Nitrogen is a critical input in agriculture, enabling farmers to produce high crop yields profitably. 

However, nitrogen compounds released into the environment can also be a source of environmental 

problems, including eutrophication and hypoxia in aquatic ecosystems, visibility-impairing haze, 

and the loss of biodiversity. 

Improved nitrogen management on cropland has been a longstanding goal of USDA conservation 

policy. Technical and financial assistance through programs such as the Environmental Quality 

Incentives Program and the Conservation Stewardship Program has promoted best management 

practices like applying nitrogen at agronomic rates or injecting it directly into the soil. For some 

sectors, such as large animal feeding operations, and in some States, nutrient management planning 

is mandatory. 

Despite such regulatory measures and government assistance, a large share of cropland does not 

follow nitrogen best management practices: in 2006, 65 percent of cropland (producing eight major 

field crops) did not follow what are considered to be nitrogen best management practices (Ribaudo 

et al., 2011). USDA’s Natural Resources Conservation Service (NRCS) found that improvements 

in at least one aspect of nitrogen management (see box, “Criteria for Good Nitrogen Management”) 

were needed on 86 percent of cropland rotations in the Upper Mississippi Basin, 87 percent of 

cropland rotations in the Chesapeake Bay watershed, 82 percent of cropland rotations in the 

Great Lakes watershed, and 93 percent of cropland rotations in the Ohio-Tennessee Basin (USDA, 

NRCS, 2010, 2011a, 2011b, 2011c). Failling to apply best management practices increaases the 

risk that excess nitrogen can move from the field to water resources or the atmosphere.

Nitrogen Management on U.S. Corn Acres, 

2001-10

Marc Ribaudo

Michael Livingston 

James Williamson

ECONOMIC BRIEF NUMBER 20 • November 2012

United States Department of Agriculture

Economic Research Service
Ribaudo, Marc, Michael 

Livingston, and James 

Williamson. Nitrogen 

Management on U.S. Corn 

Acres, 2001-10, EB-20. 

U.S. Dept. of Agriculture, 

Economic Research Service, 

November 2012. 

Recommended citation 

format for this publication:

The basic practices for improving nitrogen use efficiency are agronomic application rate, appropriate 

timing of applications, and proper application method (USDA, NRCS, 2006):

•	 Rate. Applying no more nitrogen (commercial and manure) than 40 percent more than that removed 

with the crop at harvest, based on the stated yield goal, including any carryover from the previous 

crop. This agronomic rate accounts for unavoidable environmental losses that prevent some of the 

nitrogen that is applied from actually reaching crops. 

•	 Timing. Not applying nitrogen in the fall for a crop planted in the spring.

•	 Method. Injecting (placing fertilizer directly into the soil) or incorporating (applying to the surface 

and then discing the fertilizer into the soil) nitrogen rather than broadcasting on the surface without 

incorporation.

Criteria for Good Nitrogen Management

ECONOMIC BRIEF Nitrogen Management on U.S. Corn Acres, 2001-10

UNITED STATES DEPARTMENT OF AGRICULTURE 2

Trends in Nitrogen Management

Farmers adjust the management of their crops for a variety of reasons. As input or output prices change, 

farmers’ motivation to conserve nitrogen fertilizer may change too. Other factors—such as conservation 

program benefits, yield or revenue risk, and environmental regulations (ongoing or anticipated)—also 

affect the level of nitrogen management observed on U.S. farms. An examination of nitrogen management 

on U.S. corn acres in 2001-10 indicates that farmers might be adjusting to changing economic conditions. 

Corn is the most widely planted crop in the United States and the largest user of nitrogen in terms of 

application rates per acre, total acres treated, and total applications. Over 97 percent of planted corn acres 

receive nitrogen (commercial and manure). Data from the Agricultural Resource Management Survey 

(ARMS) indicate that corn acreage treated with nitrogen increased 18 percent between 2001 and 2010, as 

farmers planted more corn in response to higher prices. 

During 2001-10, corn acres with nitrogen applied above agronomic rates declined from 41 percent to 31 

percent (table 1). This more efficient use of nitrogen is consistent with findings that application rates per 

unit of output have been declining in recent years (Turner et al., 2007). However, similar improvements 

in nitrogen management were not observed for application timing or application method (table 1). While 

limiting application rates is probably the most important factor in terms of reducing environmental 

impacts, inappropriate application methods or timing still increases the risk of nitrogen losses to the 

environment. Overall, corn acres meeting all three management criteria increased from 28 percent to 34 

percent between 2001 and 2010. Despite the increase in corn acres receiving nitrogen, the total number 

of corn acres not meeting the three criteria declined by almost 10 percent between 2001 and 2010.

