Factsheet outlining methods for managing nitrogen in sugarbeets.University of Guelph Ridgetown CampusUniversity of GuelphOntario Sugarbeet Growers' AssociationGovernment of CanadaAgricultural Adaptation CouncilGovernment of OntarioGrowing ForwardMichigan Sugar Compan

Van Eerd, L.L.

The Atrium (Univ. of Guelph)

Managing Nitrogen in Sugarbeets. Sugarbeet Factsheet         23 April 2012  Managing nitrogen fertilizer is critical to optimizing raw white sugar per ton (RWST).  Although higher rates of N fertilizer increase sugarbeet yield, high N fertility tends to decrease % sugar and RWST and increase impurities, which lowers net return to the grower and cooperative (Van Eerd et al. 2012).    The SPAD® meter measures chlorophyll content and provides a numerical indication of greenness; the darker green the leaf, the higher the reading.  The underlying principle behind this tool is that the higher the SPAD® reading, the higher the chlorophyll and the more N to the crop.  The SPAD® meter is easy to use, provides immediate results and does not require you to collect leaves to send to the lab.  Simply take 30 readings from 30 plants.  To take a reading, clamp the meter on to the most recently fully expanded new leaf, wait a few seconds and the move on to the next plant.  The machine takes the average of the 30 plants sampled and that average number is used to make N fertilizer decision or harvest decision.  At sidedress N application: Take SPAD® readings as close to the time of sidedress N fertilizer application as possible.   A reading of 31-36 is optimal for RWST production.  If reading is lower than 30, then more N fertilizer is needed.  Readings higher than 31 indicates enough N in the soil, therefore N fertilizer is not required. The SPAD® meter does not work to predict RWST later in the season but does work at harvest in mid-September through to mid-November.    At harvest:  SPAD® readings at harvest may be used to decide which field to harvest early. As a general rule, fields with lower SPAD® reading have higher RWST.  It appears that RWST to be optimal at SPAD® readings of 35 or lower. Fields with high SPAD® readings of 40 or higher tend to have lower RWST.    References: Van Eerd, L.L., K.A.Congreves, and J.W. Zandstra.  2012.  Sugar beet (Beta vulgaris L.) storage quality in large outdoor piles is impacted by pile management but not nitrogen fertilizer nor cultivar. Canadian Journal of Plant Science.  92:1-11.  Prepared by:  Dr. Laura L. Van Eerd. Ridgetown Campus, University of Guelph     x 63644    lvaneerd@uoguelph.ca   Funded by:  

Managing Nitrogen in Sugarbeets. Sugarbeet Factsheet

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Managing Nitrogen in Sugarbeets. Sugarbeet Factsheet

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