Abstract:Mathematical structure of biological classification and its convincing interpretation have been an academic issue that has aroused extensive attention in the biological circle,but few have applied statistical distribution models to the study or analysis of structure of nonbiological classification,such as Soil Taxonomy.Comparison was made between the biological classification system for soil borne plant parasitic nematodes of the Tylenchina suborder and with a nonbiological one(Chinese Soil Taxonomy as an example)in biodiversity characteristics by calculating the power law distribution and Lognormal distribution of the two systems to analyze their similarities and differences.Results show that the two systems are very similar in mathematical structure and diversity characteristics,and both are reasonable information systems,which fit well to the same distribution models, such as power law distribution and lognormal distribution.Minor differences also exist between the two.The classification system of nematodes of the Tylenchina suborder is a branching system more profuse than the Chinese Soil Taxonomy.The latter seems to be more reasonable in designing in terms of evenness values.The Willis curves show that Chinese Soil Taxonomy has a more regular structure,which is probably related to difference in classification ideology between the two scientific disciplines.

Abstract:The Lijiagang Xiashu profile in Nanjing is a unique area for Quaternary research.Samples were taken from the file with an interval of 5 cm for measuring geochemical proxy,brightness,color reflector,magnetic susceptibility and granularity.And the climate stratum during 20～120 ka BP was divided into 5 strata of loess and 5 strata of paleosol by comparison of its multi-climate proxies with other records,such as high resolution oxygen isotopic records of marine and Guliya ice core,magnetic susceptibility of Malan loess.Luminescence dating technique was also adopted in this study,distinguishing 4 climatic cycles,corresponding to the MIS2～MIS5.And the stage corresponding to MIS3 was especially warm and wet,demonstrating its significant difference from the Tibet Plateau and the loess in West China in process and intensity of the climatic change.It’s indicated that the ocean warming plays an important role on the East Asian monsoon area.

Abstract:Based on 194 soil samples collected from the studied zone in the suburbs of Suzhou,a minimum dataset(MDS) for soil quality assessment was defined and developed with the aid of multivariate statistical techniques,such as multivariate analysis,principal component analysis and correlation analysis.Different from related previous work,the study took into account effects of the pattern and duration of land-use on soil quality as an index of MDS,and worked out integrated load of each candidate soil physico-chemical variable on all principal components with eigenvalue >1 rather than just compare the load of a variable on a principal component and then rule out the others,thus avoiding losing too much soil quality information.Finally,reliability of the method was validated from different angles by applying the method to 54 Huangnitu samples,77 Huangsongtu samples and all the 194 samples.The same MDS produced suggestes that the method is very good in stability and reproducibility.Once the method is improved,it could be extrapolated to other soil types in other areas of China,so as to overcome the shortcoming of uncomparability of the results of soil quality assessment using different methods because the soils vary so much in geographic distribution and natural conditions.

Abstract:The red soil hilly region,located in the tropical and subtropical zones of Southeast China,spreads over 9 provinces and 1 autonomous region.With plentiful light,heat and water resources,it enjoys high potential for agricultural and economic development.However,soil erosion and seasonal drought are major restraints for sustainable agriculture as a result of improper land use and uneven distribution of rainfall.Soil aggregate stability has substantial effects on soil porosity and,therefore,may influence infiltration rate and runoff processes of rainfall.The objects of this study are to determine relationship between wetting rate and runoff and soil loss.Red soils derived from Quaternary red clay were collected and packed in 0.6 m×0.3m trays,separately,wetted at 3 wetting rates(2,10 and 60 mm h^-1),and then exposed to simulated rainfall with an intensityof 60 mm h^-1 in laboratory.The Le Bissonnais’method was applied to simulating the breakdown mechanisms of slaking in fastwetting,stirred wetting,and slow wetting.The aggregate stability index,i.e.mean mass diameter(MMD),indicated that fast wetting caused the most severe disruption of aggregates.The MMD in each soil ranked in the order of slow wetting,stirred wetting,fast wetting.Significant correlation was observed between soil loss,runoff rate and wetting rate.The results show that the runoff rate increased with wetting rate,ranging from 0.58 to 0.96 mm min^-1.In each soil exposed to slow wetting rate,less soil loss was noted.Wetting rate also played a great role in determining sediment materials.The largest MMD of sediment materialswas found in soils exposed to fast wetting.

