Showing papers in "Journal of resources and ecology in 2011"

Ecological Remediation of Hydrocarbon Contaminated Soils with Weed Plant

Abstract: Considerable efforts have been undertaken to accelerate the breakdown of existing anthropogenic petroleum hydrocarbons (PHCs) by appropriate in situ remediation technologies. In situ phytoremediation, using higher plants to remove, stabilize, degrade, and/or metabolize hazardous contaminants, has emerged as a promising green technology for cleaning up environments contaminated with PHCs. Weed plants are generally considered to have great potential for use in phytoremediation due to their extensive fibrous root systems and relatively robust characteristics, thus helping establish a strong rhizosphere through contaminated soils. In this review, some important mechanisms involved in phytoremedation of PHC contaminated soils, including phytoaccumulation, phytostabilization, phytodegradation, phytovolatilization, and rhizodegradation, were summarized and discussed. In recent years, a large number of laboratory approaches have been developed to further enhance the phytoremediation efficiency of PHC contaminated soils. The success of these laboratory studies has encouraged researchers to attempt phytoremediation of PHC contaminated soils in the field. However, many limitations still exist in order to successfully apply laboratory experiments to trials in the field.

Soil Erosion and Sediment Control Effects in the Three Gorges Reservoir Region, China

Abstract: The Three Gorges Reservoir, the world's largest hydropower reservoir, receives a significant sediment yield from soil erosion. Sloping farmland is the main source, exacerbated by changes in land use from relocating the inhabitants, and from engineering projects related to dam construction. Related geo-hazards, including landsliding of valley-side slopes, will further increase the sediment yield to the completed reservoir. Integrated watershed management, begun extensively in 1989, has effectively controlled soil erosion and sediment delivery to date. What is described here as the Taipinxi Mode of integrated watershed management, based on its application in the 26.14 km 2 watershed of that name in Yiling District, has been successful and is recommended for the entire region. The effects of this set of erosion-mitigation measures are assessed, using experienced formulas for soil and water conservation and information from remote sensing. The amount of soil erosion, and of sediment delivery to the reservoir were reduced by 43.75-45.94 × 10 6 t y -1 , and by 12.25-12.86 × 10 6 t y -1 , respectively, by 2005, by which time the project had been operative for 16 years.

China's Ecological Agriculture: Progress and Perspectives

Abstract: Agriculture is the basis of national economy. Through science and technology and the intensive utilization of land, great achievements have been made in agriculture. However, some agro-ecological and environmental problems are rising. Because of this, people have begun to reflect on agricultural developmental policy, patterns and technologies, and put forward new thoughts for agricultural development. In the late 20th century, China's ecologists and agronomists co-sponsored the concept of ecological agriculture with Chinese characteristics. Its essence includes a series of concepts such as integration, coordination, circulation and regeneration within agroecosystems or within systems of agriculture production, processing and marketing. After nearly 30 years of practice and development, ecological agriculture in China has achieved remarkable outcomes. However, current eco-agriculture development is unsatisfactory due to the following two factors: (i) A lack of research and accounting across a variety of agro-ecosystem service functions; (ii) It is difficult to obtain remarkable economic benefits because of the lack of market-oriented guidance, scale management, specialized production and brand popularization for the traditional autarkic peasant economy. In order to further promote the development of ecological agriculture it is necessary to engage in serious reflection on ecological agriculture in China and arrive at new understandings about circular economy, multifunctional agriculture, high-quality agriculture, industrial development, integration of the traditional essence and modern technology, and finally, the sustainable development of rural areas.

Modelling Ecosystem Water Supply Services Across the Lancang River Basin

Abstract: Ecosystem services related to water supply are now a hot topic in ecology and hydrology. Here, water supply service in the Lancang River basin was evaluated using the newly developed model InVEST. We found the mean annual water supply in Lancang River basin is approximately 7.24E+10 m 3 y -1 with 23.87% from main stream and 76.13% from the tributaries. There is an increasing trend downstream. Grasslands and forests contribute 71.66% of the total water. A comparison of water supply capacity per unit area for ecosystems of different composition indicates that there is a decreasing trend from broad- leafed forest, mixed coniferous and broad-leafed forest, bamboo forest, coniferous forest, shrub forest and grassland. Two-thirds of the total water is provided by an area covering 40% of the total basin area. This study provides guidelines for the efficient management of water resources in the Lancang River basin.

