Projected water consumption in future global agriculture: scenarios and related impacts

Global stress on water and land resources is increasing as a consequence of population growth and higher caloric food demand. Many terrestrial ecosystems have already massively been degraded for providing agricultural land, and water scarcity related to irrigation has damaged water dependent ecosystems. Coping with the food and biomass demand of an increased population, while minimizing the impacts of crop production, is therefore a massive upcoming challenge. In this context, we developed four strategies to deliver the biotic output for feeding mankind in 2050. Expansion on suitable and intensification of existing areas are compared to assess associated environmental impacts, including irrigation demand, water stress under climate change, and the productivity of the occupied land. Based on the agricultural production pattern and impacts of the strategies we identified the trade-offs between land and water use. Intensification in regions currently under deficit irrigation can increase agricultural output by up to 30%. However, intensified crop production causes enormous water stress in many locations and might not be a viable solution. Furthermore, intensification alone will not be able to meet future food demand: additionally, a reduction of waste by 50% along the food supply chain or expansion of agricultural land is required for satisfying current per-capita meat and bioenergy consumption. Suitable areas for such expansion are mainly located in Africa, followed by South America. The increased land stress is of smaller concern than the water stress modeled for the intensification case. Therefore, a combination of waste reduction with expansion on suitable pastures generally results as the best option, along with some intensification on selected areas. Our results suggested that minimizing environmental impacts requires fundamental changes in agricultural systems and international cooperation, by producing crops where it is most environmentally efficient and not where it is closest to demand or cheapest.     

Climate impacts on European agriculture and water management in the context of adaptation and mitigation—The importance of an integrated approach

We review and qualitatively assess the importance of interactions and feedbacks in assessing climate change impacts on water and agriculture in Europe. We focus particularly on the impact of future hydrological changes on agricultural greenhouse gas (GHG) mitigation and adaptation options. Future projected trends in European agriculture include northward movement of crop suitability zones and increasing crop productivity in Northern Europe, but declining productivity and suitability in Southern Europe. This may be accompanied by a widening of water resource differences between the North and South, and an increase in extreme rainfall events and droughts. Changes in future hydrology and water management practices will influence agricultural adaptation measures and alter the effectiveness of agricultural mitigation strategies. These interactions are often highly complex and influenced by a number of factors which are themselves influenced by climate. Mainly positive impacts may be anticipated for Northern Europe, where agricultural adaptation may be shaped by reduced vulnerability of production, increased water supply and reduced water demand. However, increasing flood hazards may present challenges for agriculture, and summer irrigation shortages may result from earlier spring runoff peaks in some regions. Conversely, the need for effective adaptation will be greatest in Southern Europe as a result of increased production vulnerability, reduced water supply and increased demands for irrigation. Increasing flood and drought risks will further contribute to the need for robust management practices.The impacts of future hydrological changes on agricultural mitigation in Europe will depend on the balance between changes in productivity and rates of decomposition and GHG emission, both of which depend on climatic, land and management factors. Small increases in European soil organic carbon (SOC) stocks per unit land area are anticipated considering changes in climate, management and land use, although an overall reduction in the total stock may result from a smaller agricultural land area. Adaptation in the water sector could potentially provide additional benefits to agricultural production such as reduced flood risk and increased drought resilience.The two main sources of uncertainty in climate impacts on European agriculture and water management are projections of future climate and their resulting impacts on water and agriculture. Since changes in climate, agricultural ecosystems and hydrometeorology depend on complex interactions between the atmosphere, biosphere and hydrological cycle there is a need for more integrated approaches to climate impacts assessments. Methods for assessing options which “moderate” the impact of agriculture in the wider sense will also need to consider cross-sectoral impacts and socio-economic aspects.     

