Effects of compound fertilizer granulation processes on maize yield, nutrient use efficiency, and soil properties

Although fertilization optimization is vital for enhancing crop yield and agricultural sustainability, the influence of compound fertilizer granulation processes on productivity and environmental outcomes is frequently disregarded. This study aimed to elucidate the impact of compound fertilizers produced via different granulation processes (spray granulation (SG), novel needle granulation (NNG), high-tower granulation (HTG), and drum granulation (DG)) with identical nutrient levels (N: P₂O₅: K₂O = 15:15:15) on maize ( Zea mays L.) productivity and the environment, as well as the related underlying mechanisms. A field experiment was conducted on red soil in Southwest China to systematically compare the effect of no fertilization (CK) and that of the four compound fertilizers on maize growth, yield, nutrient uptake, fertilizer nitrogen use efficiency (NUE), phosphorus use efficiency (PUE), and potassium use efficiency (KUE), soil profile nutrient distribution, and nitrogen (N) and phosphorus (P) leaching risks. The results showed that granulation processes significantly altered the physicochemical properties of fertilizers, subsequently affecting crop performance. NNG fertilizer, characterized by the fastest dissolution rate (DR) and lowest particle compressive strength, significantly increased maize yield (12156.8 kg·hm⁻², a 44% increase over CK) and NUE, PUE, and KUE (41%, 23%, and 18%). Therefore, it outperformed other processes in both yield and nutrient use efficiency and exhibited the lowest N leaching risk among the fertilizer treatments. Conversely, DG fertilizer, with the slowest DR, demonstrated the poorest agronomic performance. This study indicated that compound fertilizer granulation processes are essential for regulating crop yield and nutrient efficiency. The NNG process offers a novel pathway for producing high-yield, high-efficiency, and environmentally friendly compound fertilizers, holding significant importance for optimizing nutrient management and sustainable agricultural development.