| 中国太湖地区稻麦轮作农田硝态氮动态与氮素平衡 |
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| 作者姓名： | ZHANG Jun-Hu LIU Jian-Li ZHANG Jia-Bao CHENG Ya-Nan WANG Wei-Peng |
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| 作者单位： | Institute of Soil Science, Chinese Academy of Sciences;State Key Laboratory of Rice Biology, China National Rice Research Institute;University of Chinese Academy of Sciences |
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| 基金项目： | Supported by the National Basic Research Program (973 Program) of China (No. 2011CB100506);the National Natural Science Foundation of China (Nos. 41171179 and 40871105) |
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| 摘 要： | Nitrate-nitrogen (NO 3--N) dynamics and nitrogen (N) budgets in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region of China were studied to compare the effects of N fertilizer management over a two-year period. The experiment included four N rates for rice and wheat, respectively: N1 (125 and 94 kg N ha-1 ), N2 (225 and 169 kg N ha-1 ), N3 (325 and 244 kg N ha-1 ), and N0 (0 kg N ha-1 ). The results showed that an overlying water layer during the rice growing seasons contributed to moderate concentrations of NO 3--N in sampled waters and the concentrations of NO 3--N only showed a rising trend during the field drying stage. The NO 3--N concentrations in leachates during the wheat seasons were much higher than those during the rice seasons, particularly in the wheat seedling stage. In the wheat seedling stage, the NO 3--N concentrations of leachates were significantly higher in N treatments than in N0 treatment and increased with increasing N rates. As the NO 3--N content (below 2 mg N L-1 ) at a depth of 80 cm during the rice-wheat rotations did not respond to the applied N rates, the high levels of NO 3--N in the groundwater of paddy fields might not be directly related to NO 3--N leaching. Crop growth trends were closely related to variations of NO 3--N in leachates. A reduction in N application rate, especially in the earlier stages of crop growth, and synchronization of the peak of N uptake by the crop with N fertilizer application are key measures to reduce N loss. Above-ground biomass for rice and wheat increased significantly with increasing N rate, but there was no significant difference between N2 and N3. Increasing N rates to the levels greater than N2 not only decreased N use efficiency, but also significantly increased N loss. After two cycles of rice-wheat rotations, the apparent N losses of N1, N2 and N3 amounted to 234, 366 and 579 kg N ha-1 , respectively. With an increase of N rate from N0 to N3, the percentage of N uptake in total N inputs decreased from 63.9% to 46.9%. The apparent N losses during the rice seasons were higher than those during the wheat seasons and were related to precipitation; therefore, the application of fertilizer should take into account climate conditions and avoid application before heavy rainfall.
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| 关 键 词： | above-ground biomass crop uptake nitrate-nitrogen leaching nitrogen mineralization nitrogen transport |
| 收稿时间： | 27 April 2012 |
Nitrate-nitrogen dynamics and nitrogen budgets in rice-wheat rotations in Taihu Lake region, China |
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| ZHANG Jun-Hu,LIU Jian-Li,ZHANG Jia-Bao,CHENG Ya-Nan,WANG Wei-Peng.Nitrate-nitrogen dynamics and nitrogen budgets in rice-wheat rotations in Taihu Lake region, China[J].Pedosphere,2013,23(1):59-69. |
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| Authors: | ZHANG Jun-Hu LIU Jian-Li ZHANG Jia-Bao CHENG Ya-Nan and WANG Wei-Peng |
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| Institution: | Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006 (China);Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China);Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);University of Chinese Academy of Sciences, Beijing 100049 |
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| Abstract: | Nitrate-nitrogen (NO3--N) dynamics and nitrogen (N) budgets in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region of China were studied to compare the effects of N fertilizer management over a two-year period. The experiment included four N rates for rice and wheat, respectively: N1 (125 and 94 kg N ha-1), N2 (225 and 169 kg N ha-1), N3 (325 and 244 kg N ha-1), and N0 (0 kg N ha-1). The results showed that an overlying water layer during the rice growing seasons contributed to moderate concentrations of NO3--N in sampled waters and the concentrations of NO3--N only showed a rising trend during the field drying stage. The NO3--N concentrations in leachates during the wheat seasons were much higher than those during the rice seasons, particularly in the wheat seedling stage. In the wheat seedling stage, the NO3--N concentrations of leachates were significantly higher in N treatments than in N0 treatment and increased with increasing N rates. As the NO3--N content (below 2 mg N L-1) at a depth of 80 cm during the rice-wheat rotations did not respond to the applied N rates, the high levels of NO3--N in the groundwater of paddy fields might not be directly related to NO3--N leaching. Crop growth trends were closely related to variations of NO3--N in leachates. A reduction in N application rate, especially in the earlier stages of crop growth, and synchronization of the peak of N uptake by the crop with N fertilizer application are key measures to reduce N loss. Above-ground biomass for rice and wheat increased significantly with increasing N rate, but there was no significant difference between N2 and N3. Increasing N rates to the levels greater than N2 not only decreased N use efficiency, but also significantly increased N loss. After two cycles of rice-wheat rotations, the apparent N losses of N1, N2 and N3 amounted to 234, 366 and 579 kg N ha-1, respectively. With an increase of N rate from N0 to N3, the percentage of N uptake in total N inputs decreased from 63.9% to 46.9%. The apparent N losses during the rice seasons were higher than those during the wheat seasons and were related to precipitation; therefore, the application of fertilizer should take into account climate conditions and avoid application before heavy rainfall. |
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| Keywords: | above-ground biomass Crop uptake nitrate-nitrogen leaching nitrogen mineralization nitrogen transport |
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