辽宁省辽阳市水资源开发利用存在问题及对策

辽阳市是辽宁省水资源丰富的城市之一,而且开发利用程度高,为鞍山和辽阳的工业和城市生活用水提供了资源保证;在水资源的长期开发利用中发生诸多问题;针对存在问题,从水资源及开发利用现状提出了对策。     

巨野县水资源开发利用对策

分析了巨野县水资源特点及开发利用状况;指出了水资源开发利用中存在的问题;提出了水资源开发建议和对策措施。     

和田地区水资源现状及可利用量分析

和田地区是全国最干旱的地区之一,水资源贫乏,环境恶劣,生态系统脆弱,有限的水资源制约着当地社会经济发展和生态环境的修复;通过对和田地区水资源特性、开发利用现状及可利用量分析,提出了水资源开发利用中存在的问题及对策.     

山东省跨世纪发展的水资源问题及对策

在分析山东省水资源特点、开发利用现状及造成的外部不经济性的基础上．提出了可持续开发利用水资源的措施、即开源．包括内涵式开源和外延式开源;节流．包括农业、工业、城乡生活用水节流;防治污染、生态保护和加强水资源科学研究。     

黄山市水资源可持续开发利用构想

在综合分析水资源开发利用现状的基础上， 初步提出了黄山市水资源可持续开发利用构想。     

郑州市水资源承载力与可持续利用对策研究

通过对郑州市水资源开发利用现状的分析,指出了水资源开发利用中存在的主要问题。分析研究了郑州市水资源开发潜力及水资源承载力,提出水资源可持续开发利用的若干对策     

云水资源开发利用的外部冲突与管理研究

通过研究云水资源开发利用现状,得出如下主要结论：云水资源的开发利用存在外部冲突现象,这种冲突与我国管理云水资源开发利用行为的法律缺失有关;从经济学的角度看,云水资源具有稀缺性,云水资源的开发利用具有竞争性、先占性和外部性;为了理顺云水资源开发利用关系,建议尽快从法律上明晰云水资源的产权关系并建立开发申报协商机制。     

烟台市水资源现状及可持续开发利用的对策

分析和评价了烟台市水资源的总量、相对量、时空特性和开发利用现状。指出了存在的四大主要问题。预测了烟台市2005年,2015年缺水的最低量分别是5678万m^3和33528万m^3;从政策、开源节流和水资源的保护与管理等方面提出了持续开发利用的对策。     

新疆水资源合理开发利用与生态环境保护

从新疆水资源开发利用现状出发,分析了在水资源开发中存在的主要生态环境问题,提出了新疆水资源开发利用应采取环境保护对策。     

沂沭河流域水资源开发利用探讨

沂沭河流域水资源比较丰富,但水资源的年际、年内变化比较大,地域分布不均;水资源开发利用中存在利用率偏低,水质性缺水等问题;提出了加强水资源管理、提高节水意识、开源节流等对策措施。     

Forest fragmentation reduced carbon storage in a moist tropical forest in Bangladesh: Implications for policy development

Forest fragmentation is continued to be widespread in the tropics resulting in reduced ecosystem services including carbon storage. However, the effect of forest fragmentation is not considered in the current carbon policy. We investigated the effect of forest fragmentation on tree biomass carbon and soil organic carbon (SOC) storage in a moist tropical forest in Bangladesh. Above and below-ground tree biomass carbon were calculated by using widely accepted allometric equations and SOC was measured by sampling soils up to 10 cm depth and analyzing them in a soil laboratory. Results showed that carbon storage in tree biomass was significantly lower in fragmented forests (16.3 ± 1.37 t C ha⁻¹) than in contiguous forests (31.21 ± 2.75 t C ha⁻¹) (p < 0.001). Likewise, a significantly lower SOC was contained in the soils of fragmented forests (17.26 ± 0.83 t C ha⁻¹) than in contiguous forests (21.62 ± 0.78 t C ha⁻¹) (p < 0.001). Thus a total of 36% less carbon retained in tree biomass and soils in fragmented forests than in contiguous forests. Backward multiple linear regression analysis revealed tree density, tree height, tree DBH, height-diameter ratio (H/D) and tree species richness as influential factors of carbon variation in fragmented forests. All these structural parameters except tree species richness were significantly lower in fragmented forests, were positively associated with carbon storage and explained together 69% of the carbon storage variation. These findings suggest that the altered stand structure and tree allometry likely caused reduced carbon storage in fragmented forests and highlight the importance of landscape scale management intervention in the tropics. Here, we provided with the evidence of strong negative impact of forest fragmentation on carbon storage and argue that this effect should be in consideration which is currently overlooked in existing carbon accounting systems for tropical forests.     

