The method that linked material flow with nutrient flow was adopted in this article in order to study nitrogen and phosphorus nutrient flows in the whole process from the fertilizer input to the consumption of corn.Nutrient flow model was firstly established in corn productionconsumption system.Taking the year 2004 for example, in which the characteristics of nitrogen and phosphorus in maize ( including straw) and the efficiency of resources utilization were estimated.In 2004, 5.496×106 tons of nitrogen (N) and 2.112×106 tons of phosphorus ( P2O5) were applied into corn field in the form of chemical fertilizers; and 3.429×106 tons of nitrogen (N) and 1.394×106 tons of phosphorus ( P2O5) were harvested, in which 75%(N) and 68%( P2O5) were consumed.Corn was used for making staple feed.The total amount of N and P2O5 that came into the families, including directly by plant products and industrial products, and indirectly by animal products, occupying 22.8% and 13.6%, respectively.The ratio of returning straw to the field was quite low—phosphorus was about 80%, higher than that of nitrogen, which was 47%.So the returning straw to the field was regarded as an effective measure for phosphorus utilization. Nutrient flow began with the input of resource in the corn production-consumption system, but the utilization efficiency of resources was very low.Lots of resources were consumed by corn production, while 1 ton of nutrients in corn was produced, nitrogen and phosphorus which were consumed in the form of fertilizer were equal to 5.2 tons of coal and 12.1 tons of phosphorite, respectively.Therefore, optimizing nutrient flow in the entire corn production-consumption system was vital to the improvement of efficiency of nutrient resources and minimization environmental pollution.

Based on Principal Component Analysis (PCA) for remote sensing image, a new method was applied into identifying the spatio-temporal distribution of sea reclamation quickly and exactly. Taking Xiamen City as an example, the combinations of Remote Sensing Images, 1993 and 1996, 1996 and 1998, 1998 and 2001, 2001 and 2003, and 2003 and 2006, were identified by PCA approach for the distribution of sea reclamation in the above five periods. In order to study the driving factors of sea reclamation at different development stages of Xiamen City, several indicators such as population, throughput of sea ports, gross industrial output value, etc. were chosen into the regress equation of the driving forces. As a result, the policy of city development, rapid industrialization and rapid increase of population are the main driving factors of sea reclamation in Xiamen City. Consequently, Strategy Environmental Impact Assessment of urban policy, Sea Area Utilization Demonstration and Payment were advised for the government to governing the sea reclamation activities.

To research the changing patterns of current regional cultivated land and explore its impact on grain productivity is of great significance.Taking Northeast China as a study area,this paper analyzed the impact of the cultivated land change on grain sown area,per unit grain yield and total grain yield,and also the impact of the change of main crop planting structure on grain yield.The result shows: ⑴The cultivated land increased 188.8×10⁴ha with a general trend of increase in the northern part and decrease in the southern part in view of the spatial distribution.⑵The grain sown area has increased 162.67×10⁴ha.Per unit grain yield in most high-yield cultivated land presented an increase trend;per unit grain yield in mid-yield cultivated land presented a steady-going trend and furthermore with little increase in a few places;the changing trend of per unit grain yield in most low-yield cultivated land presented an increase trend.⑶The area of high-yield cultivated land,mid-yield cultivated land and low-yield cultivated land increased by 34.44×10⁴ha,12.57×10⁴ha and 141.83×10⁴ha respectively,but their increase amount of grain yield was 305.04×10⁴t,14.25×10⁴t and 122.88×10⁴t respectively.This shows the increase of both per unit grain yield in high-yield cultivated land and area of low-yield cultivated land promoted the increase of total grain yield in Northeast China.⑷The grain yield of four major crops in Northeast China presented different changing trends: the corn presented an "increase-decrease-increase" trend,the rice and wheat presented an "increase-decrease" trend and the bean yield increased continuously.The grain sown area of the four major crops presented a fluctuated changing trend: the corn presented an "increase-decrease-increase" trend,the bean sown area increased continuously,the rice sown area presented little increase and wheat presented an "increase-decrease" trend.In view of the regional difference,the corn production in Northeast China was further concentrated in Jilin province while that of bean,rice and wheat production further concentrated in Heilongjiang province.In a word,the grain production in Northeast China presented an obvious specialization and regionalization trend.

