Phosphorous dissolution and ensuing chemical redistribution of P in organic amendments (OA) were studied by applying a modified Hedley selective fractionation to eight water-extracted and unextracted OAs. Nine 7-day, repeated extractions were applied using a 60:1 water:dry OA (v:w) ratio at pH 8. Eight OAs were tested including five biosolids, broiler litter, dairy manure compost and municipal solid waste compost. The average PWEP₉ (percent water-extractable P following nine water-extraction cycles) for the OAs was 65 ± 9% and all of the fractions, with almost no exceptions, contributed to that figure. Organic P was depleted by mineralization (in non-stabilized sludges and broiler litter) or dissolution (stabilized composts) or both (in lime-treated biosolids) and that depletion was completed within 1–2 extraction cycles. Only the organic P of the MSWC remained undepleted. Strong linear correlations were observed between the WEP₉ values of the OAs (0.8–21 g P kg⁻¹) and several more easily determined properties, including total P content (r² = 0.84), organic N content (r² = 0.82), the sum of Hedley’s more easily dissolved SRP (soluble reactive P) and OP (r² = 0.95), and the total P and SRP extracted by 16 h of shaking with the bicarbonate reagent (r² ≥ 0.90). These findings indicate that if greater P availability is desired, the stabilization of biosolids and biowastes should be minimized. These insights into the relationships between OA characteristics and P solubility may benefit the use of OAs in agricultural systems and aid assessments of the environmental significance of their use.

通过将改良的Hedley选择性分馏技术应用于8种水提取和未提取的OAs，研究了有机修饰剂（OA）中P的磷的溶解和随之发生的化学重新分布。在pH为8的情况下，使用60：1的水：干OA（v：w）比率进行9次7天的重复提取。测试了8种OA，包括5种生物固体，肉鸡粪，奶牛粪便堆肥和城市固体废物堆肥。平均PWEP ₉OAs（9个水提取循环后的水可提取P百分比）为65±9％，所有分数（几乎没有例外）均对该数字有所贡献。有机磷通过矿化作用（在非稳定的污泥和肉鸡垫料中）或溶解（稳定的堆肥）或两者（在石灰处理的生物固体中）被消耗掉，并且消耗在1-2个萃取周期内完成。仅MSWC的有机磷仍未耗尽。在OAs的WEP ₉值（0.8-21 g P kg ^-1）和更容易确定的特性之间观察到强线性相关性，包括总P含量（r ²  = 0.84），有机N含量（r ² = 0.82），达理的更容易溶解SRP的总和（可溶性活性P）和OP（- [R ²  = 0.95），总P和SRP通过与碳酸氢盐试剂（摇动16小时萃取- [R ²  ≥0.90）。这些发现表明，如果需要更高的磷利用率，则应尽量减少生物固体和生物废物的稳定性。这些关于OA特性与P溶解度之间关系的见解可能有益于在农业系统中使用OA，并有助于评估其使用的环境意义。