Technical University of Munich, Research Department Ecology and Ecosystem Management, Chair of Soil Science, Emil-Ramann-Straße 2, 85354, Freising, Germany.
National Synchrotron Light Source II, Brookhaven National Laboratory, 743 Brookhaven Avenue, Upton, NY, 11973-5000, USA.
Sci Rep. 2017 Jun 9;7(1):3203. doi: 10.1038/s41598-017-03537-8.
Soils comprise various heterogeneously distributed pools of lithogenic, free organic, occluded, adsorbed, and precipitated phosphorus (P) forms, which differ depending on soil forming factors. Small-scale heterogeneity of element distributions recently has received increased attention in soil science due to its influence on soil functions and soil fertility. We investigated the micro-scale distribution of total P and different specific P binding forms in aggregates taken from a high-P clay-rich soil and a low-P sandy soil by combining advanced spectrometric and spectroscopic techniques to introduce new insights on P accessibility and availability in soils. Here we show that soil substrate and soil depth determine micro-scale P heterogeneity in soil aggregates. In P-rich areas of all investigated soil aggregates, P was predominantly co-located with aluminium and iron oxides and hydroxides, which are known to strongly adsorb P. Clay minerals were co-located with P only to a lesser extent. In the low-P topsoil aggregate, the majority of the P was bound organically. Aluminium and iron phosphate predominated in the quartz-rich low-P subsoil aggregate. Sorbed and mineral P phases determined P speciation in the high-P top- and subsoil, and apatite was only detected in the high-P subsoil aggregate. Our results indicate that micro-scale spatial and chemical heterogeneity of P influences P accessibility and bioavailability.
土壤包含各种不均匀分布的岩源、游离有机、封闭、吸附和沉淀磷（P）形态，这些形态因土壤形成因素而异。由于元素分布的小尺度异质性对土壤功能和肥力有影响，因此最近在土壤科学中受到了越来越多的关注。我们通过结合先进的光谱和光谱技术，研究了取自高磷粘土丰富土壤和低磷砂土壤的团聚体中总磷和不同特定磷结合形态的微尺度分布，为土壤中磷的可及性和有效性提供了新的见解。在这里，我们表明土壤基质和土壤深度决定了土壤团聚体中磷的微尺度异质性。在所研究的所有土壤团聚体的富磷区，磷主要与铝和铁的氧化物和氢氧化物共存，这些物质已知对磷具有很强的吸附能力。粘土矿物与磷的共存程度较低。在低磷表土团聚体中，大部分磷以有机形式结合。在富石英的低磷亚土团聚体中，铝铁磷酸盐占主导地位。在高磷表土和亚土中，吸附态和矿物态磷决定了磷的形态，只有在高磷亚土团聚体中检测到磷灰石。我们的结果表明，磷的微尺度空间和化学异质性影响磷的可及性和生物有效性。
