Suchergebnisse

Gully erosion is the destructive and dramatic form of land degradation in Northeast China. The region is the grain production and ecological security base of China where the fertile and productive Mollisols are distributed. Though the region was agriculturally developed relatively recently, it went through high intensity cultivation and fast succession processes within short-time scales. Coupled with irrational farming practice choice and land use, hillslope erosion and gully erosion are seriously threatening agricultural production and environmental stability in the region. The awareness of gully erosion by the local governments started in the 1970s, and conservation measures were thus implemented. In this paper, based on our survey, communications with local farmers and stakeholders as well as investigation for gully erosion for the past three years, we summarize the practical and efficient practices to manage gully erosion developed by researchers and farmers in Northeast China during the past 50 years. These practices include various drop structures, soil check dams, masonry check dams, gabion check dams, wicker check dams, continuous live wicker, a shrub plant enclosure, and an arbor plant enclosure. We specifically expound how a gully erosion practice is set up and identify the site conditions for which they are well-suited. The application of these practices depends on topography, gully size, and local economy. Bioengineering techniques in Northeast China, such as continuous live wicker, a shrub plant enclosure, and an arbor plant enclosure, are highly effective in controlling gully erosion. Problems and challenges are also presented.

© 1983 Taylor and Francis. All rights reserved. In 1971f the construction began on the largest multipurpose dam in the Philippines in Pantabangan, province of Nueva Ecija, Central Luzon region. Costing some P242 million and partly financed by the World Bankf it was completed in 1974 (Figure 8.1). Its basic purpose is to store the waters of the Upper Pampanga River for four major uses: For irrigation— One of the main goals of the government is to make the Philippines self-sufficient in rice. One of the strategies for achieving this goal is to reduce dependency on uncertain rain-fed irrigation, shift to year-round stream-fed irrigation and, thereby, increase outputs per crop and the number of crops per year. The Pantabangan dam now provides irrigation to almost 84,000 hectares (ha) of lowland rice farms. Precise production figures are not readily available, but the Ministry of Agriculture officials claim that the dam has contributed significantly not only towards ricesufficiency but towards making the Philippines a net exporter of rice as well.

ONCE A PUBLIC POLICY IS ESTABLISHED, THE IMPLICIT OR EXPLICIT COMMITMENT OF THE GOVERNMENT TO CONTINUE THAT POLICY MAKES TERMINATION DIFFICULT; THIS CASE STUDY ILLUSTRATES HOW ONE COMMITMENT THAT WAS PERCEIVED TO BE EXPLICIT WAS ANNULLED. THE CASE SUGGESTS CERTAIN GUIDELINES FOR A SUCCESSFUL POLICY TERMINATION.