National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing 210095, China.
NSW Department of Primary Industries, West Pennant Hills, NSW 2125, Australia; School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia.
Chemosphere. 2014 Sep;111:441-9. doi: 10.1016/j.chemosphere.2014.03.078. Epub 2014 May 17.
Understanding the organomineral associations in soils is of great importance. Using two-dimensional correlation spectroscopy (2DCOS) and high resolution-transmission electron microscopy (HRTEM) techniques, this study compared the binding characteristics of organic ligands to Al(III) in dissolved organic matter (DOM) from soils under short-term (3-years) and long-term (22-years) fertilizations. Three fertilization treatments were examined: (i) no fertilization (Control), (ii) chemical nitrogen, phosphorus and potassium (NPK), and (iii) NPK plus swine manure (NPKM). Soil spectra detected by the 2DCOS Fourier transform infrared (FTIR) spectroscopy showed that fertilization modified the binding characteristics of organic ligands to Al(III) in soil DOM at both short- and long- term location sites. The CH deformations in aliphatic groups played an important role in binding to Al(III) but with minor differences among the Control, NPK and NPKM at the short-term site. While at the long-term site both C-O stretching of polysaccharides or polysaccharide-like substances and aliphatic O-H were bound to Al(III) under the Control, whereas only aliphatic O-H, and only polysaccharides and silicates, were bound to Al(III) under NPK and NPKM, respectively. Images from HRTEM demonstrated that crystalline nanominerals, composed of Fe and O, were predominant in soil DOM under NPK, while amorphous nanominerals, predominant in Al, Si, and O, were dominant in soil DOM under Control and NPKM. In conclusion, fertilization strategies, especially under long-term, could affect the binding of organic ligands to Al(III) in soil DOM, which resulted in alterations in the turnover, reactivity, and bioavailability of soil organic matter. Our results demonstrated that the FTIR-2DCOS combined with HRTEM techniques could enhance our understanding in the binding characteristics of DOM to Al(III) and the resulted nanominerals in soils.
了解土壤中的有机-矿物结合物非常重要。本研究采用二维相关光谱（2DCOS）和高分辨率透射电子显微镜（HRTEM）技术，比较了短期（3 年）和长期（22 年）施肥条件下土壤中溶解有机质（DOM）中有机配体与 Al（III）的结合特征。考察了三种施肥处理：（i）不施肥（对照）、（ii）化学氮、磷、钾（NPK）和（iii）NPK 加猪粪（NPKM）。2DCOS 傅里叶变换红外（FTIR）光谱检测到的土壤光谱表明，施肥改变了土壤 DOM 中有机配体与 Al（III）的结合特征，无论是在短期还是长期的定位点。脂肪族基团中的 CH 变形在与 Al（III）结合中起着重要作用，但在短期点对照、NPK 和 NPKM 之间差异较小。而在长期点，只有在对照条件下，多糖或类似多糖物质的 C-O 伸缩和脂肪族 O-H 与 Al（III）结合，而在 NPK 和 NPKM 条件下，只有脂肪族 O-H 和多糖以及硅酸盐与 Al（III）结合。HRTEM 图像表明，由 Fe 和 O 组成的结晶纳米矿物在 NPK 下的土壤 DOM 中占优势，而无定形纳米矿物，主要由 Al、Si 和 O 组成，在对照和 NPKM 下的土壤 DOM 中占优势。总之，施肥策略，特别是长期施肥，可能会影响土壤 DOM 中有机配体与 Al（III）的结合，从而改变土壤有机质的周转、反应性和生物有效性。我们的结果表明，FTIR-2DCOS 与 HRTEM 技术相结合，可以增强我们对 DOM 与 Al（III）结合特征以及土壤中纳米矿物的理解。
