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Journal of Chemistry
Volume 2016, Article ID 2576015, 9 pages
http://dx.doi.org/10.1155/2016/2576015
Research Article

Effects of Controlled Irrigation and Drainage on Nitrogen and Phosphorus Concentrations in Paddy Water

Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China, Ministry of Education, College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China

Received 14 March 2016; Revised 13 May 2016; Accepted 16 May 2016

Academic Editor: Jun Wu

Copyright © 2016 Shi-kai Gao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Controlled irrigation and drainage (CID) has received attention for improving water quality. Under CID condition, water stress is frequently experienced in two contexts: first drought and then flooding (FDTF) and first flooding and then drought (FFTD). This study aimed to investigate the effects of FDTF and FFTD on nitrogen (N) and phosphorus (P) dynamics in paddy water at different growth stages. The effects of water stress on the migration and transformation of N and P were also investigated. Results showed that CID can decrease N and P concentrations in surface water. was the major form of N in surface drainage and percolation water. Mean total phosphorus (TP), , and concentrations were significantly higher than in FFTD during the growth stage. Mean , , and TP concentrations were significantly higher in percolation water under flooding stress than those under drought stress at growth stage, except for mean TP concentrations at milky stage (stage IV). Meanwhile, flooding can sharply increase the , , and TP concentrations in percolation water after drought. Thus, without CID, the considerably high , , and TP concentrations via runoff and leaching can be responsible for the eutrophication of water bodies in the vicinity of paddy fields during the rice growing season when water stress transforms from drought into flooding.