Soil erosion Soil conservation 64 Congresses 20 Research 13 Soils 12 Erosion 7 Sediment control 7 more ... Government policy 5 Intercropping 5 Sedimentation and deposition 5 Sweet potatoes 5 Economic aspects 4 Mathematical models 4 Measurement 4 Simulation methods 4 Soil pollution 4 Watershed management 4 Agriculture 3 Climatic factors 3 Crops and soils 3 Deforestation 3 Fertilizers 3 Land use 3 Methodology 3 Prevention and control 3 Rain and rainfall 3 Runoff 3 Soil physics 3 Soil productivity 3 Watersheds 3 less ...