Abstract:Runoff erosion formation and sediment yielding intensity on slopes of the Loess Plateau of China show apparent vertical zonation because of the complicated topography and the special climate conditions of the region.To reveal mechanism of the formation of runoff erosion and the characteristic of vertical zonation,an experiment was carried out with a simulated slope-gully system,which was composed of a 4-meter long slope(20°)and a 3-meter long gully slope(50°),and four different fluxes of runoff(2.1 L min^-1,3.2 L min^-1,5.2 L min^-1,and 7.2 L min^-1).Impacts of flux,silt content and impetus of the runoffs on sediment yield were explored.Based on the findings,a mathematical model was established for depicting sediment yielding process in the system.Results show that intensity,silt content and flowing power per unit volume of the runoff flowing down the upper slope were the major factors affecting sediment yield in the gully.Sediment yield in the gully was exponentially related to intensity of the runoff,and linearly to silt content and flowing power per unit volume of the runoff.Based on the concept of flowing power per unit volume,a value defined to be critical to sediment yielding in the gully was figured out to be 0.632.And based on the modified Yalin equation and factors affecting sediment yield,mathematical models were worked out for sediment yield on the slope and in the gully,respectively.Results of the calculation using the models were found to be satisfactorily comparable to the measured ones.

Abstract:Soil desiccation is a prominent in artificial forestlands,grasslands and croplands on the Loess Plateau,seriously threatening the effects of revegetation and sustainable development of dryland farming.Based on observation of soil moisture in deep soil layers in 53 different kinds of forestlands,grasslands and croplands in semi-humid zone,semi-arid zone and semi-arid/arid zone of the Loess Plateau,soil moisture contents,soil water overuse rate,soil desiccation indexes and thickness of desiccated soil layers in these areas various forestlands,grasslands and croplands were calculated,analyzed and compared.Results show as follows:1)Mean soil moisture contents of forestlands,grasslands and croplands were in the range of 6.46%～12.57%,6.49%～11.52% and 9.32%～16.00%,respectively;with the highest in the semi-humid zone,and the lowest in the semi-arid/arid zone.The average soil water overuse rate of forestlands,grasslands and croplands was 521 mm,491 mm,and 30 mm,respectively,and the highest among the forestlands was in the semi-arid zone,and the highest among the grasslands in the semi-humid zone and semi-arid/arid zone,and the highest among the croplands in the semi-arid/arid zone.2)The average soil desiccation index of the forestlands,grasslands and croplands was 39%,42% and 96%,respectively,falling into the category of severely desiccated, severely desiccated and slightly desiccated,separately.The most severely desiccated forestland soils were in the semi-arid zone and semi-arid/arid zone,the most severely desiccated grassland soils in the semi-humid zone and semi-arid/arid zone,and the most severely desiccated cropland soils were in the semi-arid/arid zone.The average thickness of the desiccated soil layers in forestlands,grasslands and croplands was 881 cm,836 cm and 336 cm,respectively.The thickest desiccated soil layers of forestlands were in the semi-arid zone and semi-arid/arid zone,and of grasslands and croplands in the semi-arid/arid zone.

Abstract:Centrifuging method was used to determine soil water characteristic curves of four undisturbed soils different in bulk density,and through the experiment,surfaces depicting quantitative relationship between mass water content,pressure head and bulk density in the four soil samples were obtained.Based on the measured data,effects of soil disturbance on the three-variable surfaces were analyzed,a fitting model proposed by the authors was verified,and fitting results of the packed and undisturbed soils were compared.Results show that soil disturbance obviously changed the soil three-variable surfaces.The bigger the difference in initial bulk density between packed and undisturbed soils,the greater the effect of soil disturbance on the surface. The differences in model parameters between the two treatments demonstrate the effects of soil disturbance on the three-variable surfaces.The study of soil three-variable surface for undisturbed soils is sure of some practical significance in extrapolating the study of soil hydrodynamics in soils different in bulk density to field soils.

