Laizhou Bay region is located in the north coastal zone of Shandong Province, China In this region, water is scarcy and has already bocome the most important constraint for the regions economic development In this paper, impacts of climate change(1960～2042) on water vulnerability are investigated The results are as followes:(1)According to the capacity of water supply system in 1993, in 1960～1976 wet climate(mean precipitation is 112% of the normal climate), effective water supply is 120% of the normal While in 1977～1993 dry climate(mean precipitation is 88% of the normal climate), effective water supply is 78% of the normal At water demand level in 1993(about half of the irrigation water demand is met), in wet climate, water supply and demand balance is surplus, but it changes to be deficit when in dry climate Water resource vulnerability increases from marginally vulnerable level to vulnerable level (2)Based on future climate senarios in North China, 2000～2019 mean precipitation will be 110% of the normal precipitation According to the capacity of water supply system and at the water demand level in 2000, water supply approximately meets water demand if about half of the irrigation water demand is met Water resource vulnerability is marginally vulnerable 2020～2042 mean precipitation will drop to the normal level.In the light of the planned capacity of water supply system and at the predicted water demand level in 2020, water suppy and demand balance is deficit when onlg half of the irrigation water demand is met Water resource vulnerability will rise to vulnerable level (3)After 2042, precipitation may drop to less than the normal level with temperature 1℃ higher than normal climate, water resource deficit will be more serious even if water demand is still at 2020 level So it is necessary to import more amount of stable water than present planned from outside region in order to guarantee sustainable socioeconomic development

With over half century reclamation,great changes have taken place in ecological features of wetlands in Naolihe Drainage Basin.The paper analyses the main changes,including change in wetlands,change in water condition and water quality,all related to non sustainable exploitation of wetlands.Reclaiming and destorying wetland resources has led to a series of ecological problems,such as serious soil erosion,increase in local desertification area and water erosion,only the emphasis on use without measures of protection,the divorce between reclamation and construction,resultins in decline of soil fertilities to different degrees and the intensification of environmental pollution as well as biodiversity decreasing.Naolihe Drainage Basin is an important part of Sanjiang Plain,wetland changes will seriously affect the sustainable development of Sanjiang Plain.So,as the new policy comes with the advent of the new century,Naolihe Drainage Basin will get the best period of regulation.

Based on remote sensing images in 1988,1993 and 1998,measurement of Mashans land use was conducted through methods of maximum like and probabilistic relaxation,which revealed the city's spatial process in the past 11 years.The conclusions may be distinguished as follows:(a) The results of the detection are reasonable and it is feasible to calculate the transfer matrix of land use to show spatial pattern of land use distribution as unit of image pixel.(b) The main characteristics of Mashans land use change are the obvious reduction of the existing farm land and forest land,and subsequent rapid increase in urban land along Guzhu road and tourism/vocationing district along ring road which are the main developing axes during the recent 10 years.In 1988,agricultural production was the main human driving force that impacted Mashan landscape,but in 1998,urban development became the main one.The typical agricultural landscape in 1988 has been transformed into the urban fringe landscape in 1998.(c) Under the favorable policy formulated by the central and local governments,the main driving forces of land use change in Mashan are the rapid growth of population,foreign investment,fixed assets investment and development of the tertiary industry which was based on tourist industry.The driving forces will continue to affect land use in the future.

