Nitrogen, phosphorus, potassium, magnesium, and sulphur requirements for maize grain production

Nitrogen, phosphorus, potassium, magnesium, and sulphur requirements for maize grain production were investigated at 7 sites selected in the Waikato, Bay of Plenty, and Poverty Bay to provide a range in soil nutrient status. High grain yields were achieved without pre‐plant or starter fertiliser in Poverty Bay and using only 20–25 kg of Nand P as starter in the Waikato and the Bay of Plenty. It was concluded that no pre‐plant P is required if the Olsen P test is 15 or above, and no pre‐plant K is required if the K soil test is above 4. No evidence was found to support Mg or S applications to maize. The influence of soil N on the chemical composition of the maize plant, and its implications in diagnosis of nutrient deficiencies using tissue analysis, is discussed.