Change Detection of Land Use and Riverbank in Mekong Delta, Vietnam Using Time Series Remotely Sensed Data

Abstract: By taking the advantages of remote sensing technology, changes of land cover in Ca Mau Peninsular (the Southern part of the Mekong delta) and erosion of riverbank of the Mekong River have been defined. Change detection using time-series optical and radar satellite images (Landsat, SPOT and Radarsat) is the main approach in this study. Typical land cover in Ca Mau Peninsular is mangrove; its changes are observable by analysing imageries from 1973 to 2008. The results showed that more than half of the mangrove area was converted into shrimp farms. This made forest cover severely declined. Riverbank of the Mekong River also was detected to be eroded and accreted in a complicated form. Locations along the left and right banks of Tien and Hau river are defined as hot spots that are seriously suffered erosions. Topographic maps in 1966-1968 were taken into account as base line data, which was analyzed along with satellite images from 1989 to 2009. In addition, the Digital Shoreline Analysis System (DSAS) package was taken to analyze trend of changes in terms of changing prediction.

Evaluation of Ecosystem Services Provided by 10 Typical Rice Paddies in China

Abstract: Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha -1 y -1 ; straw production was 4.65 to 9.79 t ha -1 y -1 ; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha -1 y -1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha -1 y -1 (in CO2 equivalent);

Agricultural Heritage Research in China: Progresses and Perspectives

Abstract: One of the legacies of the time honored agricultural development in China has been varied farming practices that adapt well to different natural conditions. These old but still functioning farming systems continue to inspire us to find solutions to various environmental problems caused by so-called modern agriculture. This paper reviewed the studies on agricultural heritage in China, including two categories: document-based researches and practice-oriented researches on dynamic conservation and adaptive management of these traditional agricultural heritages. Studies on the history and archaeological findings about the Chinese traditional agricultural heritage have laid a solid foundation for any further study. Dynamic conservation and adaptive management of agricultural heritage was promoted by the Globally Important Agricultural Heritage Systems (GIAHS) project initiated by FAO in 2002. Until now, researches on the conservation and adaptive management of agricultural heritages have touched on many aspects of the issue, including theoretical consideration of agricultural heritage, agrobiodiversity characteristics of agricultural heritage, multi-values of agricultural heritage dynamic conservation, substitutive industries, legislation and institutionalization for the conservation of agricultural heritage. We conclude the paper with an agenda for future studies on agricultural heritages, including the broadening of the research scope, innovative research methodologies and methods and the development of strategies that combine conservation and utilization of agricultural heritages.

Insect Diversity: Addressing an Important but Strongly Neglected Research Topic in China

Abstract: Insects are not only the most species-rich group on Earth, they also play numerous crucial roles in ecosystem functioning and the global economy. The conservation of insect diversity is therefore a topic of global importance. However, insects are mostly ignored by "biodiversity" research; for example, relationships between insect diversity and vegetation or climate change remain widely unknown. This paper makes suggestions for further research into insect diversity patterns based on two typical forest types in northern China: Changbai Mountain, northeast China and Dongling Mountain, central northern China. Plants and climate have been well studied in these areas but substantial knowledge gaps prevail in relation to insect diversity patterns. It is therefore important to investigate insect biodiversity patterns in these regions.

The Emergy-Based Ecological Footprint (EEF) of Traditional Agricultural Areas in China: A Case Study of Congjiang County, Guizhou Province

Abstract: Traditional agricultural systems are under severe threat from modernization, technological and economic changes, while substitution of traditional agriculture with so-called modern agriculture has caused serious non-point source pollution. Ecological footprint, though an approach to measure ecological sustainability, fails to reveal the true environmental condition of the traditional agricultural areas. This paper attempted to establish an enhanced emergy-based ecological footprint (EEF) which could include all the flows of ecosystem services that the local inhabitants had consumed, thus making EEF a better indicator of the regional sustainability. This new approach was then applied to evaluate the sustainability of Congjiang County in Guizhou Province, a typically traditional agricultural area in China. Results showed that the local biocapacity could only meet 64% of the total consumption needed by the local inhabitants, leaving an ecological deficit of 5.2327 gha per capita. This analysis was contrary to earlier findings obtained through the conventional method that Congjiang County was characterized by a small ecological reserve. Disaggregated analysis revealed that the consumption of waste treatment and erosion control services occupied a considerable proportion of the local ecological footprint, indicating that regional sustainability was under serious threat from waste discharge and soil erosion.

