Constructed in June 1995 at a cost of $44,700, the Defiance County demonstration site contains two 3.5-acre subirrigated fields and 20 acres of control fields with conventional drainage.
Subsurface drainage and runoff are funneled into a 0.30-acre wetland with a storage capacity of 185,000 gallons. Water is then pumped into a 0.39-acre storage reservoir with a capacity of 780,000 gallons. Here, the water is stored until needed for subirrigation.
Crop yield data from 1997 and 1999 show a slight increase in the amount of corn and soybeans produced on the subirrigated fields versus the control plot (1997: an additional 26 bushels of corn per acre; 1999: an additional 16 bushels of corn per acre and 13 bushels of soybeans per acre).
Project personnel installed an additional hydraulic control structure in the fall of 1999 that is expected to increase yields by removing a wet zone in one of the subirrigated fields.
Constructed in the spring of 1996 at a cost of $60,000, the Fulton County demonstration site on the Shininger family farm contains two 20-acre fields – one that is subirrigated and a control plot with drainage pipes only.
Subsurface and surface drainage from both fields is routed by gravity to a 1.4-acre wetland with a 1 million gallon capacity. Water is then pumped into a 1.57-acre, 2.3 million gallon storage reservoir and held until needed.
The subirrigated fields showed increased yields during each of the growing seasons from 1996 to 1999 – an average of 44 more bushels of corn per acre and 10.4 more bushels of soybeans per acre than the control plot.
“We are happy with the system, and our yields increase each year,” said Bill Shininger. “The biggest challenge was to find a good source of water. We test new varieties and expect our yields to get better.”
Van Wert County
Constructed in the fall of 1996 at a cost of $86,300, the Van Wert demonstration site contains three 15-acre fields – two that are subirrigated and one control plot with subsurface drainage only.
Surface runoff and subsurface drainage run into a concrete sump and are pumped into either a 1.95-acre wetland holding 2.3 million gallons or a 3-acre storage reservoir holding 3.4 million gallons.
In 1997 and 1998, little subsurface irrigation was needed because of normal or above average rainfall. The subirrigation that did take place actually damaged some crops because a wet zone formed in a poorly drained area of the field. Project managers installed another hydraulic control structure before the growing season in 1999 to correct this wet zone. Once the problem was corrected, subirrigated field crop production exceeded that of the control plot by 33 bushels of corn per acre and 12.8 bushels of soybeans per acre.