Based on the statistic data of crop yield and agricultural input in the period from 1981 to 2001,carbon sources and sinks of the farmland ecosystems in the 10 coastal provinces,metropolises and autonomous regions of China were estimated.Conclusions are reached as follows:(1)The total carbon sink of the farmland ecosystem in coastal China was zigzagging upward since 1981,and the total carbon emission climbing rapidly.But comparison shows the former went at a higher rate than the latter.However,the increasing rate(94%) of the indirect carbon emission caused by agricultural input exceeds that of carbon sink(44%) during the crop growing season.(2)Significant temporospatial variation is observed of total carbon sink and emission and of carbon sink and emission per unit area between different regions and among them,both total emission and emission per unit area showed a rising trend with each passing year.The drastic variation of the carbon sink in developed regions is a result of relatively higher agricultural input.The total carbon sink in relatively developed regions showed a downward trend from 1981 to 2001,which indicates that decreased acreage of farmland in the costal regions reduced carbon sink during the crop growing season.(3)The proportion of carbon fixed by the main crops in the farmland ecosystem of the coastal region against that of the whole nation′s was decreasing,which indicates that with the decrease in acreage of cropland and increase in agricultural input,the carbon sink function of the coastal region is weakened.

Impact of changes in land use on environment of resource-type cities is significant.In order to improve ecological benefit,researches have been conducted on response of the ecological carrying capacity of the cities to changes in land use,and variation of the integrated index of land use in Anshan,Fushun,and Benxi from 1996 to 2000.Results show a rising trend,though still quite normal,of the ecological carrying capacity of the three cities from 1996 to 2000.In 2000,the ecological carrying capacity of Anshan was 0.60,of Fushun 0.47,and of Benxi 0.49.Integrated index of the change in land use was 0.82 in Anshan,4.04 in Fushun,and 1.10 in Benxi.Anshan and Benxi were low,but Fushun high in land use intensity.Their ecological carrying capacity was positively correlated with their integrated index of the change in land use,basically forming a mode of mutual promotion.

In regions rapidly developing in economy,human activities often pose obstacles in protection of the natural ecology and environment,which will in turn undermine sustainability of the regions.Zoning based on the ecological-economic demand of the region for sustainable economic development is essential.The area alongside the Yangtze River in Anhui Province(the AAYRAP) is such a typical region in Central China.An evaluation index system is desgined for zoning by taking into account pressure,status and human response, linking the regional ecosystem and social-economy system and the human activity-environment interaction.Counties(cities or urban districts) are cited as basic unit and the methods of Principal Component Analysis and Hierarchical Cluster Analysis are adopted in the evaluation.Following the spatial proximity principle,the AAYRAP is divided into 7 ecological-economic types: Hefei Pollution Control and Urban Ecology Optimization Zone,Chaohu-Chuzhou Lake-Wetland Conservation and Plain Ecological Agriculture Zone,Ma′anshan-Wuhu-Tongling-Xuancheng Industrial Pollution Control and Urban Ecology Optimization Zone,South Xuancheng Ecological Agriculture and Water-Soil Conservation Zone,Anqing Plain Agriculture and Wetland Ecological Conservation Zone,Chizhou Forest Conservation and Ecological Agriculture Zone,and West Anhui Water Source-Forest Conservation Zone.Besides,a highlight to restrictions of the eco-system on regional sustainable development is given;a new eco-economic method for zoning regions under rapid development is explored;and a general direction for development of the regional ecological-economy is proposed.

To grade and evaluate scientifically the comprehensive level of the agricultural development of the eco-economic region of the 19 neighboring counties(or autonomous counties) of Chongqing with the aid of clustering analysis,20 indices reflecting agro-eco-environment,agricultural production,economic and social development,and capability of sustainable agricultural development,are selected.Results indicate that the comprehensive level of the agricultural development of the eco-economic region is in the order of the metropolis impetus area>the Sichuan basin fringe area>the middle area of Three-Gorges region>the national minority community of the southeast of Chongqing>the front area of Three-Gorges region.

