Fertiliser application during the growing season with high nutrient uptake is required for efficient fertilizer use. This is particularly true for phosphate fertilisers. In order to eliminate the risk of phosphate fixation (insolubilization) or leaching of nitrates, sulphates and potassium, it is crucial that nutrients are applied just when they are needed.
In the regrowth period at the end of winter, after a long period of cold and damp weather, nutrient availability in the soil is at its lowest, while needs are at their highest. The addition of fertilizer is crucial, because the soil can only provide a limited amount of nutrients when mineralization of organic matter is slow at low temperatures. Further, the supply from the soil is insufficient during the growth period.
During stem elongation, wheat takes up 1kg P2O5 per hectare per day, and over 1.5kg N/ha/day. Fertilization at the end of winter with NPK+S fertiliser optimises the cost of spreading, while the high quality of the product optimises the spreading itself. NPK fertiliser spreading at the start of the growth period allows rapid vegetative development, to guarantee yield and quality in the long term. NPK application in the spring also helps maintain soil fertility.
At the end of stem elongation (in May or June), the last nitrogen application is often impaired by adverse weather conditions. The risk of ammonia volatilization is high when rainfall is insufficient (below 10mm) during the three days following spreading of urea. The nitric nitrogen form is not susceptible to gaseous ammonia losses and is the preferred nitrogen form of crops. Ammonium nitrate is rich in nitric nitrogen, which facilitates the most efficient use. This has been corroborated by many agricultural trials: