CRITICAL NITROGEN CURVE AND NITROGEN NUTRITION INDEX FOR SPRING MAIZE IN NORTH-EAST CHINA |
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| Authors: | Wenjuan Li Ping He Jiyun Jin |
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| Institution: | 1. Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization , Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences , Beijing , China;2. Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization , Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences , Beijing , China;3. International Plant Nutrition Institute China Program , Beijing , China |
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| Abstract: | The study was conducted at three sites during 2008 and 2009 in the North-East China Plain (NECP). Field experiments consisted of five or six nitrogen (N) fertilization rates (0–350 kg N ha?1). Shoot biomass and N concentration (Nc) of spring maize (Zea mays L.) were determined on six sampling dates during the growing season. Nitrogen application rate had a significant effect on aerial biomass accumulation and Nc. As expected, shoot Nc declined during the growing period. A critical N dilution curve (Nc = 36.5 W ?0.48) was determined in China, which was a little different from those reported for maize in France and Germany. Besides, the N nutrition index (NNI) calculated from this critical N dilution curve was significantly related to relative grain yield, which can be expressed by a linear with plateau model (R2 = 0.66; P < 0.001). NNI can be used as a reliable indicator of the level of N deficiency during the growing season of maize. |
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| Keywords: | critical nitrogen concentration (Nc) nitrogen nutrition index (NNI) spring maize dry matter |
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