针对单一原料生物炭的局限性（秸秆基生物炭养分较贫乏，猪粪基生物炭存在重金属积累风险），创新性地采用秸秆与猪粪共热解的方式制备生物炭（Co-pyrolyzed Biochar，CPB）。对CPB特性分析结果显示，CPB的比表面积达到21.58 m²/g，较猪粪基生物炭（Pig Manure-based Biochar，PMB）的 8.54 m²/g有大幅提升；同时，CPB中氮（N）、磷（P）、钾（K）等养分含量均高于秸秆基生物炭（Crop Straw-based Biochar，CSB），尤其是P、K含量分别提高了 262.30%和 282.70%。深入研究CPB不同施用量对水稻田土壤肥力、酶活性以及水稻生长状况的结果表明，CPB成功整合了秸秆的高比表面积（21.58 m²/g）与猪粪的丰富矿质养分（P含量为 18.55 g/kg、K含量为 33.56 g/kg），并且其重金属含量较PMB显著降低（Cd、As含量分别减少41.90%和 28.00%）。在不同施用量中，以2%的施用量（CPB2）效果最为显著：与对照（CK，0）相比，土壤有效P和速效K含量分别显著提高74.82%和72.83%，有机质和全N含量分别增加12.70%和9.49%；土壤磷酸酶和过氧化氢酶活性分别提升51.19%和 23.34%；水稻增产8.37%。通过土壤综合肥力指数（Integrated Fertility Index，IFI）评估发现，CPB2处理使土壤肥力等级从Ⅲ级（CK，IFI值为0.56）提升至Ⅱ级（IFI值为0.68），其中速效K是关键驱动因子，权重为 0.112。此外，所有处理组的重金属含量均低于国家标准（Cd含量≤0.60 mg/kg），内梅罗综合指数（Pollution Index，PI）均小于0.70，表明不存在污染风险。然而，3%施用量处理（CPB3）由于微孔堵塞以及养分竞争吸附等原因，其增产效果（3.59%）显著低于CPB2处理。本研究证实，共热解生物炭通过“碳-灰分协同效应”（即多孔碳结构负载矿质养分）优化了土壤的“养分-结构-酶活性”网络体系，其中2%的施用量是稻田系统中实现“高产-低风险”的最优阈值。

In view of the limitations of biochar made from single raw materials (crop straw-based biochar is relatively nutrient-poor, and pig manure-based biochar poses a risk of heavy metal accumulation), Co-pyrolyzed Biochar(CPB) was innovatively prepared through co-pyrolysis of straw and pig manure. The results showed that the specific surface area of CPB attained 21.58 m²/g, which was a substantial increase compared to that of Pig Manure-based Biochar (PMB) at 8.54 m²/g. Meanwhile, the contents of nitrogen, phosphorus, and potassium in CPB were all higher than those in Crop Straw-based Biochar (CSB), especially the phosphorus and potassium contents which increased by 262.30% and 282.70%, respectively. This study systematically and comprehensively explored the effects of CPB on soil fertility, enzyme activity, and rice growth in paddy fields. The research results indicated that CPB successfully integrated the high specific surface area of straw (21.58 m²/g) with the abundant mineral nutrients of pig manure(phosphorus content of 18.55 g/kg and potassium content of 33.56 g/kg). Moreover, its heavy metal content was significantly lower than that of PMB, with the contents of cadmium and arsenic decreased by 41.90% and 28.00%, respectively. Among the various application rates, the 2% application rate(CPB2) had the most remarkable effects: the contents of available phosphorus and rapidly available potassium in the soil increased significantly by 74.82% and 72.83%, respectively, compared to the control (CK, 0); the contents of organic matter and total nitrogen increased by 12.70% and 9.49%, respectively; the activities of soil phosphatase and catalase increased by 51.19% and 23.34%, respectively; and the rice yield increased by 8.37% compared to CK. Evaluation using the Integrated Fertility Index (IFI) revealed that the CPB2 treatment upgraded the soil fertility grade from Grade Ⅲ (CK, IFI value of 0.56) to Grade Ⅱ (IFI value of 0.68), with rapidly available potassium being the key driving factor with a weight of 0.112. The results of heavy metal pollution assessment showed that the heavy metal contents in all treatment groups were lower than the national standards (cadmium content ≤ 0.60 mg/kg), and the Nemerow Pollution Index (Pollution Index, PI) values were all less than 0.70, indicating no pollution risk. However, the 3% application rate treatment(CPB3) had a significantly lower yield increase effect (3.59%) than the CPB2 treatment due to micropore blockage and nutrient competitive adsorption. This study confirmed that co-pyrolyzed biochar optimized the “nutrient-structure-enzyme activity” network system of soil through the “carbon-ash synergistic effect” (i.e., porous carbon structures loading mineral nutrients). Among them, the 2% application rate was the optimal threshold for achieving “high yield-low risk” in paddy field systems.