nitrogen, nitrogen use efficiency, nitrogen management, Environmental Economics and Policy,

Livingston, Michael J.

Ribaudo, Marc

English

Research Papers in Economics

  1 
 
Establishing a Baseline for Nitrogen Policy Assessment 
 
Michael Livingston 
Economic Research Service 
mlivingston@ers.usda.gov 
 
Marc Ribaudo 
Economic Research Service 
mribaudo@ers.usda.gov 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Poster prepared for presentation at the Agricultural & Applied Economics Association  
2010 AAEA,CAES, & WAEA Joint Annual Meeting, Denver, Colorado, July 25-27, 2010 
 
The views expressed in this poster are those of the authors’ and do not necessarily reflect 
those of the Economic Research Service or the U.S. Department of Agriculture 
 
 
     2 
 
Introduction 
 
Increasing emissions of reactive nitrogen (Nr) contribute to harmful changes to 
ecosystems, including acidification in forests, soils, and freshwater ecosystems; 
eutrophication and hypoxia in coastal ecosystems; biodiversity losses; regional haze; and 
global climate change. Agriculture uses more Nr and accounts for more environmental 
losses than any other economic sector (EPA, 2009). Nitrogen Use Efficiency (NUE) is 
the proportion of all nitrogen inputs that are removed in harvested crop biomass, 
contained in recycled crop residues, and incorporated into organic and inorganic soil 
nitrogen pools (Cassman et al., 2002). NUE can be increased by improving uptake 
efficiency from fertilizer applications, reducing nitrogen lost from organic or inorganic 
soil pools, or both. The most important management choices affecting NUE are 
application rates, timing (fall vs. spring), and method (surface vs. injection/incorporation) 
(Cassman et al., 2002; Iowa Soybean Association, 2008). Understanding how agriculture 
is performing in regard to these factors will help determine the design of policies for 
improving NUE, as well as potential tradeoffs between Nr emissions to air and water. 
     3 
Objective 
 
We established a baseline of nitrogen and crop management practices for eight of the 
major U.S. field crops, against which estimates of environmental benefits and producer 
costs can be made. This baseline not only provides a starting point for policy, but 
provides valuable insights on how and where policies might be targeted. 
     4 
Methodology 
 
We assess current nutrient management practices by using USDA’s Agricultural 
Resource Management Survey (ARMS) data collected from producers of barley (2003), 
corn (2005), cotton (2003), oats (2005), peanuts (2004), sorghum (2003), soybeans 
(2006), and wheat (2004).  
“Good” nitrogen management practices are those that make the largest contribution to a 
high NUE. The three criteria are: 
•  Applying nitrogen at a rate less than the product of the crop’s nitrogen 
assimilative capacity per yield-unit, the grower’s yield goal, and 1.5. We allow for 
a 50-percent overapplication to account for unavoidable environmental losses that 
farmers must consider when deciding how much fertilizer to apply.  
•  Not applying nitrogen in the fall for a crop planted in the spring. 
•  Injecting or incorporating nitrogen rather than broadcasting on the surface. 
A farmer can fall into one of eight nitrogen management categories:  
1.  All of the criteria are followed. 
2.  The rate and timing criteria are followed. 
3.  The rate and application criteria are followed. 
4.  The timing and application criteria are followed. 
5.  Only the rate criterion is followed. 
6.  Only the timing criterion is followed. 
7.  Only the application criterion is followed. 
8.  None of the criteria are followed. 
Because the crops covered were surveyed in different years, we chose one reference year, 
2006, to examine the extent to which good nitrogen management practices are being 
followed. The percentage of total acres planted and the chemical and manure nitrogen 
application rates for each management category calculated using data from the ARMS 
survey year for each crop were applied to planted acre estimates for 2006.  
     5 
Results 
 
Almost 242 million acres were planted to the survey crops in 2006, and 69 percent of 
those acres were treated with chemical and/or manure nitrogen.  
 