Higher nitrogen prices are likely a factor in the reduction in corn acres receiving excess application. 

Nitrogen fertilizer prices nearly doubled from 2000 to 2008 (fig. 1). By 2005, nearly one in four farmers 

indicated that they had reduced application rates in response to higher prices (table 2). In contrast, the 

price of nitrogen and the nitrogen/corn price ratio have fallen since 2008, making nitrogen fertilizer 

cheaper to use. By 2010, fewer farmers (relative to 2005) indicated that they reduced application rates 

or were more carefully managing nitrogen. Lower nitrogen prices relative to crop prices could perpetuate 

this trend.

Observed changes in nitrogen management vary, depending on whether nitrogen comes from synthetic 

fertilizer or animal waste. Corn acreage receiving only commercial fertilizer dropped from 84 to 82 

percent between 2005 and 2010, while corn acreage receiving manure increased from 16 to 18 percent. 

Between 2005 and 2010, management improved for farms using only commercial fertilizer: the share of 

corn acres not meeting the rate/timing/method criteria declined from 65 percent to 60 percent (table 3). 

However, no improvement in nitrogen management was observed on corn acres that received manure as 

a source of nitrogen. On farms where manure is produced and used as a nitrogen source, an increase in 

nitrogen fertilizer prices typically results in a substitution of manure nitrogen for commercial fertilizer 

2
Table 1

Nitrogen use on corn: nitrogen-treated acres and the share of treated acres that did not meet the rate, 

timing, or method criteria , by region, 2001, 2005, and 2010

Region Treated acres Did not meet rate

 

 2001 2005 2010 2001 2005 2010 

 

 1,000 Percent of treated acres

Appalachia 1,925 2,118 2,433 52 66 56 

Corn Belt 35,087 39,145 41,100 46 38 30 

Lake States 12,965 13,958 14,488 46 34 29 

Mountain 1,243 1,018 1,361 18 14 29 

Northeast 2,696 2,477 2,559 42 32 53 

Northern Plains 16,962 18,293 21,677 27 28 29 

Southeast 280 286 311 39 50 62 

Southern Plains 1,708 2,109 2,510 31 32 28 

 

Total 72,868 79,404 86,439 41 35 31 

 Did not meet rate, timing, 

Region Did not meet timing Did not meet method and method criteria

 2001 2005 2010 2001 2005 2010 2001 2005 2010

 

 Percent of treated acres

Appalachia 12 16 7 56 78 47 82 90 75

Corn Belt 41 41 44 39 34 37 77 70 68

Lake States 37 41 41 36 30 34 77 67 67

Mountain 9 20 20 33 50 26 48 62 53

Northeast 39 40 35 54 53 72 70 74 89

Northern Plains 10 15 19 36 45 39 56 67 63

Southeast 27 29 17 41 55 57 78 77 78

Southern Plains 45 38 23 33 18 19 70 74 46

 

Total 32 34 35 38 37 38 72 70 66

Source: USDA, Economic Research Service, using data from USDA’s Agricultural Resource Management Survey 

(2001, 2005, 2010), Phase II. 

 Rate, timing, and method criteria are met when nitrogen is applied at an agronomic rate, not applied in the fall, and injected 

or incorporated into the soil.

1

1

Nitrogen Management on U.S. Corn Acres, 2001-10 ECONOMIC BRIEF

3 ECONOMIC RESEARCH SERVICE

(Ribaudo et al., 2011). This substitution effect is likely the reason that nitrogen management did not 

improve on farms using manure, since most farms using manure also produced it. The share of farmers 

indicating that they substitute manure for commercial fertilizer in response to higher fertilizer prices 

increased between 2001 and 2010 (table 2), as did the percentage of corn acres receiving manure.

An increase in cropland receiving manure—which is generally more difficult to manage than commercial 

fertilizer—may heighten the need for improved nutrient management. A shift to manure in response 

to higher commercial fertilizer prices could lead to a greater demand for assistance from conservation 

programs, and greater scrutiny from resource management agencies dealing with nitrogen-related 

environmental issues. 
ECONOMIC BRIEF Nitrogen Management on U.S. Corn Acres, 2001-10

UNITED STATES DEPARTMENT OF AGRICULTURE 4

Figure 1

U.S. April nominal prices of fertilizer nutrients and nitrogen/corn price ratio

$ per pound of N $ per pound N/$ per bu corn 

Source: ERS and USDA National Agricultural Statistics Service, Agricultural Prices; and USDA, World 

Agricultural Outlook Board, World Supply and Demand. 

