Pedosphere 23(2): 205--212, 2013
ISSN 1002-0160/CN 32-1315/P
©2013 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Role of carbon substrates added in the transformation of surplus nitrate to organic nitrogen in a calcareous soil |
QIU Shao-Jun1,2, JU Xiao-Tang1 , J. INGWERSEN3, GUO Zi-De1, C. F. STANGE4, R. BISHARAT3, T. STRECK3, P. CHRISTIE1,5, and ZHANG Fu-Suo1 |
1 College of Agricultural Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China)
2Ministry of Agriculture Key Laboratory of Plant Nutrition and Fertilizer, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China)
3Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart 70593 (Germany)
4Federal Institute for Geosciences and Natural Resources, Stilleweg 2, Hannover, D-30655 (Germany)
5Agri-Environment Branch, Agri-Food and Biosciences Institute, Belfast BT9 5PX (UK) |
| ABSTRACT |
| Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs. We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N (SON). A 56-d laboratory incubation experiment using the 15N tracer (K15NO3) technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose (G) or maize straw (S) at controlled soil temperature and moisture. The dynamics and isotopic abundance of mineral N (NO3- and NH4+) and SON and greenhouse gas (N2O and CO2) emissions during the incubation were investigated. Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON, this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different (P > 0.05) from that in control soil without added C. At the end of the incubation period, amendment with glucose, a readily available C source, increased nitrate immobilization by 2.65 times and total N2O-N emission by 33.7 times, as compared with maize straw amendment. Moreover, the differences in SON and total N2O-N emission between the treatments with glucose and maize straw were significant (P < 0.05). However, the total N2O-N emission in the straw treatment was not significantly (P > 0.05) greater than that in the control. Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N2O emitted as well as restriction of NO3-N leaching. |
| Key Words: carbon amendments, available C source, greenhouse gases, N immobilization, 15N tracer |
| Citation: Qiu, S. J., Ju, X. T., Ingwersen, J., Guo, Z. D., Stange, C. F., Bisharat, R., Streck, T., Christie, P. and Zhang, F. S. 2013. Role of carbon substrates added in the transformation of surplus nitrate to organic nitrogen in a calcareous soil. Pedosphere. 23(2): 205-212. |
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