Abstract: Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 31, 2005, at a small natural wetland located in the alluvium of the Canadian River near Norman, Oklahoma, at the U.S. Geological Survey Norman Landfill Toxic Substances Hydrology Research Site. Floating pan evaporation rates were compared with evaporation rates from a nearby standard Class A evaporation pan on land. Floating pan evaporation rates were significantly less than land pan evaporation rates for the entire period and on a monthly basis. Results indicated that the use of a floating evaporation pan in a small free‐water surface better simulates actual physical conditions on the water surface that control evaporation. Floating pan to land pan ratios were 0.82 for March, 0.87 for April, 0.85 for May, 0.85 for June, 0.79 for July, and 0.69 for August. 相似文献
The involvement of local communities, as well as the private sector and the government in forest management is now an important principle of tropical forestry policy and practice and a major component of most international forestry aid programmes. This paper present an analysis on the Joint Forest Management Project initiated by two timber companies (Ghana Primewood Products Ltd and Dalhoff Larsen & Horneman) in collaboration with local people in Gwira-Banso of Ghana. Conditions required for enhancing responsibility for and commitment to local forest management, and for an effective local participatory process were also analysed. The study began with the premise that incentives and good communication will enhance participation in joint forest management.The assumption was valid and the results from the survey showed that five broad issues prioritised by respondents to be essential for co-partnership in forest management are communication, financial support, tree planting, multiple land use and benefit sharing. The Project enjoys a great deal of support from the local community, but a number of factors make the continued support of local people a challenging task, including questions of immediate livelihood sources and tenure arrangements. Although this participatory forest management has been implemented over a relatively short period, there is evidence that government and private sectors can successfully involve local people in sustainable management of the forests. 相似文献
ABSTRACT: Proper management of animal manure is crucial to the viability of the U.S. animal industry and the quality of the environment. This paper analyzes the animal manure distribution in Michigan, identifies counties with high potential for land application of manure nutrients, and proposes a manure distribution prototype model for transporting surplus manure beyond individual farms for nutrient utilization. Tabulations of animal numbers by county and by 5-digit zip code are used to identify areas with greater potential for land application of manure nutrients. Distribution of the manure nutrients from surplus areas to the nutrient utilization areas is explored in a selected watershed by taking into account manure nutrient value, soil nutrient content, crop nutrient needs, topography and hydrography. The results indicate that by appropriate planning and collaboration transport of the excessive animal manure to suitable crop fields is an appealing alternative to utilize the manure nutrients while minimizing the adverse environmental impact. Further studies are needed to determine the necessary economic and institutional programs to implement the export of the manure at the regional level. 相似文献