Standard Urea Application Rates for Crops
Urea, with 46% nitrogen content, is applied at 100-200 pounds per acre (112-224 kg/ha) for most field crops like corn or wheat, depending on soil tests and yield goals. This delivers 46-92 pounds of actual nitrogen (N) per acre. Rates increase to 300-400 pounds per acre for high-demand crops like rice on flooded fields.[1]
How Much Urea Per Acre by Crop Type
- Corn: 150-250 pounds/acre pre-plant or sidedress, targeting 120-150 pounds N/acre total.
- Wheat: 100-150 pounds/acre at planting or topdress.
- Cotton: 80-120 pounds/acre, split into 2-3 applications.
- Pasture/Forage: 50-100 pounds/acre after grazing or mowing.
Adjust based on soil nitrogen levels; overapplication risks leaching.[1][2]
Factors Affecting Urea Dosage
Soil type, pH, moisture, and organic matter dictate rates—sandy soils need 20-30% less to avoid losses. Test soil annually; aim for crop-specific N removal rates (e.g., corn removes 1 pound N per bushel yield). In no-till systems, cut rates by 10-20% due to residue effects.[2]
Urea vs. Other Nitrogen Fertilizers
Urea costs less per pound of N than ammonium nitrate (34% N) or UAN (28-32% N), but requires incorporation within 4-10 days to minimize volatilization losses (up to 30% if surface-applied on dry soils). Use urease inhibitors like NBPT to boost efficiency by 15-25%.[1][3]
Application Methods and Timing
Broadcast and incorporate immediately, or use fertigation/injection for precision. Split applications (e.g., 50% pre-plant, 50% sidedress) reduce losses. Apply in cool, moist conditions; avoid hot, dry weather.[2]
Risks of Over- or Under-Dosing
Excess urea causes nitrate leaching, groundwater pollution, and ammonia burn on leaves. Deficiency stunts growth and cuts yields by 20-50 bushels/acre in corn. Follow extension service guidelines for local rates.[3]
[1]: University of Minnesota Extension - Fertilizer Urea
[2]: USDA NRCS - Nutrient Management
[3]: Purdue Extension - Nitrogen Fertilizers