Based on the concept of “flood resource utilization”and influencing factors of adjusting the limited level of reservoirs during the flood season, an indices-evaluating system and estimating method about risk and performance related to the adjustment of limited level was set up, and the risk management countermeasure of the water level adjustment was discussed.Taking Wuqiangxi reservoir as an example, this study comprehensively evaluated the risk and performance brought by adjusting the limited level and the application the fuzzy-optimum-seeking method to adjust the limited level.According to the comprehensive analysis, it is feasible to raise the current limited level of 98.00m to 100.00m in the flood season.Under the condition of the low flood control risk,some 1.85 ×108m3 of flood probably excreted can be utilized efficiently, but this project must be carried out only at strengthening the risk management of real-time dispatching. Obviously, it is important to heighten the limited level and reserve more flood to realize the flood resource utilization.

This paper gives a comprehensive description of the researches of land use change at farm household level from the four aspects of investigation respect,research content,study method and data collecting means, and summarizes the features of the researches on land use change at farm household level.The main features are: ( 1)Most of the researches give notices on the land use change of hot regions, particularly on the tropical-forest area. ( 2) Lots of the researches attribute the land use changes on the pressure of subsistence to the population growth and the agriculture expansion which is also related with the population growth. ( 3) The attention of researches is being converted from land use type change to both land use conversion and land use intensity change. ( 4)More and more methods are applied by the researches of land use change at farm household level and integrated methods are appreciated by more and more studies. ( 5) The impacts of the decision-making behaviors of land users or managers on land use change are emphasized by most researches. ( 6) The social survey using questionnaires becomes a main toolof data collecting,but more and more investigations combine the social survey using questionnaires and the techniques of “3S” to get the data on land use change and its driving forces at farm household level, and devote to connecting the social survey data and the remote sensing data. Although much progress has been made in theory and practice of land use change research at farm household level, and some important results have been obtained, there still have certain problems in previous researches.These problems go as follows:the results of land use change study at farm household level can not be easily applied to other microeconomic agents, the results in one region should be much carefully applied to any other regions, the relation and interaction between different hierarchical data have been neglected, the acquiring cost of data which contains economic data and its corresponding space information is still an obstacle for the land use change research at agricultural household level, and the relation between spacial characteristics of farm household’s behaviors and the land use change’s spatial distribution has not been adequately emphasized.Furthermore, some suggestions of further studies on land use change at agricultural household level are put forward in this paper.These suggestions include applying multiple-level research angle, using game theory to analyze the land use change determined by the interaction of different agents, applying multilevel analysis in empirical study, emphasizing the impact of spacial characteristics of farm household’s behaviors on land use change and its spatial distribution, improving data acquisition means, building continuous survey system comp-rising of given farm households and so on.

Researches on water cycle in Taihang Mt. is vital not only to mountainous areas but also to groundwater recharge in adjacent piedmont.As one of the essential recharge sources for North China Plain (NCP) , a few results on status of water cycle and groundwater recharge into NCP have been reported, and the associated mechanisms have not been revealed clearly.Here, the mechanism and recharge processes of water in Taihang Mt. to NCP, with a case study in Niujiazhuang Catchment and the nested Shimen Catchment within it which is located at the middle of Taihang Mt., were presented.The results, from April to November 2004 for example, indicate the amount of lateral recharge from mountainous area to the adjacent piedmont was 1.53×106m3 with recharge ratio ( calculated by total recharge /total precipitation) of 0.242 in the order of upper reaches

According to meteorological datasets from 1961 to 2005,we selected drought days,relative wetness index,standard precipitation index, temperature anomaly and percentage of sunlight anomaly as evaluation indices of drought.Based on the method of information diffusion,level standards of agricultural drought that correspond to different evaluation indices were established.Then we assessed drought in Sichuan Basin during 1961-2006 with the fuzzy comprehensive evaluation method,and gave the drought occurrences frequency of each city.The results showed that severe spring drought,severe summer drought and extremely severe late-summer drought occurred in Sichuan Basin in 2006.Late-summer drought occurred in all the 17 cities,of which 13 cities witnessed extremely severe late-summer drought in the Basin.On average,the sparse precipitation weather occurred about once every 30 years in late summer.High-temperature occurred once every 60 years.About 29%of stations encountered the shortage of precipitation,and 90% of stations encountered high temperature,which occurred once over 50 years.Spring drought and summer drought mostly occurred in northwest and south of Sichuan Basin,about once per 2.5 years,late-summer drought mostly occurred in east of Sichuan Basin,about once per 2 years.

The Heihe river upstream basin was selected as a case study, the mechanisms of runoff yield and concentration in upstream mountain areas were cognized by using the rainfall-runoff relevant modules in MMS (modular modeling system) model. Considering hysteresis of rainfall seepage in non-saturated soil, and integrated the snowmelt models and frost-soil area identify models together, the existing tested-basin PRMS (precipitation-runoff models) was modified and improved in this study. The improved new PRMS is used to simulate and forecast the hydrological process in the upstream of the Heihe River, and the results showed that the improved new PRMS was more suitable for the dry and cold mountain areas of inland basins. Due to considering the frost-soil conditions, the runoff simulation and forecast error is less than 2.7%, and each element of runoff composition was simulated and forecasted more veracious than the original PRMS. Finally, the stream flow changing trends were analyzed under different climate and land cover change scenarios in future, which provided the scientific basis for the rational use and management of water resources in the Heihe River Basin.

Minimum controlling flux(MCF) and Maximum controlling pollutant load(MCP) ( for short as “dual gross”) are the key indexes for integrated regional water quality and quantity management and to sustain the ecological health of the rivers. The technical scheme for the dual gross control research has been erected primarily in this manuscript, and with such a scheme, the monthly dual gross control indexes have been derived.With the rational water resources allocation, the MCF in Tangshan can be complied except the low water year and continuous low water years.The maximum controlling COD load of rivers in Tangshan in the basic planning year, 2010 and 2020 are 16 357.57t /a, 12 659.19t /a and 11 572.50t /a, respectively, and the maximum controlling NH3 - N are 907.80t /a, 660.27t /a and 580.09t /a accordingly.With dual gross control indexes sustained by the unified water resources allocation platform, the eco-water requirement of rivers can be guaranteed under the condition of the water users competition; and the distribution of the pollutant carrying ability in a year can be derived subjectively; at the same time, the MCP can be improved.

The control measures of the slope land and types of land use are the most important factors for controlling water and soil loss,and the appropriate control measures of the slope land and types of land use could control soil erosion,protect land resource,and improve the environment effectively.In this study,based on the survey data of runoff plots,the effect of integrated water and soil conservation measures on slope surface on water and soil loss was researched.The results showed that compared with the slope land,the sediment reduction rate of terrace and narrow terrace reaches 64.83%-91.81%,this shows terrace could control soil erosion effectively,and the water and soil reduction benefits from terrace on the shady slope are better than the terrace on the sunny slope and the wide narrow terrace with ridge is better than the one without ridge.The water and sediment benefits from comprehensive water and soil conservation measure are very high,which can get to 96.21%-99.38%.At the same time,the soil erosion modulus of runoff plots with comprehensive control measure is less than the soil loss tolerance of 200t/km²·a in earthy-rocky mountain area of northern China,which is promulgated by the Ministry of Water Resources of the People's Republic of China.The natural prohibition can also control water and soil loss effectively,but as a result of comprehensive control measure induced changes of the slope surface shape,slope grade has less impact on water and soil loss.

Along with the industrialization and the urbanization process,the human being's activities of developments and constructions turned to the environmentally sensitive area unceasingly,which has created many environment negative problems against regional sustainable development.In view of the different types of characteristics regions, the classification to environmentally sensitive area, and clear distinction of the boundaries between the future regional development and protection,are of vital practical significance to the realization of the regional economic sustainable development.From the safeguard and support capacity of environmentally sensitive area to economic development and the importance of ecological function protected area of Suzhou City,the environmentally sensitive area of the city will be divided into the ecological sensitive area,surface water source sensitive area,contaminated sensitive area,high quality farmland sensitive area as well as the latent disaster sensitive area, five kinds in all.The defination of its spatial distribution can be testified from this contest,which has provided the theoretical basis for municipal building land expansion control,resource management and ecological protection.

利用3期遥感影像（20世纪70年代末MSS，20世纪90年代初和2004年TM），借助1：100000地形图、1：1000000 草地图和植被图以及野外考察景观照片，对三江源区东部8县的草地退化状况进行分析，结果表明：①东部8县草地退化，总体为轻微退化类型区，退化趋势减弱。轻度破碎化草地、轻度破碎化和轻度覆盖度下降草地类型占该区总退化类型面积的63%；②轻度退化草地以阿尼玛卿山地周围所占比例最大。中度退化草地主要位于西部和南部山体的阳坡、半阳坡，而在阴坡上很少发现。重度退化草地多数分布于河流、居民点周围；③海拔3700~4500m之间是草地退化主要发生区，两时段退化草地面积分别占总草地面积的11.88%和8.01%，而8°~25°也集聚了东部8县主要草地退化类型；④两时段草地退化比重由20世纪70年代末到90年代初11.2%减小为20世纪90年代初到2004的9.8%，但草地退化趋势仍在持续；⑤研究有助于从本底上准确把握三江源区草地退化状况，进而认识源区主体生态系统本底状况。

Under the background of globalization and informatization of the world economy, the rapid economic growth and process of urbanization in Suzhou city in future will aggravate the conservation pressure on cultivated land.It is time to consider and redefine the connotation of current cultivated land conservation concept. ( 1)Based on domestic and foreign related researches and the framework of PSR( Pressure-State-Response)model, this paper proposes the gradation evaluation indicator system of cultivated land conservation in Suzhou city among which the Pressure indicator is the environment pressure of cultivated land, and the State indicator is the soil quality and land fragmentation, and the Response indicator is per unit area yield of grain.( 2) Individual indicator evaluation results show that the environment pressure of cultivated land caused by rapid population and economic growth, urban sprawl and freeway networks infrastructure construction is very outstanding; the soil quality of cultivated land is very good, and the land is fertile; the fragmentation is evident because of the division of urban, transport land, lakes, rivers and highland terrain; the unit production ( 6683kg/ha) is higher than that of Jiangsu Province ( 5954kg/ha) and the whole country ( 4399kg/ha) .( 3) The correlative analysis of these individual indicators show that the correlative coefficient is very small, and the various relationships between indicators are performed according to different regional characteristics, and accordingly their weights are difficult to be defined.Based on the research result of correlative analysis of indicators, the paper adopts the Hierarchical Cluster Analysis method for the general gradation evaluation of cultivated land conservation.The results show that the ratio of the area of the 4 ranks is 33.6 ∶32.4 ∶26.7 ∶7.3.The cultivated land of rank S1 is located in the rural areas outside urbanization region and lake areas where four indicators are very good.The cultivated land of rank S2 is located in the Yanjiang plains and the urbanized marginal areas where the soil quality is good, and the level of food production is high.The cultivated land of rank S3 is scattered in the urbanized marginal area and lake-hilly areas where four indicators are common. The cultivated land of rank S4 is scattered in the areas around big cities and lakes hilly areas. ( 4) Then on the basis of regional characteristics and indicators relationships of each cultivated land conservation rank, the gradation system of the 4 ranks is subdivided into 9 ranks, and some conservation measures about cultivated land for each rank are also pointed out.

The spatio-temporal variability analysis of hydrometeorological factors are crucial for further understanding hydrological process and hydrological /meteorological modelling.Traditional temporal variability was quantitatively described using Coefficient of Variation based on statistics.In this paper, we combined information entropy theory with GIS spatial analysis technology to analyze the spatio-temporal variability of annual precipitation, evaporation and air temperature.A new spatio-temporal variability analysis method which is based on the differential information entropy relatively estimates is also presented.This study was conducted using 31 gauge stations precipitation, evaporation and air temperature data of Haihe river basin during the period from 1960 to 2001.The results intuitionisticly expressed the hydrologic and meteorological spatio-temporal variability rule of Haihe river basin, which lays solid foundation for further understanding the changes of water cycle of the study area.It is concluded that the spatiotemporal variability of precipitation and evaporation of the Haihe River Basin is relatively great and the spatio-temporal variability of temperature is relative small.

