ABSTRACT Human waste contains ample plant-available nitrogen (N) and phosphorus (P), which can be used to address soil nutrient deficiencies. Biological and thermochemical sanitization methods have been proposed for safely treating the solid fraction of human waste (called human solid waste [HSW] in this study) but have rarely been compared directly. Furthermore, interactions between amendments and soil properties are also unclear, as pH, texture, and the presence of oxides all affect N and P availability. We therefore evaluated the effect of three HSW sanitization methods, thermophilic composting (60°C), torrefaction (200°C), and pyrolysis (300°C, 500°C), on N and P availability following incubation in four soils with different pH (4.6–7.4), textures (clay loam to loamy fine sand), and mineralogy. We also evaluated the effect of added urine with pyrolyzed HSW (500°C) on N and P availability in soils. A trade-off between N and P availability was observed with highest heating temperature of HSW, the magnitude of which varied with soil type. Compared with pyrolyzed HSW (500°C), composted HSW increased available soil N by 15% to 25%, whereas torrefied HSW increased available soil N by 40% to 57%. The change in P availability over time increased with pyrolyzed HSW (500°C) by 41% to 106% and 84% to 165% compared with composted and torrefied HSW, respectively. Multivariate linear regression highlighted the negative correlation between P availability and both soil oxides and amendment dissolved organic carbon. Combined fertilization with pyrolyzed HSW (500°C) and urine ameliorated low N, while preserving high soil P availability, which was 44% to 147% greater than soils fertilized with urine alone. Pyrolyzed HSW (500°C) lowered pH by 0.06 to 0.38 units compared with urine-amended soils with no pyrolyzed HSW. In conclusion, low N and P availability was observed with composted HSW (29–46 kg N ha−1, 6–15 kg P ha−1); ample N and moderate P were available with torrefied HSW (71–107 kg N ha−1, 12–30 kg P ha−1), whereas excess mineral N and ample P were provided in soils amended with pyrolyzed HSW (500°C) together with urine (404–486 kg N ha−1, 33–81 kg P ha−1) albeit at the expense of mild soil acidification.

中文翻译：

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不同质地和 pH 值的土壤中生物和热化学分解的人类废物和尿液的氮和磷可用性

摘要 人类排泄物含有充足的植物可用氮 (N) 和磷 (P)，可用于解决土壤养分缺乏问题。已经提出了生物和热化学消毒方法来安全处理人类废物的固体部分（在本研究中称为人类固体废物 [HSW]），但很少直接进行比较。此外，改良剂和土壤特性之间的相互作用也不清楚，因为 pH 值、质地和氧化物的存在都会影响 N 和 P 的可用性。因此，我们评估了三种 HSW 消毒方法，即高温堆肥 (60°C)、烘焙 (200°C) 和热解 (300°C、500°C) 在四种不同土壤中培养后对 N 和 P 有效性的影响。 pH (4.6–7.4)、质地（粘土到壤质细沙）和矿物学。我们还评估了添加尿液和热解 HSW (500°C) 对土壤中 N 和 P 有效性的影响。在 HSW 的最高加热温度下观察到 N 和 P 可用性之间的权衡，其大小因土壤类型而异。与热解 HSW (500°C) 相比，堆肥 HSW 使土壤有效 N 增加了 15% 至 25%，而烘焙 HSW 将有效土壤 N 增加了 40% 至 57%。与堆肥和烘烤的 HSW 相比，热解 HSW (500°C) 的 P 可用性随时间的变化分别增加了 41% 到 106% 和 84% 到 165%。多元线性回归强调了 P 有效性与土壤氧化物和改良剂溶解有机碳之间的负相关。结合施肥与热解 HSW (500°C) 和尿液改善低氮，同时保持高土壤磷可用性，这比仅用尿液施肥的土壤高 44% 至 147%。与没有热解 HSW 的尿液改良土壤相比，热解 HSW (500°C) 将 pH 值降低了 0.06 至 0.38 个单位。总之，使用堆肥 HSW（29-46 kg N ha-1，6-15 kg P ha-1）观察到低 N 和 P 可用性；充足的 N 和适量的 P 可通过烘焙的 HSW（71-107 kg N ha-1，12-30 kg P ha-1）获得，而过量的矿物 N 和充足的 P 在用热解 HSW (500°C) 修正的土壤中提供连同尿液（404-486 kg N ha-1，33-81 kg P ha-1），尽管以轻度土壤酸化为代价。