title: Comparison of different critical nitrogen dilution curves for nitrogen diagnosis in rice.
abstract: The critical nitrogen (N) dilution curve is a suitable analytical tool for in-season estimation of N status to implement precision N management. This study was undertaken for a comprehensive comparison of N dilution curves in Japonica and Indica rice to investigate, whether a single curve can be used for both rice ecotypes and to determine the most robust plant index for assessing N status in rice ecotypes. The different N dilution curves were developed based on plant dry matter (PDM), leaf area index (LAI), leaf dry matter (LDM) and stem dry matter (SDM) for N diagnosis in Japonica and Indica rice. The comparison of N dilution curves of two rice ecotypes showed non-significant differences, therefore a single/unified curve can be used to assess plant N status for precision N management in both rice ecotypes. The relationships between PDM based, with LAI, LDM, and SDM based N nutrition index, accumulated N deficit and N requirement, indicated that leaf based approaches could be used as substitutes for PDM approach. The lower coefficient b values of LDM based curve (due to efficient physiological N use in leaves) implied that LDM was the most appropriate approach for developing N curve as compared to other approaches.
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Syed Tahir
authors.initials: ST
authors.lastname: Ata-Ul-Karim
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liu
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cao
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Tian
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu 210095, P. R. China.
authors.forename: Weixing
authors.initials: W
authors.lastname: Cao
mesh_terms: D018533:Biomass; D009584:Nitrogen / Q000378:metabolism*; D009747:Nutritional Physiological Phenomena; D012275:Oryza / Q000378:metabolism*; D018515:Plant Leaves / Q000502:physiology
chemical_list: D009584:Nitrogen