It’s a formidable task for a long time in China that how to utilize the land resources intensively and protect farmlands.The improvement of land use intensity is an important embodiment for the optimum land allocation.Market is the basic and efficient way to allocate resource. However, different market degrees can lead to different efficiencies of resource allocation and utilization.On the basis of building a framework of different land use efficiencies under the effect of market and government in different land market development stages, the article makes an empirical study on the development zones in Jiangsu province.By factor analysis and multifactors analysis model, and on the basis of the data of economy and land use in 2004, this study measured the development of land market and the intensity of land use in different land market stage.The result of the study suggests that on the whole, the stage of land market development is rather high, while the stage is different in different development zones.For example, the degree of land market in Wujiang and Nanjing development zones is 78% and 69% , respectively.The degree of land market in Yixing, Zhangjiagang and other 13 development zones is between 50% and 65%; at the same time, the degree of land market is between 30% and 50% in 23 development zones; and as for the remaining 4 development zones, the degree is only between 15% and 3 0%.So, the stage of land market in 33.4% of the development zones is in the end of transition to re latively mature stage; while the stage of land market in 57.1% of the development zones is in the m iddle transition stage.At the same time, the intensity of land use is different in different land marke t stages.The score of the intensity index of land use in the end of transition to relatively mature sta ge is 65.49, which is higher than that of the middle of transition stage.Because the score of intensit y index of the latter is only 48.85, the former is higher than the latter.So, the paper thinks the inno vation method to improve land use intensity is to change the mechanism of land management, and l et market mechanism become the main way to allocate land resource.

Qilian Mountain is famous mountain system in China and has a great many of glaciers, from which runoff is very important to the piedmont corridor area of the mountain.In addition, there is a water vapor transportation belt in this region, which brings abundant cloud and air water resources.Thus, cloud and air water resource exploiture project in the region is very meaningful and beneficial. In order to assess the synthetic benefit of cloud and air water resource exploitation, reasonable index system including 25 indexes was constructed in this paper.It involved social, economic and ecological effects.Then, choosing 11 indexes and using AHP ( analytic hierarchy process) method, each index weight was evaluated and synthetic assessment model was established clearly. In this paper, on the basis of Kang’s result about the impacts of precipitation enhancement on runoff flow from the mountain in the northwest arid region, the water resource and socioeconomic conditions after cloud and air water resource exploiation over the Qilian Mountain were predicted rationally.Finally, the synthetic benefit of cloud and air water resource exploitation over the Qilian Mountains was assessed integrally.The results showed that the social, economic and ecological benefit all would be improved remarkably after the cloud and air water resource exploitation over the Qilian Mountain.When precipitation increased by 10%, the synthetic benefit would be improved by 5.3%, and when precipitation increased by 20%, the synthetic benefit would be improved by 12.5%.

论文通过空间分析，指出了湛江(城市范围)所具有的典型海湾特性及其基本的空间结构特征，认为湛江城市发展与湛江湾的存在密不可分，而湛江湾的存在又与湛江群岛的关系极为密切，湛江海湾城市最大的特点就是先有岛，再有湾，后有港和城，把湛江定位为海湾型城市符合湛江城市发展的自然本底性质。文章重点就此定位对湛江城市发展可能造成的影响进行了分析，认为，海湾型城市定位可以提高湛江海湾资源的禀赋，有效促进湛江城市的一体化统筹发展。同时，有助于在湛江工业大发展时期到来之际，加强海湾生态环境的保护。最后就如何建设湛江海湾城市提出了一点框架性的思考

