Contribution of browse to ruminant nutrition across three agro-ecological zones of Burkina Faso

We determined the contribution of ligneous species to the diet of cattle, sheep and goats across three agro-ecological zones of Burkina Faso, and assessed their ethno-veterinary uses by livestock keepers. Regular observation and GPS-tracking of one cattle, one sheep and one goat herd each in three villages served the investigation of browsing activities on pasture. Livestock keepers (25 per village) were interviewed on the use of ligneous plants by livestock and for disease treatment, and on changes in use over the past two decades.Across the three zones 75 species were of importance. Cattle preferred Afzelia africana, Pterocarpus erinaceus and Piliostigma sp., while small ruminants primarily fed on Balanites aegyptiaca, Ziziphus mauritiana and Acacia sp. Contribution of browsing to daily eating time was highest for goats across seasons and zones; for sheep and cattle browsing was important during the hot dry season with no differences between zones. Livestock keepers reported increasing browse use by their animals, while browse species use for traditional animal health care has decreased. The combination of anthropogenic pressures and climate change affect survival and regeneration of the most preferred trees and shrubs, and threaten livestock keepers' current management practices; this needs to be counteracted adequately.     

Agricultural practices and sustainable livelihoods: Rural transformation within the Loess Plateau,China

Effective agricultural practices can enable and sustain rural livelihoods, particularly in rapidly developing and transforming areas such as the Chinese Loess Plateau. Drawing from the Sustainable Livelihoods Approach (SLA), a conceptual framework for agricultural practices and sustainable rural livelihoods for the Yangou watershed within the Chinese Loess Plateau is presented and discussed. It is found that agricultural practices that include building terraces, returning sloped farmlands to forestland and grassland, and expanding orchards all have had positive and significant impacts on farmers' livelihood assets, strategies, outcomes, and vulnerabilities. From 1997 to 2006, 48.4 ha (95%) sloped farmland in the Yangou watershed was converted to new land management, and the percentages of income from fruit sale and sale of labor to total income dramatically increased by 59% and 14%, respectively. The watershed community also experienced 159% raise in per capita net income from 1997 to 2003, while the watershed itself experienced a 99% decrease in sediment yield from 1998 to 2007. These positive and significant impacts of new agricultural practices on the sustainable rural livelihoods of the Yangou watershed are evident in the community's reduced dependence upon grain and subsidies income, the diversified strategies for livelihood, and the improved environmental indices. The successful implementation of new agricultural land management practices and policies in the Yangou watershed strongly suggest that similar transformations can be achieved in similar regions throughout China's vast rural areas of the Loess Plateau.     

Impacts of projected climate change on sediment yield and dredging costs

Changes in climate may significantly affect how sediment moves through watersheds into harbours and channels that are dredged for navigation or flood control. Here, we applied a hydrologic model driven by a large suite of climate change scenarios to simulate both historical and future sediment yield and transport in two large, adjacent watersheds in the Great Lakes region. Using historical dredging expenditure data from the U.S. Army Corps of Engineers, we then developed a pair of statistical models that link sediment discharge from each river to dredging costs at the watershed outlet. Although both watersheds show similar slight decreases in streamflow and sediment yield in the near‐term, by Mid‐Century, they diverge substantially. Dredging costs are projected to change in opposite directions for the two watersheds; we estimate that future dredging costs will decline in the St. Joseph River by 8–16% by Mid‐Century but increase by 1–6% in the Maumee River. Our results show that the impacts of climate change on sediment yield and dredging may vary significantly by watershed even within a region and that agricultural practices will play a large role in determining future streamflow and sediment loads. We also show that there are large variations in responses across climate projections that cause significant uncertainty in sediment and dredging projections.     

Impacts of environmental stressors on the water resources of intensively managed hydrologic systems

Watersheds are complex systems due to their surface and subsurface spatially connected water fluxes and biochemical processes that shape Earth's critical zone. In intensively managed landscapes, the implementation of watershed management practices (WMPs) regulate their short‐term responses, whereas climate variability controls the long‐term processes. Understanding their responses to anthropogenic and natural stressors requires a holistic approach that takes into account their multiscale spatio‐temporal linkages. The objective of this study was to simulate the impacts of spatially and temporally varying WMPs and projected climate changes on the surface and groundwater resources in the Upper Sangamon River Basin (USRB), a watershed in central Illinois greatly impacted by agricultural and industrial operations. The physically based hydrologic model MIKE‐SHE was used to simulate the hydrologic responses of the basin to different WMPs and climatic conditions. The simulation of a WMP was varied spatially across the basin to determine the spectrum of responses and critical conditions. In general, the wetlands and forested riparian buffer scenarios were found to cause a reduction in the average streamflow, whereas crop rotation had varied responses depending on the location of implementation and the climate condition assumed. Reductions of up to 30% in the average streamflow were found for the forested riparian buffer under the ESM 2M climate projections, whereas an increase of up to 13% with the crop rotation schemes under CM3 climate was predicted. The model results showed that the installation of tile drains across the USRB increased the water table depth (from ground level) by up to 56%, making crop production possible. Groundwater level in USRB appeared to be more sensitive to future climatic conditions than to WMP implementation. The impacts of WMPs are determined to depend on the climate conditions under which they are applied. Investigating individual and combined stressors' effects over the critical zone at a watershed scale can lead to a more comprehensive analysis of the risk and trade‐offs in every managerial decision that will enable an efficient use of resources.     

