Nutrient Removal from Corn Silage Harvest

Edwin Ritchey, Extension Soil Scientist, University of Kentucky

Assumptions made: 

Nutrient removal at standard harvest moisture per ton of corn silage as reported in AGR-1, Table 5:

• Nitrogen = 7.5 lbs/ton
• P₂O₅ = 3.5 lbs/ton
• K₂O = 8 lbs/ton

Pounds of N, P2O5, and K2O removed in silage at various silage yields.
	Amount of Silage Removed per Acre
Nutrient	5 tons/A	10 tons/A	15 tons/A
Nitrogen	37.5	75	112.5
P2O5	17.5	35	52.5
K2O	40	80	120

Greatest removal will be for potash.  Make sure to soil sample if silage is not typically in your rotation, potash removal will be greater than for corn for grain.

Typically, we don’t account for nitrogen removal or carryover to other crops with the exception of wheat.  Usually, wheat following well-fertilized corn should have enough nitrogen for fall growth. With limited nitrogen uptake this year in the corn, nitrogen in the fall for wheat (or other fall-seeded crops) should be sufficient. Monitor wheat growth. If the wheat appears to be N limited, then apply more than 40 lbs N/A in the fall.