Reclamation of the Sanjiang Plain for development of agriculture has led to decline of the surface water table and soil moisture,thus triggering degradation of primary marshes into swampy meadow,or typical meadow,or even directly into paddy field and dry farmland.A study was carried out to compare degraded wetlands with farmland in nutrient content in the surface soil 0-30 cm deep.Four types of degraded wetland showed a sequence of paddy field>swampy meadow>dry farmland>meadow in terms of organic matter and total N;and paddy field>dry farmland>swampy meadow>meadow in terms of readily available P.It is clearly indicated that soil nutrients dropped significantly with primary marsh degrading into meadow,and that variation of the moisture regime was the most important factor leading to decline of soil nutrients.Soil nutrients of farmlands remained quite high,because of cultivation and fertilizer application. Therefore,change in moisture regime and human disturbances are the two important factors responsible for difference between degraded wetlands and farmlands in soil nutrient content.

Five sample plots subjected to invasion by Eupatorium adenophorum in Yunnan Province and Sichuan Province were studied with the quadrat sampling method,investigating species composition and population of indigenous herbage and shrubbery,and analyzing their richness index,diversity index and evenness index.Results show that a total of 87 indigenous species were collected and among them,32 species were common indigenous plants,falling into 31 genus,and 19 families.Invasion of Eupatorium adenophorum caused significant(P<0.05 or P<0.01) decline of richness index in all the habitats involved,and of Simpson index and Shannon-Wiener index in all the plots,except for Plot d.No obvious regularity was observed with the impact on Pielou evenness index.Seasonal change in vegetation community differed between habitats.Communities dominated with annual herbs showed a more significant declining trend than those with perennial herbs and shrubs did in Simpson index,Shannon-Wiener index and Pielou index.

The Linhe-Ceke Railway was cited as subject in a case study,and soil,landform and vegetation type are selected as key factor in assessing land sensitivity to desertification.Based on remote sensing images and data related to the two sides along the Linhe-Ceke Railway,landform,soil and vegetation maps are plotted.Sensitivity of the land to desertification alongside the railway was evaluated,using the weighing-grading map superposition model.Results show that 54.5% of the two land strips alongside the whole length of railway is highly sensitive and 4.4% extremely sensitive.The two parts are the major zone distributed with drifting sands.Effective measures should be taken in the areas during the construction and operation periods so as to prevent land desertification and drifting sands from extending and aggravating.

Dustfall adsorbing capacities of 26 major species of greening trees in different functional zones in Nanjing were monitored and analyzed.Results show that dustfall adsorbing capacity varied from species to species,and displayed a seasonal trend,high in spring,low in summer,high again in autumn,and highest in winter,and a decreasing order of shrubs>evergreen arbors>deciduous arbors.The amount of dustfall on the leaves increased with the time.

Samples were collected once a month from July 30th to December 2nd from the influent and effluent waters of an aquicultural farm,dominated with fish-mussel polyculture,a mode of circular economy in pond acquiculture.Total phosphorus(TP),total nitrogen(TN),orthophosphate phosphorus(PO3-4-P),nitrate nitrogen(NO-3-N),nitrite nitrogen NO-2-N),ammonium nitrogen(NH+4-N),CODMn and chlorophyll-a(Chla) in the samples were analyzed as main quality indexes for evaluation of effect of the polyculture on purifying waste water.Results show that removal rates of all the pollutants,except for Chla,first increased and then decreased during the experiment.The removal rate of NH+4-N ranged from 25.58% to 50.82%,with an average of 38.05%,and the highest appeared on August 28th and the lowest on December 2nd.The removal rate of NO-2N,NO-3-N,PO3-4-P,TN,TP,and CODMn varied from 16.95% to 45.45%,25.23% to 48.48%,18.37% to 52.43%,19.47% to 49.39%,12.24% to 50.00%, and 31.88% to 49.63%,averaging 26.93%,34.75%,36.50%,29.66%,32.49%,and 41.21%,respectively.What is more,they all peaked on September 29th and fell to the bottom on December 2nd.The polyculture showed significant effect in removing Chla,with an average rate being 83.49%.The values of comprehensive trophic index of the effluent water was much lower than that of the influent water of the polyculture system during the test.It could be concluded that the polyculture system is highly effective in purifying wastewater of the aquaculture farm.