城市新区开发的理论与实践

近年来,随着我国城市郊区化的日益明显,城市新区作为郊区化的主要载体日益受到关注。文章分析了城市新区的概念,认为城市新区是城市郊区化过程中各种新城市地区的高级形式。从经济、社会、环境三种驱动力量的角度分析总结了城市新区开发的理论体系。并比较了中西方城市新区开发的异同,认为西方国家城市新区开发更注重社会因素,而我国城市新区开发更注重经济因素。最后指出我国城市新区开发中的问题及对策。     

ZD1245/ZD2070型水平定向钻机的设计

以ZD1245/ZD2070型水平定向钻机为例，分析了水平定向钻机主要结构设计时的一些常规性思维与做法。     

Hydrological responses to conservation practices in a catchment of the Loess Plateau,China

Since the late 1950s a series of soil conservation practices have been implemented in the Loess Plateau. It is important to assess the impact of these practices on hydrology at the catchment scale. The Jialuhe River catchment, a tributary of the Yellow River, with a drainage area of 1117 km² in the Loess Plateau, was chosen to investigate the hydrological responses to conservation practices. Parametric and non‐parametric Mann–Kendall tests were utilized to detect trends in hydrological variables or their residuals. Relationships between precipitation and hydrological variables were developed to remove the impact of precipitation variability. Significant linear decreasing trends in annual surface runoff and baseflow were identified during the treated period from 1967 to 1989, and the rate of reduction was 1·30 and 0·48 mm/year, respectively. As result, mean annual surface runoff and baseflow decreased by 32% over the period of 1967 to 1989. Seasonal runoff also decreased during the treated period with the greatest reduction occurring in summer and the smallest reduction in winter. The response of high and low daily flow to conservation practices was greater than average flows. Copyright © 2004 John Wiley & Sons, Ltd.     

Nitrate temporal and spatial patterns in 12 water-supply wells, Yucatan, Mexico

 The nitrate concentration in 12 water-supply wells were monitored for the period April 1992 to March 1993. Each water-supply well was sampled once a month. The nitrate concentrations in the 12 wells ranged from 7 to 156 mg/l. Two water-supply wells (Chacsinkin and Peto) showed concentrations that reached 3.5 times the maximum permissible limit for the Drinking Water Standard (45 mg/l). A third water-supply well (Akil) exceeds the norm for 7 out of 12 months. The use of nitrogen-rich fertilizers are responsible for high nitrate concentrations in groundwater in the southern part of Yucatan, Mexico where intensive agricultural practices exist. Received: 14 December 1999 · Accepted: 2 May 2000     

Domesticating neo-liberalism: Everyday lives and the geographies of post-socialist transformations

This paper examines the ways in which neo-liberalism is both constructed and made ‘more tolerable’ through everyday practices and livelihoods in post-socialist cities. It argues that existing conceptualisations of neo-liberalism centre too fully on the role of powerful global forces and institutions in constructing marketisation processes, and consequently neglect the ways in which everyday lives are embroiled in the formation of neo-liberal worlds. Through an exploration of the experience of neo-liberalism in the Slovak Republic and drawing upon research with households in one large housing estate in Bratislava, the paper examines the ways in which everyday lives construct neo-liberal possibilities in the attempt to make them ‘more tolerable’. In particular, the paper explores the postponement of the future by some members of the middle-aged generation failing to reap the benefits of economic reform, the role of economic practices ‘outside’ of market-based capitalist relations in constructing engagements with the formal market, and the role of domestic food production in sustaining household networks and social reproduction for some of the most marginal households in the context of low-wage employment and state benefit reductions.     

Environmental perceptions and practices of livestock keepers on the Namaqualand Commons challenge conventional rangeland management

In South Africa, interventions in communal rangelands proposed by most agriculture-sector institutions are still dominated by the belief that communal herders have little technical skills and by the tenets of “the tragedy of the Commons”, assuming that individual livestock keepers are selfish, norm free, and aiming at maximising short-term offtake and that there is no consistent management of the commons. In this study we show that practices of a diversity of livestock keepers on the Leliefontein Commons of Namaqualand are at odds with this viewpoint: access to rangeland and its use are structured by collective norms and concerns regarding both the sharing of resources and their long-term sustainability. We also show that part of the management of the commons relies on grazing practices which involve tacit and formalised technical knowledge that can be described and modelled. Livestock keepers assess the heterogeneity of the grazing quality of the commons. They are aware of the toxicity and unpalatability of some plants, of the way this differs according to the amount ingested and the availability of other forage, and of the variations of these two factors over seasons of grazing. They classify grazing areas and decide on daily grazing routes according to a complex set of criteria. Carrying capacity of each area is not considered as a fixed parameter but rather as a variable dependant on rainfall. Seasonal movements between areas are designed accordingly. These findings offer a new perspective for research agendas on technical models and extension measures for communal rangeland management particularly in arid and semi-arid areas.