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. <b> Site description:</b> 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).<br>