The impact of urbanization policy on land use change: A scenario analysis

The rapid urbanization has led to extensive land use change particularly in those developing countries. In line with the development of urbanization, arable land is decreasing dramatically, which presents the threat to the food security for human being. It is therefore essential to understand the level of impacts of urbanization on the land use change. This paper introduces a dynamic systems based method for assessing the impacts of urbanization policy on land use change with reference to the urbanization practice in China. Four typical policy scenarios are identified in implementing urbanization in China, including balanced development driven by planning, uneven development driven by planning, balanced development driven by market and uneven development driven by market and their impacts on land use change are analyzed through a dynamic system model. Land use change is considered as a dynamic system model composing five subsystems: urbanization, social, economic, environmental and land use subsystems. The key attributes in these five subsystems are interactive and they are dynamic variables. The assessment on the impacts of urbanization policy to land use change is demonstrated through employing the software iThink to the land use change dynamic model, using the data collected from the Jinyun County in China. The findings suggest that the urban construction land will continue to increase in the foreseeable future in China, whilst the agricultural land will gradually decrease. Nevertheless, different policy scenarios will have different impacts on these land changes. Thus decision makers can adopt different policies to control the rate of land use change.     

A multi-scale, multi-model approach for analyzing the future dynamics of European land use

Europe’s rural areas are expected to witness massive and rapid changes in land use due to changes in demography, global trade, technology and enlargement of the European Union. Changes in demand for agricultural products and agrarian production structure are likely to have a large impact on landscape quality and the value of natural areas. Most studies address these changes either from a macro-economic perspective focusing on changes in the agricultural sector or from a local perspective by analyzing recent changes in landscapes for small case studies. This paper describes a methodology in which a series of models has been used to link global level developments influencing land use to local level impacts. It is argued that such an approach is needed to properly address the processes at different scales that give rise to the land use dynamics in Europe. An extended version of the global economic model (GTAP) and an integrated assessment model (IMAGE) are used to calculate changes in demand for agricultural areas at the country level while a spatially explicit land use change model (CLUE-s) was used to translate these demands to land use patterns at 1 km² resolution. The global economic model ensures an appropriate treatment of macro-economic, demographic and technology developments and changes in agricultural and trade policies influencing the demand and supply for land use related products while the integrated assessment model accounts for changes in productivity as result of climate change and global land allocation. The land use change simulations at a high spatial resolution make use of country specific driving factors that influence the spatial patterns of land use, accounting for the spatial variation in the biophysical and socio-economic environment. Results indicate the large impact abandonment of agricultural land and urbanization may have on future European landscapes. Such results have the potential to support discussions on the future of the rural area and identify hot-spots of landscape change that need specific consideration. The high spatial and thematic resolution of the results allows the assessment of impacts of these changes on different environmental indicators, such as carbon sequestration and biodiversity. The global assessment allows, at the same time, to account for the tradeoffs between impacts in Europe and effects outside Europe.     

A method for the reduction of lake model prediction error

Recent work on methods of error analysis to accompany the application of lake models has not enjoyed great acceptance in part because of the magnitude of the error term. For the models that have undergone a rigorous error analysis (generally the single equation cross-sectional regression models), prediction errors for various water quality variables are often ± 30% or more. A procedure is proposed herein for the reduction of the error associated with the prediction of lake phosphorus concentration from land use and hydrologic data. Existing lake quality data are used in the prediction, and the model is employed only to project changes from the present state. This obviates the need to project all land use impacts with the model: only those proposed to change are projected. The result is a substantial reduction in prediction error for many planning scenarios.     

Impact of geochemical stressors on shallow groundwater quality

Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a 2-year period from 1999 to 2001 the monitoring wells were sampled every 3 months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land use and temporal change. Groundwater of the agricultural area showed lower levels of ferrous iron and nitrate than the residential area. The summer season data revealed more distinct differences in inorganic profiles of the two land use groundwater samples. There is a possible trend that nitrate concentrations in groundwater increased as the proportions of cultivated area increased. Water-soluble ferrous iron occurred primarily in water samples with a low dissolved oxygen concentration and/or a negative redox potential. The presence of brine waste in shallow groundwater was detected by chloride and conductivity in oil field area. Dissolved trace metals and volatile organic carbons were not in a form of concentration to be stressors. This study showed that the quality of shallow ground water could be related to regional geochemical stressors surrounding the lake.     

