
TY  - JOUR
A1  - Mao, Xi-an 
A1  - Xu, Zhi-hong 
A1  - Luo, Ren-sheng 
A1  - Mathers, Nicole J. 
A1  - Zhang, Yong-hong 
A1  - Saffigna, Paul G. 
T1  - Nitrate in soil humic acids revealed by <emph type="7">14</emph>N nuclear magnetic resonance spectroscopy
JF  - Soil Research
JO  - Soil Res.
Y1  - 2002
VL  - 40
IS  - 5
SP  - 717
EP  - 726
KW  - humic acid, nitrate-N, 14N-NMR, plant residue management, forest ecosystems.
UR  - https://doi.org/10.1071/SR01093 
N2  - Ecosystem management such as plant residue retention and prescribed burning can significantly affect soil organic matter (SOM) composition and, thereby, the closely associated carbon (C) and nitrogen (N) cycling processes, which underpin terrestrial ecosystem productivity and sustainability. Humic acid (HA) is an important SOM component and its chemical composition has attracted much attention. Here we report the first application of 14N nuclear magnetic resonance (NMR) spectroscopy to soil HA study, revealing the surprising existence of nitrate-N and ammonia-N in the HAs. This newly discovered HA nitrate-N, though in a relatively low concentrations, is closely related to soil N availability and responsive to plant residue management regimes in contrasting forest ecosystems. The HA nitrate-N may be a useful and sensitive biochemical indicator of SOM quality in response to different ecosystem management regimes. 
ER  -

