Land and water conservation fund. Hearing before the Committee on Interior and Insular Affairs, United States Senate, Eighty-eighth Congress, second session, on H.R. 3846, an act to establish a land and water conservation fund to assist the States and Federal agencies in meeting present and future outdoor recreation demands and needs of the American people, and for other purposes. July 28, 1964.

Mode of access: Internet.

Vegetation:environment relationships and water management in Shark Slough, Everglades National Park

The hydrologic regime of Shark Slough, the most extensive long hydroperiod marsh in Everglades National Park, is largely controlled by the location, volume, and timing of water delivered to it through several control structures from Water Conservation Areas north of the Park. Where natural or anthropogenic barriers to water flow are present, water management practices in this highly regulated system may result in an uneven distribution of water in the marsh, which may impact regional vegetation patterns. In this paper, we use data from 569 sampling locations along five cross-Slough transects to examine regional vegetation distribution, and to test and describe the association of marsh vegetation with several hydrologic and edaphic parameters. Analysis of vegetation:environment relationships yielded estimates of both mean and variance in soil depth, as well as annual hydroperiod, mean water depth, and 30-day maximum water depth within each cover type during the 1990’s. We found that rank abundances of the three major marsh cover types (Tall Sawgrass, Sparse Sawgrass, and Spikerush Marsh) were identical in all portions of Shark Slough, but regional trends in the relative abundance of individual communities were present. Analysis also indicated clear and consistent differences in the hydrologic regime of three marsh cover types, with hydroperiod and water depths increasing in the order Tall Sawgrass , Sparse Sawgrass , Spikerush Marsh. In contrast, soil depth decreased in the same order. Locally, these differences were quite subtle; within a management unit of Shark Slough, mean annual values for the two water depth parameters varied less than 15 cm among types, and hydroperiods varied by 65 days or less. More significantly, regional variation in hydrology equaled or exceeded the variation attributable to cover type within a small area. For instance, estimated hydroperiods for Tall Sawgrass in Northern Shark Slough were longer than for Spikerush Marsh in any of the other regions. Although some of this regional variation may reflect a natural gradient within the Slough, a large proportion is the result of compartmentalization due to current water management practices within the marsh.We conclude that hydroperiod or water depth are the most important influences on vegetation within management units, and attribute larger scale differences in vegetation pattern to the interactions among soil development, hydrology and fire regime in this pivotal portion of Everglades.

Using quantity/intensity relationships to assess the potential for ammonium leaching in a Vertosol

High concentrations of ammonium (up to 0.1 cmol/kg) have been observed below 1 m depth in a Vertosol soil near Warra in south-eastern Queensland. This study examined whether ammonium leaching could be responsible for the ammonium accumulation observed in the Warra soil. This was done by using quantity/intensity (Q/I) relationships to compare the ammonium retention capacity of the Warra soil with other similar soils throughout the region that did not contain elevated subsoil ammonium concentrations. Analysis of Q/I curves revealed that in the concentration range studied, the amount of ammonium retained on high affinity adsorption sites in all 3 soils was low, and the Warra soil was not significantly different from the other 2 soils. The ability of the soils to retain ammonium in the soil solution against leaching [i.e. their potential buffer capacity (PBC)] did differ between soils and was greatest at Warra. This indicates that at any one time the Warra soil holds more ammonium on the exchange complex and less in solution than the other soils examined. It was concluded that ammonium is no more likely to leach through the surface horizons of the Warra soil than the other soils examined. Indeed, the data indicated that the Warra soil probably has greater capacity to retain ammonium against leaching due to its greater PBC. Consequently, it is considered unlikely that leaching of ammonium has been a major contributor to the subsoil ammonium concentrations at Warra.

Farmers' strategies for managing acid upland soils in Southeast Asia: an evolutionary perspective

The acid soils of the uplands of Southeast Asia have resisted intensive agricultural use for centuries. In recent decades, however, due to rapid population growth, escalating market demand for agricultural produce, and govemment policies for land development and settlement, the acid uplands have become the focus of more intensive land-use systems, placing greater demands on farmers and requiring the development and dissemination of improved practices for soil management. In order to develop appropriate soil management technologies and plan effective interventions to facilitate their adoption, it is important to understand the goals and circumstances of farmers in the acid uplands, the range of farming systems they have developed, and the variety of socio-economic factors and trends influencing the evolution of these farming systems. Building on Boserup's model of agrarian change, an evolutionary framework is developed and applied to five case studies: a long-fallow (shifting) cultivation system in Sarawak, Malaysia; a short-fallow system in South Kalimantan, Indonesia; a continuous cropping system in Bukidnon, Philippines; a tree crop (with intercropping) system in Southern Thailand; a livestock grazing system in Daclac, Vietnam. The framework provides a useful tool to interpret and categorise farmers' evolving soil management strategies and to plan more effective soil management research and interventions. (c) 2004 Elsevier B.V. All rights reserved.

The role of social capital in the promotion of conservation farming: The case of 'landcare' in the southern Philippines

'Social capital' refers to the relationships of trust, communication, and cooperation that facilitate collective action in a community. It is particularly relevant to soil conservation in developing countries, which requires collective efforts to raise awareness of soil degradation, provide effective training in soil conservation practices, and implement soil conservation measures on individual farms. The Landcare Program in the Southern Philippines promotes simple conservation practices in upland environments through establishing and supporting community landcare groups and municipal landcare associations, thus augmenting the social capital of farmers in these locations. An evaluation of the Landcare Program in Barangay Ned, South Cotabato, based on a survey of 313 farm households and case studies of nine landcare groups, shows that, despite extreme isolation and difficult working conditions, farmers responded by rapidly forming landcare groups and a landcare association, and adopting contour barriers on their maize farms. They utilized the bonding social capital inhering in their local communities to build stocks of bridging social capital, linking them to information, training and resources from outside their immediate locality. A logistic regression model of the factors affecting adoption of contour barriers shows that farmers who had undergone the practical, farmer-based training provided by the Landcare Program, and who were members of a landcare group, were significantly more likely to adopt conservation measures. These results confirm the value of investing in social capital to promote soil conservation. Copyright (c) 2005 John Wiley & Sons, Ltd.