon(MBC),PLFAs and some soil basic properties were determined.Results showed that total PLFAs ranged from 19.82 ng g-1 to 47.28 ng g-1,and monounsaturated fatty acids with G- bacteria as indicator accounted for 29%~37% and branch fatty acids with G+ bacteria for 15%~20% of the total PLFAs.Irrigated cropland and grassland soils were significantly higher or nearly 3 times than rain-fed cropland and woodland soils in total PLFAs.Principal component analysis(PCA) indicated that PC1 consisted mainly of fatty acids of 14:0 3OH,cy19:0,12:0,br17:0 and 18:2 ω9,12,and PC2 mainly of 16:0,16:1 ω11,18:1 ω9,19:0 and a15:0.The irrigated cropland,rain-fed cropland and grassland were quite similar in microbial community structure,but significantly different from woodland soil.

    • RESPONSE OF IRIS LACTEA VAR.CHINENSIS TO NaCl AND NaHCO3 STRESS IN GROWTH AND PHOTOSYNTHESIS

      2008, 45(2):328-335. DOI: 10.11766/trxb200612190219

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      Abstract:A hydroponical culture experiment of Iris lactea was conducted to explore responses of the plants to NaCl and NaHCO3 stress(0,70,210,350 mmol L-1) for 10 days in plant growth,water status,cell membrane permeability,chlorophyll content and photosynthetic characteristics.Results indicate that Treatments NaHCO3 were much higher than Treatments NaCl,the same in Na+ concentration,in effect inhabiting growth,decreasing water content,damaging cell membrane permeability and reducing chlorophyll content,which may probably be attributed to the combinative effect of high pH and high salinity in the former.Meanwhile,under alkali-saline stress,plant shoots were affected more than roots,and plant fresh biomass decreased more than dry biomass.Plant chlorophyll content decreased with increasing stress concentration and duration of the stress.Plant electrolyte leakage was negatively correlated to water content in leaves.Non-stomatal restriction was the main cause for reduced plant photosynthetic rate under NaHCO3 stress,while under NaCl stress,both stomatal restriction and non-stomatal restriction occurred.

    • INTERACTIONS BETWEEN LOW pH AND ALUMINUM TOXICITY ON CHARACTERISTICS OF ROOT BORDER CELLS OF BUCKWHEAT

      2008, 45(2):336-340. DOI: 10.11766/trxb200702130220

      Abstract (1900) HTML (0) PDF 581.04 K (2555) Comment (0) Favorites

      Abstract:Plant roots release a large number of border cells into the rhizosphere,which act as a chemical,physical and biological interface between roots and their surrounding environment.Interactive effects of low pH and aluminum toxicity on root growth and border cell characteristics were studied.Buckwheat was grown in aeroponic culture for 12 h with Al supply varying from 0,50 to 100 μmol L-1,and solution pH from 3.5,4.5 to 5.5.Root elongation,border cell viability and mucilage layer of the plant were measured.With Al concentration increasing to 50 μ mol L-1 and 100 μmol L-1 root elongation decreased by 18.6% and 31.9% at pH 3.5,by 18.9% and 26.8% at pH 4.5,and by 8.5% both at pH5.5.The effect remained almost the same whether the plant was treated for 12 or 24 hours.With pH value decreasing to 3.5,border cell viability decreased by as much as 28.6%,but the mucilage layer was not much affected.Al treatment at 100 μ mol L-1 significantly induced a thicker mucilage layer around border cells,about 64.6% thicker.Decreasing pH exacerbated the effect of aluminum toxicity on root growth and border cell characteristics.Lowest activity of border cells and the thickest mucilage occurred under the treatment of pH 3.5 and 100 μ mol L-1 Al3+,which indicated great significant interaction between pH and Al3+ 1 The results suggest that low pH and aluminum toxicity act jointly impaire border cells,and the resultant mucilage layer around border cells plays a role of shield against Al damage.

