Subsurface drainage has increased dramatically in eastern South Dakota in the last several years driven by increases in precipitation and commodity and land prices. This research will evaluate the economic, water quality, and hydrologic impacts of drainage in South Dakota.
A network of research plots and field sites are currently being monitored for water flow and water quality. Data collected from the plots and field sites will be used to develop models to estimate the production and economic benefits and hydrologic impacts of different drainage rates and to evaluate the effectiveness of selected conservation practices for reducing nutrient losses from drained lands. Conservation practices that are being evaluated include nitrogen stabilizers, drainage water management, saturated buffers, and understory and cover crops. The data gathered from this research should result in improved drainage design recommendations for South Dakota that maximize the economic benefits of drainage and minimize potential negative environmental impacts.
The research objectives are as follows:
1. Develop guidance on drainage intensity and drain spacing for representative soils and climatic conditions in South Dakota to maximize economic benefits and minimize negative environmental impacts
2. Evaluate the impact of nitrogen stabilizers on nitrate losses from drained areas
3. Compare the water yield among conventionally drained, managed drained, and undrained fields
4. Demonstrate and evaluate the use of managed (controlled) drainage and saturated buffers for reducing nitrate losses from tile drained fields
5. Evaluate potential cover crop strategies to manage wet areas and to tie up nutrients and reduce drainage outflow
The project setup consists of multiple drained, undrained, and controlled drainage research plots at the SDSU Southeast Research Farm. Also, several cooperator field sites throughout eastern SD are being monitored to collect data from various conservation drainage practices. All sites have sensors placed in the field and at the drainage outlets of the plots. The soil, water, field, and yield data are then compared to see if there is a difference of statistical significance.
The data collected will allow producers to evaluate multiple different drainage practices for use in their operations. Additionally, the research will provide science-based drainage data for producers, policy-makers, and the public to make informed decisions regarding drainage. The results of this research will be incorporated into Extension programming and released through a variety of outlets to maximize the benefits for producers.