Home  Welcome
(Dr. Heichel)
 Welcome
(Dunker)
 Field Tour
Presentations
 Tent Exhibits  Credits & Thanks  Sponsors University of Illinois at Urbana-Champaign logo
Richard Cooke Richard Cooke
Associate Professor of Agricultural and Biological Engineering
Department of Agricultural and Biological Engineering
(217) 333-0944; rcooke@illinois.edu

No Photo
Available

Jong Ahn Chun
Graduate Research Assistant
Department of Agricultural and Biological Engineering
(217) 333-9415

Infinitely-Variable, Automated Control Structure for Drainage Water Management

In drainage water management, a control structure is placed at the outlet of a tile system to control the level of the water table in the soil. This practice is being used in Illinois to retain water in the soil profile during the fallow period (November – April), thereby reducing nitrate transport to surface water bodies. This practice also has the potential to increase crop yield by retaining water in the soil during dry periods in the growing season.


One of the main drawbacks of the use of drainage water management during the growing season is that systems have to be intensively managed so as to not inundate the plant roots. During periods of heavy summer rain, it is necessary to manually adjust the level at which water table is allowed to rise. In response to this, we have developed an infinitely-variable, automated control structure in which the allowable water table level is adjusted in response to field conditions. In this structure the water table level is not controlled by flash board risers, but by a variable orifice. The orifice opening is controlled by an electromechanical actuator with feedback circuitry that is powered by a 12-volt battery connected to a solar panel. The orifice opening at any time is a function of a set level and the existing water table level. If the existing level exceeds the set level, the size of the orifice is increased in proportion to the difference between the two levels. However, if the existing level is lower than the set level, the orifice is closed. The set level can be redefined daily to reflect rooting depth.

In the event that the battery voltage falls below a predefined voltage, the orifice is immediately opened fully, thereby reverting to free drainage conditions. In the next phase of development, a warning message will be sent either by telephone or by email to alert the operator when such a situation occurs.


structures

 
Department of Crop Sciences
College of Agriculture, Consumer and Environmental Sciences
University of Illinois Extension
Copyright © 2004 University of Illinois
Email site problems to the webmaster
Site Map