Data_Sheet_1_A suitable organic fertilizer substitution ratio could improve maize yield and soil fertility with low pollution risk.docx

Organic fertilizer substitution (OFS) is an effective strategy for reducing the chemical fertilizer usage; however, the effects of different OFS ratios (OFSRs) on maize yield, soil fertility, and heavy metal pollution risk are still unclear. Therefore, determining a suitable OFSR is important. Through the pot experiment, no fertilizer (CK) and organic fertilizer substituting 0% (CF, chemical fertilizer alone), 8% (OF8), 16% (OF16), and 24% (OF24) of the chemical N fertilizer were set to investigate the effects of different OFSRs on maize growth and yield, soil properties (available nutrients, carbon fractions, and carbon pool indices), and nutrients and heavy metals in grain and soil. The results showed that OF8, OF16, and OF24 improved soil fertility by increasing soil organic carbon (SOC, by 10.05–16.26%) and its fractions, most middle- and micro-nutrients content, and carbon pool management index (CPMI, by 17.45–30.31%) compared with CF, while improving grain nutritional quality. However, they increased heavy metals content in grain and soil and their Nemerow comprehensive pollution index (NCPI, by 4.06–16.56% in grain and 2.55–5.57% in soil) but did not cause pollution. Among them, throughout the growth period, only OF8 treatment increased soil available nitrogen (AN), phosphorus (AP), and potassium (AK) content by 3.04–11.15%, 7.11–8.05%, and 0.12–6.05%, respectively, compared with CF, which thus significantly promoted maize growth and increased yield (by 35.65%); the NCPI of grain and soil was however lower than that OF16 and OF24. In conclusion, substitution ratio of 8% was considered ideal for promoting maize growth, improving yield and soil fertility, with a low pollution risk. The results of this study would aid in guiding the scientific application of OFS technology to agricultural production, thereby contributing to resource utilization of organic waste and sustainable agricultural development.

有机肥料替代（OFS）策略是降低化学肥料使用量的有效途径；然而，不同有机肥料替代比（OFSRs）对玉米产量、土壤肥力和重金属污染风险的影响尚不明确。因此，确定适宜的OFSr比例至关重要。通过盆栽试验，设置不施肥（CK）、仅用化学肥料（CF）、有机肥料替代化学氮肥的8%（OF8）、16%（OF16）和24%（OF24）作为试验组，以探究不同OFSr对玉米生长和产量、土壤特性（有效养分、碳组分和碳库指数）、以及谷物和土壤中养分和重金属含量的影响。结果显示，与CF相比，OF8、OF16和OF24通过提高土壤有机碳（SOC，增加10.05–16.26%）及其组分、大部分中微量元素含量以及碳库管理指数（CPMI，增加17.45–30.31%）来提升土壤肥力，同时改善谷物营养品质。然而，它们增加了谷物和土壤中的重金属含量及其Nemerow综合污染指数（NCPI，在谷物中增加4.06–16.56%，在土壤中增加2.55–5.57%），但并未导致污染。其中，在整个生长期间，仅OF8处理相较于CF，分别提高了土壤中可利用氮（AN）、磷（AP）和钾（AK）的含量3.04–11.15%、7.11–8.05%和0.12–6.05%，从而显著促进了玉米生长并提高了产量（增加35.65%）；然而，谷物和土壤的NCPI却低于OF16和OF24。综上所述，8%的替代比被认为是对促进玉米生长、提高产量和土壤肥力、降低污染风险理想的。本研究结果将有助于指导OFS技术在农业生产中的科学应用，从而促进有机废弃物的资源化利用和可持续农业发展。