How much of phosphorus need to be applied for crops?
Phosphatic fertilizers are applied to bring the available P2O5 to a critical limit for a crop. By critical limit is meant the level below which no economic responses are possible to applied phosphates. Knowing the initial soil test value and recovery of added phosphates, it will be possible to work out the amount of fertilizer phosphorus needed to build up the soil phosphate to a given critical limit. The critical value is found to be about 35 kg P2O5 per ha for crops like sorghum, pearl millet, rice, and maize. If the initial soil phosphorus level is high, then maintenance application will be enough. Compiled by Dr.