Abstract:Characteristics and regularity of spatial,horizontal and vertical,distribution of soil salinity in different salinity profile types were studied and summarized through application of hierarchical cluster analysis of typical soil salinity profiles in the Yellow River Delta,and these regularities were then used to explore spatial distribution of different salinity profile types.Results show that soil salinity profiles could be obviously classified into normal,inverted and even,and a soil profile of 180 cm in depth could be divided into four layers,0～20 cm,20～80 cm,80～120 cm and 120～180 cm in terms of the vertical distribution characteristics.Soil salinity exhibited strong variation in spatial distribution,both horizontal and vertical,salt accumulation at the surface soil layer was generally significant,and the regularity of soil salinity at different layers could serve as a reference for the classification of salinity profile types.Owing to compound impact of structural and stochastic factors,soil salinity at these layers all exhibited moderate spatial variation and identical spatial autocorrelation scale.The results of Kriging interpolation and spatial analysis indicated that the spatial distribution of soil salinity in surface layer was chiefly dominated by micro-topography and climate conditions,while the spatial distribution of soil salinity at deeper layers was mainly controlled by groundwater properties. The study area was predominated with inverted salinity profile types and,followed by normal and even ones,respectively.The distribution patterns of salinity profile types reflected variation of vegetation types and land use patterns to some extent,and human agricultural activity was the crucial reason for the formation of normal and even salinity profile types.The research results can serve as a theoretical and practical basis for zoning,amelioration,management and rational utilization of saline soils in the Yellow River Delta.

Abstract:Based on the results of in-situ determination using electrochemical methods,oxidation-reduction regimes of major natural soils,upland soils and paddy soils in China were systematically summarized for the first time.The natural soils and upland soils belonged to the category of oxidizing soil,with Eh in the range of 440～730 mV,and content of reducing substances equal to 0.00～4.01×10^-5mol L^-1 of Mn²⁺,and remained basically oxidizing within a year,oxygen being the Eh-determinging factor and quite weak in transformation and translocation of materials in the soils,while the paddy soils ranged between 670～-70 mV in Eh,with the content of reducing substances equal to 0.01～17.8×10^-5mol L^-1 of Mn²⁺,and reducing substances being the Eh-determining role.And their material transformation/translocation intensity and speed was far greater than that in the natural soils and upland soils.In terms of oxidation-reduction regime varying periodically with water regime,paddy soils could be divided into three types,i.e.oxidizing,oxidizing-reducing and reducing.Soil oxidation-reduction regime is characterized by close correlation between Eh and content of reducing substances,spatial and horizontal variation,heterogeneity, wider range of variation and high reversibility.Determination in situ with electrochemical methods has paved a way to research of oxidation-reduction properties of weakly reducing soils.

Abstract:Cadmium contamination of the soil in Fuyang Valley,Zhejiang Province and Cd uptake by rice were studied, and critical values for Cd in soils deduced based on Cd risk of rice consumption.Results show that high concentrations of Cd in soil and rice grains were detected in the study area.A model is established for prediction of Cd concentration in rice grains based on multi-factor regression analysis,taking into account soil total Cd and pH.With the aid of the model,critical values of Cd in different soil pH were derived,being 0.42 mg kg^-1,0.79 mg kg^-1,1.49 mg kg^-1 and 2.81 mg kg^-1 for soils with pH at 5, 6,7 and 8,respectively.Due to the spatial heterogeneity of soil pH in the study area,a high spatial variability was observed of critical values of Cd in soil.The results indicated that total Cd content in soil exceeded their critical values in 73% of the sampling sites.Therefore,sound strategies for risk management should be implemented to protect human health.In addition,uncertainties in deduction of soil Cd critical values come mainly from the risk assessment model and rice grain Cd uptake model and soil pH is the most sensitive parameter.

Abstract:As pollution causes a series of problems with eco-environment,food safety and public human health,environ-mental risk assessment of contaminated sites has attracted extensive attention. Based on an investigation of a certain waterhead region for pollution of organic chemicals,like oils and benzene,heath risk assessment of drinking water in the region was performed using the MMSOILS model,a multimedia exposure assessment model,with Benzene as a target contaminant. The assessment shows that the total health risk value of Benzene contamination of drinking water in District A caused by the alkene plant is 9.94×10^-5,which is far too much higher than the U.S. EPA risk limit of 10^-6 and means that the contamination hazards public health. The contaminant comes mainly from the cracking installation,making the drinking water high in health risk value,being 9.82×10^-5,accounting for 98.8% of the total. According to the modeling results,risk value in District A will lower to 10^-6,posing no risk to human health,only after the Benzene concentration in the soil around the cracking installation is reduced to 1.32 mg kg^-1. The research results provide an important foundat ion for effective control of the pollution and remediation of the contaminated sites.