Benthic macroinvertebrates assemblages were collected from 29 sites in the upper reaches of the Taihu Lake watershed,i.e.the Nanhe,Yunnan,Yunbei and Taoge water systems,in Changzhou area of China in 2003.A total of 113 species were found including 18 species in Gastropoda,10 speices in Lamellibranchia,8 species in Oligochaeta,4 species in Hirudinea,6 species in Crustacean and 67 species in Insecta,with Limnodrilus hoffmeisteri and Bellamya purificata being the dominant species.The average density of the communities was 658 m^-2 with L.hoffmeisteri being the highest,i.e. 400 m^-2.Among the 29 sampling sites,Guanshanqiao was the highest in benthic macroinvertebrate diversity and its species richness,Shannon-Wiener diversity,evenness and ecological dominant index was 54,4.36,0.76 and 0.08,respectively.In terms of benthic macroinvertebrate diversity,the 4 water systems were in the order of Nanhe>Taoge>Yunnan>Yunbei.CCA analysis of the 24 species that were more than 15% in occurrence frequency and 6 environmental factors showed that total nitrogen,total phosphorus and dissolved oxygen were the major factors influencing distribution of benthic macroinvertebrates in the research area.

As an initial attempt to set up a "Freshwater Mussel Watching" system,swan mussels(Anodonta woodiana) were collected from Wuli Lake of the Taihu Lake in March 2003 for analysis by gas chromatography of dichlorodiphenyltrichloroethanes(DDT)(p,p′-DDE,o,p′-DDT,p,p′-DDD,p,p′-DDT),and α-,β-,γ-,δ-hexachlorocyclohexane (HCH) isomers in soft tissues.Except for β-HCH isomer,all DDT and HCH isomers were detected in these mussels.ΣDDTs concentration [range: 5.86～14.13 ng·g^-1 wet weight,mean±S.D.:(9.27±3.04) ng·g^-1 wet weight,n=10] were higher than ΣHCHs concentration [range: 2.45～6.46 ng·g^-1 wet weight,mean±S.D.:(4.00±1.22) ng·g^-1 wet weight,n=10].The former was dominated with p,p′-DDE,p,p′-DDD,while the latter with α-,γ-HCH,suggesting that recently input of DDT was getting little, but the input of HCH was apparent in the region.However,DDT and HCH residues in the mussel samples were still lower than the threshold values set by the Ministry of Agriculture of China,as well as FDA and FAO.

Effects of flow velocity on growth of Microcystis aeruginosa incubated in water from the Taihu Lake were studied in laboratory.Results show that when the experimental conditions were set as 25 ℃ in temperature,3 300 lx in light intensity and 10 h/14 h in light cycle,the alga grew best with the flow velocity being 30 cm·s^-1.If the flow velocity rose or fell,growth of the alga was affected to a varying extent,and to a significant extent when the flow velocity reached to or beyond 50 cm·s^-1.

Photoautotrophic biofilms were cultured and collected in different water layers of the Donghu Lake of Wuhan City from October to November 2005 in an experiment to study characteristics of their growth and activity.Several parameters including biomass,extracelluar polysaccharides,COD and dehydrogenase,were determined.Results show that the photoautotrophic biofilms in different depths experienced four growth periods like "latent adaptation period,growing period,abscising period,and regrowing period".The photoautotrophic biofilm growing in the water 20 cm in depth was higher than those in the water 100 cm in depth in growth rate,biomass and activity.The findings indicate that the physiological characteristics of the photoautotrophic biofilm in hypereutrophic water are quite similar to those in the clean natural water and eutrophication doesn′t have significant effect on the growth of biofilm.

A total of 37 samples of feces,water and soil were collected from 10 different types of livestock and poultry breeding farms in Jiangsu Province for determination of population of Fecal coliform and Samonella therein.Meanwhile drug resistance of the Escherichia coli isolated from wastewater and effect of animal excreta on population of antibiotic tolerant bacteria in soil and water were analyzed.Results show that of the 10 livestock and poultry farms studied,9 were found discharging animal feces directly into the soil and water without any pre-treatment,and their discharges significantly exceeded the criterion for population of Fecal coliform,and 19% of the fecal samples was found to have Samonella.The count of Fecal coliform in the soils applied with fresh manure was well above 10⁵ g^-1.All the Escherichia coli isolated from the wastewater showed tolerance to a number of drugs and one isolate was even able to tolerate 10 kinds of antimicrobial.The count of tetracycline or streptomycin resistant bacteria in the soil or water amended with fresh manure was much higher than in common soil or water.