N/Corn price ratio

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0

Nitrogen (N)

1990 1995 2000 2005 2010

0

0.004

0.008

0.012

0.016

0.020

Table 2

Reported changes in commercial nitrogen fertilizer management 

on corn due to price

 2001 2005 2010

Farmer reported actions Percent

Reduced nitrogen application rate 11 24* 14

 By how much 21 17* 28

Increased manure 2 3* 5

Changed the type of N 2 5* 6

Managed N more carefully 8 21* 16

Source: 2001, 2005, and 2010 ARMS, Phase II, Cost of Production Practices and Costs Report.

Notes: Data are weighted and the standard errors are calculated using the jackknife delete-a-group 

method.

* 2005 means are statistically different from 2001 at the 1% level.

# 2010 means are statistically different from 2005 and 2001 at the 1% level.

#

#

#

#

#
Nitrogen Management on U.S. Corn Acres, 2001-10 ECONOMIC BRIEF

5 ECONOMIC RESEARCH SERVICE

Conclusions

Between 2001 and 2010, the share of corn acres meeting an application rate criterion increased, 

suggesting that corn producers are applying less excess nitrogen. A combination of higher fertilizer prices, 

heightened awareness, and concerns over environmental quality may all be contributing to this trend. 

Similar improvements have not been shown in application method and application timing, most likely 

because of perceived costs of changing management. Despite improvements in nitrogen application rates, 

about 66 percent of corn acreage does not achieve the rate, timing, and method criteria that minimize 

environmental losses of nitrogen. As a result, improved nitrogen management on cropland continues to 

be a major conservation policy goal. 

Surveyed corn acres receiving manure did not show any improvement in nitrogen management between 

2001 and 2010. Since 92 percent of corn acres receiving manure do not meet the rate, timing, and 

method criteria, a continued policy focus on improved manure management may be warranted, especially 

if higher commercial fertilizer prices increase the use of manure as a source of nutrients. 

Share of treated corn acres that did not meet the rate, timing, and method criteria, 

by nitrogen (N) source, 2005 and 2010

 Acres treated with 

 Acres treated with commercial and Acres treated with 

 commercial N only manure N manure N only

 Acres Percent Percent Percent Percent Percent Percent

 treated of all not of all not of all not

 with N treated meeting treated meeting treated meeting

Year (1,000) acres criteria acres criteria acres criteria

2005 79,404 84 65 14 96 2 91

2010 86,439 82 60 15 96 3 92

Source: USDA, Economic Research Service using data from the USDA’s Agricultural Resource Management Survey (2005, 2010), 

Phase II.

Table 3
ECONOMIC BRIEF Nitrogen Management on U.S. Corn Acres, 2001-10

UNITED STATES DEPARTMENT OF AGRICULTURE 6

References

Ribaudo, M., J. Delgado, L. Hansen, M. Livingston, R. Mosheim, and J. Williamson. 2011. Nitrogen 

in Agricultural Systems: Implications for Conservation Policy. Economic Research Report 127, U.S. 

Department of Agriculture, Economic Research Service.

Turner, R.E., N.N. Rabalais, D. Scavia, and G.F. McIsaac. 2007. “Corn Belt Landscapes and Hypoxia 

of the Gulf of Mexico,” in J.I. Nassauer, M.V. Santelmann, and D. Scavia (eds.), From the Corn Belt to 

the Gulf: Societal and Environmental Implication of Alternative Agricultural Futures, Resources for the 

Future.

U.S. Department of Agriculture, Natural Resources Conservation Service (USDA, NRCS). 2006. 

“Natural Resources Conservation Service Conservation Practice Standard: Nutrient Management,” 

National Handbook of Conservation Practice.

USDA, NRCS. 2010. Assessment of the Effects of Conservation Practices on Cultivated Cropland in the 

Upper Mississippi River Basin. 

USDA, NRCS. 2011a. Assessment of the Effects of Conservation Practices on Cultivated Cropland in the 

Great Lakes Regions. 

USDA, NRCS. 2011b. Assessment of the Effects of Conservation Practices on Cultivated Cropland in the 

Chesapeake Bay. 

USDA, NRCS. 2011c. Assessment of the Effects of Conservation Practices on Cultivated Cropland in the 

Ohio-Tennessee River Basin. 

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