Agronomy Tech Tips: Phosphorus & Potassium Removal for Grain & Stover

Effective nutrient management starts with soil testing to guide fertilizer and manure use.

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Balanced soil fertility supports yield performance and long-term soil health.

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Below are typical removal rates for P₂O₅ and K₂O from grain alone vs. grain + stover harvest. Actual removal varies by crop, yield, and residue removed.

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Phosphorus (P₂O₅) Removal

• Corn grain: 0.32 lbs P₂O₅/bu. 230 bu/acre = ~73.6 lbs/acre

• Corn stover: ~4.8 lbs P₂O₅/ton (15% moisture). 5 tons/acre + 230 bu = ~97.6 lbs/acre total

• Soybean grain: 0.72 lbs P₂O₅/bu. 65 bu/acre = ~46.8 lbs/acre

• Soybean stover: ~4.7 lbs P₂O₅/ton (10% moisture). 2 tons/acre + 65 bu = ~56.2 lbs/acre total

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Potassium (K₂O) Removal

• Corn grain: 0.22 lbs K₂O/bu. 230 bu/acre = ~50.6 lbs/acre

• Corn stover: ~18 lbs K₂O/ton (15% moisture). 5 tons/acre + 230 bu = ~140.6 lbs/acre total

• Soybean grain: 1.2 lbs K₂O/bu. 65 bu/acre = ~78 lbs/acre

• Soybean stover: ~23 lbs K₂O/ton (10% moisture). 2 tons/acre + 65 bu = ~124 lbs/acre total

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Residue Harvest Timing Matters

Potassium is highly soluble and can leach from stover during rainfall.

• Baled before rain → more K removed from field

• Baled after rain → more K returned to soil

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