Water Resources Natural Resource Economics, (New March 2000) 13 Water management 13 Water resources 11 Land Resources 10 Policy and Planning 10 Pollution and Degradation 10 Sustainability 10 Irrigation 9 Soil Water Management (Irrigation and Drainage), (Revised June 2002) 8 Social Psychology and Social Anthropology, (New March 2000) 7 Watershed management 7 Land use 6 Meteorology and Climate 6 Soil Chemistry and Mineralogy 6 Water quality 6 Watersheds 6 Environmental impact 5 Plant Production 5 Water pollution 5 Water use 5 Agricultural development 4 Agriculture 4 Case studies 4 Community Participation and Development, (New March 2000) 4 Erosion: Soil and Water Conservation 4 Hydrology 4 Models 4 Planning 4 Water 4