Nitrogen input, N-15 balance and mineral N dynamics in a rice-wheat rotation in southwest China

文献类型： 外文期刊

第一作者： Lu, Shihua

作者： Lu, Shihua;Jiang, Rongfeng;Liu, Xuejun;Zeng, Xiangzhong;Goulding, Keith W. T.;Zhang, Fusuo

作者机构：

关键词： alternate soil wetting and drying; integrated nutrient management; N-15 labelled urea; nitrogen budget; nitrogen cycling; rice-wheat cropping system

期刊名称：NUTRIENT CYCLING IN AGROECOSYSTEMS （ 影响因子：3.27； 五年影响因子：3.767 ）

ISSN： 1385-1314

年卷期： 2007 年 79 卷 3 期

页码：

收录情况： SCI

摘要： A field experiment and farm survey were conducted to test nitrogen (N) inputs, N-15-labelled fertilizer balance and mineral N dynamics of a rice-wheat rotation in southwest China. Total N input in one rice-wheat cycle averaged about 448 kg N ha(-1), of which inorganic fertilizer accounted for 63% of the total. The effects of good N management strategies on N cycling were clear: an optimized N treatment with a 27% reduction in total N fertilizer input over the rotation decreased apparent N loss by 52% and increased production (sum of grain yield of rice and wheat) compared with farmers' traditional practice. In the N-15-labelled fertilizer experiment, an optimized N treatment led to significantly lower N-15 losses than farmers' traditional practice; N loss mainly occurred in the rice growing season, which accounted for 82% and 67% of the total loss from the rotation in farmers' fields and the optimized N treatment, respectively. After the wheat harvest, accumulated soil mineral N ranged from 42 to 115 kg ha(-1) in farmers' fields, of which the extractable soil NO3--N accounted for 63%. However, flooding soil for rice production significantly reduced accumulated mineral N after the wheat harvest: in the N-15 experiment, farmers' practice led to considerable accumulation of mineral N after the wheat harvest (125 kg ha(-1)), of which 69% was subsequently lost after 13 days of flooding. Results from this study indicate the importance of N management in the wheat-growing season, which affects N dynamics and N losses significantly in the following rice season. Integrated N management should be adopted for rice-wheat rotations in order to achieve a better N recovery efficiency and lower N loss.

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