The amount of chemical fertilizer nutrients applied to corn and soybean crops is more than for all other crops combined.[1-4] This is based on available data from 2021 for corn and 2023 for soybeans.
Nitrogen (N) applied to corn and soybeans accounts for ~50% of all U.S. nitrogen use.
Phosphorus (P) applied to corn and soybeans accounts for ~75% of all U.S. phosphorus use.
Potassium (K) applied to corn and soybeans accounts for ~79% of all U.S. potassium use.
Corn and soy are the nation’s 2 largest crops, both predominantly used for animal feed.
All figures in fertilizer/nutrient evaluations should be considered broad estimates. There are 3 credible databases – USDA, FAO, and IFA (Int’l Fertilizer Assoc.) that each offer detailed information, though none provide a complete evaluation including yearly updates, total of all nutrient usage, and nutrients by crop. For total annual U.S. amounts of fertilizer applied, we use the most current data from the FAO. For nutrients by crop we use USDA for selected years, since they rotate evaluations from year to year. International Fertilizer Association info is used as a check of the FAO data.
The total U.S. use of N,P,K for 2021 and 2022 obtained from FAOSTAT, Query: Fertilizers by Nutrient/U.S./ Agricultural Use. Total nutrients were converted to pounds, and the two years averaged at Nitrogen (25,517,117,325 lbs.) Phosphorus (8,232,290,974 lbs.) Potassium (9,583,552,109 lbs.) IFA figures for 2022 are a little higher at N (26,363,287 lbs.) P (8,586,995 lbs.) and K (10,165,062 lbs) probably due to including “turf and ornamentals” usage whereas FAO includes agricultural usage only.
The use of N,P,K on corn for 2021 and for soy 2023 obtained from USDA NASS Quick Stats: [Survey/Environmental/Crop/Fertilizer/Applications, measured in lbs.)] 2021 Corn: share of N = 47.6%; share of P = 49.4%; share of K = 44%. 2023 Soybeans: share of N = 2.1%, share of P = 25.2%, share of K = 35%]
These percentages are in line with IFA figures from 2018-2019 (the last published). Share for corn & soy was 51% nitrogen; 70% phosphorus, and 77% potassium. [see, Ludemann, C. et al., (2022) Global data on fertilizer use by crop and by country, Data files/Country tables. Dryad. published by the International Fertilizer Association through IFASTAT] https://datadryad.org/stash/dataset/doi:10.5061/dryad.2rbnzs7qh
In 2021 (the most recent year for which the USDA has published fertilizer use for corn), the share of total chemical fertilizers applied to corn specifically used for animal feed was about 30% of all nitrogen, 32% of all phosphorus, and 28% of all potassium.[1-3] In other words, slightly less than one-third of all U.S. chemical fertilizer was applied to corn fed to farmed animals.
The use of N,P,K on corn for 2021 obtained from USDA NASS QuickStats. [Survey/Environmental/Corn/Fertilizer/Applications: Nitrogen = 12,299,300,000 lbs., Phosphorus = 4,132,400,000 lbs., Potassium = 4,291,200,000 lbs.]
The total U.S. use of N,P,K for 2021 obtained from FAOSTAT – Fertilizers by Nutrient, U.S. 2021: Nitrogen (25,844,137,768 lbs.) Phosphorus (8,368,668,324 lbs.) Potassium (9,751,431,694 lbs.)
Share of corn used for animal feed is calculated at 64%. This includes exports used as animal feed, corn silage, and the animal feed share of corn used for ethanol. See Share of Corn Crop to Feed.
In 2023, the share of total chemical fertilizers applied to the portion of soybeans specifically used for animal feed was ~1% of all nitrogen, ~15% of phosphorus, and ~20% of potassium.[1-3]
The use of N,P,K on soybeans for 2023 [USDA NASS Quick Stats, Survey/Environmental/Crop/Fertilizer/Applications, measured in lbs., Soybeans 2023: Nitrogen = 537,000,000 lbs., Phosphorus = 2,041,600,000 lbs., Potassium = 3,287,000,000 lbs.]
The total U.S. use of N,P,K was obtained from FAOSTAT for 2022, which is the year closest to the USDA’s survey for 2023. Query: Fertilizers by Nutrient/ U.S./ Agricultural Use. Total N nitrogen = 25,190,096,882 lbs.; Total P phosphorus = 8,095,913,625 lbs.; Total K Potassium = 9,415,672,525 lbs. (lbs. converted from metric tons)]
Share of soybeans used for animal feed is calculated at 58%. This includes exports used for animal feed and soybean meal for animal feed. See Share of Soybean Crop to Feed.
