Nashua-Iowa State University Northeast Iowa Research and Demonstration Farm

Name:  Iowa State University Northeast Iowa Research and Demonstration Farm (NERF)

Location:  Near the town of Nashua in Chickasaw County, Iowa

Description:  This study site has 36, 0.4 ha plots, with state-of-the-art surface and subsurface water quality monitoring systems. 

Background:  The site has fully documented tillage and cropping records for more than 25 years.  The water quality monitoring system was installed in 1988 and since that time three major water quality studies have been completed at this site on the effects of tillage, crop rotations, and nutrient management practices on surface and groundwater quality resulting in more 10 M.S./Ph.D. theses and 30 refereed papers.

Soils:  The soils at the site include Floyd loam (fine-loamy, mixed, mesic Aquic Hapludolls), Kenyon loam (fine-loamy, mixed, mesic Typic Hapludolls), and Readlyn loam (fine-loamy, mixed, mesic Aquic Hapludolls) (Kanwar et al., 1997).  These soils have a seasonally high water table and benefit from a subsurface drainage system.

Drainage system:  Subsurface drains at this site were installed in 1979.  Each of the plots at the site is drained separately and has subsurface drain lines installed in the center of each plot at a depth of 1.2-m below the ground surface with a drain spacing of 28.5-m.  The cross subsurface drainage flow from one plot to another was avoided by installing subsurface drainage lines on the northern and southern borders of the plots and isolating the eastern and western borders with berms (Kanwar et al., 1999). The central subsurface drainage lines are intercepted at the end of the plots and are connected to individual sumps for measuring drainage effluents and collecting water samples for chemical analysis.

Treatments: 

Table 1. Treatments for Nashua manure management and water quality study beginning 2007

System

Application timings and source of N

Crop

Tillage

Application method

Application rate, kg-N/ha

1

 

Spring (UAN)

-

Corn

Soybean

Chisel Plow

Field Cultivate

Spoke inject

-

168

-

2

 

Fall (manure)

-

Corn

Soybean

Chisel Plow

Field Cultivate

Inject

-

168

-

3

3

Fall (manure)

Fall (manure)

Corn

Soybean

Chisel Plow

Field Cultivate

Inject

Inject

168

112

4a

4b

Fall (manure)

Fall (manure)

Cont. Corn

Cont. Corn

Round Bale Removal

Chisel Plow

Chisel Plow

Inject

Inject

224

224

5

 

Spring (UAN)

-

Corn/Rye cover

Soybean/ Rye cover

No Till

No Till

Spoke Inject

-

168

-

6

Fall (manure)

Corn

Soybean

No Till

No Till

Inject

-

168

-