Estimated Animal Agriculture Nitrogen and Phosphorus from Manure

Specific Indicators
Documented Nutrient Pollution Documented Impacts State Actions Underway

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About this indicator

Animal agriculture manure is a primary source of nitrogen and phosphorus to surface and groundwater. Manure runoff from cropland and pastures or discharging animal feeding operations and concentrated animal feeding operations (CAFOs) often reaches surface and groundwater systems through surface runoff or infiltration. Permitting discharging CAFOs to limit nitrogen and phosphorus discharge to surface waters, and implementing best management practices outlined in a manure management plan are critical steps to protecting water quality. This indicator shows animal agriculture manure produced in states in 2007 and 2017 (the year of the last Census of Agriculture) and expressed in terms of nitrogen and phosphorus content, rather than total amounts of manure, since different animal types produce manure with differing nitrogen and phosphorus concentrations. Data are for cattle, swine, poultry (chickens and turkeys), sheep, and horses. Data are presented as 1000s of kg of manure nitrogen and phosphorus as well as kilograms of manure nitrogen and phosphorus per km2 of farmland.

Estimated nitrogen (N) and phosphorus (P) produced from animal manure in 2007 and 2017
  Estimated animal manure in 2007 (1000 kg of N) Estimated animal manure in 2017 (1000 kg of N) Estimated animal manure in 2007 (1000 kg of P) Estimated animal manure in 2017 (1000 kg of P) Estimated animal manure per farm land area in 2007 (kg of N/km2) Estimated animal manure per farm land area in 2017 (kg of N/km2) Estimated animal manure per farm land area in 2007 (kg of P/km2) Estimated animal manure per farm land area in 2017 (kg of P/km2)
Alabama 133,956 153,055 41,438 47,296 3,678 4,407 1,138 1,362
Alaska 796 728 225 199 221 212 62 58
Arizona 50,998 57,044 12,309 13,883 483 540 117 131
Arkansas 179,024 177,070 56,005 55,610 3,183 3,150 996 989
California 327,287 323,935 75,388 76,379 3,184 3,264 733 770
Colorado 136,460 148,854 38,852 42,591 1,074 1,156 306 331
Connecticut 3,493 3,646 749 806 2,105 2,361 451 522
Delaware 20,080 20,293 5,944 6,023 9,729 9,545 2,880 2,833
Florida 101,939 103,061 30,901 31,207 2,709 2,617 821 792
Georgia 158,802 161,074 48,575 48,915 3,810 3,999 1,165 1,214
Hawaii 7,957 7,831 2,485 2,461 1,756 1,704 548 536
Idaho 115,094 134,107 27,493 32,768 2,473 2,834 591 693
Illinois 105,906 113,634 36,690 40,768 976 1,040 338 373
Indiana 103,411 113,665 35,432 38,951 1,727 1,876 592 643
Iowa 398,551 444,597 144,981 164,430 3,198 3,594 1,163 1,329
Kansas 293,838 296,306 84,863 86,700 1,568 1,600 453 468
Kentucky 144,122 141,038 43,414 43,296 2,544 2,689 766 825
Louisiana 59,630 55,989 18,259 17,452 1,819 1,730 557 539
Maine 6,109 5,267 1,391 1,182 1,118 995 255 223
Maryland 37,297 35,524 10,548 10,159 4,474 4,411 1,265 1,261
Massachusetts 3,672 3,043 818 700 1,745 1,529 389 352
Michigan 75,204 94,398 19,574 25,128 1,858 2,389 484 636
Minnesota 211,302 223,076 68,684 73,718 1,941 2,160 631 714
Mississippi 112,038 110,147 34,567 34,687 2,517 2,613 777 823
Missouri 261,450 274,520 84,045 90,007 2,228 2,442 716 801
Montana 131,048 139,670 41,155 44,343 532 594 167 189
Nebraska 314,619 339,465 96,219 104,094 1,705 1,865 521 572
Nevada 22,792 26,722 6,765 7,977 955 1,077 283 322
New Hampshire 2,676 2,592 581 594 1,407 1,506 305 345
New Jersey 4,394 3,788 1,114 1,026 1,487 1,275 377 345
New Mexico 80,695 85,828 20,699 22,236 462 522 118 135
New York 85,755 94,210 17,913 20,724 2,943 3,390 615 746
North Carolina 215,818 207,958 80,115 76,219 6,201 6,095 2,302 2,234
North Dakota 88,069 97,297 27,324 30,695 550 611 171 193
Ohio 108,025 125,120 32,516 39,110 1,907 2,214 574 692
Oklahoma 283,852 285,752 87,463 89,454 1,998 2,067 616 647
Oregon 74,777 72,489 21,237 20,716 1,127 1,122 320 321
Pennsylvania 125,555 138,231 32,946 37,876 3,978 4,693 1,044 1,286
Rhode Island 495 427 120 113 1,747 1,856 424 491
South Carolina 47,205 46,239 15,054 14,565 2,381 2,408 759 758
South Dakota 189,425 220,371 59,013 68,847 1,071 1,259 334 393
Tennessee 124,787 111,367 38,148 34,213 2,803 2,531 857 777
Texas 699,431 687,364 206,361 202,317 1,325 1,337 391 394
Utah 56,209 56,391 17,083 16,939 1,251 1,289 380 387
Vermont 15,934 16,340 3,047 3,370 3,201 3,383 612 698
Virginia 102,834 102,035 30,895 30,673 3,137 3,233 943 972
Washington 63,537 69,943 16,069 17,816 1,054 1,177 266 300
West Virginia 27,580 27,491 8,304 8,494 1,842 1,855 555 573
Wisconsin 191,761 209,563 42,098 47,562 3,117 3,616 684 821
Wyoming 69,123 73,350 21,070 22,616 566 625 172 193

