Nutrient uptake and removal
Nutrient uptake refers to the quantity of plant essential nutrient required for the crop to reach maturity – what is taken up in the aboveground portion of the plant. Nutrient removal is the nutrient content of the harvested portion of the crop that is removed from the field. In crops like silage corn or alfalfa, nutrient uptake and removal are nearly equal, as most of the aboveground biomass is harvested.
Crop nutrient removal values are important for nutrient budgeting over a rotation, and can help in determining nutrient application rates for current or future crops. In general, fertilizing phosphorus (P) and potassium (K) below the rates at which they are removed from the field results in decreasing soil test levels over time. Conversely, fertilizing P and K above crop removal rates will increase soil test levels over time.
Table 1. Average nutrient removal by common field crops in Ontario
| Crop | Unit | N1 | P2O5 | K2O | Ca | Mg | S |
|---|---|---|---|---|---|---|---|
| Grains and oilseeds (at marketing moisture content) | |||||||
| grain corn | kg/t | 11.5–17.7 | 6.6–7.9 | 4.6–5.2 | 0.12 | 1.55 | 1.2–1.3 |
| lb/bu | 0.65–1.0 | 0.37–0.44 | 0.26–0.30 | 0.007 | 0.087 | 0.07 | |
| soybean | kg/t | 62.3–66.7 | 13.3–14.7 | 23.0–23.3 | 3.0–3.7 | 2.3–3.0 | 0.67 |
| lb/bu | 3.7–4.0 | 0.80–0.88 | 1.38–1.40 | 0.18–0.22 | 0.14–0.18 | 0.033 | |
| winter wheat | kg/t | 19.1–20.9 | 9.1–10.4 | 5.78–6.22 | 0.44 | 2.67 | 1.33 |
| lb/bu | 1.15–1.25 | 0.55–0.63 | 0.35–0.37 | 0.027 | 0.16 | 0.08 | |
| barley | kg/t | 17.3–23.1 | 5.21–8.33 | 4.79–7.22 | 0.56 | 1.11 | 1.67 |
| lb/bu | 0.83–1.11 | 0.25–0.40 | 0.23–0.35 | 0.027 | 0.053 | 0.08 | |
| oat | kg/t | 18.0-24.0 | 7.5 | 5.83–6.25 | 0.833 | 1.25 | 2.08 |
| lb/bu | 0.63–0.80 | 0.25 | 0.19–0.20 | 0.027 | 0.04 | 0.067 | |
| cereal rye | kg/t | 19.3–21.8 | 6.07–8.93 | 6.07–7.14 | 1.07 | 1.43 | 1.79–3.57 |
| lb/bu | 1.08–1.22 | 0.34–0.50 | 0.34–0.40 | 0.06 | 0.08 | 0.10 | |
| dry beans | kg/t | 41.6 | 13.8 | 13.8 | 1.12 | 1.12 | 2.78 |
| lb/bu | 2.50 | 0.83 | 0.83 | 0.067 | 0.067 | 0.167 | |
| canola | kg/t | 40.0–44.4 | 22.2–26.7 | 11.1–13.3 | 4.0–5.3 | 5.33–6.67 | 6.67 |
| lb/bu | 2.0–2.2 | 1.11–1.33 | 0.56–0.67 | 0.20–0.27 | 0.27–0.33 | 0.33 | |
| Grains and oilseeds — stover or straw (based on dry weight)2 | |||||||
| corn stover | kg/t | 8.0–10.6 | 2.1–6.4 | 17.4–20.0 | 3.5–13.4 | 2.5–8.6 | 1.3–1.7 |
| lb/ton | 16.0–21.2 | 4.1–12.8 | 34.8–39.9 | 7.0–11.4 | 5.0–17.2 | 2.6–3.4 | |
| soybean stover | kg/t | 8.0–23.0 | 1.0–4.4 | 8.7–19.0 | 15.0–17.3 | 4.1–8.6 | 3.1–6.5 |