The comprehension of qualitative and quantitative analysis is the key point of present research on sustainable land use.This paper is intended to do the comprehension work in the Yangtze River Delta.First,qualitative research is done by analyzing present land use characteristics of the Yangtze River Delta.The result shows that fine land use condition,insufficient land resource amount,high exploiting intensity and quick land structure reform are the main characteristics in this area.And based on this analysis,the systematic objectives of sustainable land use in the Yangtze River Delta,which come from three administrative levels,are put forward.Second,a new quantitative pathway,social statistical method is established to evaluate the present level of sustainable land use in the Yangtze River Delta.Indicators consisting of 36 factors are selected as the evaluating index system,and weights and target values for indicators are established by using the AHP method and by referring to others' research.The method of membership function is selected to quantify the single indicator and the linear weighted function is chosen to compute the comprehensive evaluation index.And a new method is put forward to diagnose the obstacles in sustainable land use,in which the concept of obstacle amount is induced,and the corresponding formulae are used to compute it.Based on ranking obstacle amount of all indicators,what the main obstacles are and what the minors are can be found out.Then the sustainable land use evaluation practices are made in Suzhou,an important city in the Yangtze River Delta area,with the resultant comprehensive evaluating index of 63.10%.The result shows that the sustainable land use in 1998 in this area is still at a preliminary stage.And there are 12 main obstacles in sustainable land use in Suzhou.In view of the above obstacles,some practical countermeasures are identified.Through the above analysis,some conclusions are gained:(a) Qualitative method and quantitative method should be combined in sustainable land use research.Quantitative evaluation is the key point of this regional scale research .It is an effective way to survey the rationality and sustainability of current land use.(b) The practices of sustainable land use evaluation should be directed against the specific mode and objectives of land use.So the evaluating pathway must reflect the present features of regional land use.(c) The aims of evaluation lie not only on the determination of present stage of sustainable land use in specific areas,but also on the diagnosis of obstacles of sustainable land use,through which countermeasures could be raised to improve the sustainable level.

 The famous Chinese Geographer Academician HUANG Bing wei published 2 articles on the role of the forest in 1981 and 1982．These 2 articles had not only promoted the discussion on the role of the forest，but also promoted the research work in this field．Until now they still have their effect of the ecological and environmental reconstruction in China，especially in the development of the western regions of China． In China and in the whole world new progress was witnessed in this field during the last 20 years．The progress was reflected in both experimental and theoretical research． The former has provided more accurate and more credible data， while the latter has made a deeper understanding on the role of the forest，especially on hydrology and climate． Nevertheless， there are still a series of problems awaiting to be tackled because of the complexity of the problems themselves and difficulties in carrying out experiments．

On the basis of analyzing the distribution characteristics and the problems about expl-oitation/utilization of water resources in Guanzhong region,from a point of view of harmonious development among society,economy and environment,four modes on rational exploitation/uti-lization of the region's water resources are raised in an overall and systematic way,according to water resources conditions,exploitation/utilization potentials and environmental state.Moreover,in terms of geological,geomorphological,hydro-geological conditions and water resources distribu-tion characteristics,the four modes are further divided into eight sub modes.Also the paper ana-lyzes and studies water resources storage rules,current utilization situation,exploitation potential and reasonable utilization direction of all the sub modes,thereby,points out the direction for de-veloping and utilizing macroscopically water resources and offers scientific proof for allocation,planning and management of water resources.

Water resources of lakes in China play an important role in economic and social sustainable development The implementation of optimum control strategy is an essential way for the sustainable utilization of water resources in the catchment of lakes Water resources shortage,pollution and related problems such as flood hazards,changes of lake eco systems during the utilization process in China have been generally summarized in this paper It points out that the thought on optimum control of lake resources is a comprehensive control on the aspect of eco systems in lake catchment Measures of optimum control strategy for water resources of lakes in China include the following aspects: implementing catchment management of lake water resources,establishing economical type of national economy,increasing investment on science and technology for the implementation of environmental renovation suitable to local lake conditions, controlling pollution in lake catchment through whole processes and at all aspects,and implementing environmental education in lake catchment