Carbon storage in a bamboo (Bambusa vulgaris) plantation in the degraded tropical forests: Implications for policy development

Tropical forests potentially contribute to global climate change mitigation through carbon sequestration, hence a global carbon pool. In order to mitigate the global climate change impact, the Kyoto protocol developed the clean development mechanism (CDM) which supports carbon credits for plantation activities in developing countries. Unfortunately, none of the CDM forestry projects included bamboo as a carbon reservoir. Although bamboo is an integrating part of tropical forest ecosystems, it was overlooked in the initial negotiating process. The present study, therefore, investigated the carbon storage potential of a common bamboo species, Bambusa vulgaris at Lawachara forest reserve of Bangladesh. Results showed that five-year-old B. vulgaris stand stored in total 77.67 t C ha⁻¹ of which 50.44 t C ha⁻¹ were stored in the above ground biomass (culms, branches and leaves), 2.52 t C ha⁻¹ in the below ground biomass and 24.71 t C ha⁻¹ in the soils. This amount of carbon storage is much more promising than the carbon storage of many other tree species considered in the CDM projects. These findings demonstrate the potential of B. vulgaris to be considered in CDM projects as a plantation species and thereby mitigate climate change impact more efficiently.     

Characterisation and Diagnosis of Rural—Urban Interface Farming in the Tu Liem and Thanh Tri Districts of Hanoi City,Vietnam

A research project was carried out in two areas in the outskirts of Hanoi city using a combination of qualitative and quantitative methods. The objective was to study interactions among the vegetable farming systems and the peri-urban context within which they are situated. The farms studied were characterised as small-scale farms that use high inputs of soil amendments and pesticides for diversified crop rotation systems. The main source of irrigation water and nutrients for vegetable farming in southern Hanoi is wastewater from the To Lich River. In northern Hanoi, irrigation water is obtained directly from the Red River and nutrients are supplied through high fertiliser inputs. The concentrations of COD (144–287 mg l^?1), N-NH₄ ⁺ (1–25 mg l^?1), PO₄ ^3? (0.5–4 mg l^?1) and coliform (525 × 10³?28 × 10⁶ MPN 100 ml^?1) along the To Lich River was much higher than the limits specified in the Vietnamese standard for water used in agriculture. A higher Cu content in soil in Phuc Ly seems to be linked to the high input of chicken manure at the site. However, the contents of heavy metals in irrigation water, in vegetables and in the soil surface layer at the two sites were lower than the Vietnamese maximum permissible levels.     

县域节水潜力分析

以苏北泗洪县为例,在分析现状节水的基础上,进一步明确下一阶段的节水重点,并测算规划年节水水平下现状用水的节水潜力。分析结果表明:按照2020年、2030年的节水水平,泗洪县现状年节水潜力分别达6 365.1万m3和12 623.5万m3,节水潜力较大,未来泗洪县应当以节水优先为前提来统筹安排县域水资源管理的各项工作。     

Mapping changes in land use/land cover and prediction of future extension of bowé in Benin,West Africa

