Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

Note: Other indicators in this chapter will refer to the discussion of the Natural Resources Inventory (NRI) below.

The Indicator

This indicator reports the acreage of cropland in the United States. Included in this category are pastures and haylands. For the purposes of this indicator, lands that have been idled in long-term set-aside programs, such as the Conservation Reserve Program (CRP), are not included. This is in part because of the objective to report on those lands that are in active use, and because not all of the programs distinguish CRP acres equally well (the remote-sensing data from the National Land Cover Dataset [NLCD] do not separate them from active croplands). In theory, the land area utilized for animal feedlots would be included in this indicator. In practice, however, this acreage is certainly quite small and is not isolated by the various programs used in this analysis. (While the indicator definition excludes CRP lands, one of the data sources used [Economic Research Service, or ERS] does not report CRP acreage separately; thus, the ERS numbers include CRP acreage. There are other differences between the datasets; see below.)

In addition, lands used for intensive livestock feeding are included within the ambit of this indicator. However, it was not possible to determine the degree of coverage of these areas for the data sources described below.

The Data—General

Data Sources: These data were obtained from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service, National Resources Inventory (NRI) program; the USDA National Agricultural Statistical Service, Census of Agriculture; the USDA ERS, Agricultural Resources and Environmental Indicators publications; and the U.S. Geological Survey. (USGS provided access to and processing assistance with the NLCD, originally produced by a federal interagency consortium, the Multi-Resolution Land Characterization [MRLC] Consortium, see the Core National Extent indicator technical note). See details below on each program.

Comparability Among Data Sources: These four data sources are not fully consistent, and comparisons should be made with care. For example, ERS and Census of Agriculture data include croplands in Alaska and Hawaii, while NRI does not, and only the ERS data reported here include acreage in the CRP—these acres were removed from the data for Census of Agriculture and NRI. The statement that cropland, including pasture and hayland, occupies about one-fourth of the land area of the United States is based on the estimates from the four programs noted above. These estimates range, for 1997, from 445 million acres (NASS) to 496 million acres (NRI). They are compared to the land area of the lower 48 states (derived from the MRLC dataset), 1.891 billion acres. Thus, the percentages range from 22.8% to 26.2%.

USDA National Resources Inventory

Data Source: Data are from USDA, National Resources Conservation Service, Iowa State University Statistical Laboratory, Summary Report 1997 National Resources Inventory (revised December 2000).

Data Collection Methodology: The USDA Natural Resources Conservation Service, in cooperation with the Iowa State University Statistical Laboratory, conducts the NRI survey to capture data on land cover and use, soil erosion, prime farmland soils, wetlands, habitat diversity, selected conservation practices, and related resource attributes. Data are collected every 5 years from the same 800,000 sample sites in the lower 48 states, Puerto Rico, the U.S. Virgin Islands, and some Pacific Basin territories.

The estimated acreage of nonfederal cropland was classified as irrigated, non-irrigated, cultivated or noncultivated acreage. Data are collected for the NRI using a variety of imagery, field office records, historical records and data, ancillary materials, and onsite visits. The data are compiled, verified, and analyzed to provide a comprehensive summary of the state of U.S. non-federal lands. The NRI is a two-stage stratified area sample of the entire country. Stage one is the Primary Sampling Unit (PSU), and it is a sampling of an area/segment of land typically square to rectangular in shape and ranging from 40 to 640 acres but most typically 160 acres in size. Stage two requires the assignment of sampling unit points that are located within the PSU. Cropland includes pasture and areas used for the production of crops for harvest. For the purposes of this indicator, CRP lands were excluded from the NRI data.

Data Quality/Caveats: Statistics derived for the NRI database are estimates and not absolutes, resulting in some amount of uncertainty. These data are reported at the national level; state-level data are available at http://www.nrcs.usda.gov/technical/NRI/1997/obtain_data.html.