The Liaohe Delta is one of the four great deltas in China,namely,the Changjiang Delta,the Huanghe Delta,the Zhujiang Delta and the Liaohe Delta.The core position of the Liaohe Delta is located in Panjin City,Liaoning Provines.It is rich in natural resources,such as flat land resources,petroleum and natural gas resources buried underground and a vast area of reed,wetland and tideland.There are many favorable conditions for developing industry and agriculture in Liaohe Delta.To utilize the land resources fully and reasonably,the characteristics of the present structures in land utilization of the Liaohe Delta are analyzed.Some parameters concer ning land utilization structures are investigated on the spot.The optimization model of the reasonable structure in land utilization is identified by applying the linear programming method .In the optimization model,a linear inequality is built with many variables such as the areas of paddy field,dry land,reed,oilfield,salt pan and shrimp pond.And the objective function and the restrained conditions in the near future and in the long run are set out.By means of calculating optimization,the optimum composition of current land utilization in the near future and in the long run is obtained for the region of the Liaohe Delta.The values of the objective function are obtained from the optimum structure in land utilization in different period times.At the end of the paper,twelve countermeasures are put forward to realize the optimization of the land utilization structure and the sustainable land utilization of the Liaohe Delta.And the steps which ought to be taken for each countermeasure are also put forward.

The high variability of summer rainfall over northern China has great impacts on environmental and socio economic system.In this manuscript,the decadal variability is analyzed.Power spectral analysis indicates a 35 yr period dominated by low frequent variations exists.The locations of 250 mm isohyet also show great annual variations and dramatic decadal changes.The averaged latitudinal location before and after 1978 changed about 1.5 degrees.The relationship between summer rainfall over northern China and spring surface temperature over vast expanse is investigated.There are two regions found connecting to summer rainfall significantly,one is India,Pakistan and their adjacent ocean sectors where positive correlation occurs,and the other is over inner continent in central and West Asia where negative relationships exist.The spring temperature of these two regions can explain 15% of the difference in summer rainfall in northern China.

National food security is based upon grain self sufficiency in general.Cultivated land resource is an important base influencing the available grain self sufficient capability.In China,the pressure of grain demand becomes greater and greater in the 21st century owing to the continuous population growth and income increase.Conflict between population and land will become more acute because scarce cultivated land will be partly transformed irreversibly into non agricultural uses in the process of the speedy industrialization and urbanization and economic development.Through analyzing the impacts of quantity change and quality status of cultivated land on grain production,the authors identify the relationship between cultivated land change and food security in China.This research tends to offer a basis for China to set down food security strategy in the 21st century.

There exists much dispute about the influence of forest on precipitation．Presently the research is very weak to analyze the influence of afforestation and deforestation on precipitation at large scale．Therefore，changes of forest resources and precipitation in China over the past 50 years are analyzed in order to find the relation between changes of forest resources and precipitation at large scale． The main conclusions are as follows． (a) The percentage of forest coverage has been tending to increase since the foundation of P．R．China(i．e．，1949)，which rose from 8．6％ in 1948 to 13．9％ within 1989 1993， and 16． 55％ in 2001．(b) The average precipitation for forestland is 53．4 mm higher than that for non forestland，while the average precipitation variation in forestland is 9％ less than that in non forestland，which indicates that the forest has the function of mitigating variation of precipitation．In addition，the precipitation of the whole country， forestland， and non forestland all tends to drop during the past 50 years．(c)For each period of the forest survey implemented since 1949，the statistical analysis discloses that the relationship between changes of percentage of forest coverage and precipitation is insignificant．The percentage of forest coverage in China is increasing obviously，while the annual precipitation is declining．That means the increasing percentage of forest coverage does not result in the increasing of precipitation at large scale，i．e．，there is no significant relationship between the change of forest resources and the precipitation in China．(d)The research about relationship between the change of forest coverage and precipitation is a complex system， and there also exists much uncertainties (e．g．，the inherent problem of statistical data about forest resources， declining of forest quality，etc．)，which will affect the result of this research directly and(or) indirectly．Hence，it is indispensable to probe the influence of forest on precipitation by experimental verification and theoretical discussion．

This paper studies underground reservoir in terms of regional karstic geological,reser-voir formation condition,capacity analysis,calculation of the amount of precipitation and reple-nishment as well as engineering effects by taking Maguan underground reservoir in Puding coun-ty of Guizhou Province as an example.It proves Maguan underground reservoir is a typical case in effective utilization of rain water resources in karstic mountain region and is of significance in popularization.