跨界水资源冲突的主要表现形式为跨界水污染、取水、水利工程、河道采砂冲突。以区域利益为视角，运用经济学理论分析发现，跨界水资源冲突的主要动因有：①区域竞争引发跨界水资源冲突；②水资源空间特性引发跨界冲突；③水资源外部性引发跨界冲突；④水资源准公共品属性引发的跨界冲突。基于博弈理论，跨界水资源冲突协调可分三个阶段、五个步骤开展。第一个阶段为准备阶段，主要实施跨界水资源冲突信息的收集与分析处理、关键影响因子的识别；第二个阶段为协调阶段，主要包括调处方案的设计和评价；第三个阶段为实施阶段，主要为协议的达成与实施。

采用土地整理工程手段建设基本农田，有助于实现耕地数量保护与质量提高，但必须遵循因地制宜的原则。论文根据自然地理区划和各地区的地貌特征，从分布特点、地类结构和利用水平等方面，对中国耕地资源的现状进行分析；针对自然条件和经济发展水平的区域差异，提出各地区耕地资源建设和保护的方向与重点。东部季风区应重点完善农田水利设施，改造现有中低产田，提高土地生产能力；西北干旱区不宜大规模开发，要着重发展农业节水技术，提高水资源利用率，防治土地退化；青藏高原区则应限制开垦。在土地整理与耕地资源建设中，因地制宜具体表现在生态保护、量力而行和重在效用3个方面。

利用广州市郊番禺区426家农户调查数据，分析大城市郊区农户弃耕类型及原因，构建包括农户个人条件、家庭状况、农地资源特征、农户意愿、村镇经济状况、区位条件在内的Logistic模型，分析农户主动弃耕的影响因素。研究表明：①番禺区农户弃耕比例不高，为36.85%，其中主动弃耕占85.26%，被动弃耕占14.74%，但农户弃耕意愿强烈，有41.78%的农户期待弃耕；②农户主动弃耕后主要将农地经营权流转，农地依然保持耕作状态，被动弃耕的农户均为失地农民，从而被迫弃耕；③家庭农业劳动人口少、弃耕意愿强烈、农地暂未被征用、家庭收入来源多、农地转出意愿强、距市中心近、所在村镇第二三产业发达、土地质量较好及距主干道较近的农户弃耕可能性最大。

研究的主要目标是针对森林生态系统寻求适宜的补偿标准的方法，从而制定出合理的生态补偿标准。首先运用生态区位商的方法将海南省森林生态系统服务划分为一级主导生态系统服务、二级主导生态系统服务和潜在生态系统服务三类。研究结果显示生物多样性保护、景观游憩和环境净化等划分为一级主导森林生态系统服务；养分循环和水源涵养划为二级主导森林生态系统服务；气候调节、土壤保育、制氧以及林副、木产品为潜在森林生态系统服务。分类结果在现实中符合海南省森林生态系统特征情况。其次，运用恩格尔系数与皮尔生长曲线模型相结合的补偿系数法计算生态补偿系数，结果为0.170。该数据说明现今中国的经济发展刚达到小康水平，人们对于森林生态价值的认识和需求处于初级阶段，因此制定补偿系数不宜太高。根据森林生态系统服务的分类及生态补偿系数的结果，计算出分三个阶段执行的生态补偿标准：在第一阶段，补偿标准为947元/(hm²·a)；第二阶段补偿标准提高为1946元/(hm²·a)；第三阶段，补偿标准为2966元/(hm²·a)。

论文基于GIS技术，采用缓冲区与分区统计等空间分析方法，分析了北京市畜禽养殖空间分布与海拔、距居民点和道路距离之间的关系。引入畜禽粪便施用耕地空间分布可达性分析，探讨了北京地区畜禽养殖空间分布特征和畜禽粪便农田施用的可行性。结果表明，北京市畜禽养殖分布与距居民点距离以及海拔高度成反比，同时，在一定程度上也受到道路分布的影响。从粪便施用耕地可达性分析来看，全市50.8%的畜禽粪便可在1 h内被运送到可施用的农田。其中，大兴和通州区畜禽粪便产生地与可施用耕地的距离最近，1 h内分别有91.5%和89.5%的畜禽粪便可运输到附近耕地。由于单位时间可达的畜禽粪便量与适宜施用耕地分布之间存在着空间上的不均衡，北京东北部区县（密云、平谷、顺义、怀柔、延庆）畜禽粪便的耕地承载大于西南部地区（大兴、通州、房山、门头沟、昌平）。根据耕地承载能力以及分布特征，科学合理地布局畜禽养殖业，是降低局部地区畜禽粪便耕地承载压力及其环境风险、实现畜禽养殖业可持续发展的根本。