Data Access: The NRI report is available at http://www.nrcs.usda.gov/technical/NRI/1997/.

USDA Census of Agriculture

Data Source: Data are from USDA, National Agricultural Statistics Service (NASS), 2002 Census of Agriculture.

Data Collection Methodology: The Census of Agriculture is a comprehensive accounting of agricultural production information for every county in the United States. For 1992, 1997 and 2002, the census was conducted by USDA NASS; prior to 1992, the Bureau of the Census was responsible for censuses every 5 years.

The census is conducted using a mailout/mailback form, direct enumeration, telephone, personal interviews, and follow-up surveys. The mailing list, with 3.2 million contacts, is composed of individuals, businesses, and organizations that are associated with agriculture. Report forms for the 1997 and 2002 Census of Agriculture were mailed to farm and ranch operators in December 1997 and 2002 to collect data for the 1997 and 2002 calendar year.

“Total cropland” includes harvested cropland; cropland used only for pasture or grazing; crop failure; cultivated summer fallow; idle cropland; and cropland in cover crops, legumes, and soil-improvement grasses, not harvested and not pastured. Data on CRP lands were excluded for the purposes of this indicator.

Data Quality/Caveats: The data from each report form were subjected to a detailed item-by-item computer edit. Before publication, tabulated totals for each state were reviewed by state statisticians to identify inconsistencies. Comparisons were also made with previous census data, official NASS Agricultural Statistics Board numbers, and other available check data.

Data Access: The 1964–2002 data are available at http://www.nass.usda.gov/index.asp. The 1945–1959 data are not available online but can be obtained by e-mail from NASS at nass@nass.usda.gov.

National Land Cover Dataset

These data are derived from the MRLC Consortium, which is a partnership between USGS, the U.S. Forest Service, the National Oceanographic and Atmospheric Administration (NOAA), and EPA. See the explanation of the NLCD in the national extent technical note.

USDA Economic Research Service

Data Source: Data were acquired from the U.S. Department of Agriculture, ERS, Resource Economic Division, Agricultural Resources and Environmental Indicators (AREI) 2000 and AREI 1996–97.

Data Collection Methodology: ERS provides national economic data and analysis on issues related to agriculture, food, natural resources, and rural development.

The “cropland” category includes cropland harvested, crop failure, cultivated summer fallow, cropland used only for pasture, and idle cropland. CRP lands are included. ERS compiled these data from NASS Principal Crops and Census of Agriculture data. The data used here were compiled from Krupa and Daugherty (1990), Daugherty (1995), and Vesterby and Krupa (2001).

Data Access: The 1996–97 and 2000 reports may be accessed online at http://www.ers.usda.gov/Emphases/Harmony/issues/arei2000/.

2003 Web Site Update: Data for 2001 from the USDA National Resources Inventory (NRI) were the only data added in this update. The 2001 NRI can be obtained from: http://www.nrcs.usda.gov/technical/land/nri01/.

2005 Web Site Update: Data from the 2002 Census of Agriculture were the only data added in this update. The 2002 Census of Agriculture can be obtained from the NASS website as listed under “Data Access ”.

It is important to note that the 2002 Census of Agriculture used new methodology to account for incompleteness in the census mailing list. With the exception of Alaska and Hawaii, all published 2002 Census items were reweighted to correct for this undercoverage. To provide comparable data, the 1997 and 2002 data were reweighed in the same manner.

References

Daugherty, A.B. 1995. Major uses of land in the United States, 1992, AER-732, U.S. Department of Agriculture, Economic Research Service.

Krupa, K.S., and A.B. Daugherty. 1990. Major land uses: 1945- 1987, Electronic Data Product #89003, U.S. Department of Agriculture, Economic Research Service.

Vesterby, M., and K.S. Krupa. 2001. Major uses of land in the United States, 1997. Resource Economic Division, Economic Research Service, U.S. Department of Agriculture. Statistical Bulletin No. 973.