    • OPTIMIZATION OF 16S rDNA AMPLIFICATION SYSTEM OF BACTERIA IN BLACK SOIL IN NORTH CHINA

      2008, 45(2):341-347. DOI: 10.11766/trxb200612250221

      Abstract (1801) HTML (0) PDF 432.13 K (2645) Comment (0) Favorites

      Abstract:Target genes were amplified with the TD PCR method,two orthogonal experiments were designed to screen out optimal concentrat ions of various components of the PRC react ion system,while to explore annealing time,extending time and cycling frequency.Results show that soil bacteria 16S rDNA amplification system fit for black soil in North China was in 25 l volume,which was composed of 10×buffer 2.5μl,20 ng soil microbial DNA template,Mg2+ 2.5 mmol L-1,dNTPs 0 25 mmol L-1,0.3 mol L-1 primer,and 1 5UTaq enzyme.The TD PCR reaction procedure went like first keeping 95 for 5 min to make soil microbial DNA denatualized,95 for 45 s more,65~56 for 60 s,and then 72 for 90 s,and lowering the tem porature by 1 every two cycles; and starting another 10 cycles of 95 for 45 s,55 for 60 s,and 72 for 90 s,and finally staying at 72 for 10 min for extending.

    • >Reviews and Comments
    • APPLICATION OF MICROBIAL CELL-BASED BIOSENSORS IN ENVIRONMENTAL MONITORING

      2008, 45(2):348-354. DOI: 10.11766/trxb2007011580222

      Abstract (2076) HTML (0) PDF 855.72 K (3259) Comment (0) Favorites

      Abstract:Microbial cell-based biosensors take microorganism cells for biological sense organs,which are capable of quickly sensing and/or detecting total toxicity and various kinds of pollutants in the environment.More and more reports in this field have been published.With the rapid progress of the research,this technique has become more and more mature.At first,it could only monitor total toxicity of the environment with the aid of bioluminescent bacteria,and now it can be used to detect specifically various kinds of pollutants,including heavy metals(such as Hg,Cd,As,Pb,Cu,Ag,and Ni),organic pollutants(such as benzene,toluene,and PAHs),antibiotics(such as tetracycline,β-lactams),and even nutrient elements(such as nitrogen,phosphorus).Because of the characteristics of microorganism cells,this technology shows significant advantages and remarkable potentiality in the field of environmental monitoring,especially in detecting the bioavailability of pollutants.It can beused as an effective tool in in-situ environmental monitoring,quick and low in cost.So it can be expected that the technology will find more extensive application in environmental monitoring.A review of advancements in application of Microbial cell-based biosensors to environmental monitoring is presented and its future trends are also discussed.

    • >Research Notes
    • SPATIAL VARIABILITY OF SOIL NUTRIENT CHARACTERISTICS UNDER PADDY-UPLAND CROP ROTATION IN CHENGDU PLAIN

      2008, 45(2):355-359. DOI: 10.11766/trxb200610100223

      Abstract (1707) HTML (0) PDF 704.96 K (2634) Comment (0) Favorites

      Abstract:肥料是作物的粮食,研究表明,施肥对粮食增产的贡献率可高达50%以上[1].但是,我国长期存在的盲目的、非精准的不合理施肥,导致肥料当季利用率较低,特别是氮、磷肥.这既增加了种植成本,又造成水体富营养化[2,3].土壤养分特性的空间变异研究对于实现田间土壤养分精准管理、变量施肥、提高肥料利用率等都具有非常重要的意义.国外对土壤养分特性空间变异的研究始于20世纪70年代,许多土壤学家将GIS和地统计学技术引入土壤学领域研究土壤属性的空间变异规律[4,5],并取得很好的结果.国内自90年代中期以来,许多研究者都对土壤属性特别是土壤养分的空间变异进行了研究[6~8],但主要侧重于对土壤物理性质和土壤盐分的空间变异研究,在区域上主要以北方旱地的土壤养分变异研究为主.

    • ERROR ANALYSIS OF SOIL PROPERTY SPATIAL INTERPOLATION WITH RBF ARTIFICIAL NEURAL NETWORK WITH DIFFERENT INPUT METHODS

      2008, 45(2):360-365. DOI: 10.11766/trxb200612250224

      Abstract (1716) HTML (0) PDF 449.11 K (3488) Comment (0) Favorites

      Abstract:土壤是一个时空连续体,受自然和人为因素的影响,具有高度的空间异质性[1].这种空间异质性体现在土壤的物理、生化信息随空间位置的不同而呈现较大的差异,并且不同土壤性质具有不同程度的空间变异.准确掌握土壤物理、生化信息的空间变异规律,不仅是精准农业中土壤养分管理的基础,对于环境保护和治理也具有十分重要的意义.因此,土壤性质的空间插值技术研究得到了广泛的关注和重视[2~4].目前应用于土壤性质空间插值的方法主要包括基于几何学意义的移动平均法[5]、反比距离加权法[6,7]、样条函数法[8]、趋势面分析法[9,10]以及基于统计学意义的克里格(Kriging)插值法[11~13]等.

