Enter what you're putting down and the yield you're chasing. See what the crop hauls off in grain, per acre.
Units = pounds of nutrient per acre. P and K are in the oxide form (P₂O₅, K₂O), the same way a fertilizer grade is written.
Covering more than one season with this application (e.g. fall P & K for corn then beans)? Add each crop year and removal is totaled.
| Crop | N | P₂O₅ | K₂O | S |
|---|
Pounds removed per bushel of grain, or per ton of silage at about 65% moisture. These are typical published values; edit them to match your university or lab numbers.
How many pounds of surplus or deficit it takes to move the soil test 1 ppm (Bray or Mehlich-3). Common rules of thumb are about 18 for P and 8 for K. Real soils vary a lot, often 10–25 for P and 4–15 for K, depending on texture, CEC and clay type.
Positive numbers build soil levels; negative numbers draw them down. The ppm change is a rough estimate that splits the surplus or deficit evenly across the crop years and divides by the soil-test assumptions (edit these under Removal rates). Removal is one input to a plan. It doesn't account for soil test levels, N losses, or baling stover after grain corn, and corn N rates are usually set by N-rate guidelines (such as MRTN) rather than removal.