Under FACE（free-air carbon dioxide enrichment）condition,root growth was monitored of rice（C₃ crop）and barnyardgrass（C₄ weed）in hydroponics with two levels of nitrogen supply.Results show that root biomass,root volume,root length and root diameter of rice and barnyardgrass all increased significantly under FACE condition with NN（normal nitrogen）supply,the response of rice to CO₂ was higher than that of barnyardgrass.FACE condition with LN（low nitrogen）supply did not significantly promote rice growth because of N stress,but response of barnyardgrass to CO₂ was not limited by N stress,showing significant increase in growth.N concentration of the root decreased significantly in elevated CO₂ but C concentration did not change remarkably,which led to obvious increase in ratio of C/N.Elevated CO₂ also decreased remarkably the number of root hair and per-unit dry root weight of rice and barnyardgrass,which might be one of morphological reasons why root activity decreased under FACE condition.

Five vegetation communities:herbosa,shrubs,coniferous forest,theropencedrymion,and evergreen broad-leaved forest in the red soil region of the Lijiang Valley are selected as the five successive stages of the typical restoration process of degraded ecosystems to study variation of structure and biomass of the vegetation of the five different stages.Results demonstrate that with the succession going on from herbosa →shrubs→coniferous forest→theropencedrymion→evergreen broad-leaved forest,abundance and diversity index of species,biomass and productivity of vegetation all show a rising trend prior to the formation of a mature and stable biotic climax.A degraded community tends to develop to be more complex and sounder in structure.Based on the findings of the research,some advice is put forward about how to artificially accelerate ecological restoration in the red soil region of the Lijiang Valley.

A study was carried out on ecological functions of forest floor,such as standing stock of litters,N and P storage capacity,water holding capacity and detainment of heavy metals,of five typical forest communities in Nanjing.Results show that with regard to standing stock of litters,the water holding capacity and N storage capacity of forest floor,the Quercus acutissima-Q.variabilis community is the highest among the five forest communities,while as far as P and heavy metal storage capacity is concerned the Cinkgo biloba community is the highest and followed by the Quercus acutissima-Q.variabilis community.Comparatively,the Liquidambar formosana and Acer buerqerianum communities are inferior in all these aspects.So in planning and construction of urban forest parks in Nanjing,it is essential to preserve the existing zonal plant communities,Quercus acutissima-Q.variabilis-dominated deciduous broadleaved forest,or build up quasi-zonal plant communities,and maintain integrity of the forest floor of the forestland,which will eventually help improve the urban ecological environment.

Human settlement reflects geographical environment of a region.Field investigations were carried out of 5 villages in Suihua City,8 villages of the Heshan Farm in the 93 Reclamation Zone and Caiyao Village in Shuangshan Town,Nengjiang County in Heilongjiang Province.Based on the meteorological data,such as temperature,daily sunlight hours,wind speed,precipitation and frequency of wind over Class 5,etc.,of the Heshan Farm in 1980—1995,and some other factors,like topography and soil,characteristics of the distribution of villages in the hilly northeast China were analyzed.Results show sunlight hours and solar radiation decides slope aspect of rural settlements.In terms of number of rural settlements,slope aspects are in the order of southeast>southwest>northeast>northwest.Wind affects indoor temperature and may possibly damage buildings so that most rural settlements lie in the middle and lower parts of a slope.Soil characteristics and precipitation determines the lower limit of the distribution of rural settlements.These geographical factors jointly decide that a village in that region spreads out like a long narrow stripe along the slope.

Primary parameters of sodic soil in Da′an City,including exchangeable sodium percentage（ESP）,sodium adsorption ratio（SAR）,total alkalinity,pH,soil salt content,etc.were determined for analysis of characteristics and vertical distribution of alkalization in the profile.Results show 1) Na⁺ and HCO^-₃ are the major soluble ions in the soil with the former accounting for 80 percent or more of the total cations and the latter for（75%-85%） of the total anions.And NaHCO₃ is the primary cause of aggravated soil alkalization.2) The soil layer located at the depth of（20-80） cm in the soil profile is an apparent alkalized soil layer,with ESP>（25%-30%）;pH>10.3;and salt content>6.0 g·kg^-1.The characteristics of soil alkalization tend to be weaker in other soil layers in the profile.3) Soil ESP rises with soil salt content and total alkalinity,and positively correlated with SAR（r=0.711,n=40,P<0.000 1）.Based on precipitation and groundwater data available,causes of the salinity distribution pattern in the soil profile were discussed at the end.