The relations between the history,present situation and future development of exploitation and utilization of water resources and the oasis evolution and ecological balance in Tarim River are as following:In the original stage,the ecology was in a natrual balance,and the oases were distributed at the lower reaches of the rivers; in the primary stage,the ecology was in a unbalanced state,and the oases were moved towards the piedmont plains; in the inefficient stage,the eco environment is degenerated,and most of the new oases are distributed in the peripheries of the old oases; in the rational stage,the ecology will be recovered and improved,and the extension of the oases will be changed to tap the potentialities in the oases; and in the efficient stage, a virtuous circle of the eco logy will be achieved,the area of the oases will be stabilized,and the productive forces will be obviously raised.At present,the utilization of water resources in Tarim Basin is only in an inefficient level,and the pace of constructing irrigation works must be quickened so as to achieve the rational and efficient utilization of water resources as early as possible,thus the eco environment can be improved.

The Yangtze River Delta is one of the regions with most densely population,fastest economic growth and most intensive land use,the contradiction of land shortage sharpened by high speed economic development has become the problem not to be ignored which restricts regional sustainable development This paper has revealed the characteristics of high intensity land exploitation and the basic process and driving forces of change in arable land area according to the data of long series statistics of arable land area during the past 50 years and detailed investigation of land use during the recent five years The research results show that there is a trend of obvious fluctuant decrease in arable land area during the past 50 years.The changes of arable land area undergo the process from increase to steep decrease to gently decrease to rapid decrease,in which,there are three height periods of decrease in arable land,they are 1958 to 1963,round about 1985 and round about 1993 respectively The mechanism of decrease in arable land are mainly the driving forces of policy,economic development and population growth

Responses of NPP of salinized meadow in hyper arid area to global change were predicted using the NPP model,developed by the author to simulate the NPP of natural salinized meadow in northern part of Tarim Basin.The result shows that the NPP of salinized meadow in hyper arid area is the function of underground water table(UWT) and the temperature in given soil conditions.The NPP of salinized meadow decreased with increase of underground water table.Responses of NPP to change of UWT and temperature increase resulting from global change vary with different UWT of salinized meadow in hyper arid area.The impacts of global change to NPP of salinized meadow,therefore,depend on differing UWT of salinized meadow.It is extrapolated that responses of NPP of salinized meadow to global change are more sensitive with greater UWT than those with shallower UWT.

Eco agricultural systems have been developed widespreadly in the last decade and now they are integral parts of the rural development in China. Eco agricultural systems apply principles of eco economics and methods of systematic engineering to plan,design and manage the agriculture,aiming towards sustainable,stable and balanced development. In this paper,five fundamental issues of eco agricultural system in China are commented from the perspective of resource management.

 Only by understanding forest hydrological effect accurately and objectively can we get right direction from these principles． This paper proposes using systematic viewpoint to deal with the relationship between forest and water． Comprehensive adjustment function of forest and the relationship between forest and hydrologic cycle are stated and analyzed systematically depen ding on the long term research results of fixed ecological stations throughout China and similar research projects． It raises that in the development of western regions of China， scientific allotment of water resources should be considered in construction of forest grass vegetations and all industrial development should be moderate．

Up to now,great progresses in the construction of eco-environment have been made,especially afforestation in the"Three Norths"of North,Northeast and Northwest China.Accord-ing to statistics,up to1997,afforested area of the whole country had reached46.27million ha,among of them30.24million ha were located in the"Three Norths".However,in the process,some problems still exist which need to be solved as soon as possible,in particular,the relative low survival rate and preservation rate which are only25%and13%respectively.The analyses show that scarce rainfall,drought and the shortage of soil moisture are the main reasons for this phenomenon.Therefore,water resources are the cores of the reconstruction of ecosystem in Northwest China.The effective approaches to overcome the shortage of water resources there in-clude interbasin water transfer,effective water management ,resourcelization of rain water,de-veloping water-saving agricultural techniques,popularizing water-saving awareness,etc.