Copper Residue in Animal Manures and the Potential Pollution Risk in Northeast China

Abstract: A total of 224 animal manures and feeds, randomly sampled from different sizes of intensive farms in three northeastern provinces, were analyzed to determine Cu concentration. At the same time, the load of animal manure Cu on farmlands and loss to rivers in sewage irrigation areas of Liaoning Province was estimated. The results showed that the mean Cu concentrations in pig, cattle, and chicken feeds were 179.8, 16.6 and 20.8 mg kg

Spatio-temporal Distribution Pattern of Vegetation Net Primary Productivity and Its Response to Climate Change in Buryatiya Republic, Russia

Abstract: As a critical index for monitoring the response of terrestrial ecosystems to climate change, net primary productivity (NPP) is widely used to reflect the vegetation productivity under natural conditions. However, little is known about vegetation NPP in Buryatiya Republic, Russia. To fully understand temporal and spatial variations in vegetation NPP and its response to climate change, satellite images of Moderate-resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) products in conjunction with ground-based observations of climatology were used to estimate vegetation NPP in Buryatiya Republic from 2000 to 2008. Observed values of vegetation NPP and MODIS NPP products were jointly utilized to verify simulations of vegetation NPP in this area. The Carnegie Ames Stanford Approach (CASA) model was improved by adjusting its parameters with bio-temperature instead of monthly average temperature in a sub-model of soil water content. Model reliability was tested with ...

Recovery of Vegetation Canopy After Severe Fire in 2000 at the Black Hills National Forest, South Dakota, USA

Abstract: Forest fires often result in varying degrees of canopy loss in forested landscapes. The subsequent trajectory of vegetation canopy recovery is important for ecosystem processes because the canopy controls photosynthesis and evapotranspiration. The loss and recovery of a canopy is often measured by leaf area index (LAI) and other vegetation indices that are related to canopy photosynthetic capacity. In this study we used time series imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Terra satellite over the period of 2000–2009 to track the recovery of the vegetation canopy after fire. The Black Hills National Forest, South Dakota, USA experienced an extensive wildfire starting on August 24, 2000 that burned a total area of 33 785 ha, most of which was ponderosa pine forest. The MODIS data show that canopy photosynthetic capacity, as measured by LAI, recovered within 3 years (2001–2003). This recovery was attributed to rapid emergence of understory grass spec...

Consumption of Ecosystem Services: A Conceptual Framework and Case Study in Jinghe Watershed

Abstract: The global ecosystem is changing due to human and natural causes, and only the human aspects of this interaction are within our control. This paper provides a critical analysis of the interactions between humans and the ecosystem in terms of the human consumption of ecosystem services to maintain a comfortable lifestyle. It starts by reviewing human consumption of ecosystem services, and then develops a conceptual framework that links ecosystem services with consumption of these services and ecosystem management to construct a general functional model of the factors that affect the consumption of ecosystem services. A case study is introduced to show how the model can be used to provide specific assessments of patterns of direct human consumption of ecosystem services in China's Jinghe watershed.

Effect of Substituting Plantation Species for Native Shrubs on the Water-holding Characteristics of the Forest Floor on the Eastern Tibetan Plateau

Abstract: Although the forest floor plays important roles in water—holding and nutrient cycling, there is not enough knowledge of the functional changes of the forest floor resulting from changes in vegetation. To evaluate the effect on the hydrological properties of forest floor by the substitution of plantation species for native coppice, we selected four species substituting plantations and one native coppice (secondary native broad—leaved forest, dominated by Quercus liaotungensis and Corylus heterophylla var. sutchuenensis) (QC) as a comparison forest. The substituting plantations were Cercidiphyllum japonicum (Cj), Pinus tabulaeformis (Pt), Pinus armandi (Pa), Larix kaempferi (Lk). These were established in 1987 with a stocking density of approximately 2500 stem ha-1. Thickness and the amount of floor in coniferous plantations were significantly higher compared to secondary native broad—leaved forest and pure broad—leaved plantation. The maximal water—holding capacity of the floor showed the same tr...