Dynamics of soil nutrients during the natural restoration process of farmland were studied with the method of substituting time with space.Three tracts of sample fields were selected to represent three different phases of the restoration process,initial period of deserted farmland,grassland,and shrub land.Soil samples from different profile depths were collected and analyzed for soil organic matter,total nutrients and readily available nutrients.Results showed that responses to the recovery process were obviously different between the total nutrient and its corresponding available one.Soil organic matter increased with the process of the restoration.The P and K circulation shifted from under physical control to under biological control step by step,but available P increased slowly in the early stage.Available N increased after an initial decrease at the beginning.As for total nutrients,only total N showed an increasing trend with the restoration process.The deeper rooting of shrubs affected soil organic matter and available nutrients obviously in the deep soil layers.Restoration of vegetation is closely related to increase in soil fertility and this relationship is strengthened with the restoration process.

Variation of microbial communities in inoculated and natural composts was studied with the traditional incubation method and the PCR-DGGE technology.Results indicate that 1)with the traditional incubation method,the population of microbes showed a wave-like curve,i.e.up-down-updown,in both composts and bacteria dominated the microbes in population,while 2)with the PCR-DGGE technology,the population showed a similar curve,though different microbial populations dominated at different composting stages.The DGGE graph showed abundance of bands and none in predominance during the warming up phase;the number of bands decreased but predominant bands appeared during the high temperature phase,suggesting that thermophiles were dominating microbes during this phase;the number of bands increased again during the cooling phase;and the number of bands dropped and no one remained in dominancy during the maturation phase,suggesting that the microbes were getting less in populations and their metabolism was levelling off during this phase.(3)The DGGE spectrum also showed that inoculated strains assumed predominance during the high temperature phase,and inoculation increased the total count of microbes,enriched microbial diversity and accelerated succession of microbes during composting,thus shortening duration of the composting process.

Effects of duration of UV-C radiation on photosynthetic characteristics and activity of antioxidant enzyme in pea seedlings were studied.Results show that Enhanced UV-C radiation significantly decreased photosynthesis rate（P_n）,stomatal conductance（G_s）,intercellular CO₂ concentration（C_i）,transpiration rate(E_tr)and carboxylation efficiency（CE）.Prolonged duration of UV-C radiation increased the activities of POD and CAT,which soon declined,and kept the activity of SOD,and the content of chlorophyll gradually going down,but the content of MDA going up.The results suggest that enhanced UV-C radiation decreased activities of the antioxidant enzymes and made membrane peroxidated,thus leading to weakened photosynthesis.

Nitrogen is a very important element and has profound effects on crop fields and environment.Aiming at the problem of high application rate but low use efficiency of nitrogen fertilizer,a field plot experiment was conducted in a field of percogenic paddy soil in the Taihu Lake Region under wheat-rice rotation in the years of 2001 and 2002,in order to estimate NO^-₃-N,NH⁺₄-N,particulate nitrogen（PN） losses with runoff and drainage.Results indicate that the total N loss is low,about 2% of the N applied,and differs very slightly between the wheat season and rice season.Total N lost via runoff and drainage can be sorted as NO^-₃-N and PN,but the proportions of NO^-₃-N,NH⁺₄-N,and PN in the runoff and drainage flows vary from season to season.NH⁺₄-N dominates the loss in the rice season whereas PN in the wheat season.The loss of NO^-₃-N does not differ much between the two seasons.NO^-₃-N,NH⁺₄-N,and PN losses with runoff and drainage vary sharply with the N application rate,cropping season,growing stage,amount of runoff and drainage.

With diluted anaerobically pretreated wastewater from a pig farm and Spirodela oligorrhiza,TN,NH⁺₄-N and NO^-_x-N removal pathways in shallow-water duckweed-based wastewater treatment systems were studied in summer and winter.Results show that,in summer,30.5% of the TN was removed through ammonia volatilization and 15.9% and 53.6% of NH⁺₄N and NO^-_x-N through duckweed uptake/adsorption,respectively,and 33.1%,17.3% and 49.6% of NH⁺₄-N through ammonia volatilization,duckweed uptake/adsorption and nitrification,respectively,and duckweed uptake/adsorption was the only pathway for removal of NO^-_x-N.While in winter,31.7% and 68.3% of the TN was removed through ammonia volatilization and NH⁺₄-N uptake/adsorption by duckweeds,respectively,28.9%,69.5% and 1.6% of the NH⁺₄-N through ammonia volatilization,duckweed uptake/adsorption and nitrification,respectively,and the content of NO^-_x-N,however,remained unchanged.