Abstract:Degradation dynamics of fenvalerate in three soils was studied to explore effects of soil properties on degradation. Results show that the half-time of fenvalerate in the soils was 25.3,19.4,and 17.7 days,and the degradation rate constant 0.0274,0.0357,0.0392,respectively,demonstrating that fenvalerate degradated the fastest in huangni soil and the slowest in qingzi soil. Degradation of fenvalerate in soils seemed to be attributed to activities of microbes,as the degradation rate was lower in sterilized soil. The most important factors affecting its degradation rate in soil are organic matter content and pH1 Environmental factors also affect fenvalerate degradation rate. The half-time of fenvalerate decreased with rising temperature and moisture,while its degradation rate did with higher initial application rate of the pesticide.

Abstract:Fifteen paddy soil samples were collected from the major rice producing regions of the country and incubated un der anaerobic and aerobic conditions to invest igate effects of soil properties on CH₄ production.CH₄ production potentials of the 15 paddy soils differed greatly,with the total CH₄ outputs over the whole incubation period(132 days)varying in the range of 1.8~1180μgg^-1(anaerobic incubation)and of 0.41~136μgg^-1(aerobic incubation).Significant positive correlation was observed of CH₄ production with contents of soil organic carbon and total nitrogen.However,CH₄ production was not significantly affected by the other soil properties,such as particle sizes,soil pH,soil cation exchange capacity and active Fe and Mn contents.Thus soil organic matter content is the most important soil property affecting CH₄ production.Comparison with the results of the other similar experiments showed that the larger the spatial scale the soil samples represented,the less soil properties correlated with CH₄ production,and the less significant the correction of an individual soil property with CH₄ production.

Abstract:Effects of rice-planting and long-term application of inorganic fertilizers on β-proteobacteria ammonium oxidizers diversity and nitrification were investigated in a soil derived from quaternary red clay in the Ecological Experimental Station of Red Soil,Chinese Academy of Sciences.The original soil is characterized by low pH and deficiency of available nutrients,particularly phosphorus and nitrogen.After 13 years of rice cultivation,the soil showed increase in number of DGGE bands of ammonium oxidizer 16S rDNA and a DGGE pattern different from that of the original soil with a similarity being only 61%,which illustrated variation in the community structure of the ammonium oxidizers in the soil.Besides,the research findings of the experiment on effect of long-term application of inorganic fertilizers on diversity of ammonium oxidizers in the soil with the PCR-DGGE method also showed that the treatments(NP,NPK&NK)in the experiment were quite similar to each other in 16S rDNA DGGE pattern,with a similarity being up to 73%.Both nitrification rate and nitrification potential were higher in the nitrogen fertilizer treatments than the other treatments.Stepwise regression analysis showed that nitrification rate and nitrification potential were evidently increased with the increase in urease activity.It may be presumed that application of urea increased soil hydrolysable nitrogen content,and hence urease activity and growth of nitrifying bacteria in the soil,which finally led to increase in nitrification rate and nitrification potential.

Abstract:Vegetation coverage in terrestrial ecosystem affects distribution of organic matter in soils and soil density fractions,thus is an important factor controlling storage of soil organic matter. An experiment was conducted to determine soil organic carbon and nitrogen concentration,by using density fractionation,of soil samples collected from the fields of three long-term experiments and evaluate the impact of land use on soil and density fractions. Results show that(ⅰ)soils different in land use differed significantly(p<0.05)in total organic carbon(TOC)or total nitrogen(TN),and TOC had a significant positive correlation with TN(p<0.01). Natural ecosystems,subjected to human disturbance or transferred into cropland,suffered chrono TOC and TN losses,however,application of chemical fertilizer plus organic manure increased significantly TOC and TN contents in cropland. Organic carbon storage of black soil under grassland has been increasing in the past 20 years of vegetation rehabilitation;(ⅱ)OC or N contents in free-LF(free light fraction)and HF(heavy fraction)were significantly related to TOC or TN in the whole soil at p<0.05 or p<0.01,respectively,indicating that accumulation of free-LF and HF is very important to net increase in TOC or TN. Occluded-LF,randomly distributed in soils,was less important to accumulation of TOC or TN;(ⅲ)C/N ratio of free-LF was higher than that of the whole soil and other fractions,which suggested that free-LF is a major part of the labile carbon pool on account of its susceptibility to microbial decomposition;(ⅳ)OC contents of humic acid of loosely combined humus significantly correlated with TOC,indicating that increase in humic acid leads to improvement of soil fertility. Application of organic manure to cropland not only led to accumulation of organic matter and improved soil quality,but also increased the capacity of agroecosystem to sequester atmospheric CO₂.