基于低碳目标的旧城改造规划理论与实践

城市是人类福祉的主要载体,也是人类对生态系统影响的主要污染源,同时,城市也是人类减少能源消耗和环境影响的主要战场,建设低碳宜居城市是当前国内外规划师所面临的共同问题。旧城更新是城市建设的主要内容之一,本专辑所录论文的研究表明,空间规划应利用旧城更新的时机,从城市系统优化的角度出发,大力发展绿色节能建筑,建设绿色社区,协调土地与交通的相互关系,调整城市空间结构,促进绿色经济发展,减少城市建筑、交通和产业经济活动过程中的能源消耗。在采用新枝术和新方法的过程中,应注重历史遗迹保护,推动社会与环境公平。同时要完善规划管理,增强规划效力,将能耗和碳排放量作为旧城更新规划的指导性指标,并注意空间规划与行为教育、财税政策等其他管理方法相结合。     

Landscape management strategies for the control of diffuse pollution

The control of diffuse pollution is one of the major issues affecting the agricultural landscape. Policies of land use management are now being implemented as a means of improving water quality. The potential success of such policies is difficult to determine owing to the complex nature of the processes controlling the transport of diffuse pollutants such as nitrate, phosphorus and sediment. The use of buffer zones alongside water bodies in the agricultural landscape may offer a greater opportunity both for protecting the water and for increasing the habitat and amenity value of the landscape. The potential value of buffer zones in terms of water quality is dependent on landscape type and suitable design. The design of these features needs to consider the hydrology of both the buffer zone and of the landscape as a whole. In landscapes where the hydrology has been altered, additional measures may be required to establish suitable hydrological conditions. The implementation of a strategy of diffuse pollution control therefore needs to be approached on a landscape basis taking into account the nature of pollutant pathways and areas of high pollution risk.     

基于遥感的土地整理评价可行性研究

土地整理是以提高土地资源有效利用率为目的,实现国土资源集约利用的主要手段,运用遥感技术对土地整理项目进行评价,是科学化管理土地整理项目和进一步规范土地整理活动的更为全面和准确的方法.     

Application of multiple geochemical indicators, including the stable isotopes of water, to differentiate water quality evolution in a region influenced by various agricultural practices and domestic wastewater treatment and disposal

Spatial and temporal variations in groundwater chemistry indicate that the use of low TDS lake water for irrigation, on land located just south of the City of Dixon, Solano County, California, is primarily responsible for improving groundwater quality with regards to salts. The stable isotopes of water further support this finding and suggest that TDS concentrations decrease as groundwater evolves to a more highly evaporated state. This seemingly contradictory finding was primarily attributed to infiltration of low TDS Lake Berryessa surface water, which has an isotopic signature indicative of an evaporated source and is used extensively for irrigation in the area, mixing with poorer quality locally recharged shallow groundwater. Geochemical modeling using the program PHREEQC further supports the anthropogenic aquifer freshening hypotheses through computed reductions in the saturation state of carbonate minerals in the vicinity of land irrigated by lake derived water, which is undersaturated with regards to modeled carbonates. Additionally, delta(18)O and delta(2)H were found to be useful in estimating climatic variables such as temperature and humidity, illustrating the potential for applying these models in hydrologic investigations within the area. It was however found that USDA NRCS soils data and measured water chemistry were not well correlated and thus the use of soils classifications to assess potential groundwater quality impacts was of limited utility.     

Managing Agricultural Pollution Using a Linked Geographical Information System and Non-Point Source Pollution Model

This study documents the development of a link between a geographical information system (GIS) and a non-point source pollution model. The GIS ARC/INFO was linked to the agricultural non-point source pollution model and ORACLE data sources. Application of the system is demonstrated using the Bedford-Ouse catchment as a suitable case study. Water quality impacts are predicted from source data describing topography, soils, land use and river network. The model results were in agreement with observed nitrate concentrations at the catchment outlet, and more appropriate data sources are considered to be the main priority for improving model predictive ability. Management scenarios were established to assess the impact of changing agricultural management practices on predicted water quality. The approach has significant potential for the management of agricultural pollution in the UK.     