With the process of industrialization and modernization moving on,soil pollution in developed areas has become a problem that calls for much concern.How to assess the soil environment quality of this area rationally and properly is now a research topic that deserves study and discussion.Based on discussions about meanings of the background values,determination methods and evaluation criteria of soil environment,contents of seven heavy metals(Cd,Hg,As,Pb,Cr,Cu and Zn)in the soils of Changshu,a typical city in the Yangtze River Delta,were investigated through field sampling and laboratory analysis.Heavy metal pollution of the soils was evaluated with the environmental background values of the soils of Changshu and Grade Ⅱ Criterion of GB 156181995 as benchmarks.Phenomena were found of the concentration of the seven heavy metals in the soils being beyond their respective background values.Especially for Hg,Pb,Cr,Cu and Zn,their overstandard rates varied from 10% to 20%.And heavy metals,Cd,Pb,Cu,Zn and Hg,were found beyond Grade Ⅱ Criterion of GB 156181995 in concentration,and Hg in particular was overstandard in about 30% of the soil samples.As and Cr,however,were not overstandard.The results suggest that it is more advisable to use both of the standards in assessing soil environment quality for a better understanding of the status of heavy metal pollution in the soils investigated.

Distribution characteristics of heavy metals in soils of fast-urbanizing regions are discussed with Kunshan as a case for study.Results indicate that with the upper limits of the background values as indices for evaluation,about 25%,24%,22%,21%,18%,18%,14% and 4% of the 100 soil samples collected from farmland in Kunshan were exceeding the upper limit of soil content of Zn,Cu,Pb,Hg,As,Cd,Cr and Ni,respectively,suggesting external contaminants are entering the fields.According to norms of Grade Ⅱ of GB 156181995 "Standard for Soil Environment Quality",about 5%,（4%,）3% and 2% of the soil samples exceeded the limits of soil contents of Hg,Cd,Cr（dry land） and Zn,respectively.The maximum Cd content in the soil samples even reached up to 5.74 mg·kg^-1.Correlations between heavy metals varied with the soil parent material.It is held that for control of soil pollution, it is essential to give priority to prevention rather than remediation.At the same time,pollution control should be intensified in areas heavy with Cd and Hg point pollution sources,and measures taken to remediate the polluted soil.

Cu²⁺ adsorption of 24 soil samples gathered out of 4 soil layers（0—10、10—20、20—40、40—60 cm） of 6 different types of forests in Anji,Zhejiang were determined to explore relationship of Cu²⁺ adsorption with organic matter content,CEC,pH and particle composition.Results show that in terms of Cu²⁺ adsorption the six types of forests are in the order of broadleaved deciduous forest>shrubbery>tea grove>broadleaved evergreen forest>bamboo grove>pine forest.Cu²⁺ adsorption decreases with the depth of the profile.Organic matter content and CEC are the two major factors affecting soil Cu²⁺ adsorption.Based on the findings,a model is established to illuminate the relationship of Cu²⁺ adsorption with organic matter content and CEC.

Effects of Zn²⁺ pollution on Zn²⁺ uptake,chlorophyll concentration and characteristics of visible-near infrared spectrum of wheat（Triticum aestivum）were studied with solution culture,and relationships between them were discussed.The results indicate that the content of Zn²⁺ in Triticum aestivum increased while the concentration of chlorophyll decreased with the increase in Zn²⁺ concentration in the solution.Corresponding change in spectral characteristics of the leaves of the plant was observed.The spectral reflectivity ascended in the visible light zone and the strength of blue shift of the red edge intensified,showing significant correlationship.Meanwhile Zn²⁺ pollution affected spectral reflectivity of the leaves in the near infrared band,but the correlativity between the two was not so significant.

A pot experiment was conducted to investigate cadmium（Cd）content in brown rices of 46 rice cultivars of 7 genotypes.Results show that the tested rice cultivars differed sharply between genotypes and vary from（0.428-2.558）(mg·kg^-1) in Cd accumulation when the soil Cd content is 2 mg·kg^-1.In terms of Cd content in grains,the 7 genotypes of rices are in the order of special rice>conventional early rice（Indianica sp.）>three-lined hybrid rice（Indianica sp.）>two-lined hybrid rice（Indianica sp.）>conventional late rice（Indianica sp.）>conventional Japonica rice>Javanica rice.

