This publication is the first of a series of manuals that present environmental guidelines for planning and implementing ecologically sustainable projects. Attention is particularly directed to the agricultural situation and needs of developing nations. Subject areas discussed include: (1) users and uses (identifying the major purposes of the manual); (2) agriculture and environment (explaining ecological terms and processes); (3) a well-planned approach (offering strategies for project development); (4) water supply and management projects (listing water sources, transport systems, and irrigation techniques); (5) soil management through erosion control (recommending control measures and practices); (6) nutrient management (specifying types, impacts and control measures); (7) pest management (indicating application factors and environmental effects); and (8) planning framework (proposing guidelines for project designs and listing assessment criteria). Appendices contain a list of affiliated organizations and agencies and a soil distribution map. Bibliographic references are also included. (ML)