Pedosphere 12(2): 151--156, 2002
ISSN 1002-0160/CN 32-1315/P
©2002 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Nitrogen losses from flooded rice field |
| GAO Xiao-Jiang1, HU Xue-Feng2, WANG Shao-Ping2, HE Bao-Gen2 and XU Shi-Yuan2 |
1 Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China);
2 Department of geography, East China Normal University, Shanghai 200062 (China) |
| ABSTRACT |
| A field microplot experiment was conducted during the tillering stage of paddy rice to investigate nitrogen(N) Iosses from flooded rice fields following fertilizer application. After application of ammonium bicarbonate, most of nitrogen in the flood water was present as NH4-N and its concentration varied widely with time. Concentrations of both NO3-N and NO2-N in the floodwater were low due to the weakened nitrification. Under flooded anaerobic reducing conditions, soil solution concentrations of NO3-N and NH4-N were nothigh, ranging from 0.6 mg L-1 to 4.8 mg L-1, and decreased with soil depth. However, the ground water wasstill contaminated with NO3-N and NH4-N. Rainfall simulation tests showed that the N losses via runoff inrice fields were closely related to the time intervals between fertilizer applications and rainfall events. Whena large rain fell for a short period after fertilizer application, the N losses via runoff could be large, which could have a considerable effect on surface water quality. Both irrigation and N fertilizer application must be controlled and managed with great care to minimize N losses via runoff from agricultural land. |
| Key Words: flooded rice fields, fertilizer-N, N losses, runoff, water quality |
| Citation: Gao, X. J., Hu, X. F., Wang, S. P., He, B. G. and Xu, S. Y. 2002. Nitrogen losses from flooded rice field. Pedosphere. 12(2): 151-156. |
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