Desertification and land degradation are worldwide problems affecting soil, vegetation and the livelihoods of rural populations. Bowal (plural bowé) is a particular form of degraded land that occurs in tropical regions and leads to the exposure of ferricretes, which are unsuitable for farming. Bowé are more common on farmland and degraded savanna. Changes in land use/land cover were used to map a region of 6.7 million ha in northern Benin, West Africa in 1975, 1990 and 2010. The changes observed during these periods (1975–1990, 1990–2010 and 1975–2010) were used to predict the occurrence of bowé in the period up to 2050 using Markovian chain analysis. The results showed a considerable change in land use/land cover during the three periods. The types of land on which bowé occur (farmland and degraded savanna) increased in northern Benin by 5.4% per year during the period 1975–1990 and 9.5% per year during the periods 1990–2010, while the natural vegetation (forest, woodland and tree savanna) decreased by the same amount. The future scenarios also predicted the same trend. In the period 1975–1990, 1.28 million ha (26%) of natural vegetation was converted to degraded savanna and farmland while 2.23 million ha (53%) of natural vegetation was converted to degraded savanna and farmland in the period 1990–2010. Based on the dynamics recorded during the period 1975–1990 and 1990–2010 respectively, a total of 1.28 million ha (26% of the natural vegetation that was present in 1975) and 1.29 million ha (31% of the natural vegetation that was present in 1990) will be converted to farmland and degraded savanna in the study area by 2050.Thus bowalization will persist and increase in the period up to 2050. The natural vegetation could disappear if protection and restoration measures are not taken. It is thus important to take measures to stop the degradation and to implement programs to restore soils on bowé based on the soil and water conservation techniques used on highly degraded West African soils, such as zaï pit and stone rows with grass strips. Some native plants species adapted to bowalization and resistant to climate change in northern Benin (e.g. Asparagus africanus, Andropogon pseudapricus and Combretum nigricans) should be used in association with soil and water conservation techniques on bowé.     

Impact of foreign direct investment on greenhouse gas emissions in agriculture of developing countries

This research analyses the impact of foreign direct investment on greenhouse gas emissions in the agriculture sector of developing countries. Panel data from 63 developing countries for the period 2005 to 2014 was used to estimate a dynamic econometric model by applying a system‐generalised method of moments. The empirical results indicate a positive impact of foreign direct investment in agriculture on the carbon dioxide equivalent emission intensity in developing countries. The results provide weak support for the pollution havens hypothesis and imply the importance of coordination between foreign direct investment and environmental policies.     

Application of an ecosystem function framework to perceptions of community woodlands

Owners, local residents, government, and conservation organisations can express divergent preferences in the development and management of local woodlands. The perceptions of these four groups were examined, in the context of three community woodlands in Eastern England, using an ecosystem function framework. In a pilot study, residents were able to allocate a relative importance to woodland ecosystem services which were then related to “regulation”, “habitat”, and “production” or “information” functions. However residents also placed importance on negative services or “dis-services” associated with the woodland ecosystem. Therefore a fifth category of “dis-services” was included in the main survey which included 84 local residents, three woodland owners, three government institutions, and six representatives from conservation groups. Each of the four groups placed greatest importance on services associated with habitat (16–39% of the total importance) and information (30–50%) functions suggesting, in this example, mutual interest in the use of woodlands as a habitat or recreational resource. By contrast a potential area of difference was the particularly high importance placed by one owner on dis-services such as fly tipping. In addition the woodland owners placed higher importance (10–20%), than local residents and conservation groups (7–9%), on the productive services of the wood. This suggests a need for communication when production-related operations affect recreation. The ecosystem function framework appears to be a useful approach for highlighting potential tensions and areas of mutual interest in the management of semi-natural ecosystems.     

Effect of land-use conversion on C and N distribution in aggregate fractions of soils in the southern Loess Plateau,China

