Calculate N, P₂O₅, and K₂O removed by harvested crops based on yield and crop-specific nutrient content. Plan maintenance fertilization.
The Nutrient Removal by Crop Calculator estimates how much nitrogen, phosphorus (as P₂O₅), and potassium (as K₂O) are removed from the field by the harvested portion of the crop. Every bushel of grain, ton of hay, or hundredweight of produce carries nutrients away from the field that must eventually be replaced to maintain soil fertility.
Nutrient removal is the baseline for maintenance fertilization — the amount needed to keep soil test levels stable. When soil tests are at optimum levels, simply replacing crop removal is the most economical fertilizer strategy. When building or drawing down soil fertility, the removal rate is adjusted up or down accordingly.
This calculator stores nutrient concentrations for common crops and computes total removal at your entered yield. The data reflects published university extension values for nutrient content of harvested grain, forage, and produce. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation.
Nutrient removal data is the foundation of fertility budgets. If you don’t replace what the crop takes, soil fertility declines. If you add much more than removal, you waste money and risk environmental problems. Matching inputs to removal is smart, sustainable farming. Having a precise figure at your fingertips empowers better planning and more confident decisions.
Nutrient removed (lbs/ac) = Yield (units/ac) × Nutrient content (lbs/unit) Example for corn grain: N removal = Yield (bu) × 0.67 lbs N/bu P₂O₅ removal = Yield (bu) × 0.37 lbs P₂O₅/bu K₂O removal = Yield (bu) × 0.27 lbs K₂O/bu
Result: N: 134, P₂O₅: 74, K₂O: 54 lbs/ac removed
At 200 bu/ac corn: N = 200 × 0.67 = 134 lbs. P₂O₅ = 200 × 0.37 = 74 lbs. K₂O = 200 × 0.27 = 54 lbs. These amounts must be replaced to maintain soil fertility.
Published removal rates are averages from university research. Corn grain: 0.67 N, 0.37 P₂O₅, 0.27 K₂O per bushel. Soybeans: 3.3 N, 0.80 P₂O₅, 1.4 K₂O per bushel. Wheat: 1.2 N, 0.55 P₂O₅, 0.30 K₂O per bushel. Alfalfa hay: 50 N, 13 P₂O₅, 50 K₂O per ton.
A nutrient budget balances inputs (fertilizer, manure, fixation, mineralization, deposition) against outputs (crop removal, leaching, runoff, volatilization, denitrification). When inputs exceed removal, soil fertility builds. When removal exceeds inputs, it declines. The goal is to match inputs to removal plus any needed build.
High-yield zones remove more nutrients than low-yield zones in the same field. Variable-rate fertilization matches inputs to zone-specific removal rates, preventing over-application in low-yield areas and under-application in high-yield areas.
No. Uptake is the total nutrients absorbed by the plant. Removal is only the portion that leaves the field in the harvested product. Stover, roots, and dropped leaves return nutrients to the soil. Removal is typically 50–75% of uptake for grain crops.
When soil tests are at optimum levels, yes — replace removal to maintain fertility. If soil test P or K is at or above optimum, you can skip a year or apply less. If below optimum, apply more than removal to build levels.
Corn silage removes the entire above-ground plant: 20–25 tons/ac of silage removes roughly 180–250 lbs N, 80–100 lbs P₂O₅, and 200–280 lbs K₂O per acre — about 2–3× grain removal. The high potassium removal from silage is especially important to monitor, as soil K levels can decline rapidly on continuous silage fields. Planning a higher fertilizer budget for silage acres is essential to maintain long-term soil fertility.
Somewhat. High-protein wheat varieties remove more N per bushel. High-oil corn removes more N and P. However, the standard values are close enough for fertilizer planning because variety effects are typically <10%.
Micronutrient removal is much smaller: corn removes about 0.1 lbs Zn per 100 bu, and 0.01 lbs B. At these low rates, soil reserves and organic matter recycling usually maintain adequate levels, but high-yield operations should monitor.
If stover stays in the field (grain harvest), those nutrients recycle and don’t need replacement. If stover is baled and removed, add stover nutrient content to grain removal for total field export.