Water Consumption of Seven Forage Cultivars under Different Climatic Conditions in the North China Plain

Abstract: The objectives of this study were to determine the characteristics of water consumption of seven forage cultivars, ryegrass (Secale cereale L.), triticale (×Triticosecale Wittmack), sorghum hybrid sudangrass (Sorghum biolor× Sorghum Sudanense c.v.), ensilage corn (Zea mays L.), prince's feather (Amaranthus paniculatus L.), alfalfa (Medicago sativa L.), and cup plant (Silphium perfoliatum L.), in response to climate variability (especially precipitation). Field experiments were conducted at Yucheng Integrated Experiment Station from 2005 to 2009. Fifteen irrigated lysimeters were used to measure evapotranspiration (ET) and crop coefficient (K c) of these seven forage varieties under ample water supply. The mean Kc for alfalfa is 1.08, and the mean Kc for other forage varieties ranges from 0.79 to 0.94. Kc for hibernating forage is higher in wet years than that in dry years, followed by normal years, while for annual forage, Kc is higher in dry years than in normal years, and is the lowest in wet years. For perennial varieties the order is normal years, dry years, and wet years. Among the annual varieties, ensilage corn is the first choice due to its highest average forage N yield and water use efficiency (WUE). Sorghum hybrid sudangrass is another forage cultivar that grows well under all climatic conditions. It can achieve 1.08-2.31 t ha -1 y -1 N yield under all circumstances. Prince's feather is sensitive to climate change and its N yield dropped below half even when ample water was applied in dry and normal years. Ryegrass and triticale have the advantage of growing in the fallow phase after cotton is harvested in the North China Plain (NCP) and the latter performed better. For perennial varieties, alfalfa performed better than cup plant in dry years. With ample irrigation, alfalfa can achieve higher biomass and WUE under arid climate condition, but excessive rain caused reduction in production.

Estimating Evapotranspiration using Improved Fractional Vegetation Cover and Land Surface Temperature Space

Abstract: Vegetation index—land surface temperature (VI—Ts ) space has been widely used to estimate evapotranspiration and soil moisture. The limitation of this method is the uncertainty of the observed dry edge, which is usually fitted by scatter plots. Here, a method was used to locate true dry and wet edges based on energy balance formulation, and a simple method to estimate surface energy flux is proposed based on the improved Fractional vegetation cover—Land surface temperature (Fv —Ts ) space. Seventeen days of MODIS products were selected to estimate evapotranspiration and the estimated sensible heat flux (H) is compared with Large Aperture Scintillometer (LAS) data at a site in Zhengzhou. resulting in a RMSE of 44.06 W m-2, bias of 36.99 W m-2 and R 2 of 0.71. The H scatter plots of estimation versus observation show clearly that most points are around the 1:1 line. Overall, the located true and wet edges are more accurate than the observed true edge. Our results can also be applied to improve the...

Water Shortage Risk Assessment in the Haihe River Basin, China

Abstract: This paper studies water balance in the Haihe River Basin, China and assesses water shortage risk for the period 1994-2007. The authors identify that there is a water shortage problem in this area and propose that the non-intake water consumption (NIWC) is a very important water balance element. The NIWC in the Haihe River Basin flow is 5.91×10 9 m 3 in normal years. It was concluded from our evaluation that the water shortage risk during 1994-2007 was very high. Using international water risk assessment theory, multiyear risk indicators in Haihe River Basin can be calculated. Water risk rate, resiliency, stability, and vulnerability for the Haihe River Basin for the period 1994-2007 were 0.786, 0.000, 0.154 and 0.173 respectively. With the use of counter-force factors and adoption of different priorities to different water consumers, the water shortage risk can be decreased. The integrated water shortage risk indicators of the Haihe River Basin are 0.095-0.328. In this study, water availability from the South-North Water Diversion Project is also considered. By the year 2014, about 5×10 9 m 3 of water will be diverted from the Yangtse River, and the water shortage risk in the Haihe River Basin will drop from 0.229-0.297 to 0.152-0.234 under an inflow water frequency of 50%-75%. However, a risk of water shortage in this area will persist.