Mangrove wetlands are evergreen tree and shrub communities mainly consisting of mangrove plants, usually growing on the upper part of tidal flat of tropical and subtropical coasts, and periodically inundated by tidal water. Mangroves are naturally distributed in Hainan, Guangxi, Guangdong, Taiwan and Fujian provinces, with an area of about 15,000 ha.There are 26 exclusive mangrove species and 11 semi exclusive mangrove species in China. The mangrove wetland in China has low direct economic values, but plays an important role in protecting coastline, keeping coastal biodiversity and fishery resources, clarifying sea water, beautifying environment, and so on. It is a coastal ecologically critical area that is specially easy to be undervalued.The mangrove areas have been sharply reduced because of humans unreasonable exploiting activities,such as des troying mangroves for agricultural and salt fields, for aquaculture ponds and for urban construction, and the mangrove wetland resources are in danger and need urgent efficient management and protection. Eighteen mangrove natural reserves have been established. It is essential to attract scientists to take an active part in scientific researches on mangrove wetlands, to spread the knowledge about mangrove environmental functions, to reverse its decline trend and to achieve the ecological restoration and sustainable deve lopment of mangrove wetland ecosystem.

The 185.1 km long section of the Yellow River locating in Jinan City covers a drainage area of 2,778 km². Both interannual and intra annual water discharge of the Yellow River in Jinan varies greatly.The maximum quantity of runoff is 21.8 times as the minimum one.The runoff concentrates in flood season during the months of July to October,representing 60.7% of the annual value averaged on many years.In recent years,the runoff quantity of the Yellow River in Jinan shows a decreasing tendency year by year and the state of breaching of has been intensified.In 1997,the Yellow River ran dry for 132 days at the Luokou hydrological station.At the same time,the sediment content of the Yellow River in Jinan is high,averaging 24.9 kg/ m³ over years,showing an increasing trend.In recent years the quantity of water from the upper reaches has been decreased and the water using quantity has been increased.The water resources have been seriously wasted.The water has been polluted to some degrees.The regular capacity of reservoir is low,the water resources have not been dispatched and administered in a sustainable way.All these mentioned above have hindered sustained utilization of the Yellow River in Jinan section.The article,based on the analysis of existing status of water resources and the main problems in resources exploitation and utilization,on the prediction of water delivery and water demand,addresses the main countermeasures to the sustained utilization of the Yellow River water resources in Jinan section.(a)Taking sustained strategy as a principle,making overall planning and administering as a whole and making centralized dispatch.(b)Extending the present reservoirs and building new ones.Making full use of these water conservancy projects to ensure the water used in ecology.(c)Combined utilization of surface water and groundwater resources.(d)Building a water saving production system and society,improving effective utilization rate of water resources.(e)Adjusting price of water according to economic leverage.Promoting water saving awaveness and implementing water saving measures.(f)Reinforcing the dikes of the Yellow River and planting trees to control sand and prevent flood and ice dam,for the sake of achieving regional sustainable development of the Yellow River in Jinan section.

Risk analysis theory mainly refers to use scientific methods to reduce losses resulting from all kinds of uncertainties to the minimum through differentiation, estimation and disposal. Based on the theory, this article discusses the risk problems in grain yield. Given a grain yield sequence, firstly we decompose it into two main parts according to different factors that affect yield. Secondly we translate the two parts into a ratio sequence, through which we could get rid of the influence of dimension as well as productivity, and the sequence reflects the information of fluctuation of grain yield during recent years. In addition, we form a function to simulate the rate sequence and subsequently calculate the probability of a cerain risk level of the sequence using the method of integral. This kind of information conduces to disaster management as well as formulation of proper policies in disaster reduction.

