Pathways for replacing chemical fertilisers (reliant on rock P resources) with alternative P-bearing materials require assessment of soil processes, crop nutrient acquisition and potential pollution consequences. We examined bioenergy waste materials, individually and as combined ash and anaerobic digestate in terms of plant P availability and mobility. We compared initial effects on mixing of amendments with a test soil and effects after 6-weeks pot trials, with and without wheat growth, against soil and chemical fertiliser controls. Chemical extractions, ³¹P NMR spectroscopic determination of P forms and phytase-labile P assays examined processes of P release. ³¹P NMR analysis revealed that ash comprised dominantly inorganic orthophosphate P with inherent low P solubility. Initial ash mixing with soils increased solution pH, soluble P in water (pure ash alone) and in citrate (ash alone and in blends). Digestate comprised a diverse array of orthophosphate and organically-complexed P forms, similar to the test soil P compositions, with limited P solubility on initial mixing. Following no plant incubations high water-soluble P with ash additions remained but all effects on citrate-soluble P were normalised. Incubations with plants increased water-soluble P in digestate only and blended amendment treatments relative to initial mixing. When comparing to chemical fertiliser the digestate plus ash blends led to smaller water-soluble P, but equal P in above-ground biomass after incubation. The ash-digestate C:N:P ratios and P form diversity appeared to promote microbial regulation of plant P availability versus potential leaching. The results suggest that the initial days-months are important periods for amendment interactions with soils during plant establishment and the lag before strong growth when system P mobility may induce polluted runoff. Biogeochemical P solubility controls require further study across differing soils and timescales to inform management of bioenergy wastes as fertilisers, particularly in terms of trade-offs such as crop nutrition versus system P losses.

用替代的含磷物质替代化学肥料（依赖于岩石磷资源）的途径需要评估土壤过程，作物养分获取和潜在的污染后果。我们根据植物P的有效性和迁移性，分别检查了生物能源废料，以及作为灰分和厌氧消化物的组合。我们比较了与试验土壤混合的改良剂的初始效果，以及有或没有小麦生长的6周盆栽试验与土壤和化肥对照的效果。化学提取，P形式的³¹ P NMR光谱测定和植酸酶不稳定的P分析检测了P释放的过程。³¹P NMR分析表明，灰分主要包含无机正磷酸盐P，固有的低P溶解度。最初的灰分与土壤混合会增加溶液的pH值，增加水中的P（仅纯灰分）和柠檬酸盐（单独的灰分和混合灰分）中的可溶性P。Digestate包含各种各样的正磷酸盐和有机络合的P形式，类似于测试土壤的P成分，初始混合时P的溶解度有限。在没有植物温育后，仍保留了添加有灰分的高水溶性磷，但对柠檬酸盐可溶性磷的所有影响均已归一化。与植物的孵育相对于初始混合，仅在消化物中和混合的修正处理中增加了水溶性磷。与化学肥料相比，消化液和灰分混合物产生的水溶性P较小，但孵育后地上生物量的P相等。灰烬C：N：磷的比例和磷形态的多样性似乎促进了植物对磷的利用和潜在浸出的微生物调控。结果表明，最初的数月是植物建立过程中与土壤间的修正相互作用的重要时期，而当系统P的流动性可能引起径流污染时，则是生长旺盛之前的滞后时期。生物地球化学磷的溶解度控制措施需要在不同的土壤和时间范围内进行进一步研究，以告知生物能源废物作为肥料的管理，尤其是在诸如作物营养与系统磷损失等权衡方面。结果表明，最初的数月是植物建立过程中与土壤间的修正相互作用的重要时期，而当系统P的流动性可能引起径流污染时，则是生长旺盛之前的滞后时期。生物地球化学磷的溶解度控制措施需要在不同的土壤和时间范围内进行进一步研究，以告知生物能源废物作为肥料的管理，尤其是在诸如作物营养与系统磷损失等权衡方面。结果表明，最初的数月是植物建立过程中与土壤间的修正相互作用的重要时期，而当系统P的流动性可能引起径流污染时，则是生长旺盛之前的滞后时期。生物地球化学磷的溶解度控制措施需要在不同的土壤和时间范围内进行进一步研究，以告知生物能源废物作为肥料的管理，尤其是在诸如作物营养与系统磷损失等权衡方面。