The share of chemical fertilizers used on both corn and soybeans going to animal feed is ~32% of all U.S. nitrogen use, ~47% of phosphorus, and ~49% of potassium.[1-3]
Note: For corn & soybean total use, since the USDA collects fertilizer information for crops on a rotating basis, we use the most recent year for which the agency has data: 2021 for corn and 2023 for soybeans. For total use of all nutrients in the U.S., we use the average of 2021 and 2022 (the most recent) data from the FAO.
The total U.S. use of N,P,K obtained from FAOSTATS [Inputs/Fertilizers by Nutrient/United States/2021 and 2022]
Fertilizer (N,P,K) applied to corn for 2021 and Soybeans for 2023 from USDA NASS QuickStats: [Survey/Environmental/Corn/Fertilizer/applications/2021 and Soybeans/Fertilizer/applications/2023]
A 2018-2019 analysis reported that total usage on vegetables, fruits, and pulses (i.e, beans, lentils and peas) accounted for about 3% of nitrogen, 4% of phosphorus, and 6% of potassium.
Compared to this group of foods, during the same period surveyed, corn and soybeans used:
~14 times more nitrogen ~17 times more phosphorus ~14 times more potassium.[2]
Ludemann, C. et al., (2022) Global data on fertilizer use by crop and by country, Data files/Country tables. Dryad. published by the International Fertilizer Association through IFASTAT. [See Data files for Country Tables — Mineral FertiIizer Use by Crop. N 413,437MT/ 11,347,070 = 3.64%; P 165,067/ 3,931,740 = 4.20%; K 249,672/ 4,405,290 = 5.67%]
Ludemann, C. et al., (2022) [Corn and Soy together = 52.0% of N, 70.2% of P, 77.4% of K. Calculation: For N, 52.0/ 3.6 = ~14 times. For P, 70.2/ 4.2 = ~17 times. For K, 77.4/ 5.7 = ~14 times]
Chemical fertilizers (N, P, K), are widely used on alfalfa and other types of hay, all of which goes to animal feed.[1-3] Though hay is the nation’s 3rd largest crop, the USDA does not survey for the amount of fertilizer applied.[4]
Fertilizers are applied to wheat as well as many secondary crops that are partially used for animal feed, including sorghum and barley.[5-8]
Stan Smith, Ohio State University Extension (2013) Fertilizing Hay Fields, No Matter How You Slice It, It’s P to K, 1 to 4, 13 to 50! [In Ohio, recommending about 39 pounds of P and 150 pounds of K per acre]
Crop Quest (2017) Fertility Requirements of Alfalfa Production. [In Kansas, recommending about 318 pounds of nitrogen, 72 pounds of phosphorus, and 300 pounds of potassium per acre]
Univ of Minnesota Extension (2023) Fertilizing Alfalfa in Minnesota.
The reasons may be that a) hay is not used as human food and b) the number of farms growing forage crops is about 7 times the total number growing corn and soybeans, making surveys particularly time consuming.
In 2022, ~3.8 billion pounds of N,P,K pounds of fertilizer was applied to wheat of which ~11% went to animal feed. [Survey/Environmental/Winter Wheat & Spring Wheat (excluding Duram)/Fertilizer/applications, measured in lb./2022, USDA National Agricultural Statistics Service Quick Stats]
In 2019 about 445 million lbs. of N,P,K fertilizers were applied to sorghum of which we estimate ~72% went to animal feed. [Survey/Environmental/Sorghum/Fertilizer/applications, measured in lb./2019, USDA National Agricultural Statistics Service Quick Stats]
In 2023, ~290 million lbs. of N,P,K were applied to barley of which we estimate ~30% went to animal feed. [Survey/Environmental/Barley/Fertilizer/applications, measured in lb./2023) USDA National Agricultural Statistics Service, Quick Stats]
For animal feed percentages, see Share of Hay and Wheat for Feed and Share of Secondary Crops for Feed
For each American, about 128 total lbs. of nitrogen, potassium, and phosphorus were applied to U.S. croplands in 2022.[1,2]
The total U.S. use of N,P,K obtained from FAOSTAT [Inputs/Fertilizers by Nutrient/United States/2022. Total N,P, K = 42,701,683,031 lbs.]
U.S. Census Bureau, U.S. and World Population Clock. [At the end of 2022, the U.S. population was 334,130,076. Total fertilizer use in the U.S. of 42,701,683,031 lbs. / 334,130, 076 == 127.8]