Conservation practices in US agriculture and their implication for global climate change

Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was approximately 12,200,000 metric tons. By 2008, there will be an increase of approximately 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement and regulation and taxes.     

Energy and the adoption of conservation tillage in the United States

The impact of energy on the adoption of conservation tillage is of special importance in addressing concerns about the effect of agricultural production on the environment in the United States. It is the subject of this paper. After establishing that a relationship exists between the price of energy and the adoption of conservation tillage via cointegration techniques, the relationship is quantified. It is shown that while the real price of crude oil, the proxy used for the price of energy, does not affect the rate of adoption of conservation tillage, it does impact the extent to which it is used. Finally, there is no structural instability in the relationship between the relative use of conservation tillage and the real price of crude oil over the period 1963 to 1997.     

Validating verdancy or vacancy? The relationship of community gardens and vacant lands in the U.S.

Community gardens have gained attention and support in recent years because of a range of expected benefits and outcomes, and they are one of many examples of transformations of vacant land into green space. While the improvements to vacant or underutilized land are lauded, the practice of community gardening is underpinned by the assumption that it is a temporary practice on temporarily-available land. This assumption, which is at times implicit and at others explicit, maintains that support for community gardens—technical assistance and especially access to land—can be temporary. Through a genealogy of community garden advocacy in the U.S., we find that a dominant narrative of community gardening as a means to an end has been continuously reproduced for more than a century in large part by government agencies and philanthropic organizations. In recent decades, community gardeners have become key actors in advocacy, and although they portray gardening as a meaningful part of everyday city life, they also reproduce that narrative of temporariness by promoting it as a means to address various issues. We argue that this tension between means and ends—especially coming from community gardeners—is problematic. It is a challenge for community gardeners and the many other producers of green space on supposedly vacant land because their means-oriented discourse takes precedence in the public imagination; it perpetuates the notion that the land is ultimately still vacant.     

再生PE对沥青及沥青混合料技术性能影响研究

通过海南东线高速公路沥青路面层混合料采用再生PE的施工实践,就再生PE对沥青及AC-16沥青混合料技术性能影响进行了试验研究,结果表明能够大幅度提高沥青及沥青混合料的高温稳定性能,但对低温性抗裂性能影响不大,适宜在高温炎热地区沥青混凝土路面使用。     

Soil management systems and short term CO₂ emissions in a clayey soil in southern Spain

The soil in general and that destined for agricultural use, more specifically, can act as a source or sink of carbon, hence its direct involvement in strategies for mitigating climate change. A large proportion of this mitigation potential is produced by the sequestration of carbon by soils and, to a lesser extent, by a reduction in emissions from the soil.The most effective practices for increasing the organic carbon in the soils are generally those linked to conservation agriculture, which includes practices of no tillage or minimum tillage and the use of cover crops. During the farming seasons of 2006/07, 2007/08, 2008/09 and 2009/10, a trial was conducted in which the carbon dioxide emissions in soil with a high percentage of clay in the Vega de Carmona (Seville) were estimated, and it was determined how climate conditions and the adoption of conservation agriculture practices vs. the use of traditional tillage influenced the flux of gas into the atmosphere.     

制度变迁视角下的江南古镇保护——以江南六镇为例

借鉴新制度经济学和新经济史学的分析方法,从制度变迁的角度探究转型期条件下中国古镇保护发展演变的内在逻辑。在对江南水乡古镇保护三个主要历史发展阶段进行回顾分析,指出古镇区是一种具有特殊历史文化属性的稀缺性土地资源,在转型期条件下它基本处于基层地方政府的掌控之中,而具有一定利益独立性的地方政府之所以选择古镇保护,是因为保护活动在特定的历史条件下成为一项净收益（率）最高的投资活动。就本质而言,转型期中国古镇保护的发展历程也就是地方政府随着外部社会经济条件的变化;借助古镇区资源不断追逐自身利益最大化的过程。     

Farmers’ livelihood assets and adoption of sustainable land management practices in north-western highlands of Ethiopia

