Tile Drains A Comparison of Surface & Subsurface Drainage Haleahy Craven, Jonathan Farmer, Reese Freeman, & Dan Maddock

Tile Drains? little information in VT issues with runoff during heavy rain/snowmelt rows of perforated piping below ground allows water percolation to avoid saturation of soil o absorption of nutrients by plant roots

To determine whether regulation on tile drains is necessary Provide DEC with: o data on whether there is a significant difference in nutrient loading to surface waters o influential site characteristics o management recommendations Our Goals

extremely little data/info about tile drain in VT originally implemented due to increased crop yield little consideration to nutrient & sediment loading Justification

Controlled Drainage Experiments Overview ●3 separate experiments on controlled vs conventional (free) drainage. - Sites included southwestern Ontario, Quebec, and Sweden ●The Canadian experiments used a controlled drainage/subirrigation system ●Swedish experiment was only controlled drainage with no subsurface irrigation

Controlled Drainage Highlights ●Quebec Phosphorus loads - Increased P loads in drainage from controlled drainage compared to free drainage - Drainage outflow volume was reduced in controlled drainage - Majority was dissolved P Total P Loads in Free and Controlled Drainage Caroline Sanchez Valero, Chandra A. Madramootoo, Nicolas Stämpfli

Controlled Drainage Highlights Cont. ●Ontario Nitrate Loss - cumalituive draiange water volume was slightly greater in controlled system - flow weighted mean nitrate concentration was reduced in controlled (41%) ●Corn Yields - Soil moisture content was greater in controlled and water table was not as deep as compared to free drainage system - Yields increased by about 60% Nitrate in Drainage H.Y.F. Ng, C.S. Tan, C.F. Drury, J.D. Gaynor

Controlled Drainage Highlights Cont. ●Sweden N Loses - Reduced outflow rate in controlled system - High risk periods for N losses - Increased N uptake ●P loses - Conventional system - Controlled system Ingrid Wesström, Ingmar Messing Grain Yields and N uptake

Controlled Drainage Conclusions ●In most cases outflow volume is reduced in controlled systems ●Peak loading in regards to N and P occur during high outflow rates ●Increased N uptake as well as other factors, increased crop yields ●P seems a bit more unpredictable ●Better alternative to conventional ●Issues - Difficult to figure out how exactly system was controlled - There seems to be a lot of site specificity - How will experiments in VT look?

Soil Structure ●Macropore Systems ○ macroinvertebrates ○ root canals ○ cracking marine clay soils ●Preferential flow ○ Reduces nutrient uptake by plants and soils ○ Increases nutrient leaching and sediment loading to surface waters

Soil Structure Management ●Conventional Ploughing ●Shallow Till ●No till ●Structural Liming ○ Quicklime ■Clay-2H+ + CaO → Clay -Ca2++ H2O ○ Slaked Lime

Fertilization Techniques ●Broadcast fertilization ● Placement or Injection fertilization ○ Reduces losses in non-growing season and cold weather climates

DRP vs P dop ●DRP - Dissolved Reactive Phosphorus ○ Readily available to aquatic organisms ●P dop - Dissolved Organic Phosphorus + Particulate ●P t - Total Phosphorus

Considerations... and Recommendations for Site Specific Studies & Management Practices in Vermont

The Effects of Tile Drains are Site Specific ●Site Characteristics - soil - climate ●History - Joshua Faulkner: study on past tile drain activity * Recommendations - complete GIS map of present tile drains - GIS climate and soil data handouts

Proper Management is Essential! ●Care for Soil Structure - soil can change - cracks are bad ●Tilling Preferences - tilling changes soil structure ●Fertilization - green manure can leach - injection or place based methods - Timing is Everything! * Recommendations - subsurface drainage should be included into a farm’s management plan - a reviewed management plan and routine checkups based on site conditions could be required for subsurface tile drains (a review board may need to be created) - controlled drainage is generally prefered Poor management is bad!

What we did not find... Alternative Impacts ●Hydrologic Cycle - Groundwater Recharge - Nearby Communities and Ecosystems ●Future Site Goals - Developement - Remediation - Reclamation ●Impacts of Climate Change? ●Clay Soil Map of Vermont * Recommendations - No drain zones?

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