Abstract: To promote the upgrading, popularization and application of water-fertilizer integrated fertilization schemes, a field experiment was conducted using spring maize (Zea mays L.) variety Dika 159 as the test material. Five treatments were arranged in a randomized complete block design: CK (conventional liquid fertilizer), T1 (conventional liquid fertilizer + 18 L/hm² seaweed extract), T2 (conventional liquid fertilizer + 36 L/hm² seaweed extract), T3 (conventional liquid fertilizer + 54 L/hm² seaweed extract), and T4 (conventional liquid fertilizer + 72 L/hm² seaweed extract). Root indices, plant height, stem diameter, leaf area, chlorophyll relative content (SPAD value), grain yield and its components were measured. The results showed that T3 performed the best in root parameters. Compared with CK, total root length, total root surface area and total root volume under T3 were significantly increased by 217.83%, 123.91% and 68.65%, respectively. For plant growth, plant height, stem diameter, leaf area and SPAD value in T3 were improved by 7.09%, 4.33%, 6.13% and 8.36%, respectively, relative to CK. In terms of yield, T3 significantly increased grain yield by 13.16% and achieved the highest economic benefit with a 26.60% increase in net income compared with CK. In conclusion, the combined application of conventional liquid fertilizer and seaweed extract could significantly promote root development and plant growth of dryland maize, and ultimately enhance grain yield and economic benefits. The optimal application rate was 54 L/hm² of seaweed extract.

Key words: seaweed extract, liquid fertilizer, dryland maize (Zea mays L.), growth, yield, agronomy traits