In Ethiopia, farmers’ adoption and continued use of introduced land management technologies have not been widespread to reduce soil erosion and soil fertility depletion to an acceptable level. An important set of factors in farmers’ use of improved agricultural technologies is generally known to be their possession of livelihood assets. This study examines the influence of ownership of livelihood assets in farmers’ decisions to use cattle manure as land improvement technology, which is currently being promoted by Ethiopia’s agricultural extension system. The study was conducted in Dangila woreda (district) in the north-western highlands of Ethiopia. Data were collected from a survey of 201 rural households from April to June 2011 and in October 2012. Logistic regression modelling and Chi-square and t-tests were used to analyse data. The findings show that plot distance from residence, number of livestock owned, use of dung for fuel, maize–vegetable–fruit intercropping, land to man ratio and perception of land tenure security were important determinants of manure use among the farmers. Existing and future local development interventions should focus on these factors to improve the farmers’ capability to invest in cattle manure application and sustainable land management.     

Learning from farmers’ needs: Identifying obstacles to the successful implementation of field margin measures in intensive arable regions

In intensive arable areas, field margins can constitute boundary biotopes that are valuable for natural resource conservation. In order to analyse the potential for implementing more field margin measures, 865 responding farmers in intensive arable areas in three German federal states were surveyed. Determinants of their willingness to participate in field margin measures were analysed by binary logistic regression. The farmers were asked about the optimal design of field margins, and these designs are discussed within the context of nature conservation goals. The results show that farmers implement field margins less often if they are risk-averse. Farmers already implementing grassland environmental measures and mulch seeding or extensification measures with regards to herbicide and fertiliser reductions on arable land more often adopt field margin measures. Regarding the design of field margins, farmers’ preferences hardly differ between the federal states, and they do not significantly conflict with nature conservation needs in intensive arable areas. The main fear is the risk of weed spreading. Therefore, farmers prefer sown field margins, mown at least once a year and treated with restricted herbicide applications. Certain features, such as seed mixture, mowing date and plant protection measures, could be adapted in order to minimise conflicts with nature conservation objectives.     

Landscape ecological planning process for wetland, waterfowl, and farmland conservation

A landscape ecological planning process (LEP process) is described that addresses the issues of rice production and wetland habitat conservation on privately owned rice farms in Texas. The LEP process was used to evaluate proposed land-use management plans based on alternative policies for the next US Farm Bill, which would be in effect from 2003 to 2009. A system simulation model, geographic information systems (GIS) model based on expert knowledge, as well as expert opinion, were used to evaluate uncertainty about the effects of these plans and policies on different types of farms and the quality of winter habitat of lesser snow geese. The models simulated shifts in land-use, rice and cattle production, farm profitability, and use of habitat by geese. Simulation results suggested that the level of federal subsidies for all policies influenced the continuation of rice production from 2003 to 2009. In addition, the size of the farm influenced whether rice production continued until 2009. The smaller farms were more sensitive to decreases in federal subsidies than larger farms because smaller farms received less income from goose hunting leases. Winter habitat for lesser snow geese was reduced in terms of patch size and nearest neighbor distance when rice production was discontinued by 2009 for all policies. Agricultural policy experts, who were familiar with the study sites, selected the modified version of the conservation policy as the example that would most benefit farmers and geese. The experts emphasized that their policy would offer farmers more flexibility to manage their farms, to diversify their incomes, and to be good land stewards.     

Adoption of conservation easements among agricultural landowners in Colorado and Wyoming: The role of economic dependence and sense of place

The inter-mountain west is one of the most highly urbanized and rapidly growing regions in the United States. Conservation easements are one common tool used to protect rural and agricultural land from urban development. This paper examines the attitudinal and demographic characteristics of agricultural landowners to predict adoption of conservation easements. The study has two primary objectives: (1) to broaden the literature on sense of place and place attachment by including a measure of economic dependence as one dimension, and (2) to examine the relation of this dimension with attitudes towards land trusts and participation in conservation easements. Agricultural landowners (N = 2266) in Colorado and Wyoming were surveyed about their sense of place for their land, their attitudes towards land trusts, and perceived need for land conservation. Factor analysis of 12 measures of sense of place indicated that place identity, conservation ethic, and economic dependence ere distinct dimensions of sense of place among agricultural landowners. Logistic regression analyses revealed that economic dependence had a significant and negative relation with landowner's trust of and trusts and placement of a conservation easement on agricultural land, whereas a conservation ethic and spiritual attachment are positively related. Two main implications for land trusts are that time spent contacting landowners is time well spent and intake questionnaires could be used to screen and owners for both a conservation ethic and a sense of economic dependence providing information hat might improve the possibility of reaching an easement agreement.     

