Benefits of Tile Drainage

Drainage Improves:

  • Crop Yields – Proper subsurface drainage can increase crop yields by improving soil conditions and preventing waterlogged roots.
  • Field Access – Fields dry and warm faster in the spring and after rains, allowing for longer growing seasons and wider windows for planting, in-season applications, and harvest operations.
  • Consistent Crop Performance – A consistent water table depth increases uniformity within a field and reduces year-to-year yield variability caused by excess water.
  • Nutrient Use Efficiency – Better soil aeration enhances nutrient cycling while encouraging deeper root growth, resulting in more effective nutrient uptake.
  • Land Value and ROI – Drainage improvements often raise farmland productivity and value.
  • Opportunity for Optimum Water Management – Tile drainage systems can be used to better manage water through practices like Controlled Drainage (Drainage Water Management), Subsurface Irrigation, and Drainage Water Recycling.
  • Longer Growing Season – Quicker Spring soil drying and warming extends planting windows giving farmers more options for crop rotations and implementing other practices like cover crops.
  • Field Access – Fields dry faster after rain, allowing for earlier and wider windows for planting, in-season applications, and harvest operations.

Drainage Reduces:

  • Surface Runoff and Erosion – Well-drained soils provide greater capacity for infiltration where water moves through the soil profile rather than across the field surface. A well-established crop also provides vegetative cover to reduce erosion potential from surface runoff.
  • Fuel Consumption – Improved field conditions minimize tire slippage and power required for operations like tillage while also reducing the need to return to fields with wet spots that were initially non-trafficable.
  • Nitrous Oxide Emissions – Reduction in ponded areas and saturated soils decreases the amount of Nitrous Oxide (potent greenhouse gas) that’s emitted to the atmosphere.
  • Soil Salinity – Tile drainage allows the leaching of salt through the topsoil and a lower water table reduces the amount of capillary rise of saline water which can impact crop health.
  • Soil Compaction – Drier soils are less susceptible to compaction from equipment.

Drainage Basics

Precipitation is the primary source of water for crop use. As rain falls on the soil and crops, some of it evaporates, some flows over the land surface as runoff, and some infiltrates into the soil profile. The infiltrated water is absorbed into the soil and excess water moves down to the water table. As the water table rises, subsurface drain pipes maintain its level at the pipe’s buried depth (typically 3 to 4 feet) keeping the top soil layer balanced with air and water held to the soil particles.

Agricultural drainage is primarily categorized into surface and subsurface systems. Properly designed drainage systems (surface or tile) reduce flooding by improving water infiltration and controlling runoff, which in turn reduces surface erosion.

Surface Drainage involves constructing shallow ditches, shaping the land, and clearing channels to allow water to move off the surface via gravity. This also includes natural water movement across the land where designated areas are vegetated (grassed waterways), or berms (Water and Sediment Control Basins) are implemented to slow down the water and significantly reduce erosion.

Subsurface (Tile) Drainage involves installing perforated tile underground, typically 3 to 4 feet deep, to collect excess water from the root zone which is unavailable to the crop. These collection pipes discharge into a larger main drain or ditch. Tile drainage provides the opportunity for farmers to implement other in-field water management practices like controlled drainage or subsurface irrigation as well as edge of field water quality practices like saturated buffers and woodchip bioreactors.

Four Key Variables of Proper Drainage Design

  1. Drainage Coefficient - The depth of water to be removed from a field in a 24- hour period dependent on crop type, soil type, and use of surface inlets. Typically, 3/8” to ½”.
  2. Soil Properties - One of the most important components of a drainage design is how fast the water can move through the saturated soil. Investigating soil properties helps identify areas of sand or clay layers which may impact the performance of the drainage system.
  3. Topography and Outlet – Understanding where the water naturally flows helps determine how mains and laterals can be placed and if a gravity outlet or lift station is applicable.
  4. Lateral Depth and Spacing – Calculated from the design Drainage Coefficient and soil properties to determine the depth and space of laterals to maintain a consistent water table across the field.

Other Considerations

  • Investing in the future – Plan systems properly to account for future farming practices as well as changing weather patterns.
  • Mains sized for increased acreage or drainage intensity
  • Potential future farming practices – crop rotations, cover crops, no-till, applications, equipment
  • Implementation of controlled drainage, subirrigations, drainage water recycling
  • Addition of edge of field water quality practices
  • Lateral Configurations – straight runs are efficient installations, but a contoured system is more effective at intercepting more water on hillsides.
  • Nutrient Leaching – Subsurface drainage systems can convey soluble nutrients with the excess water from the crop root zone. Ensure a nutrient management plan is in place for the crops to utilize applied fertilizer.
  • Industry Resources – Design tools, calculators, technical notes, extension bulletins are widely available online and can help increase efficiency in design and installation.
  • Quality Installations – Confirm all equipment, tools, and materials are operational and available to ensure the designed system is installed in accordance with manufacturer and industry standards.

History of Drainage

  • Modern Era (1990s – Present): Today’s designs utilize GPS and laser-grade control for extreme precision. Innovation now focuses on "conservation drainage," using adjustable structures for controlled drainage to manage nutrient transport and adapt to changing climate patterns.
  • The Plastic Revolution (1960s – 1980s): In 1965, corrugated HDPE (high-density polyethylene) plastic tubing was introduced in the U.S. This lightweight, flexible material revolutionized the industry, especially when paired with the tile plow, which could dig a trench and lay the pipe in a single pass.
  • Industrialization (Late 1800s – 1950s): The mid-19th century saw the development of tile-making machines, enabling mass production of clay and concrete "shinbone" or horseshoe tiles. By the early 1900s, engine-powered trenchers began replacing hand-digging, though costs remained high for many individual farmers.
  • The "Father of Tile" (1838): Scottish immigrant John Johnston introduced systematic tile drainage to the United States on his farm in New York. He hand-laid fired clay tiles, a practice that significantly boosted his yields and eventually spread across the Midwest.
  • Ancient Beginnings (5000 BC – 1700 AD): The earliest civilizations in Mesopotamia, Egypt, and Rome used open ditches and buried conduits made of bundled brush, stones, or gravel to remove excess water. In Crete and Rome, archaeologists have found remnants of clay pipes dating back to 5000 BC.