In the paper, combining historical review and status quo, the author summarizes the zoning work of land resource use in China, then sets up index system and establishes the zoning system and grading method for land resource utilization. On the above basis, a new zoning scheme for land resource utilization including 12 land utilization regions and 67 land utilization sub regions is put forward by clustering analysis in the light of land use structure at the county level. The 12 land use regions are the following:ⅠNortheast mountains/plains, woodland/dry farmland farming/forestry region;ⅡNorthern China plain, irrigated/dry farmland and residential/industrial land farming and construction region;ⅢLoess Plateau, dry farmland/grassland/woodland farming/husbandry/forestry region;ⅣMiddle and lower reaches of the Yangtze River Plain paddy field/waters/and residential/indu strial land farming/fishery and construction region;ⅤSichuan Shannan basins, woodland/dry farmland/paddy field farming/forestry region; ⅥHilly and mountainous area south of the Yangtze River, woodland/paddy field forestry/farm ing region;ⅦYunnan Guizhou Plateau, woodland/shrubby/dry farmland forestry/farming region;ⅧSoutheast coastal areas, woodland/paddy field/garden and residential/industrial land farming/forestry/fishery and construction region;ⅨInner Mongolian Plateau, grassland/dry farmland husbandry region;ⅩNorthwestern arid lands, unused land/grassland/irrigated farmland husbandry and oasis farming region;ⅪQinghai Tibet Plateau, grassland/unused land husbandry region;ⅫSoutheast Tibet Hengduan Mountains, woodland/grassland forestry/husbandry regionIn the scheme, the Southeast Coastal Areas and the Southeast Tibet Hengduan Mountains were firstly zoned as two land use regions, and not only the important territorial development areas but also the eco environment fragile zones were emphasized on the division of land use sub region. It also provides scientific basis for effective protecting cultivated land, using land in a high efficient way, coordinating land use between industry and agriculture and avoiding blindness in land exploitation and land use.

 From the research results on soil hydrology， the effects of forest hydrology on the total runoff and the surface water transferred into ground water were analyzed．It was found out that there exits an underlying drying layer of soil underneath forestland at a depth of more than 1 to 3 m from the soil surface．The distribution of the drying layer and causes why it exits are expounded， as related to ecological attributes of the Loess Plateau． It was believed that the drying layer is in great water deficit caused by evapotranspiration，which prevents gravitational infiltration of water and the replenishment of ground water．It is determined that a forestland on the Loess Plateau reduces the total runoff as the results of the increased retention of runoff and of the reduced recharged into ground water．

The classification of water shortage degree and shortage types of various provinces,re-gions and municipalities(excluding Taiwan)throughout China was carried out in the study by using comprehensive evaluation method and taking per capita available amount of water re-sources,per unit area available amount of water resources,per capita amount of water supplied and per unit GDP available water resources as indicators.According to the water shortage com-posite index number,water sufficient district,fragile district,water deficit district and serious deficit district are identified.In light with differential value of per capita available amount of wa-ter resources,per unit area available amount of water resources,per capita amount of water sup-plied with national mean value,resources type,engineering type and overloading type are catego-rized.

The benthic macro invertebrate resources in the islands of the Changjiang estua ry were surveyed,and their ecological characteristics were studied.The results show that there were 41 species of benthic macro invertebrates on the tidal flat wetland of the three islands.The dominant species were Corbicula fluminea,Potamocorbula ustulata,Sinonovacula constricta,Helice tridens tientsinensis,and Ilyrplax deschampsi.The ecological characteristics and environmental function of the benthic invertebrate resources in the islands were analyzed.The species composition and ecological distribution of the islands in the Changjiang estuary reflected ecological characteristics in estuarine.The wetland benthic fauna in the three islands of the Changjiang estuary can be divided into three categories,i.e.fresh water species,brackish water species and sea water species,which reflected the characteristics of eco environmental transitional zone in the estua ry.The species composition and number of zoobenthos in the wetland of the islands was related to sediment composition,sedimentary rate and topography of tidal flat closely.In the tidal flat wetland of the three islands,distribution pattern of benthic fauna in space reflected its success process with the elapse of time.According to the ecological succession of vegetation and the characteristics of fauna,tidal flat wetland in the Changjiang estuary may be divided into three ecological sere,i.e.saline algae zone,bulrush community zone and reed community zone.Many species of zoobenthos have great economic value,which are principally some species of Crustacean and Mollusc.Zoobenthos in the wetland of the three islands play an important role in the estuarine ecosystem such as transporting trophic material and transforming pollutants,acting as significant channel of energy flow,and influencing on the movement and stability of sediments.Finally,some suggestions for developing and conserving the benthic invertebrate resources were proposed.