    • STUDY OF COORDINATION MECHANISM OF HUMIC ACID WITH Fe3+, Al3+, AND Mn2+WITH INFRARED SPECTROSCOPY

      2008, 45(2):366-369. DOI: 10.11766/trxb200609200225

      Abstract (2127) HTML (0) PDF 316.89 K (5154) Comment (0) Favorites

      Abstract:被称为土壤“精华”的土壤腐殖质影响着土壤的物理性质、化学性质和生物学性质;其中,腐殖酸是腐殖质的核心成分,由于含有大量的羧基、羟基等活性基团,具有很高的反应活性,对环境中金属离子具有强烈的结合力,使之成为环境中金属离子的重要络合剂和聚沉剂,从而对金属元素在环境中的迁移、转化和生物有效性起着十分重要的调控作用[1~4].腐殖酸与金属离子的相互作用一直是土壤、生态、环保等领域研究的重点,不少学者从动力学或热力学的角度研究了腐殖酸对金属离子铜、铅、镉、汞等离子的吸附和络合作用[3~13];也正是由于腐殖酸结构中有机活性基团众多,对于腐殖酸与金属离子的相互作用的确切部位或反应机理至今依然未彻底弄清楚.

    • SURFACE CHARACTERISTICS OF ORGANIC MODIFIED SOIL I.CEC AND SPECIFIC SURFACE AREA

      2008, 45(2):370-374. DOI: 10.11766/trxb200610300226

      Abstract (2144) HTML (0) PDF 1.43 M (2417) Comment (0) Favorites

      Abstract:污染物在土壤中的行为与土壤的表面化学特性密切相关,研究土壤的表面化学特性对于从微观领域了解污染物行为及其变化规律,采取有效措施减轻并消除土壤中污染物的危害,保护土壤环境和人体健康具有重要意义.为了增强土壤对有机污染物的吸附固定,国内外开始研究应用阳离子型表面活性剂对黏土矿物或土壤进行修饰,使土壤的表面性质由亲水性转变为疏水性,增大对土壤中有机污染物的吸附能力[1,2],研究表明,利用阳离子型表面活性剂修饰黏土矿物或土壤,可以显著增强土壤对水中有机污染物的吸附固定能力[3~7],但对于重金属离子却具有不同的作用[8~11].

    • DISTRIBUTION CHARACTERISTICS OF SOIL MBC AND RELEVANT FACTORS IN WOODLAND OF TAMARIX RAMASISSIMA, CENTRAL ASIA

      2008, 45(2):375-379. DOI: 10.11766/trxb200610310227

      Abstract (1722) HTML (0) PDF 909.60 K (2572) Comment (0) Favorites

      Abstract:在土壤性状空间变异性的经典统计分析中,是将土壤性状看作随机的、彼此相互独立的.然而实际中,在一定的空间范围内,土壤性状存在一定的空间依赖.地统计学方法被成功地引入土壤空间性状分析[1],并已经被证明是分析土壤性状空间分布和空间异质性的最有效方法之一[2,3].近20年来已被国内外土壤研究者广泛采用[3].土壤性状的空间变异是指一个质地视为均一的区域内,在同一时间,不同点的土壤性状存在着的明显变异性[4],这种变异性是由结构性因子和随机性因子共同作用的结果.结构性因子包括土壤形成过程中的成土母质、地形、地下水位及形成的土壤类型等因素;随机性因子是指土壤管理过程的措施、种植的作物、耕作栽培措施等.

    • QUANTITATIVE ANALYSIS OF INTERACTIONS BETWEEN FACTORS INFLUENCING POLARIZED REFLECTION OF LOESS

      2008, 45(2):380-383. DOI: 10.11766/trxb200608180228

      Abstract (1654) HTML (0) PDF 184.11 K (2135) Comment (0) Favorites

      Abstract:早期遥感土壤反射光谱的研究主要是将土壤样品表面看作郎伯体,进行垂直对地观测采集数据.大量实验表明,土壤含水量、有机物含量、氧化铁含量、机械组成以及土壤表面粗糙度均会对土壤的光谱反射率产生显著影响[1].随着遥感应用研究的深入,在20世纪70年代末,Suits、Hapke、Strahler、李小文等大批学者对地物的二向反射做了定量研究,从而使遥感进入了获取地物三维信息的崭新阶段[2~5].偏振反射是二向反射的孪生姊妹,人们在对土壤的二向反射进行研究的同时也势必要对土壤的偏振反射进行一定的研究[6].

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