Area sampling frames for agriculture in developing countries

This report summarizes the utility of area sampling frames (ASF), promoted by the Economics and Statistics Service of the U.S. Department of Agriculture, in helping 12 developing countries produce accurate agricultural data. ASF"s break down land area, with the help of aerial photographs and Landsat remote sensing images, into units suitable for sampling and data collection. They have been used since the late 1940"s in the United States to estimate crop area, yields, production, prices, and other items. This experience has proven that ASF"s yield high economic and social returns while maintaining low sampling errors. ASF data can be used to increase the productivity of small-scale agriculture in developing countries and monitor desertification (e.g., in the Sahel) by determining the status of dryland ecosystems and changing areas. Projects are carried out in four phases: (1) construction of the ASF; (2) field surveys (e.g., yields or irrigation); (3) computer classification of agricultural areas using remote sensing data; and (4) agricultural crop yield models. Phase 1 has been completed in Jamaica, Costa Rica, Tunisia and the Dominican Republic, and has been initiated in Bolivia, the Philippines, Indonesia, Morocco, Sierra Leone, Liberia, Sudan, and Ecuador. The background of ASF"s in each of these countries is provided along with the major problems encountered such as organization and supervision deficiencies, lack of training in interpretation of aerial photos and Landsat imagery, outdated maps, poor weather conditions, and a lack of cooperation from host governments. In the four countries where ASF"s are completed, problems with poor quality maps and photos, changes in agricultural regional boundaries, and conditioning biases from utilizing the same samples, have limited ASF"s effectiveness. At the time of this report, it is uncertain whether feasibility studies for Phases 3 and 4 will be undertaken. A total of 10 references (1971-80) are appended.