Climate warming and nitrogen （N） deposition change ecosystem processes, structure, and functioning whereas the phosphorus （P） composition and availability directly influence the ecosystem structure under condi- ti...Climate warming and nitrogen （N） deposition change ecosystem processes, structure, and functioning whereas the phosphorus （P） composition and availability directly influence the ecosystem structure under condi- tions of N deposition. In our study, four treatments were designed, including a control, diurnal warming （DW）, N deposition （ND）, and combined warming and N deposition （WN）. The effects of DW, ND, and WN on P composition were studied by 3~p nuclear magnetic resonance （3~p NMR） spectroscopy in a temperate grassland region of China. The results showed that the N deposition decreased the soil pH and total N （TN） concentration but increased the soil OIsen-P concentration. The solution-state 31p NMR analysis showed that the DW, ND and WN treatments slightly decreased the proportion of orthophosphate and increased that of the monoesters. An absence of myo-inositol phosphate in the DW, ND and WN treatments was observed compared with the control. Furthermore, the DW, ND and WN treatments significantly decreased the recovery of soil P in the NaOH-EDTA solution by 17%-20%. The principal component analysis found that the soil pH was positively correlated with the P recovery in the NaOH-EDTA solution. Therefore, the decreased soil P recovery in the DW and ND treatments might be caused by an indirect influence on the soil pH. Additionally, the soil moisture content was the key factor limiting the available P. The positive correlation of total carbon （TC） and TN with the soil P composition indicated the influence of climate warming and N deposition on the biological processes in the soil P cycling.展开更多
液相31P核磁共振(phosphorus-31 nuclear magnetic resonance,31P-NMR)是近年来用于分析沉积物有机磷组成的新技术.本研究围绕31P-NMR分析沉积物样品的制备过程(包括样品前处理方法、提取时间、提取剂比例、样品浓缩等)进行探讨.结果表...液相31P核磁共振(phosphorus-31 nuclear magnetic resonance,31P-NMR)是近年来用于分析沉积物有机磷组成的新技术.本研究围绕31P-NMR分析沉积物样品的制备过程(包括样品前处理方法、提取时间、提取剂比例、样品浓缩等)进行探讨.结果表明,采用风干的沉积物样品进行提取,磷的提取效率明显提高.提取过程中,沉积物磷的释放主要在前8 h,为提高磷的提取效率,可将提取时间延长至12～16 h.提取比例[m(沉积物)∶V(提取剂)]1∶8与1∶20相比,在浓缩倍数相同的情况下,前者获得的31P-NMR信号峰多于后者,因此提取比例倾向于使用1∶8.提取液样品在28℃下旋转蒸发浓缩,并经低温离心后,磷无显著损失.展开更多
基金National Natural Science Foundation of China(41171241)the National Basic Research Program of China(2011CB403204)
文摘Climate warming and nitrogen （N） deposition change ecosystem processes, structure, and functioning whereas the phosphorus （P） composition and availability directly influence the ecosystem structure under condi- tions of N deposition. In our study, four treatments were designed, including a control, diurnal warming （DW）, N deposition （ND）, and combined warming and N deposition （WN）. The effects of DW, ND, and WN on P composition were studied by 3~p nuclear magnetic resonance （3~p NMR） spectroscopy in a temperate grassland region of China. The results showed that the N deposition decreased the soil pH and total N （TN） concentration but increased the soil OIsen-P concentration. The solution-state 31p NMR analysis showed that the DW, ND and WN treatments slightly decreased the proportion of orthophosphate and increased that of the monoesters. An absence of myo-inositol phosphate in the DW, ND and WN treatments was observed compared with the control. Furthermore, the DW, ND and WN treatments significantly decreased the recovery of soil P in the NaOH-EDTA solution by 17%-20%. The principal component analysis found that the soil pH was positively correlated with the P recovery in the NaOH-EDTA solution. Therefore, the decreased soil P recovery in the DW and ND treatments might be caused by an indirect influence on the soil pH. Additionally, the soil moisture content was the key factor limiting the available P. The positive correlation of total carbon （TC） and TN with the soil P composition indicated the influence of climate warming and N deposition on the biological processes in the soil P cycling.