Abstract:Desorbable quantity and desorption intensity of soil K and their buffer power are important indices in evaluation of soil K supply capacity. An indoor soil K desorption experiment was carried out to explore soil K desorption characteristics and their eigenvalues,and pot and field experiments as well to study relationships of the eigenvalues with crop response in yield. A desorption model for soil cadmium was used to fit 7 types of soils in 32 K desorption experiments. Results show that the model fitted well with correlation coefficients reaching the level of significance. In the pot and field experiments with water spinach(Iponoea aqatica)and flowering Chinese cabbage(Brassica parachinensis),desorption eigenvalues,like quantity of desorbable soil K(Q),initial K concentration in the soil solution(C_li)and concentration/buffer power ratio(C₁/∂),were related to total K uptake or yield(fresh weight)of the vegetables,showing apparent parabola curves. Furthermore,the pot experiment with water spinach indicated that the parabola relationships fitted all the soils regardless of soil type,suggesting that Q,C_li and C₁/∂ indexes indeed reflect K supply capacity of soils. Based on the parabola relationships and 90% of the maximum yield of the investigated vegetables under field conditions,critical indices of Q and C_li were worked out,to be 104 mg kg^-1 and 31 mg L^-1 respectively for flowering Chinese cabbage,and 207 mg kg^-1 and 82 mg L^-1 respectively for water spinach. If soils have Q or CC_li determined well beyond the critical index,they do not need Kfertilization. The findings indicate that the proposed model can be cited as a new method to evaluate availability and critical index of soil K.

Abstract:Spatial distribution of large-sized soil animal communities in a microtopographical range of the Zuojia Nature Reserve was studied from the perspective of ecological series,and relationship of large-sized soil animal communities with soil factors on a small scale was explored taking into account comprehensive effect of soil factors on soil fauna.Results show that in the circumstance that there was no big change in altitude above sea level,vegetation was notable in affect ing large-sized soil fauna. Difference in vegetation was limited between the four habitats,ridge,mesoslope,down-slope,and vale of the sunny slope and shady slope of the studied region,soil factors played an important role in distribution of the soil fauna along the slope in the research region.In a microtopographical range,the changes in soil organic matter,soil water content,pH,total N,and total P tended to be approximate,whereas the change in soil temperature was just the opposite.The effects of the six soil indices on distribution of dominating groups of large-sized soil animals were significant.

Abstract:A Fusarium oxysporum-selective cultivation medium was used to investigate numbers of Fusarium oxysporum in soils under polytunnel greenhouse cultivation different in vegetable species,different in cultivation history,different in culture systems and different in depth.Results show that the number in the soil under cucumber was as high as 1.6×10⁴cfug^-1 dry soil,significantly higher than that in the soils under eggplant and under celery.And the number tended to increase with the years of cultivation,and was 22% higher in the soil 4 years in history than in the soil only 1 year. It was much lower in the aggregate than in the soil,being only 1.1×10×10⁴cfug^-1 dry soil. Maybe greenhouse vegetable cultivation using aggregate instead of soil is one way for the country to develop greenhouse vegetables in the future. The number of Fusarium oxysporum decreased with the increase in soil depth,indicating that Fusarium oxysporum rarely moved into deeper soil. All these findings may serve as primary microbiological bases for sustainable utilization of greenhouse vegetable soils in the future.