The purpose of this study was to assess the effect of grassland (GL) conversion to cropland (CL) and cropland conversion to forest (FL) and orchard (OL) on soil C and N distribution in dry aggregate size fractions in Nihegou catchment of the southern Loess Plateau, China. Four main land-use changes were analyzed in different agronomic management systems in 2006. The soil is wind-deposited loessial parent materials with a rather homogeneous silty clay loam texture classified as Calcic Cambosols. The GL was long-term over-used grassland. The CL was changed from GL after 33 years tillage with conventional tillage and fertilizer. The FL and OL originated from long-term CL after 23- and 7-year planted, respectively. Samples were taken at soil depths of 0–20 cm and 20–50 cm and were subjected to a physical fractionation process by way of aggregate size. Soil aggregate size fractions, total C and N contents and distributions were determined on all soil samples. Three dry aggregate fractions of very coarse (2.0–0.2 mm), coarse (0.2–0.05 mm) and fine (<0.05 mm) were obtained by shaking and sieving for 20 min. After 33 years of tillage, CL had 22% lower content of very coarse aggregates (2.0–0.2 mm) and 34% higher contents of fine aggregates (<0.05 mm) than GL. FL and OL soils had increased 9% and 10% contents of very coarse aggregates, and decreased 2% and 8% contents of fine aggregates compared to the CL. C and N losses in whole CL soils were 31% and 26% higher than those in GL. However, conversion of land uses from CL to FL (after 23 years) and OL (after 7 years) has increased C and N stocks by 76% and 40% in FL soils and by 66% and 63% in OL soils, respectively. This accessorial C and N stocks were higher in very coarse aggregate fractions (1.10 kg C m⁻² and 0.13 kg N m⁻² in FL soils, 1.43 kg C m⁻² and 0.17 kg N m⁻² in OL soils); moreover, the C and N stocks in fine aggregate fraction increased by 8% and 33% in FL soils and by 58% and 69% in OL soils, respectively. This results showed that C and N turnover and loss in aggregate fractions of this silty clay loam soils was very fast. Conversion of land uses from CL to FL and OL has obviously recovered the soil structure, and improved soil quality.     

Effect of land-use change on soil fertility characteristics within water-stable aggregates of two cultivated soils in northern Iran

Forest and pastureland soils in highland of northern Iran are being seriously degraded and destructed due to extensive agricultural activities. These land use changes are usually accompanied by decreasing in concentrations of soil organic carbon and nutrients and also deterioration of soil structure in these regions. However, studies on concentration of nutrients and carbohydrates in soils suggest that the location of nutrients within aggregates of each size should be determined. This study was to evaluate the nutrient elements and carbohydrate distributions within water-stable aggregates (WSA) of virgin forest and pasture lands under different land uses in Alborz maintain range, northern Iran. In September 2006, soil samples were collected from depths of 0–20 cm in Typic Haploxerolls soils. The overall pattern indicated that the mean weight diameter (MWD) and WSA were greater in the virgin pasture and forest soils compared with the adjacent cultivated (ex-forest and ex-pasture) soils and aggregates of >1.0 mm size were dominant in the virgin soils, whereas the cultivated soils comprised aggregates of the size ≤0.5 mm. Distribution of organic carbon, nitrogen, phosphorus and carbohydrates within the WSA showed preferential enrichment of these parameters in the macroaggregate fraction (4.75–1.0 mm) for the virgin soils and microaggregate fraction (>0.25 mm) for the exposed soils. Cultivation decreased the concentration of carbohydrates by 23.6% and 20.6% in ex-forest and ex-pasture lands, respectively. Average distribution of total exchangeable bases within WSA showed that the cultivation of forest and pasture soils significantly led to reduce in these nutrient in the 4.75–2.0 mm fraction and increase in concentration of these exchangeable cations in <0.25 mm fractions. In general, results indicated that cultivation significantly led to 71% and 6% reductions in total exchangeable bases within the 4.75–2.0 and <0.25 mm aggregate fraction, respectively, for virgin soil. Since smaller aggregates are preferentially removed by erosion, this study emphasizes the need for sustainable soil management practices that they will minimize nutrient loss when forest or pastures lands are converted to croplands.     

Food supply chains and sustainability: evidence from specialist food producers in the Scottish/English borders

Despite an increasing interest in more sustainable forms of land management, few analyses have examined whether ‘local’ or ‘alternative’ food supply systems are sustainable in environmental, economic and social terms. Using SUSTAIN's ‘sustainable food’ criteria, this paper analyses the sustainability of a number of ‘speciality’ food supply chains operated by small rural enterprises in the Scottish/English borders. Results indicate that, in the main, the case study businesses are not particularly sustainable; instead, driven by a strong economic imperative, they often have to ‘dip’ into various ‘links’ associated with more conventional (commodity-based) food supply chains. The paper concludes by warning against the tendency to conflate terms such as ‘local’, ‘alternative’, ‘speciality’ and ‘sustainable’.