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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Sugarcane for Temperate Climates

Location: Sugarcane Research Unit

Title: Managing damaging freeze events in Louisiana sugarcane

item Legendre, Benjamin -
item Birkett, Harold -
item Gravois, Kenneth -
item Waguespack, Herman -
item Dufrene, Edwis
item Duet, Michael
item Jackson, Windell -
item Stein, Jeanie -

Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: April 10, 2014
Publication Date: N/A

Technical Abstract: Exposure of sugarcane to damaging frosts occurs in approximately 25% of the sugarcane producing countries of the world, but is most frequent on the mainland of the United States, especially in the state of Louisiana. The frequent winter freezes that occur in the sugarcane areas of Louisiana have forced the industry to adapt to a short growing season (about 7 months) and a short milling season (about 3 months). The nature and extent of damage to sugarcane by a freeze depends on the intensity and duration of the freeze, and the weather conditions after the freeze can control or accelerate deterioration. A series of damaging freezes occurred in Louisiana from November 26-30, 2013 where the low temperatures ranged from -2.2°C (28°F) in the southern area of the sugarcane belt to -4.4°C (24°F) in the northern area of the belt with the line of demarcation being roughly the areas north and south of the I-10 corridor. The duration of the freeze event below I-10 was approximately 6-10 hours, whereas, the duration north of I-10 was greater than 10 hours. At this point in the harvest, approximately 60% of the 14-million ton Louisiana crop had been processed by the state’s 11 factories. Immediately following the November freeze events personnel from the LSU AgCenter, the American Sugar Cane League and the USDA-ARS Sugarcane Research Unit did field inspections of the damage to the crop by the freeze. Visual ratings were taken for all commercial and some candidate varieties for both leaf and stalk cold tolerance in the field. In the southern area there was minimal damage to the stalk with only the apical meristem or terminal bud affected. However, in the more northern areas, the freeze events affected the entire stalk. With approximately 40% of the crop still remaining in the field and to study the reaction of commercial and candidate varieties to these early freeze events, the Outfield Variety Test at Alma Plantation, Lakeland, LA, located in the northern area above I-10 and US Highway 190, was chosen for the study. The test included the commercial varieties, HoCP96-540, L01-283, L01-299, L03-371 and HoCP04-838, and the candidate varieties, Ho07-613, L09-112, HoCP09-804 and Ho09-840. Ten-stalk samples were hand-cut at ground level but not stripped or topped from each of three replications for the first of three sampling dates, Dec. 12, 19 and 26, 2013. Another set of samples was cut on Jan. 3, 2014 but this time the samples were hand stripped and tops were removed approximately 30 cm (12 in) below the apical meristem (terminal bud). All samples were immediately transported, weighed and processed at the Sugar Research Station at St. Gabriel using the press method of analyses. Juice samples were analyzed for Brix by refractometer and sucrose by polarimetry and bagasse (residue) samples were analyzed for moisture (by drying). The Brix, sucrose, purity and fiber content of the cane were then calculated from these analyses after which the estimated yield of theoretical recoverable sugar per ton of cane (TRS/TC) was calculated. Juice samples were also analyzed for pH, titratable acidity, total polysaccharides, mannitol and dextran. Further, results were compared to actual factory data for daily core juice pH, crusher juice polysaccharides, syrup purities, C massecuite viscosities and sugar yield from Alma Plantation (Lakeland, LA) and syrup purities and sugar yield from the Leighton factory located at Thibodaux, LA (in the southern area below I-10). Immediately following the field assessment, the LSU AgCenter issued best management practices (BMP) to be used in reducing the impact of the freeze events on sugar yield. Those BMPs stressed the need to deliver high quality cane to the factories free of mud, deteriorated tops and leaves and other trash. The BMP’s indicated that growers and processors should not panic as the industry had experienced freeze events of this magnitude many times before. Since areas of higher elevation tend to be warmer, the BMPs recommended that growers should harvest fields with lower elevation first. Also, growers were informed that varieties with poor stalk cold tolerance, i.e., L99-226, L99-233 and L03-371, should be harvested first. Other items discussed in the BMPs included standing vs. down cane, topping height and whether or not one should burn. It also warned of overnight sleeper loads that could lead to increased deterioration. Data from the Outfield Test at Alma indicated that most of the parameters measured for the samples with tops and leaves, i.e., pH, titratable acidity, total polysaccharides, TRS/TC, remained relatively stable (unchanged) over the sampling period although it became increasingly impossible to clarify juice samples in the lab with aluminum chloride on the Dec. 26 sampling date. The Alma factory data, however, showed that the core lab juice pH, syrup purity and sugar yield started a slow decline over the same period. On the other hand, total polysaccharides in the crusher juice and C-massecuite viscosity at Alma showed significant declines after the freeze events with the BMPs in place. For the Leighton factory operating south of I-10, syrup purities and sugar yield actually continued to rise in spite of the freeze events and a wet harvest. In general, ambient temperatures following the freeze events were cooler than normal although there was one record daily high temperature of 29°C (84°F) on Dec. 5. With the BMPs in place, the Alma factory experienced no difficulties in the boiling house without any indication of c-axis elongation of sugar crystals even with the last strike of the 2013-2014, which was processed crop on Jan. 6. It is interesting to note that on the final sampling date of the Outfield Test, Jan. 3, where tops and leaves were removed, there was no problem in clarifying juice samples in the lab at the Sugar Research Station while at the same time there was a significant reduction in juice pH and total polysaccharides and higher TRS/TC for all varieties in the test from the previous sampling date, Dec 26. All other parameters remained the same as the Dec. 26 sampling dates when all tops and leaves were not removed. These data showed that the BMPs implemented at the time of the freeze proved to be an effective tool in mitigating the effects of the freeze events of the magnitude that occurred on Nov. 28-30 and that factories could continue to operate with minimal problems in the boiling house so long as the frozen tops and leaves were removed. Even with these BMPs in place, however, it appears that the freeze events of Nov. 28-30 reduced overall state sugar yields by approximately 5.0 kg/tonne (10 lbs/ton) and by removing the top 30 cm (10 in) of the stalk, field yields were reduced by approximately 6.75 tonnes/ha (3 tons/ac) such that the overall loss in sugar yield per hectare for the 2013-2014 crop amounted to about 33.6 kg/ha (30 lbs/ac).

Last Modified: 8/25/2016
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