为了探讨不同有机肥条件下施氮水平对土壤水解酶活性和夏玉米、冬小麦产量的影响，在陕西省眉县进行田间试验，研究和分析土壤水解酶活性及玉米、小麦产量。研究涉及无( 0 kg/hm²)、中(22500 kg/hm²)2个有机肥条件和N₀(0 kg/hm²)、N₁ (60 kg/hm²)、N₂(120 kg/hm²)、N₃(180 kg/hm²)4个施氮水平。结果表明，施氮对3种土壤水解酶活性均有明显影响，而不同的土壤水解酶对施氮量的响应有所差异。无有机肥和中有机肥条件下，施氮可以提高蔗糖酶活性，前者中量氮肥效果最好，后者低量氮肥效果最佳。无有机肥条件下，低量氮肥可以提高脲酶活性，但中量和高量会抑制其活性，中有机肥条件下，随着施氮量的增加脲酶活性降低。无有机肥和中有机肥条件下，碱性磷酸酶活性随着施氮量的增加呈升高趋势。玉米-小麦生长期内，土壤蔗糖酶、脲酶和碱性磷酸酶活性随生长进程的变化趋势各不相同。无有机肥和中有机肥条件下，施氮明显提高了玉米、小麦产量，低量氮肥对玉米增产效果最好，中量氮肥对小麦增产效果最佳。

耕地保护是保证区域社会经济可持续发展的基础所在，保护的程度不够会危及到粮食安全、社会稳定，保护过度又会影响到建设用地的供给。选择合理的耕地保护目标，成为了一个亟待解决的问题。论文在系统研究耕地保护的影响因素，以及耕地与其他各类用地关系的基础上，构建了情景-多目标规划模型（SMOP）。以浙江省为例，通过模型的运算，得出了不同情景模式下耕地的保有量。结果表明，8个情景模式中，只有情景B和F求出了最优解（低人口增长水平、生存用粮自给、较高的粮食单产水平情景以及高人口增长水平、生存用粮自给、较高的粮食单产水平情景）。通过进一步分析，其他情景模式无法得出最优解的原因是耕地需求超过了耕地供给能力。也就是说在其他情景模式下，耕地均存在一定的缺口，粮食安全受到了不同程度的威胁。情景G（高人口增长水平、营养用粮自给、稳定的粮食单产水平情景）的耕地缺口数和耕地压力指数最大。浙江省必须从挖掘耕地生产潜力以及建立健全粮食市场入手才能实现经济发展和粮食安全的双赢。SMOP模型能够较好地体现系统的复杂性和不确定性，其结果真实地反映了浙江省的资源禀赋和未来的发展可能。

将海拔高度等反映区域特性的因子作为变量引入GIS空间化模型是提高气象数据估算精度的重要途径。根据聚类的思想，将研究区域进行聚类分区，使分区内积温分布特征一致性趋强。然后利用统计方法寻找各分区年积温随海拔变化的规律，以获得较高精度的估算结果。论文提出的基于分区DEM修正反距离空间化方法，与常用的空间化方法如克里格法、反距离平方法相比，解决了积温空间分布复杂性的问题，并一定程度上考虑了气象站点空间分布的稀疏性、不均匀性以及受海拔和区域差异等因素对积温分布的影响，具有较高的估算精度，适合于较大范围的年积温空间化。另外，由于气象台站分布在相对较低的区域，高海拔区域积温估算精度很低，利用此方法解决了高海拔区域积温估算的精度问题。

The mountain areas in the Kezilesu, Kashi, and Hotan regions of Xinjiang which belong to the West Kunlun Mountains occupy 90 percent, 57 percent, and 42 percent of their respective total areas. The surroundings are very gool for developing animal husbandry. The rational utilization according to the natural ecolJgical conditions of the different vertical zones of the mountains can give full play to the productive effect of land resources.At present, the land use in the valleys is most intensive. Thereafter, unified planning of the mountains is important for preventing land, from deterioration due to overgrazing. The distribution of loess of the Kunlun Mountains has obvious relations to the attributes of the land resources and productivity.