Secondary Impacts of Major Land Use Projects

Causal models are hypothesized to explain the induced land use impacts of two types of major projects—large industrial/office parks with 3,600 to 9,100 employees, and large residential developments of 1,100 to 5,300 dwelling units. Using data from forty case studies nationwide, the statistical techniques of path analysis are applied to test the causal models and to determine their parameters. The models indicate that significant statistical relationships exist among variables representing twelve land use types and variables representing induced and noninduced land use growth. Separate predictive equations of land use development for operational purposes were developed because of simultaneity in some of the causal relationships. This analytical tool provides an assessment of the secondary land use and air quality impacts in the area of a planned major development.     

Low-intensity Husbandry as a Cost-efficient Way to Preserve Dry Grasslands

Abstract

Dry grasslands represent unique ecosystems that are known for high biodiversity. Land use changes have led to a decline in Europe. Shrub encroachment is a major problem in incorrectly or unmanaged areas, and affects not only flora and fauna but also leads to changes in the appearance of the landscape. Our study was conducted on the island of Hiddensee, north-east Germany, where today dry grasslands are endangered by shrub encroachment. We analysed the current land use under consideration of farming costs as well as current agricultural subsidies. Our results show that revenues of low-intensity cattle husbandry only account for 61% of total costs and that farming becomes profitable only with subsidies. Our study illustrates that goats can be a cost-efficient solution for areas with high shrub cover in contrast to manual clearing. The maintenance of dry grasslands is therefore more cost-efficient with grazing animals than with technical-manual labour.     

Changes in agricultural landscape pattern and its spatial relationship with forestland in the State of Selangor, peninsular Malaysia

In Malaysia, the development of two major agricultural crops, i.e. oil palm and rubber, is one of the primary causes of forest loss. However, understanding of this relationship has not been quantified, which is vital to improve the planning and management of the agricultural land uses. To understand the relationship, this study addresses their dynamic change, patchiness and spatial relationship with forestland in the State of Selangor, Malaysia as a case study. Data development and analysis were based on three land-use maps of 1966, 1981 and 1995 where forest and, wetland forest and marshland land use categories were referred to as forestland. Two defined natural landscapes; forest and wetland landscapes were used as a basic unit of analysis to determine the patchiness of the agricultural lands at the expense of large tract of forestland. During the periods studied, oil palm area increased whereas rubber area reduced. The development of oil palm had caused loss much of forestland, particularly wetland forest and marshland. Its expansion at the expense of large tract of wetland forest and marshland earnestly occurred between 1966 and 1981 but slowed down between 1981 and 1995. By using the landscape type approach this study recommended a way to determine the patchiness of the agricultural lands at the expense of large tract of forestland. With these findings, we conclude that it is important to understanding the relationship quantitatively in order to describe the implications for land development of the agricultural crops.     

Strategic land-use allocation: dealing with spatial relationships and fragmentation of agriculture

In The Netherlands, a debate continues to take place on how to allocate the available space among several types of land use. The rural area is under constant pressure from urban developments. Multi-purpose land use is becoming more and more important.Land-use allocation problems can be identified as complex planning problems, with a large number of stakeholders involved. Therefore the decisions made with respect to land use must be clear and transparent to these stakeholders. Various methods have been developed to support land allocation issues. Typically, however, the analysis of topological relationships, initiated by biophysical and socio-economic processes, and the spatial configuration of different land uses, is often neglected, especially for agricultural planning. Neglecting the spatial configuration and these relationships can result in spatial fragmentation of land use, thus endangering sustainable land use.This paper focuses on a method to address land-use allocation issues where the topological relationships are taken into account. The method is implemented in a Geographical Information System (GIS). Two cases for Dutch agriculture are discussed.     