Carbon Emissions from Forest Vegetation Caused by Three Major Disturbances in China

Abstract: To investigate forest carbon sequestration and its role in addressing global climatic change, it is important to assess carbon emissions caused by major disturbances from forest ecosystems to the atmosphere. Based on forestry statistics on the occurrence of each disturbance and acceptable assumptions on the process and proportion of biomass carbon transferred to other pools due to each disturbance, this paper estimates the direct carbon emission from Chinese forest vegetation caused by three major disturbances, that is, wood harvesting, fire, and DPR, from 1990 to 2009. Results showed that over the past two decades, Chinese forests have been disturbed rather intensively by wood harvesting, fires, and DPR, with clear upward occurrence trends of the three disturbances in the early 21 st century. As a result, the average annual carbon emissions caused by wood harvesting, fires, and DPR were 34.25 Tg, 1.61 Tg, and 4.29 Tg, respectively, during 1990-2009. The aggregate annual carbon emission due to these three major disturbances was 40.15 Tg during 1990-2009, which was 30.79 Tg during 1990-1999 and 49.51 Tg during 2000-2009. According to the analysis of carbon emissions from different forest regions, there were obvious regional characteristics of the average annual carbon emission caused by each disturbance. However, it was difficult to identify clear cause and effect relationships among disturbances to explain the spatial variation of carbon emissions from forest vegetation in China. Disturbances have significant influences on carbon balance of forest ecosystems in China. This finding suggests the opportunities for increasing forest carbon sequestration by disturbance-aimed sustainable long-term management of forest resources, as well as the necessity of considering the role of major disturbances in carbon budget models for forest ecosystems or terrestrial ecosystems.

Ecosystem Regulating Services and Their Valuation of Hainan Island, China

Abstract: Ecosystem services were defined as the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life. They include provisioning, regulating, cultural, and supporting services. These form the basis on which regional environmental reserves and development are assessed and for the valuation of ecosystem services. In this paper Hainan Island is used as an example to explore methods of regulating services based on the structure and processes of a natural ecosystem. Ecosystems were classified into 13 types: valley rain forest, mountainous rain forest, tropical monsoon forest, mountainous coppice forest, mountainous evergreen forest, tropical coniferous forest, shrubs, plantation, timber forest, windbreak forest, mangrove, savanna, and crop land. Regulating services and their economic values for Hainan Island ecosystems were assessed and evaluated in terms of water—holding, soil conservancy, nutrient cycle, C fixation and windbreak function...

Quantitative Assessment of Seismic Mortality Risks in China

Abstract: Based on the forming mechanism of seismic hazard risk, we established a seismic vulnerability curve on population and determined earthquake occurrence parameters. We then assessed the risk of seismic hazard mortality at the county level across China using the assessment model, and analyzed spatial patterns. We adopted past, present, and future disaster-breeding materials to assess the probability of earthquakes. In order to determine the earthquake parameters of 2355 counties accurately, we integrated history seismic intensities, seismic activity fault belts distributions and seismic peak ground acceleration. Based on data of seismic disasters from 1990 to 2009 in China, linear fitting between seismic intensities and mortalities was performed. And a vulnerability curve of seismic mortality, which was appropriate for seismic risk assessment, was established. Seismic mortality risks were assessed quantitatively at the county level using the model and the spatial patterns were analyzed. Seismic mortality risks of 2355 counties with intensities from Ⅴ to Ⅺ were analyzed thoroughly. This study indicates that under different seismic intensities, China's eastern and central regions are generally confronted with higher risk than western regions. High-risk areas are scattered in Shandong and Jiangsu, northern Anhui and eastern Heilongjiang and Jilin, where populations are dense and the environment is conducive to disasters. Risk- free areas displayed patchy distributions nationwide, and patterns were mostly unchanged.

The Categories and Benefit-Sharing of Traditional Knowledge Associated with Biodiversity

Abstract: A milestone in the Year of Biodiversity is that the Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization to the Convention on Biological Diversity (CBD) was adopted in the 10th Conference of Parties (COP 10) held in Nagoya, Japan, Oct 18–29, 2010 Traditional knowledge (TK) is a key issue in the Protocol's text and its negotiating period This paper aimed to protect TK by defining its concepts and categories and promoting benefit—sharing with TK's holders Based on the analysis for the TK concepts of relevant international organizations and conventions, in particularly on the author's current years' research work on TK in the ethnic areas of China, this paper proposes the categories and the classification system for the TK associated with biological resources, ie (i) the knowledge for traditional use of agricultural bio-species and genetic resources; (ii) the knowledge for traditional use of medicinal bio-species; (iii) tr

Agricultural Land Use Intensity and Its Determinants in Ecologically-vulnerable Areas in North China: A Case Study of Taipusi County, Inner Mongolia Autonomous Region

Abstract: Based on rural household survey data in Taipusi County in Inner Mongolia Autonomous Region, this article analyzes agricultural land use intensity and its determinants. The results reveal marked differences of agricultural land use intensity among households with different ages of householders, proportion of non-farm participants, total agricultural land area, land fragmentation and land utilization capacity. (i) Households with older householders and households with a smaller proportion of non-farming laborers generally spend more time on managing their land and invest less capital and materials than other households. The proportion of non-farming laborers within younger households is relatively high, and they tend to invest more capital and materials because the income derived from non-farm employment relaxes their financial constraints, (ii) Land fragmentation is an important determinant of land use intensity. Households with a bigger land size per plot usually spend less time and invest more ...

