Effects of one-time application of controlled-release compound fertilizer on peanut yield and nitrogen loss in sloping farmland

Introduction Nitrogen (N) loss via surface runoff is a critical issue in sloping farmland, contributing to non-point source pollution and limiting crop productivity. In peanut (Arachis hypogaea L.) production, improving nitrogen use efficiency (NUE) while minimizing environmental risks is essential for achieving sustainable agricultural development. Controlled-release compound fertilizers (CRF) may provide a promising approach to synchronizing N release with crop demand and reducing nutrient losses in runoff. This study aimed to evaluate the effects of one-time basal application of CRF on N runoff losses, NUE, and peanut yield in sloped peanut fields. Methods A two-year field experiment was conducted in Linyi, Shandong Province, using the peanut variety ‘Huayu 25’. Treatments fertilizers included CRF and conventional compound fertilizer (CF), both with an N-P 2 O 5 -K 2 O ratio of 15-15-15, applied at two application rates (800 and 560 kg hm -2 , representing 100% and 70% of the recommended rate) for both CRF and CF, along with a no-fertilizer control. Fertilizer release characteristics, peanut biomass and N uptake, and surface runoff nitrate (NO 3 − –N) and ammonium nitrogen (NH 4 + –N) concentrations and peanut yield were assessed. Results Compared with 100%CF treatment in 2022 and 2023, 100%CRF treatment significantly reduced NO 3 − –N and NH 4 + –N concentrations in runoff by 21.6%–38.1% and 7.7%–63.6%, respectively, while increasing dry matter accumulation by 10.9%–12.2%, N uptake by 5.9%–6.0%, and NUE by 39.9%–40.5%. Kernel yields of 100%CRF were 6.3%–13.8% higher than those under 100%CF. Notably, the 70% CRF treatment still outperformed the 100%CF treatment in terms of yield, with increases by 3.5%–7.1% across the two years. The results highlight the potential of CRF to improve NUE and sustain or even enhance yield under reduced N inputs, offering a viable strategy for environmentally responsible and productivity-enhancing fertilization in sloping agroecosystems. Discussion The findings indicate that CRF can simultaneously improve crop productivity and mitigate environmental pollution risks in sloping agroecosystems. Reduced-rate CRF application has strong potential as a sustainable fertilization strategy for peanut production, contributing to efficient nutrient management and environmentally responsible agriculture.