The effect of soil organic matter on long-term availability of phosphorus in soil: Evaluation in a biological P mining experiment
The effect of soil organic matter on long-term availability of phosphorus in soil: Evaluation in a biological P mining experiment
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DOI：
10.1016/j.geoderma.2022.115965
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发表时间：
2022
期刊：
影响因子：
6.1
通讯作者：
J. Hawkins;C. Vermeiren;M. Blackwell;T. Darch;S. Granger;S. Dunham;J. Hernandez-Allica;E. Smolders;S. McGrath
中科院分区：
文献类型：
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作者：
J. Hawkins;C. Vermeiren;M. Blackwell;T. Darch;S. Granger;S. Dunham;J. Hernandez-Allica;E. Smolders;S. McGrath
植物从过度施肥的农业土壤中吸收遗留的磷（P）可以提供一种解决方案，以减少对有限的矿物磷资源的依赖。本研究评估了传统的P在土壤中的长期可用性与加速生物采矿试验，从而测试在何种程度上这种可用性是受土壤有机碳（SOC）。采用盆栽试验方法，在25个有机碳含量为1.2 ~ 24%的土壤中，通过连续种植和收获多年生黑麦草（Loliumperenne），进行为期15个月的磷素释放试验。平均而言，磷的累积吸收量为与结晶不良的铁（Fe）和铝（Al）（氧）氢氧化物（草酸盐可提取的P; Pox）相关的磷的19%。平均而言，一半的磷可以以足够快的速度被吸收，以保持作物产量超过其潜力的90%。在产量下降10%之前吸收的磷被称为临界累积吸磷量（CCP），它与土壤的同位素交换性P或“E值”（CCP/E24 h中值= 0.81）惊人地匹配，而Olsen P（CCP/POlsen中值= 1.51）明显低估了它。植物可利用的过氧化物酶的分数增加的比例增加的P或SOC的总和的Feoxand Alox，这表明增强的SOC含量减少老化的P，防止其扩散到微孔。在初始磷饱和度较低的土壤中，有机碳对磷有效性的影响更为明显。生物采矿的结果与（无菌）磷解吸实验中确定的土壤有效磷库的比较不能确认有机磷对植物磷供应的显着贡献。基于我们研究中的一组土壤，我们的研究结果表明，施肥良好的农业土壤中的遗留磷可以作为植物几年到几十年的充足磷源，并且只要SOC对这种长期可用性产生积极影响土壤中的磷不饱和。
The plant uptake of legacy phosphorus (P) from over-fertilised agricultural soils could offer a solution to decrease dependency on finite mineral P resources. This study evaluated the long-term availability of legacy P in soils with an accelerated biological mining assay, thereby testing to what extent this availability is affected by soil organic carbon (SOC). A 15-month-long pot trial was set-up, in which 25 soils with 1.2–24% SOC were mined for P by continuous cropping and harvesting of ryegrass (Lolium perenne) in a plant growth cabinet. The cumulative uptake of P was, on average, 19% of the P associated with poorly crystalline iron (Fe) and aluminium (Al) (oxy)hydroxides (oxalate-extractable P; Pox). On average, half of this P could be taken up at rates fast enough to maintain crop production at > 90% of its potential. This P taken up before a 10% reduction in yield occurred, termed the critical cumulative P uptake (CCP), strikingly matched with the isotopically exchangeable P or “E value” of a soil (median CCP/E24h= 0.81), whereas it was markedly underestimated by Olsen P (median CCP/POlsen= 1.51). The fractions of plant-available Poxincreased at increasing ratios of either P or SOC to the sum of Feoxand Alox, suggesting that enhanced SOC contents reduce ageing of P by preventing its diffusion into micropores. That effect of SOC on P availability was more pronounced in soils with a low initial P saturation status. The comparison of the results from biological mining with available soil P pools determined in a (sterile) P desorption experiment could not confirm a significant contribution of organic P to plant P supply. Based on the set of soils in our study, our findings suggest that legacy P in well-fertilised agricultural soils could act as a sufficient P source for plants for several years to decades, and that this long-term availability is positively affected by SOC as long as the soil is not saturated with P.