Sutherland-Iowa State University Northwest Iowa Research and Demonstraton Farm

Location:  This farm is located near Sutherland in O'Brien County, Iowa

                   Figure 1: Site map

Description:  The total area is approximately 32 acres of which 26 acres are used as experimental plots and the remainder as border and buffer.  A total of 32 experimental plots are available which are 160 ft x 225 ft.

Drainage design:  Subsurface drainage lines were installed in 2013 parallel to the long dimension through the center of each plot and on the borders between plots (80 ft. spacing).  See Figures 2 and 3.

Figure 2:  Drainage design

Figure 3:  Example of subsurface drainage layout for four plots.


Treatment Number


Nitrogen Application Time

Nitrogen Application Rate (lb N/acre)*


Conventional tillage**

Fall (Anhydrous Ammonia with nitrapyrin)



Conventional tillage

Spring (Anhydrous Ammonia)



Conventional tillage

Split with variable N at sidedress (40 lb/acre of UAN at planting plus in-season adjusted rate no later than mid-vegetative growth stage)

Yearly variable based on in-season adjusted rate


Conventional tillage




* For corn plots only. The 135 lb N/acre rate is based on the Corn Nitrogen Rate Calculator output for corn following soybean in Iowa at a 0.10 price ratio (

** Fall chisel corn stalks with spring disk/field cultivate, and spring disk/field cultivate soybean stubble.