W. L. Powers

1887

• Land drainage
• Care, use and economic value of farm manure
• Composition and rating of Willamette Valley soils
• Composition, rating, and conservation of Willamette Valley soils
• Contributions of soil science to the welfare of Oregon
• Crop rotation and soil fertility
• Drainage and improvement of wet land
• Drainage and improvement of white land and similar wet land
• Drainage practices for Oregon
• Duty of water in irrigation
• Farm drainage
• Fundamental principles of modern irrigation practice