Determining a critical nitrogen dilution curve for sugarcane

Autor(es)

Almeida de Oliveira, Emidio Cantidio ^[1] ; de Castro Gava, Glauber Jose ^[2] ; Ocheuze Trivelin, Paulo Cesar ^[3] ; Otto, Rafael ^[4] ; Junqueira Franco, Henrique Coutinho ^[5]

Afiliação do(s) autor(es)

^[1] Fed Rural Univ Pernambuco UFRPE, Dept Agron, Soil Sci Area, BR-52171900 Recife, PE - Brazil

^[2] Sao Paulo State Agribusiness Technol Agcy APTA, BR-17201970 Jau, SP - Brazil

^[3] CENA, Stable Isotope Lab, BR-13400970 Piracicaba, SP - Brazil

^[4] Luiz de Queiroz Coll Agr ESALQ, BR-13418900 Piracicaba, SP - Brazil

^[5] Brazilian Bioethanol Sci & Technol Lab CTBE, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE; v. 176, n. 5, p. 712-723, OCT 2013.
• Citações Web of Science: 9

Resumo

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 SAo 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 120kg N ha(-1) and a control treatment without N. After the plant cane harvest, rates of 0, 50, 100, or 150kg N ha(-1) were applied to the control plot and the 120kg 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. (AU)