Controlled Drainage, R1-150

The experimental site was established in 2000 at Gärds Köpinge, (southeast Sweden, in the county of Skåne (55^o56’N, 14^o10’E). It has been a long-term experiment since 2009. The study area has a semi-humid climate with a mean annual air temperature of 7.6 ^oC (using 1961–1990 data from a meteorological network station at Kristianstad).

Two months (January and February) have a mean air temperature below zero degrees. The mean annual precipitation is 562 mm. At the site, the topsoil (0–40 cm) is a weakly structured loamy sand with an organic matter content of five percent. The subsoil (40–100 cm) is a sand with low organic matter content, which restricts the main microbiological activity to the topsoil. Below 1 m depth, there is a clay layer, which effectively restricts downward seepage.

The experimental site is divided into four plots, including two plots with conventional subsurface drainage and two plots with controlled drainage. The plot size was 36 m x 40 m. Each plot is drained separately by four parallel lateral drains spaced 9 m apart. Plastic sheeting to a depth of 1.6 m to prevent lateral leakage and subsurface interactions isolates the plots. The outlets were connected to a weir allowing the groundwater to potentially rise to a pre-selected minimum height, after which outflow occurred. All plots are incorporated into an ordinary Swedish conventional farming system.

Contact: Ingrid Wesström, senior lecturer, Department of Soil and Environment, ingrid.wesstrom@slu.se, +4618673492