Determining the optimal rotational felling period, for both natural and artificial forests, was and still is one of the most important problem in forest management. But the questions such as how to determine it, what principles to base on, or what models to use, etc. are still problems.In this paper, the author tried to explore the principles, acording to which the optimal rotational felling period can be determined. Here five basic principles-productive, economic, ecological, social and systematic-were proposed.Since the function of forest is multi-effect, not single, so generally speaking, the rotational felling period is a multiobjective programme:According to this general model, different mathematical models can be deduced from different streesed point.Finally, some simple mathematical models were discussed.

The Maimacuo nature reserve is situated in the northwestern part of the Qiangtang Plateau in Tibet, extending from 80°40' to 83°30'E and from 33°30' to 34°40'N with an area of about 25 thousand km2. In administrative division the reserve is part of both Ritu county and Gaize county.The basic character of the topography in the reserve is that the high mountain alternates wi h the lake basin. The climate is cold and dry. The annual temperature approximates to0℃——1℃, and the mean temperature is - l4℃ in the coldest month (January) and 10℃ inthe warmest month (July). The frost-free period lasts from 20 to 40 days every year and the annual pricitation is 150-200 mm.The basic vegetation type is the high-cold steppe. The plants grow well and have 6 main formations as follows. Form. Stipa purpurea, Form. Stipa subsessififlora var. basiplumosa, Form, Carcx moorcroftii, Form. Artemisia nanschanica, Form. Artemisia strackeyi, and Form. Oxy-tropis microphylla.The reserve is rich in wild animals. There are rare or nearly extinct wild animals among them, such as Poephagus mutus, Pantnolops hodgsoni, Asinus kiang, Ovis ammon, Pan-thera uncia, etc. These wild animals are seldom seen in Tibet.Seeing that the primeval high-cold steppe ecosystem remains in this region and has important scientific value, the author suggests that the Maimacuo nature reserve be protected as, the representative ecosystem of Tibet.

本文系统地介绍了世界黄金资源的地理分布,产出状况,成因探讨与远景储量,工业储量及开采量,黄金价格与市场等方面的较为严格的数理统计资料,在前人工作的基础上,将中国黄金资源与世界黄金资源进行了比较研究,提出了中国和世界黄金资源的开发方向与黄金市场及价格方面的预测: 世界黄金资源的找矿方向正从高品位——大储量或高品位——小储量的找矿及采矿方向转移到低品位——大储量方向上来,在中国亦应该及时把寻找低品位——大储量的黄金矿床作为主攻方向。 世界的黄金市场将会更加开放,随着宇航事业的发展与新材料科学的进步,黄金的工业用途将进一步加大,用量将会逐渐增长,世界黄金产量的增长,将会抵消黄金价格的上涨。

The so-called arid regions of China in this paper do not include the semiarid regions and only refer to such lands as Xinjiang, the Hexi corridor of Gansu, the Qaidam basin of Qin-ghai, northern Ningxia, western Inner Mongolia, etc.The runoff in China's arid regions shows horizontal zonality and vertical zonality, the latter being more obvious. The lofty mountain masses, such as Altai, Tianshan, Qilian, Kun-lun, Altun, Helan, ect., are capable of intercepting moist air currents to produce mere precipitation than that occurring on the surrounding plains. Therefore, from the viewpoint of runoff situation, the arid regions can clearly be divided into the belts of the runoff formation and those of the runoff disappearance. The runoff formation belts and the runoff disappearance belts in arid regions have fundamental difference in hydrological regime.The hydrological regime of the river and its evolution depend mainly upon the supply sources of the runoff. The diversity of the runoff supply sources is one of the hydrological cha-racteristilies in the arid regions. The melt water from the alpine ice and snow has great impact on the hydrological regime of the river.The groud water of the piedmont plain comes mainly from surface water, while the river water below the plain comes partly from ground water. Between the river water and the ground water exists a relation of mutual supply, i.e., mutual transformation.