Background and aims: Localized supply of P plus ammonium improves root-proliferation and nutrient-uptake by maize (Zea mays L.) at seedling stage, but it is largely unknown how localized supply of nutrients at both early and late stages influences maize-growth, nutrient-uptake and grain-yield. Methods: A 2-year field experimentation with maize was conducted with localized application of P plus ammonium as diammonium phosphate (LDAP) or ammonium sulfate plus P (LASP) at sowing or jointing stage, with broadcast urea and P (BURP) or no nitrogen (F0) as controls. Results: Localized supply of P plus ammonium significantly increased root-proliferation, shoot dry-weight and nutrient-uptake at seedling stage. The positive effect disappeared at 53 days after sowing. However, plant-growth and nutrient-uptake increased again after the second localized application of P plus ammonium at jointing. The density and average length of the first-order lateral roots in local patches increased by 50 % in LDAP and LASP compared with F0 and BURP. Maize-yield increased by 8-10 % compared with BURP. Agronomic N efficiency and N-use efficiency increased by 41-48 % and 25-57 % compared with the BURP. Conclusions: It is suggested that enhanced root-proliferation in the nutrient-rich patches with localized supply of ammonium and P at sowing and jointing stages is essential for improving nutrient-uptake and ultimately grain-yield. © 2013 Springer Science+Business Media Dordrecht.