Agro-pedological Assessment of the Traditional Yuanyang Rice Terraces of Yunnan Province, China

Abstract: As a contribution to a long-term evaluation of the sustainability of agro-ecosystems in the Yuanyang rice terraces, this paper reviews the bio-physical environment of the terraced landscape in a small catchment around Qingkou village and assesses soil fertility in the village crop growing area. A soil- landscape organization pattern was developed using a geomorphopedological approach. Anthropogenic, climatic and topographic factors were identified as the main soil forming factors. Soil capability and associated edaphic constraints were assessed and the main soil types were identified and classified using FAO protocols. Spatial patterns of soil fertility appear quite homogeneous. Soils are acid and cation exchange capacity and nutrient reserves are generally low. The agro-ecosystem has largely been developed by the Hani population. This agro-ecosystem has succeeded in maintaining a relatively dynamic nutrient circulation system. Current research is focusing on: (i) the evaluation of the representativeness of the studied area compared to the whole terraced system in the Yuanyang terraced landscape; (ii) measurements of nutrients flows at the field scale; (iii) the effects of soil properties on crop yields; and (iv) up-scaling field levels results to larger spatial units.

Ecoagriculture in China: A Systems Approach

Abstract: Ecoagriculture in China began in the late 1970's/early 1980's. This system aims to bring about the most effective coordination of social, economic and ecological factors in agricultural practices. Key approaches include ecological planning at the landscape level, cycling system design at the ecosystem level, and the re—establishment of the importance of biodiversity. The social and economic environment favoured for ecoagriculture is important in order to enable its development. For the social environment, it is important to set up the necessary moral standards involved through educational, legislative and evaluation systems. For the economic environment, efficient government subsidy policies, an effective market system to deal with pollutant discharge, and efficient markets for the sale of ecologically—friendly products.

Spatial Distribution and Temporal Dynamics of Soil Carbon Removal Caused by Water Erosion in China

Abstract: Using water erosion data from three national soil erosion remote-sensing surveys (the first: 1985-1986; the second: 1995-1996; the third: 2000-2001) and carbon density data from the second national soil survey (1979-1992), we computed soil carbon removal caused by water erosion, and analyzed its spatial distribution and temporal dynamics in China. Results revealed that the total removal of soil carbon caused by water erosion was about 74.61 Tg C y -1 , of which 51.49 Tg C y -1 was organic carbon, and 23.12 Tg C y -1 was inorganic carbon. The main erosion level of the whole is moderate erosion. Among the seven erosion regions, the Southwest Karst Region had the most significant removal of soil organic carbon, which was 26.48% of the total and mainly due to its moderate erosion. In contrast, about 67.62% of the soil inorganic carbon removal occurred in the Loess Plateau Region, which mainly due to its highly intense and intense erosion. As a whole, the removals of soil carbon caused by water erosion represented a decreasing trend among the three national soil erosion remote-sensing surveys. Between the first and the second survey, soil carbon removal decreased by 11.66 Tg C y -1 , of which 81.93% was organic carbon.

Study on Diversity of Arthropod Community in a Rice-duck Integrated Farming System in South China

Abstract: The integration of ducks into rice farming has raised concerns about possible effects on arthropod communities due to frequent predation by ducks. This paper conducted a study using three treatments, including integrated rice-duck cultivation (RD), conventional rice cultivation (CC) and a control treatment (CK), to investigate the impact of rice-duck farming on the diversity of arthropod communities in the field. The results revealed that arthropod numbers in both RD and CC treatments showed varying degrees of reduction when compared with the CK treatment. Arthropod individual numbers, Simpson (D) and Shannon's diversity index (H' ) values in RD were higher than those in CC. Arthropod individual numbers, richness index (R), D and H'values in both tillering and booting phases of the late rice were significantly higher in RD treatment than those in CC treatment. Rice-duck integration system was favorable for the maintenance of arthropod diversity in the cropping field and may help to lessen the de...

