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Determining a critical nitrogen dilution curve for sugarcane
Author(s) -
de Oliveira Emídio Cantídio Almeida,
de Castro Gava Glauber José,
Trivelin Paulo Cesar Ocheuze,
Otto Rafael,
Franco Henrique Coutinho Junqueira
Publication year - 2013
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201200133
Subject(s) - cane , crop , biomass (ecology) , dilution , nitrogen , limiting , agronomy , ratooning , mathematics , environmental science , horticulture , biology , chemistry , sugar , food science , mechanical engineering , physics , organic chemistry , engineering , thermodynamics
Adequate measurements of the nitrogen (N) concentration in the aboveground biomass of sugarcane throughout the growth cycle can be obtained using the critical N dilution curve (CNDC) concept, which provides an N‐nutrition index (NNI). The aim of this work was to determine the CNDC value for Brazilian sugarcane variety SP81‐3250, establish the critical concentration of N, and determine the NNI in the aboveground biomass throughout the cane plant and first ratoon crop cycles. The study was performed in three experimental areas located in São Paulo, Brazil, during the crop cycles of 2005/2006 (18‐month cane plant) and 2006/2007 (first ratoon). The plant cane crop was fertilized with treatments of 40, 80, or 120 kg N ha –1 and a control treatment without N. After the plant cane harvest, rates of 0, 50, 100, or 150 kg N ha –1 were applied to the control plot and the 120 kg N ha –1 –treatment plot in a split‐plot experimental design with four repetitions. Throughout both sugarcane cycles, measurements of aboveground biomass were used to determine the dry‐mass (DM) production and N concentration for each treatment. CNDC varied between the growth cycles, with a higher N concentration observed in the initial stages of the first ratoon and a lower N dilution observed throughout the plant cane cycle. The NNI value indicated excessive N storage in the initial stages and limiting concentrations at the end of the growth cycle. CNDC and NNI allow for the identification of the N‐nutrition variation rate and the period in which the nutrient concentration limits the production of aboveground biomass. The equations for the critical N (Ncr) level obtained in this study for plant cane (Ncr = 19.0 DM –0.369 ) and ratoons (Ncr = 20.3 DM –0.469 ) can potentially be used as N‐nutritional diagnostic parameters for sugarcane N nutrition.