Impacts of 4R Nitrogen Management on Crop Production and Nitrate-Nitrogen Loss in Tile Drainage


Project Objectives As part of this field research and demonstration project, we propose to evaluate various promising N management methods and technologies by documenting the nitrate-N export and crop yield from several systems (Table 1). The specific objectives of this project are to: 1. Determine the effects of N fertilizer application and N fertilizer application timing on nitrate-N leaching losses along with potential impacts on crop yield. 2. Read more

Year of initiation:2014
Year of completion:?

Interpretive Summary

This three-year study near Sutherland, Iowa began in January 2015 to evaluate three nitrogen (N) management practices in corn at 135 lbs of N/A (150 kg N/ha) and a no N control.

This three-year study near Sutherland, Iowa began in January 2015 to evaluate three N management practices in corn at 135 lb N/A (150 kg N/ha), and a no N control: 1) fall anhydrous ammonia with nitrification inhibitor (Nitrapyrin), 2) spring anhydrous ammonia (no inhibitor), and 3) split N application with variable N at sidedress (40 lb N/A (45 kg/ha) of urea 2 x 2 in. (5 x 5 cm) starter at planting plus in-season urease-inhibitor (Agrotain®) treated urea.

In addition to local impacts on surface and groundwater quality, N and P loads from the U. S. Corn Belt are suspected as primary drivers of hypoxia in the Gulf of Mexico. Based on the need for nitrate-N reductions to meet water quality goals, new agricultural management practices are needed that have the potential to significantly reduce nitrate-N losses at minimal cost or even economic benefits to farm operations.

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Updates & Reports


2016 Annual Report


2015 Annual Report


Project Description

Project Leader

Matthew Helmers, Iowa State University

Project Cooperators

John Sawyer, Iowa State University

IPNI Staff

Tai McClellan Maaz


Americas \ Northern America \ USA \ Iowa


4r place, 4r rate, 4r research fund, 4r source, 4r time

maize, soybean

Nitrogen (N)