Legendre B.,Audubon Sugar Institute |
Eggleston G.,U.S. Department of Agriculture |
Birkett H.,Audubon Sugar Institute |
Mrini M.,Sucreries Raffineries De Cannes SURAC |
And 4 more authors.
International Sugar Journal | Year: 2014
Exposure of sugarcane to damaging frosts occurs in approximately 25% of the sugarcane producing countries world-wide. A series of damaging freezes, -2.6, -3.3 and -2.1 °C, occurred in Morocco on 4, 5 and 13 February 2012, respectively, only 2 weeks after the commencement of the harvest season. Furthermore, the sugarcane had not reached maturity with factory sugar recovery yields under 8.0%. The use of pH (litmus) paper in the field is considered a good indicator of possible deterioration of the juice when the pH is 5.0 or less, and can be used to define the level of topping to remove the deteriorated portion of the stalk prior to milling. In all, thirty fields of the three leading varieties, CP 70-321, CP 66-346, and L 62-96, were inspected. Only 13% of the fields had a juice pH of 5.0 or less which was generally limited to the uppermost internodes. The worst damage occurred in fields with cane yields of < 40 t/ha, regardless of variety, and which had received no irrigation water and were harvested after June 2011, the previous year. Concentrations of mannitol and/or dextran in the juice are much more reliable indicators of sugarcane Leuconostoc deterioration. Because of high levels of brown leaves (>10%) in delivered cane, there were high levels of polysaccharide found in the juice that contributed to the measurement of high haze dextran levels; however, the absence of mannitol confirmed little or no deterioration had occurred from the growth of Leuconostoc. The key to success in reducing significant losses through deterioration when freezes occur are good management and close cooperation between growers and processors. Final recommendations on how to manage a freeze in both the field and factory are described.