Water resources Water Resources 11 Water management 8 Land resources 6 Sustainability 6 Biodiversity 5 Mineral resources 5 Natural Resource Economics, (New March 2000) 5 Ecosystems 4 Energy resources 4 Food resources 4 Forest resources 4 Land Resources 4 Natural resources 4 Pollution and Degradation 4 Renewable resources 4 Soil Water Management (Irrigation and Drainage), (Revised June 2002) 4 Water 4 Watershed management 4 agriculture 4 Agricultural development 3 Case studies 3 Climatic change 3 Disaster management 3 Earth sciences 3 Environmental studies 3 Hydrology 3 India 3 Land use 3 Nuclear pollution 3