Drain flow record

Using the Hooghoudt equation and measured water table depths, together with linear regression method, a long-term drain flow record for a controlled drainage (CD) experiment at the Davis Purdue Agriculture Center was constructed. Site description: The Davis Purdue Agricultural Center (DPAC) is a research farm in eastern Indiana. The controlled drainage experimental site is the 0.16 km2 field split into four quadrants, northwest (NW), southwest (SW), northeast (NE), and southeast (SE) with areas of 3.5 ha, 3.5 ha, 3.6 ha, and 3.7 ha. This field has a slope of less than 1%. Soils at the site consist of Blount (somewhat poorly drained), Condit (poorly drained), Pewamo (very poorly drained) and a small portion of Glynwood (moderately well drained) series. The drainage system was installed in 2004. Laterals have an approximate depth of 1 m and spacing of 14m. Drainage in the SE and NW quadrants was controlled during some periods while the SW and NE were allowed to freely drain at all times. A more detailed description of the methods can be found in Saadat et al. (2018).