Layered and reduced fertilization enhances high-quality, high-yield, and efficient peanut production

Optimizing fertilization is essential for achieving sustainable crop production and improving fertilizer use efficiency (FUE). Layered fertilization, which strategically distributes nutrients within the soil profile, has the potential to promote root development and enhance both yield and FUE. However, its effects in peanut ( Arachis hypogaea L.) remain largely unexplored, leaving its role in nutrient management for this globally important legume unclear. This study tested the hypothesis that layered fertilization increases peanutyield and FUE by modifying root morphology and physiological activity. The experiment included two conventional fertilization controls: farmer's broadcast fertilization (BC) and BC combined with deep soil loosening to 25 cm (BCT), both receiving 750 kg ha −1 of compound fertilizer (N–P 2 O 5 –K 2 O, 15–15–15). Two layered fertilization schemes were evaluated: double-layered (10 and 25 cm, DLF) and triple-layered (10, 15, and 25 cm, TLF), each applied at 100 %, 90 %, or 80 % of the control rate, resulting in six treatments: DLF100, DLF90, DLF80, TLF100, TLF90, and TLF80. Both BC and BCT exhibited similar effects on the measured parameters. Layered fertilization significantly enhanced root growth, physiological activity, and antioxidant enzyme function compared with BC and BCT. Treatments DLF100, DLF90, TLF100, and TLF90 increased pod yield by 8.4–17.3 %, while DLF100 and TLF100 improved the oleic/linoleic acid ratio by 6.5–12.7 %. Partial factor productivity, agronomic efficiency, fertilizer contribution rate, and nitrogen-use efficiency were increased by 16.6–33.5 %, 40.6–60.3 %, 11.8–36.5 %, and 2.6–18.0 percentage points, respectively, under layered fertilization compared with BC and BCT. And net income was significantly elevated by 16.7 %, 8.3 %, 18.4 %, and 11.2 % under DLF100, TLF100, DLF90, and TLF90, respectively. The partial least squares path model (PLS-PM) analysis revealed that layered fertilization strategies and rates shaped root traits (explaining 61.0–70.1 % of the variation), which subsequently accounted for 90.4–93.6 % of pod yield and 87.0–95.1 % of kernel quality variation. Layered and reduced fertilization improved peanut yield, kernel quality, and FUE through coordinated enhancement of root morphology and physiology. Given its operational simplicity and economic advantages, DLF100 or DLF90 is recommended over TLF for practical application. This study provides a more efficient fertilization strategy for peanut production, reducing fertilizer input while enhancing yield, quality, and FUE. • Layered fertilization at 100 % or 90 % rates enhanced root traits and improved peanut yield and FUE. • DLF100 and DLF90 increased yield by 8.4–17.3 % and net income by 16.7–18.4 %. • Key fertilizer efficiency indicators (PFP, AE, FCR) increased by up to 11.8–60.3 %. • Root traits explained >90 % of variation in yield and kernel quality. • DLF matched TLF agronomically but exhibited superior economic performance.