期刊
AGRICULTURE ECOSYSTEMS & ENVIRONMENT
卷 197, 期 -, 页码 212-221出版社
ELSEVIER
DOI: 10.1016/j.agee.2014.08.002
关键词
DNDC model; Nitrogen loading; Runoff; Leaching; Lysimeter; Rice paddy field
资金
- National Key Technology Research and Development Program of the Ministry of Science and Technology of China [2012BAD15B03]
- Major Program of National Natural Science Foundation of China [71333010]
Nitrogen (N) contamination from rice paddy cultivation has threatened the quality of water resources in the upper reaches of the Huangpu River. In this study, a 3-year experiment (2009-2011) was conducted at a typical rice field in the Huangpu River watershed. The rates of N loading via surface runoff and subsurface leaching from the field were measured with a permanently installed lysimeter system. In the experiment, four treatments were tested, including applications of only chemical fertilizer (CT), only organic manure (OT), a mixture of the two types of fertilizers (MT) and a control (CK). The field data indicated that the average rates of the seasonal N loading induced by both runoff and leaching for CK, CT, MT and OT were 3.38, 16.79, 15.07 and 7.14 kg N/ha, respectively. However, OT decreased the rice yields to 5482 kg/ha, whereas MT maintained the optimal yields of 6818 kg/ha. A process-based model, denitrification-decomposition or DNDC, was adopted to assist with interpreting and integrating the experimental results. DNDC has been calibrated and validated against the field data and accurately simulated the N losses via surface runoff and subsurface leaching from the paddy field. The modeled seasonal N loading rates for CK, CT, MT and OT were 3.25, 18.84, 15.54 and 6.46 kg N/ha, respectively, which were in accordance with field observations. The modeled rice yields (4126-7365 kg/ha) across the treatments were also in agreement with the observations (3788-6818 kg/ha), though approximately 8% higher than observations. The results of sensitivity analysis indicated that increases in precipitation or fertilization or decreases in soil clay fraction increased the N loading rate. In addition, the scenario simulation tests indicated that the application of urea at a rate of 170 kg N/ha was the optimal fertilization method for the rice field, which maintained the optimal rice yields with a relatively low rate of N loading of 11.55 kg N/ha. The revised DNDC model proved to be an effective tool for assessing best management practices that reduce N loading in rice paddy field in China. (C) 2014 Elsevier B.V. All rights reserved.
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