Abstract:A pot culture experiment was carried out to study effect of combined incubation of DEHP degrading bacteria and arbuscular mycorrhizal(AM)fungi on bioremediation of DEHP polluted soil and growth of mung bean. Two bacterial strains,i. e. Bacillus sp. DW1 and Gordona sp. DH3,and one strain of AM fungi,Acaulospora laevis 90034,were inoculated,alone or in combination,to the soil amended with 100 mg kg^-1 DEHP. A treatment of uninoculated soil was set as control(CK). The plants were harvested 60 days after seedling emergence. Results of the experiment show that AMfungi colonized well in the roots of mung bean. Dry mass of the plant was increased and P nutrition improved by AMF inocula. But inoculation of just DW1 and DH3 did not show any significant effect on mycorrhizal colonization and plant growth. However,the three strains of inoculants, whether inoculated alone or in combination,could obviously promote degradation of DEHP in the soil,but the best synergistic effect on DEHP degradation was found when strains DW1,DH3 and AM fungi wer inoculated in combination. Besides,the inoculation of AMF decreased DEHP accumulation in the shoots of mung bean. The findings in the experiment may serve as scientific basis for bioremediation of DEHP-contaminated soils.

Abstract:Bioremediation of metsulfuron-methyl contamined soil with S113(Methylopila sp.)was studied under laboratory conditions. S113 was capable of utilizing metsulfuron-methyl as its sole carbon source for growth and degrading 98.38% of the 50 mg L^-1 metsulfuron-methyl within 72 h. Addition of S113 could prominently accelerate degrading of metsulfuron-methyl. When S113 was inoculated into the soil at a rate of 10 8 cells g^-1 dry soil,76.9% of the metsulfuron-2methyl(10 mg kg^-1 dry soil)in the soil was degraded after 30 days,whereas only 11.9% was degraded in CK.When inoculation rate decreased to 105 g^-1 dry soil,the action of S113 degrading metsulfuron-methyl in soil was not distinct,showing that degradation rate was related positively to the amount of inoculation,When metsulfuron-methyl was low in concentration,S113 was effective. When the concentration of metsulfuron-methyl was increased to 50 mg kg^-1,metsulfuron-methyl degradation rate was only 39.6%. Soil temperature also affected metsulfuron 2methyl degradation rate1 When it was 30℃,the rate reached 75.9% in 30 days,whereas when it was 25℃ and 20℃,the rate was lower to 53.5% and 2319%,respectively. Pouring S113 solution around the roots with S113 solution could mitigate the inhibitive effect of metsulfuron-methyl at 40 or 80μg kg^-1 on maize growth to a varying degree. When the concentration of metsulfuron-methyl increased to 120μg kg^-1,the mitigating effects were not distinct. The findings suggest that arti-ficial inoculation of S113 could effectively degrade metsulfuron-methyl in soil.

Abstract:As the technology of X-ray absorption fine structure(XAFS)spectroscopy is capable of probing in situ shells of 2 or 3 neighbors closest to an absorbing atom,thus obtaining information about electronic and chemical structures of the target element such as oxidation state,next nearest neighbors,bond distances,and coordination numbers,it has become one of the most important tools in analyzing microscopic structure,and its use has revolutionized,and will continue to,our understanding of important chemical properties and processes. To promot its application to soil science in China,a brief introduction is given to the foundation of XAFS;and issues of concerns in sample preparation,test and data analysis. Besides a review is presented with emphasis on its application in studying speciation of heavy metals and nutrients in soils,and processes and mechanism of the reactions at soil solid-solution interface. Finally,limitations and prospects of XAFS are also discussed. Owing to complexity of the soil interface reactions,it is advisable to apply XAFS in combination with other structure analysis techniques such as X-ray diffraction,nuclear magnetic resonance,infrared spectroscopy,electron paramagnetic resonance,electron microscopy,etc. Some macroscopic approaches such as bulk adsorption,kinetic reactions,and mathematic computation,should be also used. At that time,soil scientists must and will increasingly collaborate with other scientists and engineers. Only in this way,is it possible to elucidate in spatial and temporal scale the complex reactions at environmental interfaces involving inorganic and organic and microbial components of the soils.

