Soil water 17 Irrigation 16 Soil Water Management (Irrigation and Drainage), (Revised June 2002) 15 Soils 10 SOIL WATER 9 Soil reaction 9 Water management 9 Water Resources 8 Erosion control 7 Mineral soils 6 Natural Resource Economics, (New March 2000) 6 Plant Production 6 Soil Erosion 6 Fertilizer management 5 Organic Soils 5 Policy and Planning 5 Soil Biology 5 Soil water relationship 5 soil water 5 Crop production 4 Crop yield 4 Irrigation systems 4 Mineral Soils 4 Soil Colloids 4 Soil Ecology 4 Soil Organisms Soil Erosion 4 Soil Physical Properties 4 Soil Taxonomy 4 Soil collids 4 Tillage Systems 4