Land use Land Resources 11 Agriculture 8 Natural resources 7 Forests and Forest Trees (Biology and Ecology) 6 Land tenure 6 Water Resources 6 History 5 India 5 Natural Resource Economics, (New March 2000) 5 Sustainability 5 Watershed management 5 Biological Resources (General) 4 Conservation of natural resources 4 Economic development 4 Forests 4 Land degradation 4 Land management 4 Pollution and Degradation 4 Tribes 4 Water quality management 4 Water resources development 4 Animal Ecology 3 Biological Resources (Plant) 3 Case studies 3 Community development 3 Environmental management 3 Geology 3 Grasslands 3 Grasslands and Rangelands 3