How much fertilizer can be placed safely with seed?
Even though this may seem like a simple question, the answer is complex. Fertilizer source, seeding equipment, soil properties and conditions, crop type, seed quality, and risk factors must all be considered before this question can be answered. Fertilizer source Seed-placed fertilizer causes damage through ammonia toxicity and/or “salt effects”. Urea (46-0-0) and liquid UAN (urea ammonium nitrate, usually 28-0-0) are fertilizers that primarily cause ammonia toxicity in the seedrow. Salt effects are usually associated with ammonium sulphate (21-0-0-24 or similar analyses), potash, ammonium nitrate and ammonium phosphate. Cereals, oilseeds, pulses, and grasses suffer permanent damage if exposed to high concentrations of ammonia. Small seeded crops like canola or flax are permanently damaged by high salt concentrations in the seedrow. Salt effects may delay cereal germination and emergence but with salt dilution through rainfall, these crops will recover and grow normally. Most seed-plac