Sources: The number of animals per state are from USDA’s 2007 and 2017 Census. Estimated manure N and P contents are from Ruddy et al. 2006. 2007 and 2017 farm land acreage is from USDA's National Agricultural Statistics Service: Farm Numbers, Farms and Land in Farms, Final Estimates, 2003-2007; 2017.

Download the Manure data table (xlsx) (17.28 KB)

Sources of data

  1. U.S. Department of Agriculture. 2009. 2007 Census of agriculture: United States summary and state data. Vol 1. AC-07-A-51.
  2. U.S. Department of Agriculture. 2019. 2017 Census of agriculture: United States summary and state data.
  3. Ruddy, B.C., D.L. Lorenz, and D.K. Mueller. 2006. County-level estimates of nutrient inputs to the land surface of the conterminous United States, 1982–2001: U.S. Geological Survey Scientific Investigations Report 2006-5012.
  4. U.S. Department of Agriculture. National Agricultural Statistics Service, Farms and Land in Farms, Final Estimates, 2003–2007. Refer to the Table 825 of the U.S. Census Bureau’s 2012 Statistical Abstract, Agriculture: Farms and Farmland.
  5. U.S. Department of Agriculture. National Agricultural Statistics Service, Farms and Land in Farms, Final Estimates, 2017., Agriculture: Farms and Farmland.

Data source information

Data were collected for the following animal types: cattle (milk cows, beef cows, steers, heifers, slaughtered cattle), hogs and pigs, chicken (broilers, layers, and pullets), turkeys, sheep, lambs, horses, and ponies. The numbers of animals were collected from the 2007 and 2017 U.S. Department of Agriculture (USDA) Census, except for steers, heifers, and on-farm cattle slaughter, as the USDA Census no longer reports on these cattle categories. Inventory for these animals were estimated per Ruddy et al. 2006. Manure nitrogen and phosphorus production rates (kg/animal/day) for each animal type are also from Ruddy et al. 2006. Farm land acreage is from the National Agricultural Statistics Service. The current definition of a farm, first used for the 1974 census, is any place from which $1,000 or more of agricultural products were produced and sold, or normally would have been sold, during the census year. Acreage designated as ‘‘land in farms’’ consists primarily of agricultural land used for crops, pasture, or grazing. Acres were converted to km2 for this indicator in order to be consistent with other indicators.

What to consider when using these data

  • The rate of delivery of nitrogen and phosphorus from land-applied fertilizer such as manure to streams is dependent on the amount, timing, and placement of application, as well as best management practices to minimize runoff from fields.
  • In cases where certain states did not report total numbers of hogs and pigs or poultry to the 2007 or 2017 USDA Census, the total number of head was estimated based on reported number of head for counties that reported by head, plus an estimate of the number of head for counties that reported by farm size, by using the median value in the ranges reported for each farm size.
  • The 2007 and 2017 USDA Census do not differentiate between tom and hen turkeys. Therefore, the averages of the manure nitrogen/phosphorus production rates (kg/animal/day) for tom and hen turkeys provided by Ruddy et al. 2006 were used as estimates of the manure nitrogen/phosphorus production rates for all turkeys.
  • Based on a review of the literature, USDA sites, and university extension programs, weaning age is variable with reported average values of 120-220 days (cattle are considered calves until weaning). Heifers not used for breeding are typically slaughtered at 9-10 months. Therefore, it was assumed (consistent with Ruddy et al. 2006) that 50% of the cattle, excluding cows, were slaughtered within their first year of life and that the average lifespan was 170 days.
  • All other cattle, excluding cows and slaughtered cattle, were assumed heifers or steers in equal proportions, based on Ruddy et al. 2006 procedures.

References and links to other data sources

  1. U.S. Department of Agriculture.  Manure management webpage.
  2. U.S. EPA. Animal Feeding Operations - NPDES CAFO Permitting webpage.
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Last updated on November 30, 2023