Groundwater has been changing extensively affected by human activities combined with desiccating climate conditions.In modern times,population growth,accompanied by development of industrial and agricultural production and the petroleum exploitation,brought about rapid expansion of artificial oasis with abruptly increasing of water demand.As a consequence,the artificial hydraulic irrigation project took the place of natural river system,the reservoirs took the place of natural lakes which in turn enhanced the space time redistribution of surface water based on natural evolution,and so did groundwater.The groundwater recharge reduced by 26.2% in 46 years from 1950 to 1995 in southern piedmont of the Tarim Basin based on mean yearly population increase rate of 27.7‰ associated with water use rate increasing from 24.6% to 58.4%.At the same time seepage of artificial water system plays a leading role to groundwater recharge,which is up to 57.6% whilst that of the river bed reduce to 33.7%.As a result,groundwater table generally dropped by 3～5 m except some irrigated areas and surroundings of plain reservoirs.Spring water discharge also reduced by about 28.7% and discharge zone continuously moved away to the north with values of 0.5～1.2 kilometers in the past 40a.Meanwhile,groundwater contamination began to rise up quickly,especially in some towns and irrigated areas a lot of organic nutrients such as NH4 N,DOC and SRP were brought to aquifers where groundwater was recharged by surface water.Besides,groundwater evolution has led to serious plant degradation and land desertification.

Resources and environment are the key part and base for regional agricultural sustainable development.Ecological safety for agricultural and rural development means that resources and environment on which agricultural and rural development depend are balance,and agro ecosystem is health.There are many characteristics on ecological safety,such as strategy,integrity,regionality,hierarchicity,dynamic and periodicity.As a case study of Jiaxing city,Zhejiang province,the paper discusses the method and process of evaluation of ecological safety on agricultural sustainable development,and identifies an indicator system of ecological safety that has 23 indicators group on resource ecology environment pressure,quality and protection ability.Mathematics model on indicators calculation is set up.Indicator standards on ecological safety are given.The approach to and strategy for constructing ecological safety on agricultural sustainable development are pointed out by taking Jiaxing city as a case in this article as well.

The structure and layout of land use have been greatly changed because of the low lying land submergence,resettlement,movement of new towns and industrial and mining enterprises resulting from the construction of the Three Gorges Reservoir Area(TGRA).Therefore,how to construct the new macro patterns of land use types according to the principle of landscape ecology and sustainable developmental norm are not only the keystone of resettling a million of migrants and allocation of production in TGRA in the next ten years,but also are related to harmonious and sustainable development of economy,society,resources and environment in the future.In this paper,the ways and process of conversion of land use types under the forced conditions including land submergence and use allocation are analyzed.Then,with a view to different hierarchies from factor controlling,zone design to optimal system models,the models and measures of land eco design are put forward.Based upon which,considering the harmonious development of industries,the optimal allocation schemes of land use are formulated.

 Based on analysis of the inborn condition of soil water resource and soil water cycle and balance in Loess Plateau，soil hydrological efficiency in artificial forest system， soil desiccation—the formation of soil arid layer and the problem of afforestation were discussed in this paper．

Based on fixed and consecutive measurements of soil moisture in hilly area of loess during wet and dry years,spatio-temporal relationships between land use types and their struc-tures were analyzed.The results are as follows:(a)the effects of land use on soil moisture are sta-tistically different in dry year,but not in wet year;(b)the annual changes of soil moisture during wet year are consuming type for shrub land,and balance type and increasing type for intercrop-ping land,orchard,woodland,grassland,fallow land and cropland.However,these changes of soil moisture during dry year are consuming type for all land uses;(c)from wet year to dry year,profile types of soil moisture change from decreasing type to fluctuation type,and from fluctua-tion type to increasing type;and(d)soil moisture of single land use structure has increasing trend from hill top to bottom,but complicated distribution patterns are found for multiple land use structure along slopes.