Abstract―

Humin plays a key role in various environmental processes like nutrient retention, carbon sequestration together with contaminant migration. Due to the resistance of humin to microbial degradation, exploring the mineralization process of phosphorus associated with humin is relevant to evaluate the lability of organic phosphorus and to develop a sustainable nutrient management strategy in ecosystems. Herein, humin was obtained from three climatically contrasting forest soils, including brown coniferous forest soil (Humic Cambisol), dark brown soil (Haplic Luvisol), as well as yellow brown soil (Haplic Luvisol), by treatment via a mixture of HF-HCl after soluble humic components were removed. The lability of phosphorus bound to humin and humic acid was examined by hydrolysis reaction with phytase from wheat, acid phosphatase from potato, and nuclease P1 from Penicillium citrinum alone or in combination. The results demonstrated that humin contained labile inorganic phosphorus as well as organic phosphorus. In the labile organic phosphorus, phytate-like phosphorus displayed the greatest proportion followed by simple monoester phosphorus and polynucleotide-like phosphorus. The labile total phosphorus was lower in humin than in humic acid. Among the three soils, labile total phosphorus was greater in brown coniferous forest soil than in yellow brown soil for humin and in dark brown soil than in yellow brown soil for humic acid. The labile total phosphorus was positively correlated well with Mn and Zn contents in humin and humic acid. Moreover, the lower proportion of labile total phosphorus in yellow brown soil could also be attributed to its higher pH value and silt and clay-size fractions compared to brown coniferous forest soil and dark brown soil. Our results can provide new information on the potential role of humin in P cycling and nutrition and are of significance for sustainable nutrient management in ecosystems.

中文翻译：

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森林土壤中腐殖质中酶促不稳定的磷形态

摘要-

腐殖质在各种环境过程中发挥关键作用，例如养分保留，碳固存以及污染物迁移。由于腐殖质对微生物降解的抵抗力，探索与腐殖质相关的磷的矿化过程与评估有机磷的稳定性以及制定生态系统可持续养分管理策略有关。在此，通过混合HF-HCl处理，从三种具有气候差异的森林土壤中获得了腐殖质，包括棕色针叶林土壤（Humic Cambisol），深棕色土壤（Haplic Luvisol）以及黄棕色土壤（Haplic Luvisol）。去除可溶性腐殖质成分后。通过与小麦中的植酸酶，马铃薯中的酸性磷酸酶进行水解反应，研究了与腐殖质和腐殖酸结合的磷的不稳定性。青 桔单独或组合使用。结果表明，胡敏中含有不稳定的无机磷和有机磷。在不稳定的有机磷中，植酸样磷占最大比例，其次是简单的单酯磷和多核苷酸样磷。腐殖质中不稳定的总磷低于腐殖酸。在这三种土壤中，对于腐殖质而言，棕色针叶林土壤的不稳定总磷高于黄棕色土壤，而对于腐殖酸，深棕色土壤的不稳定总磷高于黄棕色土壤。不稳定的总磷与腐殖质和腐殖酸中的Mn和Zn含量呈正相关。此外，与棕色针叶林土壤和深棕色土壤相比，黄棕色土壤中不稳定的总磷比例较低，也可能归因于其较高的pH值以及粉砂和黏土级分。我们的研究结果可以提供有关腐殖质在磷循环和营养中潜在作用的新信息，对于生态系统中可持续养分管理具有重要意义。