A field experiment was conducted during the two successive summer seasons of 2022 and 2023 under sandy soil conditions at Ismailia Agricultural Research Station of Ismailia Governorate, Egypt. This study aims to investigate the effect of mineral N fertilizer application at three rates i.e. 50, 75 and 100 % from recommended dose and application of ammonium humatat four rates of N without humat, 10, 15 and 20 g N L^-1 (H₀, H₁₀, H₁₅ and H₂₀) along with two application methods (soil and foliar application) on the yield, yield components, chemical composition of maize plants (Zea maize L.) grown and available NPK in sandy soil. The obtained results indicated that grain and straw yields as well as content of available nutrients were affected significantly by increased levels of mineral N, rates of ammonium humat and application  methods. In most cases, the highest mean values in both grain and straw yields were recorded at the treatment of 75 % mineral N * H₂₀ with the foliar application, which gave results equal to or better than those received 100 % mineral N solo. A similar trend was detected with respect to NPK uptake by both grain and straw yields. Also, the highest of available NPK content in the soil due to the soil application of humat. In view of the above-mentioned results, it has been concluded that the efficiency of mineral N fertilizer increased with the application of ammonium humat as which with 20 g N L^-1 (foliar or soil addition) and reflected on the yield and chemical composition of maize plants and also, can be used as a partial substitute to 25 % of mineral – N fertilizer under sandy soil conditions.