低成本可复制绿色住区的设计与探索

将绿色建筑的可持续设计理念融入项目的规划阶段,因地制宜地利用场地地形高差,合理进行建筑分布,利用计算机技术辅助建筑实现绿色方案的整体策划。从绿色建筑的节地、节能、节水、节材、室内环境及运营管理等六方面构建建筑的绿色技术体系,采用被动式、低成本的绿色技术策略,达到重庆市绿色建筑的预定目标,为进行低成本绿色建筑的设计提供一种思路。     

Defining alternative futures and projecting their effects on the spatial distribution of wildlife habitats

This study had two purposes: (1) to inform a public process that would propose land use zoning for the Chico Creek Watershed in Washington State, USA and (2) to develop and demonstrate the use of readily accessible analytical tools and data for similar public processes across Washington. Three development alternatives (Planned Trend, Moderate, and Conservation) were designed by local citizens and county planners. We created artificial landscapes that depicted how land use zoning and land management practices would effect the spatial distribution of vegetation types. Wildlife–habitat relationship models were constructed for nine focal species. Using computer software known as HABSCAPES, the spatial distributions of habitats were mapped for each species. Under all alternatives the amount of forest vegetation decreased but the amount of mature conifer forest increased relative to current conditions. The relative habitat area index was 0.75, 0.69, 0.71, and 0.71 for the current condition, Planned Trend, Moderate, and Conservation alternatives, respectively. For six species, all future alternatives resulted in less habitat than the current condition, but for three species, all future alternatives resulted in more habitat. When species status was used to weight outcomes, the moderate alternative provided slightly more conservation benefit than the conservation alternative. Lessons learned about public land use planning processes are discussed.     

注重综合性思考突出新农村特色--北京延庆县八达岭镇新农村社区规划

就如何进行新农村社区的规划设计,笔者在实践中进行了总结,提出了应以农民为核心,以农民利益为出发点,以促进农村发展为目标,始终贯彻农民是使用者、受益者的思想;指出新农村社区规划应从农村经济产业、土地集约、社会结构、生产活动与生态、人文环境等多方面进行综合思考,并在空间规划中逐项落实的设计思路,介绍了在北京延庆八达岭镇的新村规划中所做的努力.     

Landwise or land foolish? Free conservation advice for farmers in the wider english countryside

This paper examines the development of a policy for the provision of free conservation advice to farmers in England by the Farming and Wildlife Advisory Group and ADAS. It explores the nature and extent of current advisory provision. Drawing on a policy evaluation of advice provision undertaken for MAFF, the paper examines the effectiveness of advice from three perspectives: the quality of written advice, the extent to which advice is accepted and acted upon by farmers, the evidence of conservation practice from on-site assessments. The paper concludes with a consideration of some of the policy issues that emerge, particularly the need for an improved system of co-ordination and delivery.     

A comprehensive conservation strategy for Georgia's greenways

In 1976 the State of Georgia published the Environmental Corridor Study (K. Dawson, W. Munnikhuysen and R. Roark, 1976. Georgia Environmental Corridor Study. Office of Planning and Research, Dept. Natural Resources, Atlanta, GA). The study is a survey of greenway potential, focusing on a statewide interconnected system. The study process combined intrinsic values (natural resources, environmental quality and aesthetics) with extrinsic values (human use, accessibility, market demand and land use) and endangeredness to provide priorities for greenway conservation. In coordination with a unique program titled Heritage Trust, initiated by then-Governor Jimmy Carter to explore conservation easements, zoning and direct acquisition, the corridor study became recognized as an excellent source of information for greenway implementation. Under Heritage Trust, over 40 000 ha of land were acquired. The current governor, Zell Miller, established Preservation 2000, a program which is continuing the work of Heritage Trust for the 1990s. To quote from the recent Preservation 2000 brochure (H. Young, 1993. Preservation 2000 Program: Summary of Program and Progress. Dept. Natural Resources, Atlanta, GA). ‘By the end of 1994, the state will acquire [an additional 40 000 hectares] of natural areas, parks, greenways and other wild lands.’ The State of Georgia has also updated the corridor study in the Georgia Trails and Greenways Plan (A. Soriano, 1992. Georgia Trails and Greenways Plan. Dept. Natural Resources, Atlanta, GA), which provides technical assistance to local communities on issues of greenway planning including outdoor recreation planning process, land and water conservation programs, management issues and agency action plans. Unique to all of the planning and acquisition programs has been the hypothesis that, when site nominations are made for conservation purchase on a statewide basis irrespective of greenways, most priority conservation areas are found to be within greenway boundaries. This is certainly due to the substantial conservation potential of greenways. Of Heritage Trust nominations, 90% were within greenway corridors. This percentage has increased to 93% with the Preservation 2000 program. Greenways are increasing rapidly in importance as an overall conservation strategy in many areas throughout the world.     