A simple model for screening the local impacts of atmospheric ammonia

The dry deposition of ammonia from the atmosphere to the surface can lead to eutrophication of sensitive ecosystems and acidification of the soil. A large proportion of the ammonia emitted from agricultural sources can be deposited within a few kilometres and, therefore, impacts of ammonia dry deposition often occur near to the source. To assess these impacts, short-range atmospheric dispersion models are often applied to simulate the emission, dispersion and deposition of ammonia. However, these models can be time-consuming to run and often require detailed input data and, therefore, for multiple assessments it is useful to have a method of screening to discard scenarios where impacts are expected to be negligible. The SCAIL model (Simple Calculation of Ammonia Impact Limits) has been developed for this purpose. SCAIL estimates the atmospheric concentration and dry deposition at the nearest edge of a sensitive ecosystem (receptor) downwind of an ammonia source. These estimates are calculated based on simple meteorological data, the emission rate of the source, land cover type and distance to the receptor. Analysis of the model predictions showed that uncertainty in the model input data leads to an uncertainty in concentration and dry deposition estimates of 25–30% and 40–45% respectively. Detailed atmospheric dispersion models will also have similar uncertainties since they use similar types of input data. Comparison of the concentration predictions with previous measurements made around eight farms showed that the model significantly underestimated concentrations although the model performance was similar to existing screening techniques. The measurement dataset was used to calibrate the SCAIL model which subsequently performed better, using independent verification data, than existing models calibrated in a similar way. The benefits of the SCAIL model are already being seen in the UK, where it is used to screen farms for potential impacts on statutory nature conservation areas.     

Stream cation concentrations and losses from drainage basins with contrasting land uses in Southern Ontario

The concentration and loss of major cations from 22 watersheds near Toronto, Ontario, was measured over a 27-month period. Calcium and potassium concentrations exhibited a positive relationship with crop area and a negative correlation with abandoned farm land + forest and areas of sand + sandy loam soil. The influence of soil properties and farming activities on streám cation levels could not be separated because of multicollinearity between land use and soils. An absence of correlation between crop area and annual losses of calcium and potassium can be attributed to lower annual stream discharges in agricultural watersheds in comparison to watersheds containing extensive areas of forest and abandoned farm land. Stream concentrations and losses of potassium and sodium were positively correlated with urban land use. Detailed water sampling in the vicinity of urban centres confirmed that these areas are important contributors of sodium, and to a lesser extent, of potassium to streams. Magnesium concentration was influenced mainly by differences in watershed hydrology and no correlation was evident with urban or agricultural land use.     

Ag-PIE: a GIS-based screening model for assessing agricultural pressures and impacts on water quality on a European scale

Diffuse pollution of water resources from agricultural sources is a major environmental issue in the European Union, and has been dealt with by specific legislation: the Nitrate Directive of 1991 and the Water Framework Directive of 2000. These attempts to provide a coordinated approach to solving environmental problems require methods and tools for spatial analysis and modelling on a continental scale, with river basins being used as spatial units. This paper presents a screening model (Ag-PIE), developed in a GIS environment, for the assessment of pressures from agricultural land use and the consequent impacts on surface and groundwater. Ag-PIE has been applied at the European scale (EU15), with focus on nitrogen pollution from chemical fertilisers and manure. The model adopts a multi-criteria evaluation procedure applied to spatial data layers which represent the variety of factors affecting the pollution process. The DPSIR (Driving forces, Pressures, State, Impact, Responses) approach is applied to provide the modelling approach with a conceptual framework and to further analyse and communicate results. Ag-PIE is ultimately aimed at providing a tool making use of state-of-the-art geographical databases to support policy-makers at the European level. The scale of reference adopted is the river basin, in particular those that extend across national boundaries. The quality of the results obtained has been assessed against existing related studies and monitoring reports and by means of sensitivity analysis. Conclusions are driven by considering the potential of Ag-PIE in devising policy support and its strengths and weaknesses in view of identifying future research needs.     

山野小屋

该项目建于挪威南部一个陡峭的斜坡上,面对着一片小型的高山湖泊。该项目位置隐秘,远离所有可以通往湖边的小径,只有夏天乘船、冬天湖面结冰时乘滑雪板才能抵达。拥有这片土地的家庭住在湖对面一个僻静的农场,农场有一个泊位,泊位中停着一只小划艇。多年以来,这个小湖始终是家人垂钓、游泳或独自露营的首选之地。近年来,这个美丽的地方逐渐被越来越多的人发现。回归自然的渴望和拥有隐居于此、远离世俗的可能性,赋予了这个交通不便之地的价值;最偏远的一处在一块石头后面,阴影遮挡,且没有通讯和网络信号。过去被认为是不方便的元素,现在反而变得愈发奢侈难寻。