The plant’s efficient use of nitrogen implies that, once established, the crop will require relatively low annual application rates. Nitrogen fertilizer is not needed in the first two years and is counterproductive by encouraging greater weed growth during establishment. Soils should have phosphorus and potassium levels adequate for corn planting. Nutrient application should be adjusted to replace the amounts exported in harvested biomass, though optimal rates are still being tested.
Annual estimated nutrient removal:
• Phosphorus – 1.5 lbs. per ton of biomass
• Potassium – 8 lbs. per ton of biomass
• Nitrogen – 8 to 10 lbs. per ton of biomass