Landwise or land foolish? Free conservation advice for farmers in the wider english countryside

This paper examines the development of a policy for the provision of free conservation advice to farmers in England by the Farming and Wildlife Advisory Group and ADAS. It explores the nature and extent of current advisory provision. Drawing on a policy evaluation of advice provision undertaken for MAFF, the paper examines the effectiveness of advice from three perspectives: the quality of written advice, the extent to which advice is accepted and acted upon by farmers, the evidence of conservation practice from on‐site assessments. The paper concludes with a consideration of some of the policy issues that emerge, particularly the need for an improved system of co‐ordination and delivery.     

Toward a sustainable land management of vernacular landscape in the highlands of south-western Saudi Arabia: indigenous and statutory experiences

The vernacular landscape of the highlands of south-western Saudi Arabia comprises three distinct elements: natural, agricultural and built. The highlands are currently facing land use planning problems which result in deforestation, despite significant attempts at afforestation by several governmental agencies (especially the Ministry of Agriculture and Water) and by municipal governments in the area. Intentions towards more sustainable forms of land management now characterize official documents. With regard to landscape issues, this is marked by a discourse of sustainable land management and the sponsorship of initiatives addressing the relationship between land management and the environment. This paper demonstrates that the approach to sustainable land management is technical, rational and scientific. A more balanced approach would combine scientific knowledge and practice with traditional expertise.     

Toward a sustainable land management of vernacular landscape in the highlands of south‐western Saudi Arabia: indigenous and statutory experiences

The vernacular landscape of the highlands of south‐western Saudi Arabia comprises three distinct elements: natural, agricultural and built. The highlands are currently facing land use planning problems which result in deforestation, despite significant attempts at afforestation by several governmental agencies (especially the Ministry of Agriculture and Water) and by municipal governments in the area. Intentions towards more sustainable forms of land management now characterize official documents. With regard to landscape issues, this is marked by a discourse of sustainable land management and the sponsorship of initiatives addressing the relationship between land management and the environment. This paper demonstrates that the approach to sustainable land management is technical, rational and scientific. A more balanced approach would combine scientific knowledge and practice with traditional expertise.     

厦门海沧钟山村城市化进程中的创新性探索

农村城市化解决了现有城市扩张过程中对城市建设用地的迫切需求,为城区的快速发展提供了广阔空间。但是,农村城市化工程的实施,不可避免地带来了大量农民的土地被征用,如何才能使农民失地不失收成为了一个新的课题。厦门市海沧区政府坚持以人为本和可持续发展,充分考虑农民的权利,在钟山村的开发改造中,不仅改善了人居环境,还解决了被征地农民的生产、生活问题,实现了城市和农村的"双赢",符合"科学发展观"的要求,其实践探索具有创新意义。     

The Case for a Uniform Land Use Classification

The development of effective metropolitan planning research requires the adoption of a uniform land use classification for all cities in the United States. Classification systems now vary from city to city, and the data resulting from land use surveys are therefore not comparable among the cities. Comparative studies are essential if we are to understand the regularities of urban form and land use distributions that hold for cities in general. The suggested classification scheme is a modification of the Standard Industrial Classification. It would permit adaptation to special local requirements but would still allow comparisons of land use among cities.