Emergy Evaluation of Agro-ecosystem of Shiyang River Basin, Northwestern China

Abstract: This paper presents an ecological analysis of agricultural systems in arid region of Northwestern China. Emergy analysis, a method for environmental accounting developed by H.T. Odum in the Eighties, is appropriate for this task because of its ability to transform different types of inputs to a common form (solar emergy) in order to allow scientific and objective comparisons across different period and regions. Taking Liangzhou and Minqin oases, located in the middle and lower reaches of the Shiyang River basin in Gansu province as a case study, the detailed structure of the agricultural process, input/output and emergy indicators of the systems are examined and compared for the years 1986 and 2000. Both the total emergy input and the total yield increased in the two oases. In Liangzhou Oasis the emergy of livestock production exceeded the traditional crop production, which still is the dominant production in Minqin Oasis. The emergy investment ratio, EIR, although increased in the investigated period, was less than 0.5 in both Liangzhou and Minqin oases, indicating that purchased materials and services were less than half the value of indigenous emergy sources exploited. As a consequence, the emergy yield ratio, EYR, was very high in both Liangzhou and Minqin oases. However, the increasing environmental loading ratio, ELR, and the decreasing environmental sustainability index, ESI, in the two oases illustrate a weakening sustainability of the two agro-ecosystems, and this tendency was more evident in the downstream Minqin Oasis, calling for more attention to the environmental degradation in the region.

Stakeholder Perceptions of Changing Ecosystem Services Consumption in the Jinghe Watershed: A Household Survey and PRA

Abstract: This paper presents cognitive awareness levels of ecosystem services and their consumption by farmers in Guyuan City, which lies in the Jinghe watershed. Household Surveys and Participatory Rural Assessment (PRA) were used to determine differences in farmers cognitive awareness levels. The household survey results showed that farmers have a cognitive awareness of 11 ecosystem services: food supply, air purification, environmental purification, soil and water conservation, clean water supply, natural disaster minimization, increasing income, fuel wood supply, aesthetic recreation, fodder supply and sand stabilization. The job-related requirements of a farmers' daily life, their direct consumption of ecosystem services and the importance of ecosystem services to them all influence their cognitive awareness of ecosystem services. Through group interviews the PRA method can provide the opportunity for information exchange and discussion. The process can help farmers to gain more cognitive awareness of ecosystem services. Large changes in ecosystem services have been observed in the study area. Food production and fuel wood supply have decreased markedly, yet incomes have increased. Spatial and temporal variables, changes in ecosystem services and the level of income all have an impact on farmers' food supply and resource consumption. Overall, the total consumption of food (cereal and potato) and fuel wood declines for most farmers and consumption of vegetables, meat, coals and gas have increased.

Quantitative Assessment and Spatial Characteristics of Agricultural Drought Risk in the Jinghe Watershed, Northwestern China

Abstract: Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural drought risk in the Jinghe watershed of western China at a 1-km grid scale. A conceptual framework, which emphasizes the combined roles of hazard and vulnerability in defining risk, is used. The Z index method in a GIS environment is used to map the spatial extent of drought hazards. The key social and physical factors that define agricultural drought in the context of the Jinghe watershed are indentified and corresponding thematic maps are prepared. Risk is calculated by the integration of hazard and vulnerability. Results show that the risk gradient follows a north-south and west-east tendency and that agricultural droughts pose the highest risk to northern and northwestern sections of the Jinghe watershed.

Estimates of Variation in Chinese Terrestrial Carbon Storage Under an Environmental Conservation Policy Scenario for 2000-2025

Abstract: Policies always have strong impacts on land-use and land-cover change (LUCC), and thus indirectly affect the terrestrial carbon balance. In this paper, land use change from 2010 to 2025 in China was simulated with the Dynamics Land System (DLS) under an environmental conservation policy scenario, and the projected effect of this policy scenario on Chinese terrestrial carbon storage was evaluated. Under the simulation, forest coverage will increase by 23% while cropland and grassland will decrease by 37% and 11% respectively. Due to the large expansion of forest coverage, the forest carbon storage will have an accumulation of 66.0 Tg C y -1. This will take place mainly in central China in a band from the northeast to southwest. Grasslands, however, will be a carbon source of 5.7 Tg C y-1 in the same period as a result of the transformation of grassland to woodlands or deserts. As the carbon storage capacity of forest soil is considerably higher than that of grassland and cropland, such LUCC will ...