| lb/ton | 4.0–46.0 | 2.0–8.8 | 17.4–37.9 | 30.0–34.6 | 8.1–17.2 | 6.2–13.0 | |
| winter wheat straw | kg/t | 4.4–9.6 | 1.0–4.9 | 12.0–23.2 | 1.6–10.4 | 0.4–7.1 | 2.7 |
| lb/ton | 8.8–19.2 | 2.0–9.8 | 24.0–46.4 | 3.2–20.8 | 0.7 | 5.4 | |
| barley straw | kg/t | 6.5-7.0 | 1.6-2.6 | 8.4-20 | — | — | — |
| lb/ton | 13.0-14.0 | 3.2-5.2 | 16.8-40 | — | — | — | |
| oat straw | kg/t | 6.0 | 3.2 | 19.0 | 2.4 | 0.7 | 2.3 |
| lb/ton | 12.0 | 6.4 | 37.9 | 4.8 | 1.3 | 4.5 | |
| cereal rye straw | kg/t | 6 | 6.1-8.2 | 6.3 | — | 0.3 | 1.0 |
| lb/ton | 12.0 | 12.2-16.4 | 12.5 | — | 0.6 | 2.0 | |
| Forages (based on dry weight)3,4 | |||||||
| corn silage | kg/t | 10.8–15.0 | 4.6–6.8 | 8.3–15.2 | 1.6–3.1 | 1.1–1.9 | 0.8–1.0 |
| lb/ton | 21.6–29.9 | 9.3–13.6 | 16.6–30.4 | 3.3–6.1 | 2.3–3.8 | 1.6–2.0 | |
| legume haylage | kg/t | 26.6–36.8 | 5.3–8.7 | 22.4–35.5 | 11.3–17.7 | 1.9–3.6 | 1.9–2.0 |
| lb/ton | 53.2–73.4 | 10.6–17.5 | 44.8–70.8 | 22.6–35.4 | 3.8–7.2 | 3.8–4.0 | |
| mixed haylage | kg/t | 22.8–33.9 | 5.2–7.8 | 22.4–35.6 | 9.5–16.4 | 1.6–3.4 | 1.5–2.9 |
| lb/ton | 45.6–67.6 | 10.4–15.6 | 44.8–71.0 | 19.0–32.8 | 3.2–6.8 | 3.0–5.8 | |
| grass haylage | kg/t | 16.2–27.4 | 4.9–7.8 | 20.4–35.9 | 5.3–11.3 | 1.3–2.6 | 0.8 |
| lb/ton | 32.3–54.8 | 9.8–15.5 | 40.8–71.8 | 10.5–22.5 | 2.5–5.3 | 1.6 | |
| legume hay, 1st cut | kg/t | 22.3–33.1 | 5.2–8.0 | 20.6–35.1 | 10.1–15.4 | 2.1–3.4 | 1.9–2.7 |
| lb/ton | 44.6–66.2 | 10.4–16.0 | 41.2–70.0 | 20.2–30.8 | 4.2–6.8 | 3.8–5.4 | |
| mixed hay, 1st cut | kg/t | 17.2–27.4 | 5.0–7.2 | 17.0–29.8 | 8.2–13.5 | 1.8–3.0 | 1.3–2.1 |
| lb/ton | 34.4–54.6 | 10.0–14.4 | 34.0–59.4 | 16.4–27.0 | 3.6–6.0 | 2.6–4.2 | |
| grass, 1st cut | kg/t | 10.2–22.7 | 4.4–7.0 | 13.9–28.1 | 5.3–10.6 | 1.4–2.6 | 1.4–2.0 |
| lb/ton | 20.5–45.3 | 8.8–14.0 | 27.8–56.0 | 10.5–21.3 | 2.8–5.3 | 2.8–4.0 | |
| mixed hay, 2nd cut5 | kg/t | 25.4–35.9 | 5.7–7.8 | 19.7–31.9 | 11.4–17.0 | 2.3–3.8 | 1.8–2.8 |
| lb/ton | 50.7–71.7 | 11.3–15.7 | 39.7–63.7 | 22.7–34.0 | 4.7–7.7 | 3.7–5.7 | |
1 Soybeans, dry beans, and forage legumes get most of their nitrogen from the air.
2 The range of P2O5 and K2O in cereal straw and dry hay will be reduced (leached) if heavy or frequent rainfall occurs while the material is in windrows in the field.
3 To convert from “as harvested” to “dry matter yield,” multiply the as-harvested yield by the dry matter content of the crop.
4 The range of N removal is large, because hay is harvested at a wide range of protein levels. Generally, higher protein means lower yield.
5 Second cut generally has a higher legume content.