South Dakota farmers work hard to protect streams, ponds, rivers, lakes and wetlands. Practices include:
- Keeping water edges in their natural state, to help control runoff and erosion and allow water insects, animals and fish to thrive.
- Using cover crops to help reduce soil erosion.
- Placing natural vegetation “filter strips” to intercept and trap pollutants and soil from fields before they reach waterways.
- Aligning furrows to reduce the amount of runoff from rain or irrigation.
- Using diversion channels to send runoff to safe areas and prevent excessive erosion.
- Making use of buffer strips and grass waterways in ditches to capture sediments or nutrients and prevent erosion.
Drain tiling is another way of managing water. During the past several years, precipitation in South Dakota has been far above average, which has created hardships for farmers. Tiling helps with:
- Reducing storm water runoff and downstream flooding through absorption.
- Reducing water damage to public roads.
- Decreasing crop loss due to drowning.
- Increasing soil surface temperatures, which helps seeds germinate.
- Allowing plant roots to grow deeper into the soil so they can absorb more nutrients.
- Providing enough oxygen for plant roots to mature properly.
- Increasing the number of days available for planting and harvesting crops.
- Improving soil structure by avoiding soil compaction and structural damage.
- Promoting energy-conserving farming practices such as no-till and conservation tillage.
- Reducing loss of sediment and nutrients.
- Allowing for more efficient use of resources.
Former SDSU Extension Precision Farming Specialist Gregg Carlson says, “Contrary to the misconception of many environmentalists, tile drainage can result in significant positive environmental consequences. During those times when precipitation exceeds the sum of evapotranspiration and the soils’ water-holding capacity, runoff and erosion associated with the runoff is inevitable. Tile drainage reduces runoff by slowly lowering the water table between precipitation events, creating a sink for future precipitation, resulting in the opportunity for infiltration rather than runoff, thus reducing erosion.” (iGrow)
South Dakota Corn is funding several research projects on drainage through South Dakota State University. One of the studies includes installing and monitoring drainage denitrifying bioreactors in eastern South Dakota. These bioreactors for drainage water treatment use a subsurface trench along the edge of the field which is filled with wood chips that support denitrifying bacteria, resulting in the removal of nitrate from the drainage water. Another study tests water flow and water quality, using data to evaluate the effectiveness of selected conservation practices for reducing nutrient losses from drained lands. Conservation practices to be evaluated include nitrogen stabilizers, drainage water management, saturated buffers and understory and cover crops. Learn more about this study.