期刊
PHYSICS AND CHEMISTRY OF THE EARTH
卷 36, 期 9-11, 页码 395-400出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.pce.2010.03.017
关键词
Nitrate leaching; N fertilization rate; Rainfall; Temperature; Winter wheat; Taihu watershed
资金
- National Key Science and Technology Project: Water Pollution Control and Treatment [2008ZX07101-006]
- National Natural Science Foundation of China [40901142]
- Normal Scientific Project Research Foundation of Zhejiang Province [20070235]
Cropland derived nitrate leaching was a major reason for groundwater pollution. The objective of this study was to on-farm investigate the behavior of nitrate leaching affected by N fertilization rates, rainfall, and temperature in a rainfed winter wheat field in Taihu watershed. The experiment had five urea-N rates (0-360 kg N ha(-1) in 90-kg increments), and nitrate-N in leachate was daily collected by wedge-shaped fiberglass wick lysimeters during four stages (seeding stage, SS; tillering stage. TS; booting stage, BS; harvesting stage, HS). Results showed that: (1) higher potential of leachate would be engendered when the rainfall intensity was over 5.9 mm d(-1); (2) variations of nitrate concentrations in leachate were well responsed to three split fertilizations, which increased with the increase of urea-N applied rates. A similar variation pattern of nitrate concentrations was observed in -0.3 m and -0.6 m soil leachate. Besides, the nitrate concentrations in leachate could be raised with the sharply increase of air temperature, especially in the SS and TS stages; (3) the fluxes of nitrate leaching were significantly affected by N rates (P < 0.05) with the loss ratio varied from 4.0% to 8.5% for five treatments, and the fluxes in four wheat growing stages followed the order of TS > HS > BS > SS. The N application rate of 180 kg N ha(-1) optimized wheat production, but N application over that rate greatly increased nitrate leaching potential. Therefore, options other than lowering the N application rate need to be considered to reduce environmental impacts while maintain winter wheat production. (c) 2010 Elsevier Ltd. All rights reserved.
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