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).