Contents of 4 common metal elements(K,Na,Ca and Mg),18 trace metal elements(V,Ba,Sr,Be,Bi,Ti,Sn,Li,Nb,Zr,Ga,Th,Sc,La,Sb,Ni,Ce and Y) and 10 heavy metal elements(Cu,Pb,Zn,Cd,Cr,Co,Ni,Fe,Mn and Mo) in five soilless cultivated vegetables were analyzed for comparison with unpolluted terrestrial vegetables so as to evaluate food safety of the soilless cultivated vegetables.For all the five soilless cultivated vegetables of the polluted water,enrichment level of metal elements was found different.Their average enrichment coefficients of common metal elements were(2-150) times.Their average accumulation of trace metal elements was higher than in the unpolluted terrestrial vegetables.And their enrichment coefficients of heavy metal elements were mostly 10 times.No significant difference was found between the soilless cultivated vegetables and the terristrial vegetables in heavy metal accumulation.Contents of heavy metals in all treated and non-treated vegetables are lower than the national standards for food safety.

In a pot experiment impact of Ni addition on growth and Absorption and accumulation of mineral nutrients of pakchois in the drab soil was studied.Variation of pakchoi biomass,Ni content in pakchois and available Ni content in soil are three major indexes to characterize critical value of Ni toxicity.Results show with Ni application rate rising from（0-25） mg·kg^-1,the fresh weight of pakchois increased,but its dry weights decreased.With Ni application rate rising on,the biomass of pakchois decreased remarkably.Ni content in pakchois was negatively related to the biomass of the plant.Ni application affected the plant adsorption and accumulation of other mineral nutrients,which showed certain synergia or antagonism.With the reduction of biomass by 10% as an index,the critical value of Ni toxicity in drab soil was defined to be（57.22） mg·kg^-1 and 8.59 mg·kg^-1 for total Ni and available Ni（extracted by DTPA）in the soil respectively,and 20.51 mg·kg^-1 Ni in stems and leaves of pakchois.

A two-year field experiment was carried out to evaluate degradation behavior and environmental safety of triadimefon WP in the soil/rape ecosystem and three simulant kinetic models were built up to simulate dynamic degradation of triadimefon in the soil/rape ecosystem and compared with each other.The results show that the fitting results of all the three kinetic models reached the level of statistic significance in relationship.However,the GM(1,1)and the retardation kinetic models were better than the other in simulating degradation of triadimefon in the soil/rape ecosystem.The half-life of triadimefon in the soil of 2003 and 2004 were 3.48 and 4.38 d,respectively,and in rape 1.98 and 3.78 d,respectively.The dynamic degradation of triadimefon in the soil/rape ecosystem was much influenced by the environmental temperature.

Olaquindox,arsanilic acid,and oxytetracycline are three common kinds of veterinary drugs and feed additives.Their eco-toxicological effects on zebrafish(Brachydanio rerio)and carp(Cyprinus carpio)were studied through acute toxicity test,and embryo test of zebrafish,and single kidney cell gel electrophoresis test(SCGE)in vivo of carp.Results show that acute toxicities of the three substances were not significant at concentrations of the ecological sense;olaquindox and arsanilicacid showed a significant teratogenic effect on the embryo,olaquindox and oxytetracycline could bring about obvious great DNA damage to carp kidney cells in vivo and have potential genotoxicity to fish.

Three guidelines are set forth for evaluation of soil contamination at the scale of a region or a specific site in view of ambiguity of the definition for soil contamination at present.The three guidelines,mainly based on chemical levels,are upper limit of soil environmental background,Grade Ⅱ criteria of the national soil environmental quality standard(GB 15618) and threshold value of soil contamination.The upper limit of soil environmental background,which corresponds to the local soil environmental background,is a critical value for discriminating between pedogenic source and anthropogenic inputs of chemicals as well as a target value for protecting the soil environment.If a chemical would be higher than this upper limit,measures should be undertaken in exploration and control of its potential anthropogenic sources in order to protect the soil quality from further impact of these sources.The soil environmental quality standard,which is equivalent to Grade Ⅱ criteria of the national soil environment quality standard,is a screening level for distinguishing uncontaminated soils from contaminated soils preliminarily.If the level of a chemical in the soil is lower than this standard,it indicates that the soil is not contaminated.Otherwise,the soil might be contaminated potentially and further investigation and/or risk assessments of the eco-environment and human health should be recommended.The threshold value of soil contamination,which could be acquired through risk assessment of the problem soil,is a critical value for determining whether the soil is contaminated or not.Beyond this value,the soil is contaminated and countermeasures should be undertaken to control the pollutant sources and remedy the contaminated soil.

New Zealand deems management of nature reserves and preservation of biospecies as its foundation for sustainable development.In the aspect of management of nature reserves,New Zealand has established perfect management systems,legal policies and special management patterns.The authors explore for implication to China of the successful experience of New Zealand in management of nature reserves from the angle of following six aspects,i.e.management system,laws and policies,controlled open management,public participation, increased input in research,and fund raising.