Thirty soil samples were collected from the top layers of farmlands in some selected sites,in Xinghua,Wujiang,Yixing and Luhe of Nanjing in Jiangsu Province and tested for contents of 16 types of polycyclic aromatic hydrocarbons(PAHs) with the aid of HPLC.Contents of PAHs varied widely from 45.6 to 2 286.8 μg·kg^-1,averaging 1 370.3 and 801.1 μg·kg^-1,respectively,for samples from Xinghua and Wujiang,signifying severe pollution,and 210.8 and 126.7 μg·kg^-1,respectively,for those from Yixing and Luhe,meaning slight pollution or zero pollution.Based on the relative abundances of PAHs different in ring number,the ratios of Phe/Ant and Fla/Pyr and the findings of the site investigations,it was found that PAHs in the soils came from a number of sources,such as exhaust from automotives,combustion of coal,burning of straws and wood,leakage of petroleum,etc.

In order to investigate the soil quality in non-polluted food bases in Nanjing,a total of 70 soil samples were collected from the surface soil layer in Baguazhou,Nanjing for analysis of residues of organochlorine pesticides(OCPs)(α-,β-,γ-,and δ-HCH,o,p′-DDT,p,p′-DDT,o,p′-DDE,p,p′-DDE,and p,p′-DDD) and their characteristics.OCPs were extracted by ASE(accelerated solvent extractor) with acetone/petroleum ether(1/4,V/V),cleaned up with silica gel column and quantified by capillary gas chromatography with a 63Ni electron capture detector(GC-μECD).Results show that total OCPs residues in the soils ranged between 6.18 and 84.72 μg·kg^-1,averaging 18.63 μg·kg^-1.The concentration of DDT was much higher than that of HCH in soils.DDT residues ranged from 3.36 to 74.19 μg·kg^-1 with an average being 12.61 μg·kg^-1,while HCH residue did from 2.48 to 17.80 μg·kg^-1 with an average being 6.02 μg·kg^-1.Both DDT and HCH in all the soil samples were far below the threshold value of 500 μg·kg^-1 in the Chinese "Non-Polluted Food Base Soil Quality Standards".However,most of them were much higher than the criteria for non-polluted soils in the "Guideline for Soil Protection of the Netherlands".

Based on the soil geochemical data obtained during the agricultural geo-environmental survey of Zhejiang Province and the basic conception of geochemical background values,the soil geochemical baseline was divided into 13 statistical units in light of types of soil parent materials.The three major agricultural regions of Zhejiang Province were fixed as statistical units for soil environmental background values.After repeatedly crossing out anomalous values,mean values,standard deviations and variation coefficients of 52 elements(or oxides) were obtained,and may be cited as major geochemical data for formulation of regional soil environmental quality standards,and evaluation and remediation of soil pollution.

To study heavy metals(lead,cadmium,copper and zinc) contamination of soils and vegetables on roadsides,samples of soils,vegetables and dust were collected alongside the Chenhai and Beiyan highways on the Chongming Island for analysis of Pb,Cd,Cu and Zn contents.With the upper limit of the background values of Shanghai set as criterion for evaluation,10.1%、25.4%、6.5% and 8.7% of the soil samples exceeded the criterion for Pb,Cd,Cu and Zn,respectively.When the evaluation was based on the criteria in the farmland environmental quality evaluation standards for edible agricultural products(HJ 332-2006),21.0% of the soil samples were beyond the criterion for Cd,less than 3% beyond the criterion for Pb,but none beyond the criterion for the other two.And when the vegetable samples were evaluated based on the national tolerance limit of heavy metals in foods,43.2% exceeded the criterion for Pb,18.6% for Cd and less than 5% for Zn and Cu.All the findings suggest that the soils and vegetables,within 50 m,alongside the roads low in traffic load will get contaminated with heavy metals after long terms of road service. Flying dust is an important potential source of heavy metal contamination in the roadside environment.

Three sample plots of different habitat were selected in Yunnan and Sichuan to study effects of invasion of Eupatorium adenophorum on content of available nitrogen,available phosphorus and available potassium in soil.Results show that available nitrogen,available phosphorus and available potassium decreased by 33.9%,44.2%,and 32.2%,respectively,in Plot a; only available phosphorus did by 30.1% in Plot b;and no significant change was observed in Plot c.During the experiment,Plot a was found lower than the control in soil nutrient content,regardless of time period,and especially during the period from July to October of 2005,which suggests that the effect of the invasion of Eupatorium adenophorum varied from habitat to habitat,and was related to the growth rhythm of Eupatorium adenophorum.