Abstract:近几十年来,随着世界经济和人口的迅速增长,全球大气活性氮排放量急剧上升^[1]。活性氮大气排放的增加使得从大气沉降到地面的氮素数量也迅速增加,从而有可能导致自然或半自然生态系统(如森林、草地和湖泊等)富营养化土壤或水体酸化以及生物多样性降低等危害^[2~5]。为了有效地评价大气氮沉降的生态环境效应,欧美一些国家进行了大量的氮沉降监测工作,并建立起了比较完善的氮沉降监测网络,如联合国欧洲经济委员会欧洲监测与评价计划(UN ECE-EMEP)、美国的国家大气沉降计划(NADP)和清洁空气状况与趋势网(CASTNet)以及加拿大的空气与降水监测网(CAPMoN)等。

Abstract:我国亚热带山地丘陵红壤区植被受人为严重破坏后,表土易遭侵蚀,是我国仅次于黄土高原的严重侵蚀区,并形成了大面积的侵蚀退化生态系统。该区先后对此类退化系统生态进行了许多恢复与重建工作,植被覆盖发生了巨大变化,并在植物多样性、土壤肥力、水源涵养、营养元素循环、能量流动等方面做了许多有益的研究与探索^[1~6],但目前有关植被恢复对土壤有机质尤其是轻组有机质影响的研究比较缺乏。土壤有机质是土壤质量和健康的重要指标,对维持土壤生产力具有重要作用^[7]。

Abstract:氧化锰矿物是土壤和沉积物中的重要组分,在土壤中的含量一般不超过10g kg^-1。但其颗粒细小,常以膜状赋存于土壤颗粒表面,并在土壤界面的化学反应中起着重要作用;其电荷零点(PZC)低、比表面积大、负电荷量多,对某些重金属元素有吸附固定作用,影响并决定着它们在土壤和沉积物中的浓度、形态、化学行为及生物毒性^[1~10]。氧化锰矿物对重金属离子的吸附特性一直是许多土壤与环境科学工作者研究的重点,其吸附顺序一般为:Pb>Cu>Mn>Co>Zn>Ni>Ca>Mg,并普遍认为是专性吸附^[3~5]。其专性吸附机理常有配位、内层交换、水解—吸附、表面络合和同晶替代等理论^[3]。

Abstract:钼、锰是植物生长所必需的微量元素,对作物的生长发育、产量和品质都有明显影响。钼在植物氮代谢中起着关键作用,主要与钼是硝酸还原酶和固氮酶等含钼酶类的重要组成成分有关^[1]。同时钼对维持叶绿体的正常结构也是必不可少的,缺钼会导致植物叶绿素含量减少,光合强度降低^[2]。锰对作物的光合作用、氮、碳和脂类代谢有密切关系,并是多种酶的组分与活化剂,锰营养的丰缺对大豆的生长发育、产量及抗逆性有显著影响^[3]。在钼或锰营养方面,目前研究较多是钼或锰对大豆的产量、品质和生理活性的影响,例如施钼能提高豆科植物根瘤菌数量,促进植株生长,增加生物量和产量^[4~6]。

Abstract:2004年在我国西南地区的新垦红壤山地建立了烟草基地,该基地的地理位置是N26°28'~29',E101°51'~53',开发总面积约为267hm²。2005年和2006年连续两年基地的烤烟都出现了大面积的烟叶呈‘倒勺子状'翻卷的症状,初步诊断是生理缺钙所致^[1~3]。已有研究^[2,3]从田间考察、对土壤和有机肥的检测、病株的组织分析以及水培试验等证明该症状是由于使用了一种含有过量磷酸根、硫酸根等阴离子的商品有机肥1号(是某肥料厂专门为该基地生产的一批有机肥)所诱发的,其机理是过量的磷酸根和硫酸根与根际土壤中本来就不富裕的有效钙反应形成磷酸钙沉淀和难溶性的硫酸钙,使烟株难以吸收足够的钙而诱发缺

Abstract:山东省是典型的冬小麦—夏玉米一年两熟制地区,土壤干旱与湿润交替变化,是旱地农业与灌溉农业中作物经常面临的田间环境,由于降雨时空分配极不均匀,干、湿季节十分明显,常引起季节性干旱,尤其是冬小麦生长期间,缺水现象比较普遍。植物在极端环境下对水分胁迫的生理反应和适应机制等水分生理生态方面研究已有报道^[1~6]。