Application Rate by Crop 
•  The application rate was not met on 27.6 million acres, or 16.5 percent of treated 
acres.  
•  Corn and wheat had the highest share not meeting the criterion (fig. 1).  
•  Almost 2.4 million tons of nitrogen (28 percent of nitrogen applied to the eight 
crops) were applied to crop acres not meeting the rate criterion.  
•  Corn accounted for more than half (fig. 2). 
•  The Northern Plains and Corn Belt contained the largest share of acres not 
meeting the rate criterion (fig. 3). 
•  34 percent of nitrogen applied to crop acres not meeting the rate criterion was 
applied in the Corn Belt. 
 
 
Figure 1. Acres treated with chemical and/or manure nitrogen not meeting the rate, 
timing, or method criteria by crop, 2006 
 
 
 
   
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did not meet rate did not meet timing did not meet method  6 
Figure 2. Amount of chemical and/or manure nitrogen applied to cropland not 
meeting the rate, timing, or method criteria by crop, 2006 
 
 
 
Figure 3. Acres treated with chemical and/or manure nitrogen not meeting the rate, 
timing, or method criteria by region, 2006 
 
   
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did not meet rate did not meet timing did not meet method  7 
Timing 
•  The timing criterion was not met on almost 40.4 million acres of cropland, or 24.1 
percent of treated acres.  
•  Almost 34 percent of treated corn acres received fertilizer in the fall, accounting 
for over 63 percent of the surveyed acres not meeting the timing criterion.  
•  Almost 23 percent of nitrogen was applied well before plants needed it, with corn 
accounting for over 74 percent of the total.  
•  The Corn Belt accounted for 36 percent of total crop acres not meeting the timing 
criterion.  
•  The Corn Belt accounted for 43 percent of the total nitrogen applied to crop acres 
not meeting the timing criterion. 
Method 
•  Nitrogen was not incorporated into the soil on almost 61.8 million of the surveyed 
crop acres, or 37 percent of the treated acres.  
•  24 percent of the nitrogen applied (2.1 million tons) was not incorporated or 
injected.  
•  Corn accounted for almost 46 percent of the treated acres not meeting the method 
criterion and for over 55 percent of the nitrogen applied without incorporation.  
•  The Northern Plains accounted for 31 percent of the treated acres not meeting the 
method criterion. 
•  The Corn Belt accounted for 34 percent of unincorporated nitrogen. 
 
All Three Measures 
•  About 39 percent of the acres treated with nitrogen met all three criteria (fig. 4).  
•  Only 1.7 percent of the treated acres did not meet any of the criteria.  
•  39 percent of the nitrogen applied was done so in a manner that maximizes NUE.  
•  Corn had the smallest share of treated acres meeting all three criteria. 
•  Mountain and Northern Plains regions had the highest share of acres meeting all 
three criteria (fig. 5).  
•  Appalachia and Corn Belt regions had the smallest.  
 
 
     8 
Figure 4. Share of treated crop acres by nitrogen management category by crop, 
2006 
 
 
Figure 5. Share of treated crop acres by nitrogen management category by 
production region, 2006 
 
 
   
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rate timing method none  9 
Implications 
 
The survey data indicate that a high percentage of crop acres are meeting at least some of 
the nitrogen management criteria. One crop, however, meets the criteria less often—corn. 
Corn is the most intensive user of nitrogen and the most widely planted crop. Over 65 
percent of nitrogen applied to all major field crops is applied to corn. Corn grown in the 
Mississippi Basin is a major source of nutrients contributing to Gulf hypoxia. Recent 
demand pressures due to the biofuels mandate as well as the need to feed a growing 
world population suggest that corn acreage and the intensity of corn production are likely 
to increase. Together, these factors could increase Nr emissions to the environment unless 
nitrogen use efficiency is improved.  
     10 
References 
 
Cassman, K.G., A. Dobermann, and D.T. Walters. 2002. “Agroecosystems, Nitrogen-use 
Efficiency, and Nitrogen Management,” Ambio 31(2):132-40. 
 
Iowa Soybean Association. 2008. “Managing Nitrogen for Economic and Environmental 
Performance,” On-Farm Network Update (July):2-11. 
 
U.S. Environmental Protection Agency. 2009. Reactive Nitrogen in the United States; An 
Analysis of Inputs, Flows, Consequences, and Management Options: A Report of the EPA 
Science Advisory Board. Draft  
 
 

Establishing a Baseline for Nitrogen Policy Assessment

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